ES 82 24mm vs Stellaylyra 30mm superview

[theknopsy]

Hi all, I am deliberating purchasing the ES 82* 24mm eyepiece, however is there much point having this larger AFOV at 24mm as according to the astronomy FOV simulator each eyepiece would give a similar field of view as a result of the different magnifications. So I was wondering if it would be best to wait and get the 30mm ES 82*. Thanks for any advice!

[Ratlet]

Why are you wanting to get the 24mm?  You looking for a wider FOV, sharper image?

[Zermelo]

Hello, welcome to SGL.

One advantage of having the same true field of view at a higher magnification (i.e. the ES 24mm in your example) is that it reduces the effect of light pollution in the background sky, helping with the visibility of fainter, extended objects like galaxies.

Were you particularly wanting the 82 degrees? There are the various "ultraflat" clones at 24mm/65° and 30mm/70° - for example the Stellalyra versions, or those by APM and Altair. These are very well corrected, even in fast scopes. The Superviews are cheaper, but do show aberrations towards the edges. I wrote up a quick comparison of the Altair UFF and Superview 30mm here.

The 24mm UFFs are in 1.25" format, hence the limitation on the field compared with the 2" EPs.

Some more discussions:

https://stargazerslounge.com/topic/400497-wide-field-eyepiece-for-fast-scopes-any-suggestions/#comment-4295371

https://stargazerslounge.com/topic/403780-celestron-ultima-edge-30mm-apm-uff-stellalyra-uf/

 

[theknopsy]

2 minutes ago, Ratlet said:

Why are you wanting to get the 24mm?  You looking for a wider FOV, sharper image?

Hi, yes both really the large FOV and a sharper image as others have said in other discussions. The 30mm does suffer a bit round the edges. 

[theknopsy]

12 minutes ago, Zermelo said:

Hello, welcome to SGL.

One advantage of having the same true field of view at a higher magnification (i.e. the ES 24mm in your example) is that it reduces the effect of light pollution in the background sky, helping with the visibility of fainter, extended objects like galaxies.

Were you particularly wanting the 82 degrees? There are the various "ultraflat" clones at 24mm/65° and 30mm/70° - for example the Stellalyra versions, or those by APM and Altair. These are very well corrected, even in fast scopes. The Superviews are cheaper, but do show aberrations towards the edges. I wrote up a quick comparison of the Altair UFF and Superview 30mm here.

The 24mm UFFs are in 1.25" format, hence the limitation on the field compared with the 2" EPs.

Some more discussions:

https://stargazerslounge.com/topic/400497-wide-field-eyepiece-for-fast-scopes-any-suggestions/#comment-4295371

https://stargazerslounge.com/topic/403780-celestron-ultima-edge-30mm-apm-uff-stellalyra-uf/

 

Hi @Zermelo thanks for that-I didn’t know that about reducing the background light so good to keep in mind, especially when not in lower Bortle skies! Thanks also for the links you posted. Really useful reading! Also yes I was ideally looking for an 82° EP in a 2 inch format.

Edited March 28, 2023 by theknopsy
Extra information to add.

[Louis D]

Be conscious of the weight of 2" 82 degree eyepieces.  The 30mm ES-82 and 31mm Nagler T5 are both quite heavy in particular.

[bosun21]

1 hour ago, theknopsy said:

So I was wondering if it would be best to wait and get the 30mm ES 82*.

The ES 30mm 82 degrees suffers from aberrations in the outer part of the field. The APM(Stella Lyra) 30mm UFF is a better corrected eyepiece albeit 70 degrees. They are also much cheaper and better value for money IMO. Good luck with whichever you choose.

[theknopsy]

6 minutes ago, bosun21 said:

The ES 30mm 82 degrees suffers from aberrations in the outer part of the field. The APM(Stella Lyra) 30mm UFF is a better corrected eyepiece albeit 70 degrees. They are also much cheaper and better value for money IMO. Good luck with whichever you choose.

Hi Bosun, I am currently looking at a used ES 82 23mm which is at a similar price to the 30mm UFF on FLO. Which actually has quite an informative review on it- perhaps a contender! 

