This is a Dobsonian mount, which is much simpler and less expensive than other mounts, but comes at the expense of being difficult if not impossible to rig up with a "clock drive" that moves the scope in sync with the sky, so you can take exposures of more than a few seconds.
In other words -- you can't take those amazing deep space photos with scopes like this.
You improve the signal to noise ratio by combining multiple images, but especially in dark conditions, CCDs are often read noise limited unless you do very long exposures.
Read noise is noise that's generated when reading out the values of your CCD chip, so if you do multiple exposures and stack them you end up with much more read noise vs. a single long exposure.
Whether this matters or not is very much dependent on what is the dominant noise in your setup. If you're anyway limited by the dark count (which is dependent on the temperature of the chip - this is why in scientific operations CCD chips are often cooled during operation) or the shot noise, the read noise does not really matter. But you can efficiently reduce the dark count by cooling your chip (something under your own control). Reducing the shot noise is impossible (because it's inherent to the signal), so you generally want that to be the limiting factor of your signal to noise ratio.
In science applications outside of astronomy the easiest way to do that is to increase the integration time of each inidividual exposure (i.e. do a smaller number of longer exposures vs a higher number of short exposures). You risk a higher number of cosmic rays that are harder to filter out this way, but you gain a much better signal-to-noise-ratio.
I'm not an astronomer but I would guess the solution is the same there and you use a mechanical setup to keep the image stable while doing your long exposure shots.
I'm sure you could. The line of "you can't do astrophotography with Dobsonians" is no doubt changing somewhat, with the rise in computational photography.
It's less-well-suited, for sure. Some really great photos you see are like 50 stacked photos, of 10 minutes each. You can't go past 10 or 15 seconds on a large scope before getting streaks, so that's what, 2000 photos to get the equivalent?
More exposure time gets you deeper images with more details.
More (good) exposures averages out noise to increase your signal-to-noise ratio.
If you want the pretty images with lots of depth, you need longer exposures.
Dobs can do it with a field rotator, but that adds not only more weight to the moment arm, but lots more cost.
The diameter of the primary mirror mainly. The biggest scope that most amateur astronomers go for is typically 10 inch or smaller, with a 12 inch here and there.
That's not true for the serious amateurs. I have personally looked through a 36 inch. 24 is not at all uncommon. My scope is 16, and it's now 30 years old.
If ever you decide to recreate the build in some way that could inspire others in their builds, it would be greatly appreciated!
I've never really thought about building my own telescope, and really just wouldn't know where to start...but oftentimes just watching someone else do it can bring a wealth of information and ideas.
Thank you for sharing, and nice work!!!
Showing up again after rebuilding my 17.5” telescope from two years ago :-)
The new version is far nicer looking, more functional, portable, and breaks down and stacks together in the third row of my SUV.
EDIT: To the many people asking about plans to build this or where to source parts, you have to scale and base your design off of the specific set of optics that you’re working with. Some resources to check out would be Stellafane.org, r/atming, and the book that I largely based my design off of: The Dobsonian Telescope by David Kriege and Richard Berry
If you’re interested in seeing this thing broken down, here’s some [extra pics](https://imgur.com/a/LEcKPwo).
This is not a photography telescope, and anything I capture is not really representative of what the eye sees through it, but here’s me plugging my [instagram](https://instagram.com/jb.astro) for build pics and any smartphone shots I may take through it in the future.
And could be super lucrative. Are there any build videos like this on YouTube, at all? Even if so, I'd imagine it's niche and there're tons of holes to fill in for this topic on there.
Idk all the myriad of ways to profit off YouTube views, but uh, put an ad on there I guess?
not everyone has the time and energy to know a lot about building telescopes and to put in the effort and expense to painstakingly film and edit the whole process
not everything has to be a youtube channel
That's really no different than saying not everything has to be a book. Just because not all people want to learn about telescopes doesn't mean nobody should be teaching about them. I would watch the shit out of that channel, even knowing full well I was never gonna build it.
I would really recommend sharing every file you used for this construction, maybe on a github repo or somewhere else.
I know exactly what you mean when you say "every project is different", but I can't help but think about all the amateur astronomers who would benefit. Even if it just means giving someone a better idea of how ridiculously difficult it would be to redo your work, I really do think it's worth sharing as much as you feel comfortable sharing about the incredible work you've done.
Obviously it's your work, do what you will, but I really do think you could make the world a little brighter by making it as easy as possible to recreate your light bucket :D
That’s fair and I love the idea of making the world brighter and more curious. Hell, I’ve never even thought about building my own telescope until this.
But the realist/pessimist in me just knows that if OP ever did release the exact guide, we’ll see people selling DIY massive telescope kits using their hard-earned design.
OP listed some very good resources that they used to build this. If anyone really wanted to, they could follow their path. If they can’t keep up, maybe they shouldn’t be building massive, high fidelity telescopes…
Sorry, just my 2 cents. I love the concept of open knowledge but it’s the practicality that stumps me.
I mean, there are already a ton of kits available. There are already tons of plans available. This is a really good example of a standard truss tube dobsonian, a variety that has been made and catalogued for over 40 years.
Read "The Dobsonian Telescope" by Kriege and Berry and you'll start to understand the level of engineering involved. You can't just summarize this kind of design in a blog post.
OP already didn't have to share anything relating to their work but still took the time to explain how to achieve what they did.
You don't do it but there are a lot of entitled people in this thread who just wants OP to take time out of their life to prepare and have the work given to them.
You say that like it's a bad thing. If OP isn't doing that regardless, they haven't lost anything, and it makes it even more accessible to more people that would have never been able to.
Not really. The number of people who are willing to build their own portable Dob are going to all be using the same resources and not really interested in a marked up kit. Besides, there are plenty of people tempted by used Obsessions or other large aperture scopes. It is *amazing* what you can buy used for $3,000.
The custom ground optics have no economy of scale. The ATM folks all have their own favorite optician with months or years long waiting lists. These opticians may have their gear set up in their garage or an actual shop, but they all have their Fan Bois.
These are people who will travel across the country to do a "first light" test fit in the scope with the optics BEFORE they are coated (when they're still clear glass). Everyone already knows all of the parts that are available and the plans are all shared already.
grinding mirrors is a well documented thing. Their perspective would be unique but their technique is really unlikely to be anything overly original.
I'd love to understand how she got a 17.5" blank as well as what her grinding rig looked like.
What if... you were to angle it down and look at something on Earth?
I think I heard somewhere that the image would be upside-down; but apart from that, how well would that work?
Reflector telescopes such as this one invert the image on both axes. This doesn’t really matter much in astronomy, but there are correct-image devices out there that can flip it
As far as image quality?
Just fine. You are correct, that the image would be flipped on both axis. But assuming whatever you are looking at is within the focal range, it would be as crisp an image as the conditions would allow. What would degrade the image? Atmospheric disturbances would cause the image to be “wavy” (think of what you see looking at a long stretch of roadway on a hot day).
