53 replies to this topic

[snakehelah]

Hello,

 

I've been naked-eye viewing stars and planets for a long time... decided to go ahead and get a used 8" dob - it came with default plossl 25mm, 10mm and additional 6.3mm and some 2x plastic barlow.

I love the 25mm! But the others are not really fun to use at all due to their small pupil, I don't want to be squinting all the time and I wear glasses as well so it makes it difficult to use them.

 

I've spent some time reading on the forums, reddit, etc. about all the available eyepieces and what their use case is for various objects, etc.

 

Still, I am curious what various dob 8" owners have and use on the daily, or what they recommend - I noticed I do have a 2" adapter with the scope - are there any pros or cons of using 1.25 vs 2" eyepieces? What if I were to want to get a larger aperture dob in some years? Are there some overlaps between eyepieces that work for different apertures?
 

So far, I've narrowed down these options:
Baader Hyperion Universal Mark IV zoom eyepiece + zoom Barlow lens set

This seems widely recommended as the best starter kit you can get for your money with the biggest benefit being convenience. I was seriously considering this one, just because not switching eyepieces seems like a very convenient thing. But ultimately a lot of people recommend just having 1-2 solid pieces such as a 10mm + a 25-30 mm wide FOV one and that for similar money (minus the barlow).

I noticed one user - astro.catshill in his blogpost explains that there also needs to be a 35mm 2" extension that you use if you want to go for this combo. I assume the below extension would work?

Omegon 2“ Extension tube, 35mm optical path - I've heard that if you want to use 2" scopes on the Classic 200P 8" Dob, you might need some additional extension to accomodate the focus (on top of the 2" adapter) - is this true? 

Other eyepieces:

Omegon Oberon 32mm 2'' - haven't been able to find any reviews on this online that would give any sort of definitive review. Only some vague posts about it being a copy of another eyepiece and that the 82 fov is actually 70, though the weight of this piece seems overkill...

 

Omegon Redline SW 32mm 2" cheaper alternative to the above.

Omegon SWA 32mm, 2” eyepiece - similar as above...?

 

Baader Hyperion 31mm, aspheric - hyperion line from baader seems to get mixed feedback.

Baader Hyperion 13 mm - consensus is morpheus is a better investment, but I doubt I will care much for the more premium lineup considering im moving from the default scopes. 

What I also saw was recommended from Chinese options as insanely good for the price (how do these compare to the ones above?):
Angeleyes 70° FMC 14mm 1.25''
Sky Rover 2 inch 70 degree UF 30mm

Edited by snakehelah, 25 March 2025 - 09:46 AM.

[oninoyakamo]

An 8" f/6 Dob is Ed Ting's favorite scope. He recommends Tele Vue's 27mm Panoptic and 13mm Nagler as ideal for it

[snakehelah]

An 8" f/6 Dob is Ed Ting's favorite scope. He recommends Tele Vue's 27mm Panoptic and 13mm Nagler as ideal for it

Saw his channel and some videos and did notice he swears they are in another league entirely.

That said, not only are they usually out of stock in Europe (at least it seems so) seems like these are also the most premium/expensive options there are. I was thinking more about the mid range.

[SeattleScott]

An 8" f/6 Dob is Ed Ting's favorite scope. He recommends Tele Vue's 27mm Panoptic and 13mm Nagler as ideal for it

He also prefers a 13 Type 1 Nagler to a 13 Type 6 Nagler. Ed is not what I would call a discriminating connoisseur of eyepieces. Nothing against a 27 Panoptic, but it wouldn’t be my choice for a low power eyepiece at F6.

[Barlowbill]

Get the Baader Zoom with Barlow and nothing else.  Use it for a couple of years then think about something else.  An alternative would be, in addition the the Baader, pick up the 2", 28mm Astro-Tech, 82* UWA.  

[snakehelah]

Get the Baader Zoom with Barlow and nothing else.  Use it for a couple of years then think about something else.  An alternative would be, in addition the the Baader, pick up the 2", 28mm Astro-Tech, 82* UWA.  

As I understand the Techno Sky UWA 82° 28mm is the same as the Astro tech. I'll check it out.  

