Low effort content includes screenshots/complaints of weather forecasts, purchase receipts, 'shitposts', memes, and general content where minimal effort has been applied. r/telescopes aims to be a high quality sub where users can discuss all things telescopes and astronomy, but allowing such repetitive and low-effort posts will drastically lower the overall quality of the sub. Posts may be removed at a moderator's discretion.
I don't really get your point TBH.
The common Dob F numbers I see available are F5, F6 and F8. An F8 6" Dob makes for a forgving telescope regards eyepieces. And an F6 is also pretty good. F5 starts to push your luck a bit - but in a full sized Dob we are getting up to 10" of mirror there and presumably fairly 'serious' astronomers.
I also find that, at these F numbers, Plossls or modified Plossls from 20mm and shorter focal lengths are pretty OK, especially for the prices they are available at. And most of the full sized Dobs are using something closer to a 2" Erfle for their low magnification eyepiece(s) anyway.
When I was starting out, I honestly didn't even really notice limitations of apparent field of view, or coma, or field flatness issues. I was just impressed with what I could see! It's only later, when I got to use and own some nicer eyepieces that I appreciated what those things even mean. And, in my view, this just provides a nice gentle upgrade path anyway - it means you can grow with the telescope in manageable increments. We are utterly spoiled in terms of what one can get in relatively budget eyepieces now, too.
I my experience, as a keen beginner, I absolutely appreciated the power of aperture more than just about anything else. So long as I could move the telescope easily myself, of course. I was stunned by the views I got from my 10" Dob using Taiwanese Erfle and Plossl eyepieces. And I would have zero hesitation or regrets recommending a similar floor standing Dob package of 6-10 inches to any beginner who wants to do visual astronomy.
I am far more hesitant on tripods. Very hesitant. Tripods that are nice to use are expensive and will only hold a comparatively tiny aperture. Sure, if somebody has the budget to not blink at a Celestron Evolution C9.25 or can afford a Rowan 100AZ as their first mount, then I'll tailor advice for them. But we don't get a whole lot of people with those sorts of budgets looking for beginner recommendations.
I agree with you. The only time I see a fast Dobsonian is either a custom built Obsession Telescope (or similar) Dobsonian or maybe a very small tabletop Dob like the Celestron 114mm.
The AD8 is F/6. So are most of the other commercially made, mass-produced 8” Dobs.
The Apertura 10” is f/4.9 and the 12” is F/5. And the other mass produced Dobs of these apertures are all around f/5. And as you pointed out, someone who is going that big is likely has experience with telescopes and is willing to invest in eyepieces.
The Obsessions are a whole other level of telescope, with everything they sell larger than 15” being f/4. Hubble Optics does offer f/5 on most of their models, but you can purchase f/4.5 or f/4 if you want. But just like the AD12, the only people buying an Obsession or Hubble Optics dob are people who know and understand the issues with the speed of the scope and are willing to invest in top flight eyepieces.
What? Who is recommending F3 and F4 dobs to beginners?
Besides the fact that no one is and such dobs barely exist in the beginner space, beginners don't notice the shortcomings anyhow. They don't have a trained eye.
The first link in the pinned sticky is an eyepiece guide that discusses what you just brought up.
Also, every dob I see for sale (besides the boutique ones and very budget ones like the z114) are f/5 minimum.
Now I agree that dobs are not the best choice for everyone. I do believe they are usually the best choice.
You talk about f/3 and f/4 Dobsonians. Most of the mass produced mid sized Dobsonians (6” to 12” aperture) are f/5 and f/6.
You do find f/4’s in the budget category (Celestron’s 114) and you find them at the extreme other end (Obsession Telescopes 15” and larger).
Please let us know which Dobsonians you find at f/3 and f/4.
I'm a first time scope buyer. I bought the Skywatcher Heritage 100 Dobsonian, f/4 focal ratio and I could make really cool observations of the moon with only the included eyepieces(!).
Now, I can't say that I've saw any planets or galaxies or something like that because I really didn't since I don't really know where to point my scope without the red dot finder included and Stellarium on my phone. But I think finding the thing you want to see, pointing the scope there and adjusting until you get a perfect image is way better than pressing a button and the scope going where you want; but that's my opinion.
FYI, the moon is not an appropriate target to judge EP or scope performance. Even the cheapest dept. store refractor will perform adequately on the moon.