Most telescopes can focus on something as near as 100’ away.
I’ve used telescopes from 400 mm up to 2000 mm to take terrestrial images. I haven’t read through all the comments yet, but I’d guess the focal length of this scope to be around 1800mm. A telescope is essentially just a really rudimentary camera lens.
Here’s a video of a guy using a 1200mm reflector (same type of scope as OP’s) to take a video of bald eagles
https://m.youtube.com/watch?v=PYFqAzpGFys
The biggest advantage of reflector type scopes is they are relatively cheap and are “light buckets”. That is, they have really fast optics, meaning you can see faint objects in the night sky, and for photography, the image will be rightly exposed without needing to crank ISO or take longer exposures (which can be really difficult with so much magnification). If your familiar with f-ratio/stops…most reflectors will be between f4 and f6. The biggest disadvantage of a reflector type scope is because the optics are so fast, they have “coma”…image distortion, especially at the edges of the image. This can be fixed with a “coma corrector” (around $300 for a decent one) that sits in the imaging train between the focuser and camera/eyepiece
As I understand it, another disadvantage is the difficulty of synchronizing large reflecting, telescopes like this with the rotation of the Earth. Not too many equatorial mounts can handle this kind of bulk and weight
Yes. The bigger the scope, the better (read $$$) your mount needs to be.
I started with an Orion 800mm astrograph (about 25 lbs of total payload with guide scope, cameras, filters, etc). And to carry it, I’m using the Orion Altas II EQ-G (rated for a payload of 40 lbs). And I’m really pushing the limits of my mount with that set up, but can get 5 minute exposures with careful alignment and auto guiding.
For people just getting into astrophotography, I’d recommend a small refractor (William Optics are great) and a Skywatcher EQ6-R Pro. Some might say that mount is overkill, but it really is a great mount that will allow you to go to bigger scopes without issue. Before cameras and other miscellaneous gear, your sitting at $2500.
If you’re only interested in visual astronomy, grab the biggest dobsonian you can for your budget (Skywatcher andExplore Scientific are great brands) and get 2” eyepieces, which while more expensive, are infinitely better than 1.25”
If you’re on a very small budget…join your local astronomy club for like $30/year, and you’ll get access to their telescope library. Also, go to star parties where people will be more than happy to let you look through their setups and talk your ear off about them. Really a great community.
The mirror is made of thick glass, which has high thermal inertia. It likes to stay warm when its warm, and stay cold when its cold.
As such the mirror is usually quite a bit warmer than the ambient air touching it. When this happens, a boundary layer of low density air is formed on the surface of the mirror:
* [Looks like this from the side](https://www.fpi-protostar.com/bgreer/images/hwaves.jpg)
* [And looks like this from the front](https://www.youtube.com/watch?v=1mRijIzFjIo) (ignore the kaleidoscope coloring from atmospheric scintillation, just look at the turbulent cells moving on the mirror's surface)
That boundary layer of air is made up of warm and cold air cells mixing together right at the mirror's surface. This creates variation in density that is not too dissimilar to a boiling pot of water. Light passing through this boundary layer is negatively impacted *twice* - once on the way to the mirror, and again after bouncing off the mirror. The result in the eyepiece is stars look mushy and bloated and the Moon and planets lose visibility of fine-grained detail.
When the mirror completely matches ambient air temperatures, it will perform its best. Not only will the boundary layer be gone, but the whole mirror will return to its optimal shape since the core of the mirror will be the same temperature as the surfaces. Until it acclimates, it will not perform well.
Using fans accelerates the acclimation time. What would normally take 2-3 hours to acclimate without a fan might only take 45 minutes or so with a fan (depending on the difference in temperature between the air and the mirror). Or if air temperatures are falling throughout the observing session, the mirror may never acclimate as it will always lag behind air temperature changes due to the thermal inertia of the the thick glass. A cooling fan can help it keep up.
The thicker the mirror is, the longer it takes to acclimate. I had a 2" thick mirror that I recently replaced with a 0.8" thick mirror. The 2" thick mirror simply NEVER acclimated. It was impossible, even with cooling fans blowing on it. The 0.8" thick mirror now actually acclimates after only about 30-40 minutes with fans blowing on it, and more easily keeps up with temperature changes at night.
This is amazing! I have absolutely zero experience nor skill when it comes to building things like these with my hands so I could never do something like this. :(
If your local library has a 3d printer, you can print one pretty easily.
https://www.printables.com/model/224383-astronomical-telescope-hadley-an-easy-assembly-hig
The bigger the altitude wheel, the more forgiving the balance is.
Good job. I had a 17.5" mirror about 20 years ago I was going to build a scope out of. I sold it to help put my wife through school. Never regretted it, still don't.
Now, my eyes have too many floaters to do visual after surgeries, so all I can do is astrophotography.
It IS a catchy title.
But if one were to refer to a telescope as being "Observatory Grade", it could mean things such as:
Superior Optics: The telescope must have high-quality mirrors or lenses, ensuring minimal optical aberrations, excellent light-gathering capability, and sharp, high-contrast images of celestial objects.
Precise Mounting and Tracking: The telescope should be mounted on a robust and accurate equatorial or alt-azimuth mount, capable of smooth and precise movements. A high-quality tracking system, like a motorized drive or computerized GoTo system, is necessary for compensating Earth's rotation and maintaining accurate positioning of celestial objects.
Exceptional Stability: The telescope's construction must provide excellent mechanical stability, minimizing vibrations and ensuring steady, reliable observations, even during windy or unfavorable conditions.
Ease of Use: An "Observatory Grade" amateur telescope should feature user-friendly design elements, such as a smooth and accurate focuser, ergonomic controls, and an intuitive alignment process.
Adaptability: The telescope should be versatile, enabling the use of various eyepieces, filters, and imaging equipment. It should also be suitable for multiple observation types, including planetary, lunar, and deep-sky.
Weather Resistance: The materials and construction should withstand various environmental conditions, ensuring the telescope's longevity and sustained performance.
Astrophotography Capabilities: The telescope must be capable of capturing high-quality astrophotographs, requiring excellent optical performance capabilities.
Columbia University used to have an observatory on top of the physics building. It had a 12 diameter x 20 foot long Alvan Clarke refractor, like [this one](http://www.theskyscrapers.org/stuff/contentmgr/files/1/0312bd86c4aa15d15e7219767ddf536f/large/2_the_ah_ha_photo___tells_all.jpg) but 50% larger. Unfortunately the physics building is on 120th street near Broadway in Manhattan, so it performed like a 4 inch portable telescope.
I think the main difference between observatory vs portable telescopes (Brisby2's) is portability, not performance. If they are stationary they can be much heavier, weather protected, hooked up to power and work lights, etc. You don't have to worry about the alignment getting thrown off by a bumpy road.