[SeattleScott]

Ok so first of all, 2” is about low power, wide field views to make finding stuff easier. There is value to having one 2” eyepiece for the widest possible view. The field stop dictates how wide the view is. A 25mm Plossl has a field stop around maybe 23mm. The widest possible field stop in 2” format is 46mm. So you could get as much as twice as wide of a view as you are currently getting with a 2” eyepiece, although I wouldn’t recommend one with a 46mm field stop at F6. The 30mm UFF has a 36.2mm field stop. The 27 Panoptic checks in at 30.5mm. The 28mm UWA registers 40.8mm. 30.5 will go noticeably wider than 23, but 36-40 is really more where you want to be. There is the 35 Panoptic at 38mm field stop if you want to go Televue. That would be my suggestion if you want a Panoptic. Yes it is a bigger, heavier eyepiece, but it goes much wider. Helpful for a beginner trying to find stuff. I think Ed likes the 27 because it goes wide enough for him to find stuff being experienced, it is small and light for a 2” eyepiece, and apparently it has about the perfect amount of eye relief for him (a subjective personal thing that won’t necessarily translate for others). Sure, Panoptics are sharp, but other eyepieces are sharp too. Panoptics are an older design and not really top tier these days, although still plenty good at F6. (Again, remember Ed loves his decades-old first generation Nagler.)

As for the zoom, if you don’t want to swap eyepieces, you are in the wrong hobby. The zoom will not eliminate swapping eyepieces. It will reduce swapping eyepieces. It doesn’t go wide enough at low power, approximately equal to a 20mm Plossl. So you will start with a low power eyepiece to find a target, then put the zoom in. So you will pretty much always swap eyepieces at least once. And for high power, the zoom doesn’t go high enough, so you would need the barlow or a high power eyepiece (perhaps mostly for lunar/planetary viewing). So more eyepiece swapping, and the BHZ barlow seems like more hassle because you have to screw it on and off rather than just drop it in. Now the BHZ offers pretty good correction, especially at F6. It is relatively wide AFOV, for a zoom. And it will certainly decrease the need to swap eyepieces. It isn’t a bad piece of kit. I just don’t want you to be under any illusions of it eliminating eyepiece swapping.

Of your suggestions, the bottom two are worth considering. I would pass on the others at F6.

[SeattleScott]

Oh, by the way, don’t forget a collimation tool if you don’t already have one. It doesn’t matter how good your eyepieces are if your mirrors aren’t aligned!

[vtornado]

Hello,

 

I've been naked-eye viewing stars and planets for a long time... decided to go ahead and get a used 8" dob - it came with default plossl 25mm, 10mm and additional 6.3mm and some 2x plastic barlow.

I love the 25mm! But the others are not really fun to use at all due to their small pupil, I don't want to be squinting all the time and I wear glasses as well so it makes it difficult to use them.

 

Still, I am curious what various dob 8" owners have and use on the daily, or what they recommend - I noticed I do have a 2" adapter with the scope - are there any pros or cons of using 1.25 vs 2" eyepieces? What if I were to want to get a larger aperture dob in some years? Are there some overlaps between eyepieces that work for different apertures?

 

I only comment on thing that I have personally looked through.
 

So far, I've narrowed down these options:
Baader Hyperion Universal Mark IV zoom eyepiece + zoom Barlow lens set

The Baader is a good zoom, but ... it is expensive.  One could buy a handful of 60 degree eyepieces for its price.  Yes it is infinitely adjustible and you won't have to switch eyepieces.   The longer focal length 60 degree eyepieces will outperform it.

Omegon Oberon 32mm 2'' - haven't been able to find any reviews on this online that would give any sort of definitive review. Only some vague posts about it being a copy of another eyepiece and that the 82 fov is actually 70, though the weight of this piece seems overkill... ??? don't know.

 

Omegon Redline SW 32mm 2" cheaper alternative to the above. ??? don't know

 

I am using a Orion Q70 32mm is it perfect?  No.   But used it was around $75.00.

 

Baader Hyperion 31mm, aspheric - hyperion line from baader seems to get mixed feedback.  I think the color, scatter, and transmission are excellent, The eyepiece is not well corrected in the outer field.  The Orion Q series is cheaper and about as well corrected.