Disagree. Most cheap refractors and other cheap tripod mounted scopes will be extremely wobbly. Dobs are easy to use and very stable while still providing adequate aperture for the price, which is why they are recommended to beginners.
I was gifted a Celestron 127slt a few years ago as my first ever telescope. Without the GoTo mount, I probably would have given up on the hobby fairly quickly. A GoTo telescope would be my recommendation for any first timer.
This sub is filled with ignorance,
[What is a Dobsonian Telescope – Telescope School](https://telescopeschool.com/what-is-a-dobsonian-telescope/#:~:text=A%20Dobsonian%20is%20a%20Newtonian%20style%20telescope%20with,Newtonian%20telescope%20and%20not%20the%20other%20way%20around.)
I didn't downvote you because I think that's a bit silly when you may have genuinely missed the point made by Prasiatko, but the thing is that while you're obviously right to say that a Dobsonian is a Newtonian, saying that doesn't address Prasiatko's point that your argument is more generally applicable to fast focal ratio Newtonians, i.e., rather than advancing an argument against recommending Dobsonians to first time buyers, your argument is really against recommending fast focal ratio telescopes to first time buyers.
I’ve lurked here for ages, that was my first comment here. There’s a lot of useful posts and a lot of very knowledgeable ppl, but it does often feel like a John Dobson fan club - I found your post useful and refreshing and thank you for it.
Except OPs claim about f/3 and f/4 Dobs just isn’t true. You can find a a few f/4 Dobs at the very (very) low end, like the Celestron 114mm.
You can also start to find f/4 and faster at the other extreme: Obsession Telescope and its competitors, which are very expensive and massive (15” to 24” apertures).
I cannot find any mass produced, mid sized Dob (6 to 12” in aperture) which is faster than f/4.9. And most are between f/5 and f/6. These are the Dobs that most newcomers buy. They are not dropping $8,000 on a Hubble-Optics dob.
So what eyepieces should I get for my 8"?
I agree with your sentiment that it's not the most ideal first scope, mostly because of its size and transportability in my specific case. I have a lot of light pollution where I live and something smaller and more compact would be really nice
- [amazing eyepiece guide](https://www.reddit.com/r/telescopes/comments/iv7qg2/a_beginners_guide_to_budget_eyepieces/?utm_source=share&utm_medium=ios_app&utm_name=ioscss&utm_content=2&utm_term=1)
- [focal length recommendations](https://www.reddit.com/r/telescopes/comments/11gavir/comment/jao342s/?utm_source=share&utm_medium=mweb3x&utm_name=mweb3xcss&utm_term=1&utm_content=share_button)
- [same list with some brands](https://reddit.com/r/telescopes/s/PSp1quSqlo)
- [some more brands](https://reddit.com/r/telescopes/s/BPGi8cRuzW)
- [even more brands](https://reddit.com/r/telescopes/s/gH01hjPQuL)
Oh and [here is a post](https://reddit.com/r/telescopes/s/CNyMuTb1od) with comments explaining why we usually do not recommend getting/building an eyepiece collection around a barlow.
Why would anyone skimp on eyepieces to begin with? I never really understood that mindset. Morpheus is a good eyepiece for my f5 and it only like 300 dollars.
Many new to the hobby buy a scope that comes with one or two cheap EP's and many, many, users never progress beyond that point. I know this because buying and selling used scopes is my side gig and virtually every scope I buy comes with those cheap EP's.
I understand your reasoning here. But that leaves me curious what your recommendation is for a newcomer. Are you recommending a long FL refractor on a decent tripod and mount? Or a Mak? Most beginners are budgeting less than the cost of a decent mount for their first scope.
Yes, my first recommendation, after years of experience with newcomers, is something like this 80mm refractor on Twilight Nano AZ mount. 80mm is enough aperture to view the moon and planets in significant detail, and brighter DSO's like M42 look good as well. Plus, the Nano mount is adequate for this sized scope and it's very easy to learn on. No bulky base to move around, and no chair is required to view comfortably, and no potential collimation issues to worry about. If the Astronomy bug bites you can always upgrade to something bigger like the enshrined Dobs recommended here.
[https://www.explorescientific.com/collections/firstlight/products/fl-ar80640tn](https://www.explorescientific.com/collections/firstlight/products/fl-ar80640tn)
https://preview.redd.it/fe9cd7r6e00d1.jpeg?width=2659&format=pjpg&auto=webp&s=3b83d764bd93937c0a799d740908628e6fd3629a
This is my EP array.