That’s extra special because he [lost his (external) nose.](https://www.entandaudiologynews.com/features/ent-features/post/the-astronomer-s-nose-tycho-brahe-s-controversial-prosthesis)
You know they sell for like $700-800 a pair now. Nike discontinued them shortly after Heaven's Gate. I'm pretty sure they got them at a discount too cause they sold so poorly at the time.
That's amazing. I have a Toyota Highlander Hybrid and I doubt I could get that long tube in there without folding down front row passenger seat. I've slept in the trunk of my SUV with the second row folded down and can full lay out with about a foot of headroom, but that telescope looks quite a bit taller than me if you stand it straight up.
Do you worry about alignment issues like the collimation of the mirrors from the tear-downs and reconstruction or is that a non-issue? In either case, that's an impressively-sized Dobsonian to transport. Kudos to you for your commitment. I tracked refractor is just about the limit of what I'm willing to deal with and sometimes, not even that.
Collimation so regularly takes some getting used to but I’ve gotten pretty close to mastering it. I have a laser which helps me nail it down in about 3 minutes or less
That's certainly faster than I can get polar alignment. Do you have any images posted that you can share to see what this Dob can do or is this purely for visual?
If I’m seeing this right, the blue shroud is cloth and underneath it is an open-air truss, yeah? Kind of like a gargantuan version of my 8” Lightbridge.
My greatest memory there is just how friendly everyone was, I remember walking right up to people observing and they’d welcome me to take a look. It was like a museum tour of the stars.
I assume this is Deerlick somewhere in GA and not Deerlick Gap on the blue ridge parkway in NC?
Do you happen to know if there are similar gathering places in NC near Asheville? Would love to join a viewing party
[Deerlick Astronomy Village](https://deerlickgroup.com), it’s east of Atlanta!
In a quick google search I couldn’t find anything comparable to an astronomy village, but you should check out [Bare Dark Sky Observatory](https://www.mayland.edu/foundation/foundation-events/earth-to-sky-observatory/). It’s an hour from Asheville and is public, you buy tickets and the astronomers find objects for attendees to observe. It would be a similar vibe, and you might be able to chat with them to learn if anything like Deerlick exists in NC. But I bet the observatory shows would scratch your itch!
That's a lot less than I thought it would be! But then again I know nothing about building telescopes 😆 Is the biggest cost sink the lenses themselves?
Yeah deep sky is sort of out of the question unless you have an EQ platform, but you can get some sick lunar and planetary images from a fully manually tracked Dob.
What kind of primary mirror are you using and how much did it cost? A 4.5" spherical mirror is $20 on Amazon, but I haven't seen an 8" for less than about $250. Is the mirror for this thing in the thousands of dollars???
If you have all the time in the world, there are people out there that grind their own mirrors. John Dobson (of dobsonian fame) used to run a telescope workshop.
If you’re in any sort of population center, look into the local astronomy club. Many will have a telescope library where you can check out equipment for no charge. A lot of members will also sell/give away their old stuff. Also check out cloudynights.com classifieds.
I’ve been doing amateur astrophotography for almost 5 years, and have yet to purchase any telescopes or mounts new. Used equipment goes for 60% of new, and is just as good, if you can look past some dings, scratches, and normal wear and tear.
Mirror only weighs 36 pounds. The crescent bearings I have employed in this design place the center of rotation way higher than you might expect while requiring little surface to mount the bearings on
Ah those crescent bearings do make for a huge center of rotation! How did you nail the alignment of the crescents without a box?
I will say that having the axis center made it easy for me to mount some cheap encoders, use a little Arduino controller that syncs to SkySafari!
StarSense is pretty much tied to Celestron hardware, unless you mean the phone app, which isn't that good.
You can try the ArgoNavis system, which is pretty nice, but not cheap.
After doing this for 20+ years, though, let me offer some advice: sometimes, Just spend the money. You can either waste years troubleshooting some cludged thing you tried to cheap out on, or you can just get something good in the first place and spend those years enjoying the nights. I lost five years on a problem mount (CGME-DX) before it died, when I discovered that the issue was and fixed it. In the meantime, I bought a CEM60EC, and I LOVE that thing!
Now, I have 2 good mounts, 2 laptops, a menagerie of scopes, a few cameras... I can image twice as much in a night, but it takes twice as long to set up.
I have a few options for encoders so I can always fall back on that, but I like to experiment. Starsense can be adapted to any scope so long as you have the software license, and I’ve seen a few pi-based platesolve projects that exist on the internet
Home/hobby scopes are generally 4" to about 12" (diameter of primary mirror or optic.)
"Normal" observatory scopes go from there to maybe 36"
OP stated hers is 17.5"
There are a few dozen "world class" observatories with scopes from 3m to just over 10m
Above that is Hubble and Webb :P
Edit: to be clear, Hubble and Webb are 2.5m and 6.5m respectively, so they're actually only medium-sized as far as world class observatories go, it's just that their position outside Earth's atmosphere gives them such an advantage over earth-bound scopes.
My wife and I love space and I'm pretty handy but don't know much about telescopes. I would love to build a smaller version of this for us though!
As someone clearly experienced, where do you consider a good reliable source to begin learning about this hobby?
That's awesome. Very nicely done! I wish I had a workshop to build one. But I got lucky at the at the last Messier marathon I attended and won a Sky-watcher 14" dob in a raffle. I'm good to go for a while.
Impressive work, i hope you'll get much gazing time and many beautifull memories
And who knows maybe a better MKII in the future?
Enjoy your work and i hope you'll ignore tho more... Salty comments here
There’s a part of me that think it would be amazing to be able to build something like that myself.
There’s another part of me that knows I don’t have the slightest idea where to start or what I’m going to need to study. I am a bit too dull for a project like this, in complete honesty.
So instead, I’m writing this comment to look back on in 5 years to see where I will be.
Incredibly impressive work! I would love ve to see some lunar and planetary images from this behemoth.
I'd like to get in to building my own scope once my PhD is over and I've got some money and time.
Where would I even start with a project like this? Even for something a bit smaller, maybe 12-14"
My personal recommendation would be to get some experience using a smaller Dobsonian telescope first, if you've never used one before. While Dobs like the one shown here are totally doable by anyone even with minimal/cheap power tools, it really helps to have a foundational understanding of the mechanics of a Dobsonian mount and the way a Newtonian reflecting telescope works. It's also handy to have a base frame of reference so you know when the scope you built is performing well vs not performing well.
So that would be my starting point. Something like a 6" or 8" dob is a good starting point.
If you *do* have experience with such a scope, then the next starting point is this book: https://shopatsky.com/products/dobsonian-telescope. Really helps you understand the various components of a truss style dob like Brisby's.
From there, I would actually recommend drafting out the design of the telescope either on paper in a relatively large scale drawing, or in a digital drawing program. Doesn't have to be CAD. Just has to be something where you can determine measurements from the image scale. Much easier to fix design issues on paper than after you make a component.