Baader Hyperion 13 mm - consensus is morpheus is a better investment, but I doubt I will care much for the more premium lineup considering im moving from the default scopes. Don't have this.

Omegon 2“ Extension tube, 35mm optical path - i've heard that if you want to use 2" scopes on the Classic 200P 8" Dob, you might need some additional extension to accomodate the focus (on top of the 2" adapter) - is this true? At least this was what astro.catshill wrote in his blogpost for the barlow+hyperion zoom combo when using the default 2" adapter. Not entirely sure about 2" eyepieces though.

 

Some modern dobs are optimized to allow for taking pictures, and they require an extension tube to reach focus for some eyepieces.   Depending upon how old your dob is will determine if you need an extension or not.  I had a modern sky watcher and needed one.  I have a older orion skyquest and do not.  The best strategy would be to get the eyepiece and if you need to not seat it all the way in to reach focus, you will need an extension.  If it is the other way (you need more in focus)  that can be a problem.

What I also saw was recommended from Chinese options as insanely good for the price (how do these compare to the ones above?):
Angeleyes 70° FMC 14mm 1.25''
Sky Rover 2 inch 70 degree UF 30mm  I think this is the same as the APM UFF 30/70  This is a superb eyepiece and reasonably priced.  I had one but was forced to sell it due to financiancial issuses.

 

[snakehelah]

Ok so first of all, 2” is about low power, wide field views to make finding stuff easier. There is value to having one 2” eyepiece for the widest possible view. The field stop dictates how wide the view is. A 25mm Plossl has a field stop around maybe 23mm. The widest possible field stop in 2” format is 46mm. So you could get as much as twice as wide of a view as you are currently getting with a 2” eyepiece, although I wouldn’t recommend one with a 46mm field stop at F6. The 30mm UFF has a 36.2mm field stop. The 27 Panoptic checks in at 30.5mm. The 28mm UWA registers 40.8mm. 30.5 will go noticeably wider than 23, but 36-40 is really more where you want to be. There is the 35 Panoptic at 38mm field stop if you want to go Televue. That would be my suggestion if you want a Panoptic. Yes it is a bigger, heavier eyepiece, but it goes much wider. Helpful for a beginner trying to find stuff. I think Ed likes the 27 because it goes wide enough for him to find stuff being experienced, it is small and light for a 2” eyepiece, and apparently it has about the perfect amount of eye relief for him (a subjective personal thing that won’t necessarily translate for others). Sure, Panoptics are sharp, but other eyepieces are sharp too. Panoptics are an older design and not really top tier these days, although still plenty good at F6. (Again, remember Ed loves his decades-old first generation Nagler.)

As for the zoom, if you don’t want to swap eyepieces, you are in the wrong hobby. The zoom will not eliminate swapping eyepieces. It will reduce swapping eyepieces. It doesn’t go wide enough at low power, approximately equal to a 20mm Plossl. So you will start with a low power eyepiece to find a target, then put the zoom in. So you will pretty much always swap eyepieces at least once. And for high power, the zoom doesn’t go high enough, so you would need the barlow or a high power eyepiece (perhaps mostly for lunar/planetary viewing). So more eyepiece swapping, and the BHZ barlow seems like more hassle because you have to screw it on and off rather than just drop it in. Now the BHZ offers pretty good correction, especially at F6. It is relatively wide AFOV, for a zoom. And it will certainly decrease the need to swap eyepieces. It isn’t a bad piece of kit. I just don’t want you to be under any illusions of it eliminating eyepiece swapping.

Of your suggestions, the bottom two are worth considering. I would pass on the others at F6.

Thanks for the explanations and suggestions. I wasn't implying I don't want to swap eyepieces. I was just curious about the zoom piece because a lot of people swear the best point about it is the convenience. The zoom + barlow are still around the price of something like 2 mid tier eyepieces, hence why I was on the fence about it vs getting 2 dedicated pieces instead. Maybe a barlow to top it off.

The Tecnosky UWA 28mm 82° does seem like a good one. As you mentioned the last 2 (aliexpress) options are the viable ones from my list, any particular reason why? I guess it comes down to the Tecnosky vs the Sky Rover 2 inch 70 degree UF 30mm. I mean, I do like to support the "local" markets so I'd opt for an EU option more than the Chinese one, but if the Sky Rover is much better I'd probably make a compromise.