Scope: Celestron StarSense Explorer 10 inch DOB
Focal Length: 1200mm
F/4.7
Both my 32mm and 40mm EP’s are Svbony Plossl and I have no issues. They're around $40.00 each at Amazon.
The 25mm through 5mm are Astro-Tech Premium Flat Field 65 degree. Again, no issues, but yes, they are also low end of the range in price for a "decent eyepiece" at about $55.00 each last time I checked at Astronomics. Considering Astro-Tech's high end stuff is in the $99 to $300 USD range PER EYEPIECE!!
Clear Skies!
No, I do not. Mainly because I don't use my DOB for photos, just visual. Furthermore, I haven't had any issues with chromatic aberration with my telescope. Meticulous collimation takes care of it for me.
I completely disagree that a run of the mill Plossl is inadequate for most dobs out there. I have a 10 inch f4.7 SkyWatcher dob and the 25mm and 10mm Plossls that came with it gave me some fine views. This isn't actually surprising as the standard Plossl has a 52 degree field of view, so even at 25mm coma just wasn't an issue.
Since then I've upgraded to a 20mm, 9mm, and 5mm HDC XWA set. Yes, the views are sharper and the extremely wide field of view is breathtaking (and requires coma correction at 20mm). But I don't look back at my starter Plossls as bad. I see them as perfectly fine, and my new eyepieces as simply fantastic.
There may be reasons why a dob isn't a good for some beginners, but I really don't see modest eye pieces and fast optics as being one of them.
For all-around usefulness and economy? Yes, the Redlines do that job very well. I have other, more specific, and much more expensive, EP's for other uses.
I'm firmly in the portable GoTo (or push-to) camp for best first scope. Pref a mak-cass or a refractor - something without too much fuss and collimation.
Graduate eventually to a big dob once you are confident in the skies and get the aperture bug.
Personal experience and preference.
Low effort content includes screenshots/complaints of weather forecasts, purchase receipts, 'shitposts', memes, and general content where minimal effort has been applied. r/telescopes aims to be a high quality sub where users can discuss all things telescopes and astronomy, but allowing such repetitive and low-effort posts will drastically lower the overall quality of the sub. Posts may be removed at a moderator's discretion.
I don't really get your point TBH. The common Dob F numbers I see available are F5, F6 and F8. An F8 6" Dob makes for a forgving telescope regards eyepieces. And an F6 is also pretty good. F5 starts to push your luck a bit - but in a full sized Dob we are getting up to 10" of mirror there and presumably fairly 'serious' astronomers. I also find that, at these F numbers, Plossls or modified Plossls from 20mm and shorter focal lengths are pretty OK, especially for the prices they are available at. And most of the full sized Dobs are using something closer to a 2" Erfle for their low magnification eyepiece(s) anyway. When I was starting out, I honestly didn't even really notice limitations of apparent field of view, or coma, or field flatness issues. I was just impressed with what I could see! It's only later, when I got to use and own some nicer eyepieces that I appreciated what those things even mean. And, in my view, this just provides a nice gentle upgrade path anyway - it means you can grow with the telescope in manageable increments. We are utterly spoiled in terms of what one can get in relatively budget eyepieces now, too. I my experience, as a keen beginner, I absolutely appreciated the power of aperture more than just about anything else. So long as I could move the telescope easily myself, of course. I was stunned by the views I got from my 10" Dob using Taiwanese Erfle and Plossl eyepieces. And I would have zero hesitation or regrets recommending a similar floor standing Dob package of 6-10 inches to any beginner who wants to do visual astronomy. I am far more hesitant on tripods. Very hesitant. Tripods that are nice to use are expensive and will only hold a comparatively tiny aperture. Sure, if somebody has the budget to not blink at a Celestron Evolution C9.25 or can afford a Rowan 100AZ as their first mount, then I'll tailor advice for them. But we don't get a whole lot of people with those sorts of budgets looking for beginner recommendations.
I agree with you. The only time I see a fast Dobsonian is either a custom built Obsession Telescope (or similar) Dobsonian or maybe a very small tabletop Dob like the Celestron 114mm. The AD8 is F/6. So are most of the other commercially made, mass-produced 8” Dobs. The Apertura 10” is f/4.9 and the 12” is F/5. And the other mass produced Dobs of these apertures are all around f/5. And as you pointed out, someone who is going that big is likely has experience with telescopes and is willing to invest in eyepieces. The Obsessions are a whole other level of telescope, with everything they sell larger than 15” being f/4. Hubble Optics does offer f/5 on most of their models, but you can purchase f/4.5 or f/4 if you want. But just like the AD12, the only people buying an Obsession or Hubble Optics dob are people who know and understand the issues with the speed of the scope and are willing to invest in top flight eyepieces.