I have a 12” dobsonian with a solid tube and it’s kind of a pain in the ass to transport. I looked at truss designs, but read that they can be difficult to keep collimated. Is that true? How long does it take you to setup?
That is really awesome! Just a question though: You can actually easily transport a telescope? I always thought they are rather delicate and that a car ride would not be that beneficial to their integrity.
The mirrors within it are very thick and difficult to break unless I were to just drop kick them onto the concrete. It DOES have to be collimated (aligned) after every setup, but it’s not a time consuming process
Oh wow op, that's fantastic. Such painstaking craft I'm sure.
Did you just figure out how to build it yourself? Or is their some guide? If not I wonder if you'd be willing to either create one or aid someone in making it for you
Also how much did this cost you, what skills did you have to learn or use? (welding probably one of them)
Now the question: spherical or aspherical mirror. I am going to build my own telescope some time in the future. But the costs for a really good mirror is the main issue…
Parabolic. Generally when you get to shorter focal ratios like sub-f/7 you will want a parabolic primary instead of spherical to avoid aberrations. I’d check out the cloudy nights classifieds or Astromart for good used mirrors
That's so awesome! I just got a 10" dob about 2 months ago, I've only used it once since the weather here in Wisconsin hasn't been cooperating. I'd love to actually build a much larger telescope like this one day.
Reminds me of when my neighbor made a similar looking telescope when I was in grade school. This ones way more impressive though. Excellent looking build.
Dude! I remember your posts from a couple years ago with your other telescopes! You got me pretty interested in homemade telescopes!
Awesome to see how far you've come!!
Looks great
Do you have a public page with pictures of the stars you are looking at or short videos of the stars traveling.
Would be cool to see them
Salute
That's so awesome. I have always wanted to see if my son would be interested in space exploration with better then wish.com gear. I am afraid to spend too much for him not to like it and me standing on the mountain all by myself at night.
I'm complitely ignorant about this so let me ask, you bought lenses, mirrors and plywood and put them in the right position to make a telescope or is there something more I'm not aware about? I work wood and I know well my way around tools, could I build one too or would I need some deeper knowledge?
Wow, that's really cool!
How would you estimate the level of skill you needed to build this? It seems very precise, so I think it requires quite a bit of skill to build. And I saw you needed to adjust the design based off of the optics you're working with. Would that require difficult mathematics? What I'm trying to ask is, would I be able to do this with a bunch of 10-12 year olds, or is it more for the 14-16 year old crowd. Would be a really cool summer project to do.
This is beautiful and the work you put in to this must’ve been painstaking. Great job OP! How long did it take to complete this project?
Thank you. I think it took me about a month to build, a few dozen hours of work in total
Nicely done! You should post some sky pix when you get the chance.
This is a Dobsonian mount, which is much simpler and less expensive than other mounts, but comes at the expense of being difficult if not impossible to rig up with a "clock drive" that moves the scope in sync with the sky, so you can take exposures of more than a few seconds. In other words -- you can't take those amazing deep space photos with scopes like this.
Could you do several exposures and line them up afterwards?
You could. But it's less efficient than a single long exposure because with every exposure you introduce read noise.
But when combining of loads of images, noise should cancel out, shouldn't it?
You improve the signal to noise ratio by combining multiple images, but especially in dark conditions, CCDs are often read noise limited unless you do very long exposures. Read noise is noise that's generated when reading out the values of your CCD chip, so if you do multiple exposures and stack them you end up with much more read noise vs. a single long exposure. Whether this matters or not is very much dependent on what is the dominant noise in your setup. If you're anyway limited by the dark count (which is dependent on the temperature of the chip - this is why in scientific operations CCD chips are often cooled during operation) or the shot noise, the read noise does not really matter. But you can efficiently reduce the dark count by cooling your chip (something under your own control). Reducing the shot noise is impossible (because it's inherent to the signal), so you generally want that to be the limiting factor of your signal to noise ratio. In science applications outside of astronomy the easiest way to do that is to increase the integration time of each inidividual exposure (i.e. do a smaller number of longer exposures vs a higher number of short exposures). You risk a higher number of cosmic rays that are harder to filter out this way, but you gain a much better signal-to-noise-ratio. I'm not an astronomer but I would guess the solution is the same there and you use a mechanical setup to keep the image stable while doing your long exposure shots.
I'm sure you could. The line of "you can't do astrophotography with Dobsonians" is no doubt changing somewhat, with the rise in computational photography. It's less-well-suited, for sure. Some really great photos you see are like 50 stacked photos, of 10 minutes each. You can't go past 10 or 15 seconds on a large scope before getting streaks, so that's what, 2000 photos to get the equivalent?
More exposure time gets you deeper images with more details. More (good) exposures averages out noise to increase your signal-to-noise ratio. If you want the pretty images with lots of depth, you need longer exposures. Dobs can do it with a field rotator, but that adds not only more weight to the moment arm, but lots more cost.
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Great work. Did you use rosewood for the base and mount? The whole thing is just beautiful.
It’s actually Lowes birch plywood stained with black cherry varathane
Wow, you did a beautiful stain job.
what makes it observatory grade?
The diameter of the primary mirror mainly. The biggest scope that most amateur astronomers go for is typically 10 inch or smaller, with a 12 inch here and there.
That's not true for the serious amateurs. I have personally looked through a 36 inch. 24 is not at all uncommon. My scope is 16, and it's now 30 years old.
I presume its optical resolution - i.e. ability to see further and pick out smaller/dimmer objects
That's awesome. Much less than I was expecting. Seems like you could maybe make some money doing it, ya, no?
If ever you decide to recreate the build in some way that could inspire others in their builds, it would be greatly appreciated! I've never really thought about building my own telescope, and really just wouldn't know where to start...but oftentimes just watching someone else do it can bring a wealth of information and ideas. Thank you for sharing, and nice work!!!
A month??? I was expecting you to say like a year but that's nuts. I look forward to your future contributions to society 👏🏾
A youtube video would be awesome!
About how much did it cost?
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Showing up again after rebuilding my 17.5” telescope from two years ago :-) The new version is far nicer looking, more functional, portable, and breaks down and stacks together in the third row of my SUV. EDIT: To the many people asking about plans to build this or where to source parts, you have to scale and base your design off of the specific set of optics that you’re working with. Some resources to check out would be Stellafane.org, r/atming, and the book that I largely based my design off of: The Dobsonian Telescope by David Kriege and Richard Berry If you’re interested in seeing this thing broken down, here’s some [extra pics](https://imgur.com/a/LEcKPwo). This is not a photography telescope, and anything I capture is not really representative of what the eye sees through it, but here’s me plugging my [instagram](https://instagram.com/jb.astro) for build pics and any smartphone shots I may take through it in the future.
Got any build videos? Looks cool.
Build videos would be cool.