What do you think about the Baader Hyperion 13 mm? One of the reasons I brought it up is because there's a used option that's available in my area for this one, so I could get it cheaper. 100$/euros-ish. Or is the Angeleyes 70° FMC 14mm 1.25'' still the better one?

Otherwise, I am kind of thinking about going for the baader zoom and barlow bundle + Tecnosky UWA 28mm 82°. Do you recommend the barlow bundle as that seems like a better deal?

Edited by snakehelah, 25 March 2025 - 11:11 AM.

[SeattleScott]

I have the 30mm 70 and can vouch for how well corrected it is. People speak highly of the 28mm UWA as well, although it is heavier, and has less eye relief (not compatible with glasses).

I don’t have the 14mm but it has a good reputation and should perform very well at F6. It probably won’t have quite the edge correction or contrast of premium brands, but it should come pretty close, at a very reasonable price.

The 13 Hyperion has a poor reputation, and bench tests show the edge correction is rather poor in fast scopes. It may well be the worst performer in a suspect series. It won’t be terrible at F6, but you can do better for the price.

The BHZ and zoom is a nice bit of kit, and it does add some convenience. But at the end of the day it is still a zoom. Just one of the better ones. For me it doesn’t add much convenience because I start at low power, and generally just jump right to more or less optimal magnification from there. But a zoom is nice for a beginner who doesn’t know the optimal magnification for various targets already. It is also a rather expensive zoom. If you end up going with $300 fixed eyepieces anyway, you could have had one with the price you pay for the BHZ.

As for the barlow, you need something for high power, and there is a certain logic to using a zoom to dial in ideal magnification for the seeing. The BHZ zoom is reputed to pair really well with the BHZ barlow, although again it is a bit of a hassle if you have to keep swapping it in and out, compared to a normal drop in barlow. If you only use it on one or two targets in an evening, it’s not as big of a deal. The flip side is zooms aren’t optimized for the full focal range, and so depending on what magnification you end up at, you likely aren’t getting maximum contrast. It is also a complex eyepiece with internal moving parts and can suffer from a bit of light scatter compared to something like a Tak LE or TOE. The people who swear by zooms for planets do so because of the ability to match magnification to seeing. They aren’t comparing the zoom to Takahashi or Televue eyepieces. Basically you sacrifice a touch of contrast to get flexibility with magnification. Some people will gladly take that deal. Others not so much.

Edited by SeattleScott, 25 March 2025 - 12:24 PM.

[snakehelah]

I have the 30mm 70 and can vouch for how well corrected it is. People speak highly of the 28mm UWA as well, although it is heavier, and has less eye relief (not compatible with glasses).

I don’t have the 14mm but it has a good reputation and should perform very well at F6. It probably won’t have quite the edge correction or contrast of premium brands, but it should come pretty close, at a very reasonable price.

The 13 Hyperion has a poor reputation, and bench tests show the edge correction is rather poor in fast scopes. It may well be the worst performer in a suspect series. It won’t be terrible at F6, but you can do better for the price.

The BHZ and zoom is a nice bit of kit, and it does add some convenience. But at the end of the day it is still a zoom. Just one of the better ones. For me it doesn’t add much convenience because I start at low power, and generally just jump right to more or less optimal magnification from there. But a zoom is nice for a beginner who doesn’t know the optimal magnification for various targets already. It is also a rather expensive zoom. If you end up going with $300 fixed eyepieces anyway, you could have had one with the price you pay for the BHZ.

As for the barlow, you need something for high power, and there is a certain logic to using a zoom to dial in ideal magnification for the seeing. The BHZ zoom is reputed to pair really well with the BHZ barlow, although again it is a bit of a hassle if you have to keep swapping it in and out, compared to a normal drop in barlow. If you only use it on one or two targets in an evening, it’s not as big of a deal. The flip side is zooms aren’t optimized for the full focal range, and so depending on what magnification you end up at, you likely aren’t getting maximum contrast. It is also a complex eyepiece with internal moving parts and can suffer from a bit of light scatter compared to something like a Tak LE or TOE. The people who swear by zooms for planets do so because of the ability to match magnification to seeing. They aren’t comparing the zoom to Takahashi or Televue eyepieces. Basically you sacrifice a touch of contrast to get flexibility with magnification. Some people will gladly take that deal. Others not so much.