[bosun21]

8 minutes ago, theknopsy said:

Hi Bosun, I am currently looking at a used ES 82 23mm which is at a similar price to the 30mm UFF on FLO. Which actually has quite an informative review on it- perhaps a contender! 

What is the focal length of your scope(s) as with longer focal lengths it becomes somewhat diminishing returns for eyepieces that are too close together in focal length. For example it makes more sense to say have an 18mm , skip the 24mm and go straight to a 30mm. This is applicable for longer focal length scopes. What other focal lengths do you have at or below 24mm? Is the 23mm a Celestron Luminos?

Edited March 28, 2023 by bosun21
Typo

[theknopsy]

Just now, bosun21 said:

What is the focal length of your scope(s) as with longer focal lengths it becomes somewhat diminishing returns for eyepieces that are too close together in focal length. For example it makes more sense to say have an 18mm , skip the 24mm and go straight to a 30mm. This is applicable for longer focal length scopes. What other focal lengths do you have at or below 24mm?

I have an 8 inch 1200mm dob (f/6). I have a  68° 30mm as my largest focal length and  then 16mm, 12mm, 8mm and 7mm (16mm & 7mm are Nirvana 82° EPs and 12mm & 8mm are BST’s).

[bosun21]

1 minute ago, theknopsy said:

I have an 8 inch 1200mm dob (f/6). I have a  68° 30mm as my largest focal length and  then 16mm, 12mm, 8mm and 7mm (16mm & 7mm are Nirvana 82° EPs and 12mm & 8mm are BST’s).

You already have a nice selection and range of eyepieces for magnification. I would personally be happy with this unless you definitely want a wider field at 30mm. Take into consideration that the wider 82 degrees 30mm will provide this but not without some aberrations in the additional FOV gained.

[theknopsy]

1 minute ago, bosun21 said:

You already have a nice selection and range of eyepieces for magnification. I would personally be happy with this unless you definitely want a wider field at 30mm. Take into consideration that the wider 82 degrees 30mm will provide this but not without some aberrations in the additional FOV gained.

Thanks, yes that is my deliberation, perhaps the 24mm would be slightly redundant in my current setup. 

[bosun21]

If your existing 30mm is the SuperView that came with your scope then you would immediately see the improvement by buying a 30mm UFF. If you have bad light pollution then a 24mm would provide a darker background sky at a similar magnification. Think things over as there’s no rush and you can consider all your options. Good luck with whichever you decide to choose.

[Shimrod]

9 hours ago, theknopsy said:

Thanks, yes that is my deliberation, perhaps the 24mm would be slightly redundant in my current setup. 

I've no experience of this eyepiece, but if you are after a wider field of view, the Celestron Luminos 31mm (82 degree) eyepiece is on sale at Amazon until this evening at £193 - about £80 off normal price. It's a large and heavy eyepiece though (over 1kg).

[Dave scutt]

The 30mm ES 82° is a beast and is heavy at 1 kg.

I had to use a coma corrector at f 4.9 as it wasn't sharp to the edge.

But when I had the 30mm and the 24mm the 24mm stayed in the box and I used the 30mm alot more

[Don Pensack]

True field is determined by the internal field stop diameter.

The eyepieces mentioned have field widths of:

30mm 70° UltraFlat Field--36.3mm

28mm 82° (Nirvana/Long Perng/etc.)--40.8mm

30mm ES 82°--42.4mm

TeleVue 31mm Nagler--42.0mm

Celestron Luminos 31mm--42mm?

24mm ES 82°--33.5mm

24mm 65° UltraFaltField--27.6mm

Advantage to the 28-31mm range for true field of view.

Advantage to the 24mm for darker background sky, with a larger true field at 2" than in 1.25"

To calculate the true field for each, use this formula:

True field = (field stop diameter / telescope focal length) x 57.296

 

I'll throw in one eyepiece to the mix to think about:

20mm 100° XWA eyepiece--34.8mm  That is more true field than the 24mm 82°