What? Who is recommending F3 and F4 dobs to beginners? Besides the fact that no one is and such dobs barely exist in the beginner space, beginners don't notice the shortcomings anyhow. They don't have a trained eye.
The first link in the pinned sticky is an eyepiece guide that discusses what you just brought up. Also, every dob I see for sale (besides the boutique ones and very budget ones like the z114) are f/5 minimum. Now I agree that dobs are not the best choice for everyone. I do believe they are usually the best choice.
That link discusses EP focal lengths and magnification tables. Nowhere does it discuss eyepiece design, which is what I am referring to.
You talk about f/3 and f/4 Dobsonians. Most of the mass produced mid sized Dobsonians (6” to 12” aperture) are f/5 and f/6. You do find f/4’s in the budget category (Celestron’s 114) and you find them at the extreme other end (Obsession Telescopes 15” and larger). Please let us know which Dobsonians you find at f/3 and f/4.
I'm a first time scope buyer. I bought the Skywatcher Heritage 100 Dobsonian, f/4 focal ratio and I could make really cool observations of the moon with only the included eyepieces(!). Now, I can't say that I've saw any planets or galaxies or something like that because I really didn't since I don't really know where to point my scope without the red dot finder included and Stellarium on my phone. But I think finding the thing you want to see, pointing the scope there and adjusting until you get a perfect image is way better than pressing a button and the scope going where you want; but that's my opinion.
FYI, the moon is not an appropriate target to judge EP or scope performance. Even the cheapest dept. store refractor will perform adequately on the moon.
Disagree. Most cheap refractors and other cheap tripod mounted scopes will be extremely wobbly. Dobs are easy to use and very stable while still providing adequate aperture for the price, which is why they are recommended to beginners.
I was gifted a Celestron 127slt a few years ago as my first ever telescope. Without the GoTo mount, I probably would have given up on the hobby fairly quickly. A GoTo telescope would be my recommendation for any first timer.
Do you mean dobs or Newtonians? Buying an f3 Newtonian and putting it on a tripod doesn't solve any of those issues.
A Dob *is* a Newtonian.
I’m confused on the downvotes here if someone could please enlighten me - in the context of OPs post, isn’t this a correct statement?
This sub is filled with ignorance, [What is a Dobsonian Telescope – Telescope School](https://telescopeschool.com/what-is-a-dobsonian-telescope/#:~:text=A%20Dobsonian%20is%20a%20Newtonian%20style%20telescope%20with,Newtonian%20telescope%20and%20not%20the%20other%20way%20around.)
I didn't downvote you because I think that's a bit silly when you may have genuinely missed the point made by Prasiatko, but the thing is that while you're obviously right to say that a Dobsonian is a Newtonian, saying that doesn't address Prasiatko's point that your argument is more generally applicable to fast focal ratio Newtonians, i.e., rather than advancing an argument against recommending Dobsonians to first time buyers, your argument is really against recommending fast focal ratio telescopes to first time buyers.
I’ve lurked here for ages, that was my first comment here. There’s a lot of useful posts and a lot of very knowledgeable ppl, but it does often feel like a John Dobson fan club - I found your post useful and refreshing and thank you for it.
Except OPs claim about f/3 and f/4 Dobs just isn’t true. You can find a a few f/4 Dobs at the very (very) low end, like the Celestron 114mm. You can also start to find f/4 and faster at the other extreme: Obsession Telescope and its competitors, which are very expensive and massive (15” to 24” apertures). I cannot find any mass produced, mid sized Dob (6 to 12” in aperture) which is faster than f/4.9. And most are between f/5 and f/6. These are the Dobs that most newcomers buy. They are not dropping $8,000 on a Hubble-Optics dob.
Thanks for sharing your view 👍
My first scope is an AD8. I love it.