Thanks for the advice! I'll ponder it a bit more for the eyepieces, there's another one:
https://www.tecnosky...ld-30mm-75.html

This one has better eye relief and from what i heard it's like the Sky rover.

For the eye relief, I mean I do wear glasses and I've tried focusing with and without them when looking, maybe I'm wrong but it did feel like the view with glasses was more sharp. 

For the baader zoom + barlow combo. I assume from various sources I need an extension for it to focus well:
https://www.tecnosky...rante-35mm.html

There's just a few other concerns I have. Namely the "neck breaker" finder scope. I can use it relatively fine, but it does start to cramp up the back/neck after an hour of use. Are the angled alternatives really better? I've seen people also go for "red dot scopes", so was wondering if the finder scope is actually worthy of an upgrade.

Edited by snakehelah, 25 March 2025 - 01:16 PM.

[SeattleScott]

Looks like the exact same eyepiece, just marketed as 75 AFOV instead of 70.

You probably have astigmatism so glasses improve the view at low power. At high power it probably doesn’t matter.

The angled finders are better ergonomically but it can make it harder to point accurately. The ideal, assuming you don’t live near an airport, is a dual finder mount with a green laser for pointing, and an angled finder for magnification. Or, get an observing chair to improve the ergonomics of looking straight through the finder.

[Spile]

I would also recommend combining the Baader zoom, matching Barlow and a 2” wide angle https://astro.catshi...-zoom-eyepiece/

[snakehelah]

Looks like the exact same eyepiece, just marketed as 75 AFOV instead of 70.

You probably have astigmatism so glasses improve the view at low power. At high power it probably doesn’t matter.

The angled finders are better ergonomically but it can make it harder to point accurately. The ideal, assuming you don’t live near an airport, is a dual finder mount with a green laser for pointing, and an angled finder for magnification. Or, get an observing chair to improve the ergonomics of looking straight through the finder.

I do have mild astigmatism. But since the stock eyepieces are the only thing I have to work with atm it did feel better to actually do it without glasses since I was able to push the view in further, especially on the 10mm and 6.3mm, but is it such a small hole to look through on these two compared to the 25mm.

This evening, finally, some clouds parted and I had a decent look at Jupiter, I don't think the red spot was facing me this time but I could make out the stripes, might have been my imagination but it def felt like it had colors.

For planet detail, I'm curious how much you can actually push it with the better eyepieces - the Baader zoom in this case, compared to the stock pieces I have.

Mars for example was definitely not as visible/detailed as Jupiter. Didn't feel like I could make out much detail, then again this year round I assume it doesn't have the best conditions, like Venus had.

Before I got the dob 8" Venus was so bright it was crazy even for the naked eye, but now it's always hiding below the horizon during the evening sadly.

Got to look at Pleiades as well and I can definitely see why people recommend the bigger FOV eyepieces. It's nice to even just look around random patches of sky with the 25mm. It says it has a 52 degree FOV, will the 30mm 75 degree FOV really be that much bigger?

[snakehelah]

I would also recommend combining the Baader zoom, matching Barlow and a 2” wide angle https://astro.catshi...-zoom-eyepiece/

Thanks. For the Baader zoom + barlow as I understand for my skywatcher classic 200p 8" dob, you explain that an extension 35mm is needed for proper focus. Would this be what I would need in addition to the baader zoom bundle? 

https://www.tecnosky...rante-35mm.html

Edited by snakehelah, 25 March 2025 - 06:22 PM.

[SeattleScott]

It is unlikely the Baader zoom would provide any sharper image in the center of the field. Honestly, if I was a betting man, I would bet on the Plossl winning. What you get with the BHZ is wider AFOV (at some FL settings, less over 20mm setting) and bigger eye lens, and the ability to change magnification. You would be unlikely to see any improvement in the view. In a faster scope, the BHZ might be a little sharper at the edge of the field, but probably won’t make much difference at F6.