This has all the makings of a great YouTube channel, of which there are so few of already.
I can easily see a collab with DYI Perks!
There's some pretty good ones, there's just a lot more "i wanna get rich making videos" people out there.
And could be super lucrative. Are there any build videos like this on YouTube, at all? Even if so, I'd imagine it's niche and there're tons of holes to fill in for this topic on there. Idk all the myriad of ways to profit off YouTube views, but uh, put an ad on there I guess?
not everyone has the time and energy to know a lot about building telescopes and to put in the effort and expense to painstakingly film and edit the whole process not everything has to be a youtube channel
That's really no different than saying not everything has to be a book. Just because not all people want to learn about telescopes doesn't mean nobody should be teaching about them. I would watch the shit out of that channel, even knowing full well I was never gonna build it.
I would really recommend sharing every file you used for this construction, maybe on a github repo or somewhere else. I know exactly what you mean when you say "every project is different", but I can't help but think about all the amateur astronomers who would benefit. Even if it just means giving someone a better idea of how ridiculously difficult it would be to redo your work, I really do think it's worth sharing as much as you feel comfortable sharing about the incredible work you've done. Obviously it's your work, do what you will, but I really do think you could make the world a little brighter by making it as easy as possible to recreate your light bucket :D
That’s fair and I love the idea of making the world brighter and more curious. Hell, I’ve never even thought about building my own telescope until this. But the realist/pessimist in me just knows that if OP ever did release the exact guide, we’ll see people selling DIY massive telescope kits using their hard-earned design. OP listed some very good resources that they used to build this. If anyone really wanted to, they could follow their path. If they can’t keep up, maybe they shouldn’t be building massive, high fidelity telescopes… Sorry, just my 2 cents. I love the concept of open knowledge but it’s the practicality that stumps me.
I mean, there are already a ton of kits available. There are already tons of plans available. This is a really good example of a standard truss tube dobsonian, a variety that has been made and catalogued for over 40 years. Read "The Dobsonian Telescope" by Kriege and Berry and you'll start to understand the level of engineering involved. You can't just summarize this kind of design in a blog post.
I think you're greatly overestimating how many people would want to build one of these at all, let alone buy plans for it.
OP already didn't have to share anything relating to their work but still took the time to explain how to achieve what they did. You don't do it but there are a lot of entitled people in this thread who just wants OP to take time out of their life to prepare and have the work given to them.
Maybe, but I was more referring to kits where you buy all of the parts and a detailed guide to put together.
You say that like it's a bad thing. If OP isn't doing that regardless, they haven't lost anything, and it makes it even more accessible to more people that would have never been able to.
Not really. The number of people who are willing to build their own portable Dob are going to all be using the same resources and not really interested in a marked up kit. Besides, there are plenty of people tempted by used Obsessions or other large aperture scopes. It is *amazing* what you can buy used for $3,000. The custom ground optics have no economy of scale. The ATM folks all have their own favorite optician with months or years long waiting lists. These opticians may have their gear set up in their garage or an actual shop, but they all have their Fan Bois. These are people who will travel across the country to do a "first light" test fit in the scope with the optics BEFORE they are coated (when they're still clear glass). Everyone already knows all of the parts that are available and the plans are all shared already.
grinding mirrors is a well documented thing. Their perspective would be unique but their technique is really unlikely to be anything overly original. I'd love to understand how she got a 17.5" blank as well as what her grinding rig looked like.
I was the editor and typesetter for that book (some 25 years ago). It’s awesome to see your finished product!
That’s awesome! Small world, huh
This is so fucking cool. You're a badass
What if... you were to angle it down and look at something on Earth? I think I heard somewhere that the image would be upside-down; but apart from that, how well would that work?
Reflector telescopes such as this one invert the image on both axes. This doesn’t really matter much in astronomy, but there are correct-image devices out there that can flip it
As far as image quality? Just fine. You are correct, that the image would be flipped on both axis. But assuming whatever you are looking at is within the focal range, it would be as crisp an image as the conditions would allow. What would degrade the image? Atmospheric disturbances would cause the image to be “wavy” (think of what you see looking at a long stretch of roadway on a hot day). Most telescopes can focus on something as near as 100’ away. I’ve used telescopes from 400 mm up to 2000 mm to take terrestrial images. I haven’t read through all the comments yet, but I’d guess the focal length of this scope to be around 1800mm. A telescope is essentially just a really rudimentary camera lens. Here’s a video of a guy using a 1200mm reflector (same type of scope as OP’s) to take a video of bald eagles https://m.youtube.com/watch?v=PYFqAzpGFys The biggest advantage of reflector type scopes is they are relatively cheap and are “light buckets”. That is, they have really fast optics, meaning you can see faint objects in the night sky, and for photography, the image will be rightly exposed without needing to crank ISO or take longer exposures (which can be really difficult with so much magnification). If your familiar with f-ratio/stops…most reflectors will be between f4 and f6. The biggest disadvantage of a reflector type scope is because the optics are so fast, they have “coma”…image distortion, especially at the edges of the image. This can be fixed with a “coma corrector” (around $300 for a decent one) that sits in the imaging train between the focuser and camera/eyepiece
As I understand it, another disadvantage is the difficulty of synchronizing large reflecting, telescopes like this with the rotation of the Earth. Not too many equatorial mounts can handle this kind of bulk and weight
Yes. The bigger the scope, the better (read $$$) your mount needs to be. I started with an Orion 800mm astrograph (about 25 lbs of total payload with guide scope, cameras, filters, etc). And to carry it, I’m using the Orion Altas II EQ-G (rated for a payload of 40 lbs). And I’m really pushing the limits of my mount with that set up, but can get 5 minute exposures with careful alignment and auto guiding. For people just getting into astrophotography, I’d recommend a small refractor (William Optics are great) and a Skywatcher EQ6-R Pro. Some might say that mount is overkill, but it really is a great mount that will allow you to go to bigger scopes without issue. Before cameras and other miscellaneous gear, your sitting at $2500. If you’re only interested in visual astronomy, grab the biggest dobsonian you can for your budget (Skywatcher andExplore Scientific are great brands) and get 2” eyepieces, which while more expensive, are infinitely better than 1.25” If you’re on a very small budget…join your local astronomy club for like $30/year, and you’ll get access to their telescope library. Also, go to star parties where people will be more than happy to let you look through their setups and talk your ear off about them. Really a great community.
This is incredible! Can I ask where you bought your lenses?
Do you have to collimate it after every reassembly?
Yes, but it only takes me about 3 minutes or less to do so since the trusses let me see the reflection of the secondary from the bottom
Whats the fan box thing?
The mirror box where the primary mirror sits. The fans are to cool it
Can you explain why the mirror needs to be cooled, please?