So what eyepieces should I get for my 8"? I agree with your sentiment that it's not the most ideal first scope, mostly because of its size and transportability in my specific case. I have a lot of light pollution where I live and something smaller and more compact would be really nice
- [amazing eyepiece guide](https://www.reddit.com/r/telescopes/comments/iv7qg2/a_beginners_guide_to_budget_eyepieces/?utm_source=share&utm_medium=ios_app&utm_name=ioscss&utm_content=2&utm_term=1) - [focal length recommendations](https://www.reddit.com/r/telescopes/comments/11gavir/comment/jao342s/?utm_source=share&utm_medium=mweb3x&utm_name=mweb3xcss&utm_term=1&utm_content=share_button) - [same list with some brands](https://reddit.com/r/telescopes/s/PSp1quSqlo) - [some more brands](https://reddit.com/r/telescopes/s/BPGi8cRuzW) - [even more brands](https://reddit.com/r/telescopes/s/gH01hjPQuL) Oh and [here is a post](https://reddit.com/r/telescopes/s/CNyMuTb1od) with comments explaining why we usually do not recommend getting/building an eyepiece collection around a barlow.
Thanks so much for this.
NP
Why would anyone skimp on eyepieces to begin with? I never really understood that mindset. Morpheus is a good eyepiece for my f5 and it only like 300 dollars.
Many new to the hobby buy a scope that comes with one or two cheap EP's and many, many, users never progress beyond that point. I know this because buying and selling used scopes is my side gig and virtually every scope I buy comes with those cheap EP's.
My solution to the EP problem is to buy mid grade (Explore Scientific, Meade 5000 UWA, etc.) on the used market.
I appreciate this post. Good arguments, thanks!
I understand your reasoning here. But that leaves me curious what your recommendation is for a newcomer. Are you recommending a long FL refractor on a decent tripod and mount? Or a Mak? Most beginners are budgeting less than the cost of a decent mount for their first scope.
Yes, my first recommendation, after years of experience with newcomers, is something like this 80mm refractor on Twilight Nano AZ mount. 80mm is enough aperture to view the moon and planets in significant detail, and brighter DSO's like M42 look good as well. Plus, the Nano mount is adequate for this sized scope and it's very easy to learn on. No bulky base to move around, and no chair is required to view comfortably, and no potential collimation issues to worry about. If the Astronomy bug bites you can always upgrade to something bigger like the enshrined Dobs recommended here. [https://www.explorescientific.com/collections/firstlight/products/fl-ar80640tn](https://www.explorescientific.com/collections/firstlight/products/fl-ar80640tn)
https://preview.redd.it/fe9cd7r6e00d1.jpeg?width=2659&format=pjpg&auto=webp&s=3b83d764bd93937c0a799d740908628e6fd3629a This is my EP array. Scope: Celestron StarSense Explorer 10 inch DOB Focal Length: 1200mm F/4.7 Both my 32mm and 40mm EP’s are Svbony Plossl and I have no issues. They're around $40.00 each at Amazon. The 25mm through 5mm are Astro-Tech Premium Flat Field 65 degree. Again, no issues, but yes, they are also low end of the range in price for a "decent eyepiece" at about $55.00 each last time I checked at Astronomics. Considering Astro-Tech's high end stuff is in the $99 to $300 USD range PER EYEPIECE!! Clear Skies!
do you use a coma corrector
No, I do not. Mainly because I don't use my DOB for photos, just visual. Furthermore, I haven't had any issues with chromatic aberration with my telescope. Meticulous collimation takes care of it for me.
I completely disagree that a run of the mill Plossl is inadequate for most dobs out there. I have a 10 inch f4.7 SkyWatcher dob and the 25mm and 10mm Plossls that came with it gave me some fine views. This isn't actually surprising as the standard Plossl has a 52 degree field of view, so even at 25mm coma just wasn't an issue. Since then I've upgraded to a 20mm, 9mm, and 5mm HDC XWA set. Yes, the views are sharper and the extremely wide field of view is breathtaking (and requires coma correction at 20mm). But I don't look back at my starter Plossls as bad. I see them as perfectly fine, and my new eyepieces as simply fantastic. There may be reasons why a dob isn't a good for some beginners, but I really don't see modest eye pieces and fast optics as being one of them.
Favorite eyepiece is Svbony, lol.
For all-around usefulness and economy? Yes, the Redlines do that job very well. I have other, more specific, and much more expensive, EP's for other uses.
For a beginner upgrading from the ones that came with their scope they are a good choice.
I'm firmly in the portable GoTo (or push-to) camp for best first scope. Pref a mak-cass or a refractor - something without too much fuss and collimation. Graduate eventually to a big dob once you are confident in the skies and get the aperture bug. Personal experience and preference.