StellaLyra 8" Dobsonian- best BST starguider eyepieces.

[Don Pensack]

My experience with the UFFs is:

--the 30mm is well corrected down to f/4.5 (maybe faster, but 30mm on faster scopes may not be advisable).  "Best of Breed" in this series.

Half the weight of other 30-31mm 2" eyepieces, and a lot better corrected than the 31mm Hyperion.

--the 24mm is well corrected up to the edge but a little shy of the 30mm correction at the edge.  Glasses compatible.

More eye relief than any other maximum field 24mm (it has a 27.6mm field stop), with less rectilinear distortion than other 24mm max field eyepieces.

--the 18mm is as well corrected as the 24mm and also glasses compatible.  A small size for its field size.

--the 15mm is a little less corrected at the edge and not glasses compatible.  Nice in binoviewers.

--the 10.5mm (it's not really 10mm) is fairly well corrected, but feels more like most inexpensive 60° eyepieces.  Not glasses compatible.  Very light and a small size.

[Louis D]

1 hour ago, great_bear said:

Is a 24mm UFF likely to be better corrected at F5 than a 24mm SWA (Meade 5k)?

Here's what Ernest in Russia had to say (after Google Translate) when running the 24mm APM UFF through his testing:

Direct comparison in the focuser of a fast (1:5) 24 mm telescopeES68 and UFF showed that the quality of correction of field aberrations in UFF is better than in ES68. In fact, in the image that UFF builds, at 90% of the field of view there are only signs of small focus variations (higher-order curvature) - you can choose the focus at which the field of view looks very uniform and only at the very edge of the field diaphragm image quality drops sharply. But in ES68, visible manifestations of curvature and astigmatism start from about half of the field of view and gradually increase towards the edge of the field of view. Both eyepieces are excellently corrected in terms of chromatism. Straight line distortion is excellently corrected in UFF, angular distortion is better corrected in ES68. UFF is more massive and overall.
24 mm Panoptic lighter and more compact, in terms of monochromatic aberrations the field is corrected better than in UFF. But UFF and ES68 build an image more free from chromatism.
All three eyepieces have virtually the same effective field stop (TFOV) diameter.
Both Panoptic and ES68 lose a lot to this UFF in terms of eye relief.

[noodlehat]

On 08/01/2023 at 18:35, Mr Spock said:

Don't rule out high powers just because some say you can't use it. When conditions allow I use my 12" at x380 with great success. 

For your Dob, I'd recommend the 12mm and 8mm plus x2 Barlow. That will give you x100, x150, x200 and x300 - a really nice spread.

For wide field I'd suggest the 30mm StellaLyra UF. That would give x40 and 1.75°. Just right for getting the Pleiades in 😜

Hi, to add onto this thread.. For those of us just starting out, i'm awaiting stock of the StellaLyra 12" Dob... we should basically aim for 2 or 3 good eye pieces as you outlined?  Using a 2x Barlow ( any recommendation for which one on the StellaLyra 12"?to give additional magnification options rather than buying the extra eye pieces? And this is a better route than going for say the Baader Hyperion Zoom?

Regarding the AFOV with the suggested Nivarnas, is there any reason one would not want the larger AFOV at particular magnification levels? Does that more depend on what your trying to view? 

Many thanks.

Edited March 6, 2023 by noodlehat

[Mr Spock]

35 minutes ago, noodlehat said:

Regarding the AFOV with the suggested Nivarnas, is there any reason one would not want the larger AFOV at particular magnification levels? Does that more depend on what your trying to view? 

With Dobs, if you don't have an EQ platform, then things move across the field of view fairly quickly. So the wider the fov of the eyepiece, the more time you have between nudges.

A good eyepiece requires a good Barlow. I'd recommend the TeleVue. The 13mm and 10mm Nirvanas give x117 and x152 in the 12". With the x2 you'll get x234 and x304, which is a nice high power spread. That would be my choice if I were limiting myself to two eyepieces and a Barlow. However...
...that 30mm UFF is a lovely low power eyepiece. It's really well corrected and the difference between that and the included StellaLyra 30mm is night and day. But maybe that could be an upgrade later. The SL would be ok for now.

While some people like zooms for their convenience, I prefer the better corrected optics and wider fields of single focal length eyepieces. Plus the Nirvanas are quite small. A quality Barlow doesn't detract from the image quality either.

[noodlehat]

9 hours ago, Mr Spock said:

While some people like zooms for their convenience, I prefer the better corrected optics and wider fields of single focal length eyepieces.

Many thanks, this was my conclusion also after some reading of various threads and getting a better understanding. The FOV seemed to shrink very low on some of the focal lengths on the zooms. Budget wise Id say its best to pay a little extra for the correct/ better quality view one time than want to upgrade a zoom in a yr or 2.

 

 

[Louis D]

Except at very high powers where the new Svbony 3-8mm zoom excels, I find myself jumping in 3x increments generally.  Thus, a 3x zoom like an 8-24mm works out to 1 to 2 useful focal lengths for me.  I tend to start at 40mm with a 2" eyepiece, then I jump up to a 12mm to 17mm eyepiece to get a closer look, if it comfortably fits in the field of view.  From there, I generally jump up to a 5mm to 7mm eyepiece if it is a small object or has some fine details I want to examine more closely.  Thus, most 3x zooms only cover the middle range and miss at both ends.  I'd need a 2", 8x zoom (5-40mm) with a 70 degree AFOV to be really useful for my style of observing.  If it was well corrected like XWs and Deloses with 18mm of usable eye relief, I'd easily pay $1000+ for one just for the convenience.  However, I've never heard of anyone seriously considering bringing such a zoom to market.