[snakehelah]

Thanks for the advice!

Went for the Tecnosky Ultra Flat Field 30mm 75° and Hyperion Zoom 8-24mm+Barlow combo.

I was undecided between the 30mm and 28 mm as the 28 does have more FOV but just went with the 30mm. Hope I chose well!

Edited by snakehelah, 26 March 2025 - 06:44 AM.

[SeattleScott]

The 30mm will work with your glasses to clean up your astigmatism. With the 28, you typically can’t see the whole view with glasses, which kind of defeats the purpose of having the wider view.

[azure1961p]

Two barlows , 2x and 3x made by Televue. 

[snakehelah]

The 30mm will work with your glasses to clean up your astigmatism. With the 28, you typically can’t see the whole view with glasses, which kind of defeats the purpose of having the wider view.

I do try looking with and without glasses to compare but it was impossible to get good looks via the plossls with glasses, so I had to go without them, I guess I did notice a little astigmatism but not too much. But I do need glasses for the finder scope.

By the way, is the baader zoom and 30mm "future proof"? Meaning, if I ever decide to get a 12" dob for example, I assume these would work just as well? I understand 2" and 1,25" is the standard but I also saw posts about f/ratio affecting the eyepieces.

P.S

Unrelated, but the person I bought the dob 8" from told me he did some modification to the bottom of the telescope. He said I basically wouldn't need to collimate the bottom mirror anymore due to this modification, or w/e.

I didn't 100% understand what he did there at the time but he assured me everything works fine with its light gathering ability and that I don't even need to collimate it when I get it back home.

From my understanding the collimation seemed fine after my first sessions. I know this is a huge point for starting with these telescopes, any ideas what modifications may be done? He said he changed some screws. It has 3 screws in a triangle on the bottom.

For cleaning, how much of an impact cleaning the mirrors would actually have on the light gathering? At what intervals do people normally clean them? I was considering cleaning the mirror but it looks somewhat clean, maybe a small amount of dust on it.

Edited by snakehelah, 26 March 2025 - 10:55 AM.

[SeattleScott]

Interesting, might have sort of locked in primary collimation, so only secondary needs to be adjusted. Could be convenient, but if the tube takes a bit of a blow and gets a small dent, you might not be able to align mirrors. That’s one of the the beauties of a Newt. They can suffer a blow, even get a significant dent, and you can fix the view by realigning the mirror. Try doing that with a refractor.

I wouldn’t clean the mirror for a small amount of dust. Cleaning intervals will vary widely based on how much a scope is used and how dusty (or pollenly) the climate is. I even heard of a bird flying over and pooping on a mirror. How rude! Basically, once you feel like there is enough dust and stuff that it is starting to impact the reflectivity and how sharp your reflection looks in the mirror, clean it.

The BHZ scores pretty well for edge correction. Based on test scores, I think most people would be happy with the edge correction down to F5. Lower than F5 and opinions might be mixed. So if you got a 12” F4.5, you might feel like the BHZ could use an upgrade. But I think most like it well enough down to F5.

In terms of future proof, I have heard it might not have quite enough ER for glasses at all focal length settings. So this could be a small issue depending on what focal lengths you benefit from glasses. But mostly it is more the narrow AFOV and lacking a little sharpness compared to premium fixed eyepieces. Personally I feel like the BHZ is about 90% as sharp as premium glass. Is 90% good enough, or will you someday want to upgrade to get that last 10%? And the AFOV gets narrow at the longer focal lengths. The irony of zooms is that their selling point is the ability to optimize magnification. But for extended objects, they can make it impossible to achieve optimal magnification. A 10 Ethos goes just as wide as the BHZ at the 24mm setting. So for a target that fits nicely in a 10 Ethos, you would have to observe the same target at half the magnification with the BHZ. A number of people think of the BHZ as an 8-12mm zoom and use wider fixed eyepieces above 12mm because of the narrow AFOV of the BHZ above 12mm. So if you decide you want those wide views at longer focal lengths, and want that last 10% contrast, and decide it is worth more money and eyepiece swapping to achieve these things, the BHZ could get demoted to public outreach.