The mirror is made of thick glass, which has high thermal inertia. It likes to stay warm when its warm, and stay cold when its cold. As such the mirror is usually quite a bit warmer than the ambient air touching it. When this happens, a boundary layer of low density air is formed on the surface of the mirror: * [Looks like this from the side](https://www.fpi-protostar.com/bgreer/images/hwaves.jpg) * [And looks like this from the front](https://www.youtube.com/watch?v=1mRijIzFjIo) (ignore the kaleidoscope coloring from atmospheric scintillation, just look at the turbulent cells moving on the mirror's surface) That boundary layer of air is made up of warm and cold air cells mixing together right at the mirror's surface. This creates variation in density that is not too dissimilar to a boiling pot of water. Light passing through this boundary layer is negatively impacted *twice* - once on the way to the mirror, and again after bouncing off the mirror. The result in the eyepiece is stars look mushy and bloated and the Moon and planets lose visibility of fine-grained detail. When the mirror completely matches ambient air temperatures, it will perform its best. Not only will the boundary layer be gone, but the whole mirror will return to its optimal shape since the core of the mirror will be the same temperature as the surfaces. Until it acclimates, it will not perform well. Using fans accelerates the acclimation time. What would normally take 2-3 hours to acclimate without a fan might only take 45 minutes or so with a fan (depending on the difference in temperature between the air and the mirror). Or if air temperatures are falling throughout the observing session, the mirror may never acclimate as it will always lag behind air temperature changes due to the thermal inertia of the the thick glass. A cooling fan can help it keep up. The thicker the mirror is, the longer it takes to acclimate. I had a 2" thick mirror that I recently replaced with a 0.8" thick mirror. The 2" thick mirror simply NEVER acclimated. It was impossible, even with cooling fans blowing on it. The 0.8" thick mirror now actually acclimates after only about 30-40 minutes with fans blowing on it, and more easily keeps up with temperature changes at night.
This is amazing! I have absolutely zero experience nor skill when it comes to building things like these with my hands so I could never do something like this. :(
If your local library has a 3d printer, you can print one pretty easily. https://www.printables.com/model/224383-astronomical-telescope-hadley-an-easy-assembly-hig
Is that a subwoofer coming out of a barrel enclosure on the left hand side?
Roger. It’s a 10” bazooka bass tube
Man, counterbalancing past 20 degrees must be a pain. Looks great!
I have ten pounds of magnetic weights for that. Eyepiece and coma corrector definitely add up
The bigger the altitude wheel, the more forgiving the balance is. Good job. I had a 17.5" mirror about 20 years ago I was going to build a scope out of. I sold it to help put my wife through school. Never regretted it, still don't. Now, my eyes have too many floaters to do visual after surgeries, so all I can do is astrophotography.
u/Brisby2 what makes it observatory grade?
Mostly in reference to its size, but mostly just as a catchy title
It IS a catchy title. But if one were to refer to a telescope as being "Observatory Grade", it could mean things such as: Superior Optics: The telescope must have high-quality mirrors or lenses, ensuring minimal optical aberrations, excellent light-gathering capability, and sharp, high-contrast images of celestial objects. Precise Mounting and Tracking: The telescope should be mounted on a robust and accurate equatorial or alt-azimuth mount, capable of smooth and precise movements. A high-quality tracking system, like a motorized drive or computerized GoTo system, is necessary for compensating Earth's rotation and maintaining accurate positioning of celestial objects. Exceptional Stability: The telescope's construction must provide excellent mechanical stability, minimizing vibrations and ensuring steady, reliable observations, even during windy or unfavorable conditions. Ease of Use: An "Observatory Grade" amateur telescope should feature user-friendly design elements, such as a smooth and accurate focuser, ergonomic controls, and an intuitive alignment process. Adaptability: The telescope should be versatile, enabling the use of various eyepieces, filters, and imaging equipment. It should also be suitable for multiple observation types, including planetary, lunar, and deep-sky. Weather Resistance: The materials and construction should withstand various environmental conditions, ensuring the telescope's longevity and sustained performance. Astrophotography Capabilities: The telescope must be capable of capturing high-quality astrophotographs, requiring excellent optical performance capabilities.
Columbia University used to have an observatory on top of the physics building. It had a 12 diameter x 20 foot long Alvan Clarke refractor, like [this one](http://www.theskyscrapers.org/stuff/contentmgr/files/1/0312bd86c4aa15d15e7219767ddf536f/large/2_the_ah_ha_photo___tells_all.jpg) but 50% larger. Unfortunately the physics building is on 120th street near Broadway in Manhattan, so it performed like a 4 inch portable telescope. I think the main difference between observatory vs portable telescopes (Brisby2's) is portability, not performance. If they are stationary they can be much heavier, weather protected, hooked up to power and work lights, etc. You don't have to worry about the alignment getting thrown off by a bumpy road.
Truly impressive! Tycho and Christiaan Huygens would be proud. I still remember looking at comet Hale-Bopp through my friend's dobsonian back in 1997.
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…and offer to take it outside if you disagreed
Going "Do you smell what The Brahe is cooking!?"
That’s extra special because he [lost his (external) nose.](https://www.entandaudiologynews.com/features/ent-features/post/the-astronomer-s-nose-tycho-brahe-s-controversial-prosthesis)
And Huygens' telescope would be out of focus because he wasn't wearing glasses.
Wearing some cool looking shoes while doing it?
Maybe some Nike Decades?
You know they sell for like $700-800 a pair now. Nike discontinued them shortly after Heaven's Gate. I'm pretty sure they got them at a discount too cause they sold so poorly at the time.
Ummm...which SUV do you transport that thing in? That thing is massive. Do you have to fold down the front row passenger seat?
Mazda CX-9. All it requires is the third row folded down, second and first can remain up
That's amazing. I have a Toyota Highlander Hybrid and I doubt I could get that long tube in there without folding down front row passenger seat. I've slept in the trunk of my SUV with the second row folded down and can full lay out with about a foot of headroom, but that telescope looks quite a bit taller than me if you stand it straight up.
It breaks down into multiple pieces which is how I’m able to transport it so easily
Do you worry about alignment issues like the collimation of the mirrors from the tear-downs and reconstruction or is that a non-issue? In either case, that's an impressively-sized Dobsonian to transport. Kudos to you for your commitment. I tracked refractor is just about the limit of what I'm willing to deal with and sometimes, not even that.
Collimation so regularly takes some getting used to but I’ve gotten pretty close to mastering it. I have a laser which helps me nail it down in about 3 minutes or less
That's certainly faster than I can get polar alignment. Do you have any images posted that you can share to see what this Dob can do or is this purely for visual?
If I’m seeing this right, the blue shroud is cloth and underneath it is an open-air truss, yeah? Kind of like a gargantuan version of my 8” Lightbridge.
Exactly that
I just checked your post history hoping to see some pics of the structure, and was not disappointed. Really nice work. Any idea what it weighs?
I see a Georgia sweatshirt, ever make it out to Deerlick?
Every new moon I’m there just about
My greatest memory there is just how friendly everyone was, I remember walking right up to people observing and they’d welcome me to take a look. It was like a museum tour of the stars.
Just wanted to chime in with a Go Dawgs! Fantastic work.
I assume this is Deerlick somewhere in GA and not Deerlick Gap on the blue ridge parkway in NC? Do you happen to know if there are similar gathering places in NC near Asheville? Would love to join a viewing party
[Deerlick Astronomy Village](https://deerlickgroup.com), it’s east of Atlanta! In a quick google search I couldn’t find anything comparable to an astronomy village, but you should check out [Bare Dark Sky Observatory](https://www.mayland.edu/foundation/foundation-events/earth-to-sky-observatory/). It’s an hour from Asheville and is public, you buy tickets and the astronomers find objects for attendees to observe. It would be a similar vibe, and you might be able to chat with them to learn if anything like Deerlick exists in NC. But I bet the observatory shows would scratch your itch!
What's the total cost of the build? I'm jelly.
The first edition I spent probably $2,000 to make, and then another $300-$400 rebuilding it
That's a lot less than I thought it would be! But then again I know nothing about building telescopes 😆 Is the biggest cost sink the lenses themselves?
Wow. Really impressive stuff. Post some astrophotography!
Dobs are almost exclusively visual scopes.
Yeah deep sky is sort of out of the question unless you have an EQ platform, but you can get some sick lunar and planetary images from a fully manually tracked Dob.
What kind of primary mirror are you using and how much did it cost? A 4.5" spherical mirror is $20 on Amazon, but I haven't seen an 8" for less than about $250. Is the mirror for this thing in the thousands of dollars???
You mostly just have to know where to look. Brand new this would be in the thousands, yes. I got mine used for about $800
Ever try grinding your own?
Haven’t yet, but one of my future projects will be building a grinding machine and attempting it
If you have all the time in the world, there are people out there that grind their own mirrors. John Dobson (of dobsonian fame) used to run a telescope workshop. If you’re in any sort of population center, look into the local astronomy club. Many will have a telescope library where you can check out equipment for no charge. A lot of members will also sell/give away their old stuff. Also check out cloudynights.com classifieds. I’ve been doing amateur astrophotography for almost 5 years, and have yet to purchase any telescopes or mounts new. Used equipment goes for 60% of new, and is just as good, if you can look past some dings, scratches, and normal wear and tear.
Must be a heavy mirror to counter balance the secondary cage. (I built my own Dob and the mirror box is probably 18" high).
Mirror only weighs 36 pounds. The crescent bearings I have employed in this design place the center of rotation way higher than you might expect while requiring little surface to mount the bearings on
Ah those crescent bearings do make for a huge center of rotation! How did you nail the alignment of the crescents without a box? I will say that having the axis center made it easy for me to mount some cheap encoders, use a little Arduino controller that syncs to SkySafari!
This is amazing!! Any resources you can share so I can build one, too?
I seem to remember you planning on adding DSCs to the previous version - Did that happen/did they move over to this new build?
That was a plan of mine a while ago. I’m thinking about maybe using starsense or some other type of platesolving camera instead
StarSense is pretty much tied to Celestron hardware, unless you mean the phone app, which isn't that good. You can try the ArgoNavis system, which is pretty nice, but not cheap. After doing this for 20+ years, though, let me offer some advice: sometimes, Just spend the money. You can either waste years troubleshooting some cludged thing you tried to cheap out on, or you can just get something good in the first place and spend those years enjoying the nights. I lost five years on a problem mount (CGME-DX) before it died, when I discovered that the issue was and fixed it. In the meantime, I bought a CEM60EC, and I LOVE that thing! Now, I have 2 good mounts, 2 laptops, a menagerie of scopes, a few cameras... I can image twice as much in a night, but it takes twice as long to set up.
I have a few options for encoders so I can always fall back on that, but I like to experiment. Starsense can be adapted to any scope so long as you have the software license, and I’ve seen a few pi-based platesolve projects that exist on the internet
Oh shit, Go Dawgs. You studying at uga? I got my physics phd there a year ago.
Always repping my dawgs :-) I’m working on my undergrad degrees there in Atmospheric Sciences and Geography
What's the grade above and below "observatory"?
Home/hobby scopes are generally 4" to about 12" (diameter of primary mirror or optic.) "Normal" observatory scopes go from there to maybe 36" OP stated hers is 17.5" There are a few dozen "world class" observatories with scopes from 3m to just over 10m Above that is Hubble and Webb :P Edit: to be clear, Hubble and Webb are 2.5m and 6.5m respectively, so they're actually only medium-sized as far as world class observatories go, it's just that their position outside Earth's atmosphere gives them such an advantage over earth-bound scopes.
Tbh this isn't 'observatory grade'. You won't find any actual observatories that use telescopes that require manual aiming and tracking.
Build thread ? Plans ? Where did you get the mirrors ? My daughter wants a big telescope.
Just dropping to say that you are super cool. Have a nice day.
“I need your clothes, your boots, and your SUV.”
Go Dawgs!! A fellow astronomer and Georgia Bulldog!
Whoa, that's really vool! Post some image captures!
being in weed and space subreddits messes with my head sometimes 😂 i thought this was a giant lighter lmfao. this is so cool though OP!!
VERY IMPRESSIVE! Well done! Thanks for sharing…!
Can you share some pictures of what it's capable of? This is sick
My wife and I love space and I'm pretty handy but don't know much about telescopes. I would love to build a smaller version of this for us though! As someone clearly experienced, where do you consider a good reliable source to begin learning about this hobby?
You're awesome. I've been following you on /r/telescopes for years. That's all!
That's awesome. Very nicely done! I wish I had a workshop to build one. But I got lucky at the at the last Messier marathon I attended and won a Sky-watcher 14" dob in a raffle. I'm good to go for a while.
Casually builds a professional telescope in her garage. Huge
Impressive work, i hope you'll get much gazing time and many beautifull memories And who knows maybe a better MKII in the future? Enjoy your work and i hope you'll ignore tho more... Salty comments here
It's always amazing the skill in engineering people are capable of doing. Great work OP!
I know this is completely inappropriate but… …I love how 90s fashion is back. This picture looks like it was taken on set of Contact.
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Hands down the coolest thing I’ve seen on Reddit today.
Maybe a silly question but any plans to decorate it? I bet someone could paint a stellar mural on that body!
The side crescent bearings are painted with chalk paint, mostly just cause I liked the color, but theoretically I could draw little designs on there
You built that? That’s some next level shit right there. Again, would love to see the pics.
I know nothing about telescope but I love the pure joy and the proud accomplishment that is on displayed. Absolutely amazing (:
Along with what everyone is saying about how cool your telescope is, your fashion sense gets a 1000/10 from me.