[snakehelah]

Interesting, might have sort of locked in primary collimation, so only secondary needs to be adjusted. Could be convenient, but if the tube takes a bit of a blow and gets a small dent, you might not be able to align mirrors. That’s one of the the beauties of a Newt. They can suffer a blow, even get a significant dent, and you can fix the view by realigning the mirror. Try doing that with a refractor.

I wouldn’t clean the mirror for a small amount of dust. Cleaning intervals will vary widely based on how much a scope is used and how dusty (or pollenly) the climate is. I even heard of a bird flying over and pooping on a mirror. How rude! Basically, once you feel like there is enough dust and stuff that it is starting to impact the reflectivity and how sharp your reflection looks in the mirror, clean it.

The BHZ scores pretty well for edge correction. Based on test scores, I think most people would be happy with the edge correction down to F5. Lower than F5 and opinions might be mixed. So if you got a 12” F4.5, you might feel like the BHZ could use an upgrade. But I think most like it well enough down to F5.

In terms of future proof, I have heard it might not have quite enough ER for glasses at all focal length settings. So this could be a small issue depending on what focal lengths you benefit from glasses. But mostly it is more the narrow AFOV and lacking a little sharpness compared to premium fixed eyepieces. Personally I feel like the BHZ is about 90% as sharp as premium glass. Is 90% good enough, or will you someday want to upgrade to get that last 10%? And the AFOV gets narrow at the longer focal lengths. The irony of zooms is that their selling point is the ability to optimize magnification. But for extended objects, they can make it impossible to achieve optimal magnification. A 10 Ethos goes just as wide as the BHZ at the 24mm setting. So for a target that fits nicely in a 10 Ethos, you would have to observe the same target at half the magnification with the BHZ. A number of people think of the BHZ as an 8-12mm zoom and use wider fixed eyepieces above 12mm because of the narrow AFOV of the BHZ above 12mm. So if you decide you want those wide views at longer focal lengths, and want that last 10% contrast, and decide it is worth more money and eyepiece swapping to achieve these things, the BHZ could get demoted to public outreach.

You're right. I believe the modification he made was locking the primary mirror in place. From tutorials I do understand how one would adjust the primary, no idea about the secondary.

One more reason I wanted to clean it was to better inspect the state of the mirror, I can't quite see it from the top of the tube. I mean it reflects nicely, but I can definitely see it's not pristine fresh new. When I was buying it I did my best to inspect for any scratches but it seems its not easy to tell at the top of the tube, without actually taking it out regarding the micro-side of things.

Either way, from what I saw even 12" like the GSO has f/5 so the tecnosky 30mm and baader zoom should be good if I ever upgrade there.

The 16" is f4.5 but the size of that thing would probably be too big of an issue to consider that aperture upgrade. I mean, not only does it double in price going from 12" to 16" but weight as well, seems bonkers.

Really I seem to be covered for a quite a few years. I'm no expert but I've no doubt good conditions and object alignment is something that is more of a rare occasion in the astronomy world depending on what you wanna look at. Before I got the scope it was all clear skies and suddenly it's cloudy for weeks!!!

Edited by snakehelah, 26 March 2025 - 01:40 PM.

[SeattleScott]

Mass produced 12” Dobs are typically F5. There are expensive custom 12” Dobs that can be less than F5, whatever you want really. But if you are ordering one of those, you probably aren’t concerned about the price of eyepieces.

[Spile]

Thanks. For the Baader zoom + barlow as I understand for my skywatcher classic 200p 8" dob, you explain that an extension 35mm is needed for proper focus. Would this be what I would need in addition to the baader zoom bundle? 

https://www.tecnosky...rante-35mm.html

First of all I would recommend using the supplied 2” adapter and fitting the 1.25” collar. As I explain in my blog this is necessary to allow the Barlow to rotate so it makes sense to leave them fitted all the time especially when you need to swap it out for a true 2” eyepiece. You don’t need to stack extenders as I do but when using the Barlow you will need to retract the EP a couple of mm. It’s not a big deal.

Elsewhere in this thread collimation has been mentioned. Please take a look at my guide which hopefully you will find useful.

I think you have made sensible, cost effective choices that will provide hours of visual pleasure.