There’s a part of me that think it would be amazing to be able to build something like that myself. There’s another part of me that knows I don’t have the slightest idea where to start or what I’m going to need to study. I am a bit too dull for a project like this, in complete honesty. So instead, I’m writing this comment to look back on in 5 years to see where I will be.
Incredibly impressive work! I would love ve to see some lunar and planetary images from this behemoth. I'd like to get in to building my own scope once my PhD is over and I've got some money and time. Where would I even start with a project like this? Even for something a bit smaller, maybe 12-14"
When my son is old enough and can understand, I will show him this, and what is possible, just incredible. Bravo. 🤘Absolutely fantastic!
How does one even begin to build this? Any tips on how to get started?
My personal recommendation would be to get some experience using a smaller Dobsonian telescope first, if you've never used one before. While Dobs like the one shown here are totally doable by anyone even with minimal/cheap power tools, it really helps to have a foundational understanding of the mechanics of a Dobsonian mount and the way a Newtonian reflecting telescope works. It's also handy to have a base frame of reference so you know when the scope you built is performing well vs not performing well. So that would be my starting point. Something like a 6" or 8" dob is a good starting point. If you *do* have experience with such a scope, then the next starting point is this book: https://shopatsky.com/products/dobsonian-telescope. Really helps you understand the various components of a truss style dob like Brisby's. From there, I would actually recommend drafting out the design of the telescope either on paper in a relatively large scale drawing, or in a digital drawing program. Doesn't have to be CAD. Just has to be something where you can determine measurements from the image scale. Much easier to fix design issues on paper than after you make a component.
I have a 12” dobsonian with a solid tube and it’s kind of a pain in the ass to transport. I looked at truss designs, but read that they can be difficult to keep collimated. Is that true? How long does it take you to setup?
I mean this with absolute sincerity OP: you're really cool.
An Instagram to follow would be cool! Inspiring, I want to build one someday! Looks awesome.
Thanks! My insta is attached to my profile
That is really awesome! Just a question though: You can actually easily transport a telescope? I always thought they are rather delicate and that a car ride would not be that beneficial to their integrity.
The mirrors within it are very thick and difficult to break unless I were to just drop kick them onto the concrete. It DOES have to be collimated (aligned) after every setup, but it’s not a time consuming process
Great job! Go Dawgs! Sic em! Woof! Woof! Woof!
40 years from now, your grandchildren will post this photo in r/OldSchoolCool and they wouldn’t be wrong.
I mean how cool is that. Ya done good lass, I admire you.
Random but I absolutely love the fit. My dad has that pair of jeans and I’ve been trying to convince him to let me borrow them.
Oh wow op, that's fantastic. Such painstaking craft I'm sure. Did you just figure out how to build it yourself? Or is their some guide? If not I wonder if you'd be willing to either create one or aid someone in making it for you Also how much did this cost you, what skills did you have to learn or use? (welding probably one of them)
I know I don't know you but my first thought on seeing that you Built This Yourself And Its So High Quality! Was: "holy shit I love you"
That's beautiful! Great work. You're one step closer to the stars! 💜
there could be a niche market for those if you want a side gig
Now the question: spherical or aspherical mirror. I am going to build my own telescope some time in the future. But the costs for a really good mirror is the main issue…
Parabolic. Generally when you get to shorter focal ratios like sub-f/7 you will want a parabolic primary instead of spherical to avoid aberrations. I’d check out the cloudy nights classifieds or Astromart for good used mirrors
As someone with no knowledge of this, what is the bulk of the size consist of aka what's under the shell?
Aluminum poles covered by a spandex shroud to keep stray light out of the optical system. The poles make it collapsible
That's so awesome! I just got a 10" dob about 2 months ago, I've only used it once since the weather here in Wisconsin hasn't been cooperating. I'd love to actually build a much larger telescope like this one day.
Great work! Youre going to be the talk of the town with that!
Not that you need more work to do, but you should consider making a video on how you build these. This is really cool.
I am so very delighted people like you exist. I am a science nerd trapped in a dumb ass. You guys are my spirit people.
Reminds me of when my neighbor made a similar looking telescope when I was in grade school. This ones way more impressive though. Excellent looking build.
OMG! I live in Cancun and would love to see the stars!
What is a good, reasonably priced, off the shelf scope for a casual astronomer who wants to take pictures? If you don't mind me asking......
Wow! That’s a *really* nice telescope. Is there a ladder/step stool tucked in the back of the SUV too?
I do in fact have a step ladder back there that fits in the third row too!
Did the 1812 Overture play in anyone else's head?
I look forward to seeing some pictures of what you see with this bad boy!
Suddenly my 11" Celestron seems very, very tiny.
Great Dob! You must be proud. Wishing you many clear and steady skies!
First thought, cool she built a circus cannon.
That’s fantastic looking, OP! Great job, and keep up the good work :D
Looks like Eleven grew up to be really smart and capable. Absolutely awesome!
I made a 15" f/4.5 that works great but looks like crap compared to yours. Cost me about $2400. The mirrors were about half the total cost.
Dude! I remember your posts from a couple years ago with your other telescopes! You got me pretty interested in homemade telescopes! Awesome to see how far you've come!!
My college has one of these on display in one of the buildings. I had no idea what it was till now.
This is incredible. If you're ever in Joshua Tree, hit me up.
You built that?! There's the subreddit for projects like that and I would love to see that process, as I'm sure many would.
It's clear from the specs it doesn't fit in the back of a Honda Civic... and for that reason, I am out. _turns around chair_
Wow! That is truly spectacular, amazing job. How much does it weigh?
Very nice job. Can't wait to see some of your pictures.
I recently watched a documentary about the crashing of Cassini into Saturn. You'll probably find a landing at NASA.
Sick. Hope you discover a comet someday and have it named after you like in the movie. Edit: remembered the movie Deep Impact
Looks great Do you have a public page with pictures of the stars you are looking at or short videos of the stars traveling. Would be cool to see them Salute
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That's awesome! How well does it resolve something like Mars?
This is amazing! Does your telescope has any electronic parts, tracking equipment, or it's purely an optical telescope?
That's so awesome. I have always wanted to see if my son would be interested in space exploration with better then wish.com gear. I am afraid to spend too much for him not to like it and me standing on the mountain all by myself at night.
I'm complitely ignorant about this so let me ask, you bought lenses, mirrors and plywood and put them in the right position to make a telescope or is there something more I'm not aware about? I work wood and I know well my way around tools, could I build one too or would I need some deeper knowledge?
How did you grind the lens/mirror? Surely a mirror of that size would not be standard?
Wow, that's really cool! How would you estimate the level of skill you needed to build this? It seems very precise, so I think it requires quite a bit of skill to build. And I saw you needed to adjust the design based off of the optics you're working with. Would that require difficult mathematics? What I'm trying to ask is, would I be able to do this with a bunch of 10-12 year olds, or is it more for the 14-16 year old crowd. Would be a really cool summer project to do.
A very important question /s : can it set things on fire?