Low power ep’s

[tripleped]

Looking for recommendations for wide fov ep’s for DSO viewing. I use a 25mm televue plossl which is great but looking to widen the fov   Looking at mid range price point so probably not a TV or ES. Suggestions without breaking the bank? Prefer a 1.25mm 

[John]

What scope will you be using the eyepiece in ?

 

[Louis D]

Do you mean wide true field of view or wide apparent field of view?  In the 1.25" size, a 32mm Plossl will be only moderately wider than  the 25mm.

[tripleped]

10” DOB. f4.7 Skywatcher 

have to confess some ignorance on the true vs apparent fov question.  I should know the difference but I don’t. Any help appreciated! Guess I’m just looking for a little bit more of that “open space” view.  Would be nice for instance to get entire Hyades and Pleades in one fov or close to it. 

[wulfrun]

49 minutes ago, tripleped said:

10” DOB. f4.7 Skywatcher 

have to confess some ignorance on the true vs apparent fov question.  I should know the difference but I don’t. Any help appreciated! Guess I’m just looking for a little bit more of that “open space” view.  Would be nice for instance to get entire Hyades and Pleades in one fov or close to it. 

Apparent FOV is the field of view the eyepiece itself has. True FOV is the field of view the scope has with that eyepiece in it, i.e. how much sky the setup can see. True FOV = apparent FOV/magnification. Magnification=scope FL/eyepiece FL. So your scope is 1200mm FL and your eyepiece is 25mm. Mag therefore is 1200/25=48. Assuming a 50-degree AFOV for your plossl, you get 50/48 for TFOV, a touch over one degree. Pleiades is roughly 2 degrees so I think you'll struggle to find a suitable, cheap 1.25" eyepiece to double your FOV.

Edited January 23, 2021 by wulfrun

[tripleped]

Good to know.  What if I’m willing to venture into a 2” ep ? Are there any good options there at a reasonable price point?

[wulfrun]

11 minutes ago, tripleped said:

Good to know.  What if I’m willing to venture into a 2” ep ? Are there any good options there at a reasonable price point?

To get 2 degrees something like the OVL PanaView 38mm (£85) would do it, on paper. I know precious little about 2" so I'll leave that to others to comment on. I don't know if that's a recommended route or not, so don't order yet!

https://www.firstlightoptics.com/ovl-eyepieces/panaview-2-eyepieces.html

Edited January 23, 2021 by wulfrun

[Pixies]

These are often recommended as a reasonable quality wide-field 2" that aren't too pricey:

https://www.firstlightoptics.com/ovl-eyepieces/aero-ed-swa-2-eyepieces.html

I have the 30mm - but don't get on with it due to my astigmatism. The 35mm is apparently the best in the range. Your scope is pretty fast, though. So it will be demanding of EPs.

[John]

33 minutes ago, Pixies said:

.... Your scope is pretty fast, though. So it will be demanding of EPs.

That's the challenge. You might actually be best to stick with the 25mm Tele Vue plossl as your low power for now. They are well corrected eyepieces and the exit pupil generated (eyepiece focal length divided by focal ratio of scope) is 5.3mm which is useful.

You can get eyepieces that show more sky but to get such eyepieces that show well corrected wide fields in an F/4.7 scope, has quite a price tag associated with it.

 

[Ally8446]

Would this be suitable.....? 

http://apm-telescopes-englisch.shopgate.com/item/333631373637

I have one and it is simply magnificent. 

[Don Pensack]

On 23/01/2021 at 14:10, Ally8446 said:

Would this be suitable.....? 

http://apm-telescopes-englisch.shopgate.com/item/333631373637

I have one and it is simply magnificent. 

In my opinion, that eyepiece is superb in every way at f/5.

It has become my dark sky low power eyepiece, and was stunning on the Veil Nebula with a good O-III filter.

[Ally8446]

11 hours ago, Don Pensack said:

In my opinion, that eyepiece is superb in every way at f/5.

It has become my dark sky low power eyepiece, and was stunning on the Veil Nebula with a good O-III filter.

My OOUK is F6.3 and the APM 30mm UFF is mind blowing in it. It really does feel like I've got my head in a glass bubble looking into the cosmos. They're not cheap but omg they're worth every penny. 

p.s. I caught the Veil in it last winter  😲😲 amazing

[scarp15]

Perhaps consider, look out for a used 24mm Panoptic if your preference is to remain with 1.25" barrel eyepieces. 68 degree apparent field, 15mm eye relief, trade in your 25mm plossl as part cost. 

[Second Time Around]

I've got a 28mm Maxvision in the for sale section.  This is the same as the 2 inch Explore Scientific 68 degree but in a bigger housing.  I'm selling it as it doesn't accept a Dioptrx unless it's de-cloaked.  Price is £65.

To be fair, I'll leave it to others to comment on its quality.  It's definitely not as good as the 30mm APM UFF, but then it's a lot less expensive.  If you can afford it I'd go for the APM - I'd have bought it myself if it took a Dioptrx.

[F15Rules]

57 minutes ago, Second Time Around said:

I've got a 28mm Maxvision in the for sale section.  This is the same as the 2 inch Explore Scientific 68 degree but in a bigger housing.  I'm selling it as it doesn't accept a Dioptrx unless it's de-cloaked.  Price is £65.

To be fair, I'll leave it to others to comment on its quality.  It's definitely not as good as the 30mm APM UFF, but then it's a lot less expensive.  If you can afford it I'd go for the APM - I'd have bought it myself if it took a Dioptrx.

Although the Maxvision and Explore Scientific ranges quoted are mostly optically the same, I believe the one exception to that is the 28mm size: in this case I understand the Maxvision version is significantly better than the ES version.

I owned the ES 24, 28 and 34mm versions and the 24mm and 34mm were very clearly better than the 28mm.. (the 24mm ES or Maxvision are 1.25" barrels and are very good optically).

The Maxvision 28mm referred to as being for sale above is a very good eyepiece at a very good price, IMO👍 .

I currently have the Aero 30mm which I'm happy with (but my scope is F8.1), it gives 68degrees in a 2" barrel.

Dave

Edited January 26, 2021 by F15Rules

[John]

I had the Maxvision 24mm 68 degrees 1.25 inch eyepiece for a while and I used it in my 12 inch F/5.3 dobsonian. It was a pretty good wide field eyepiece. Later I got an Explore Scientific 24mm 68 and found no noticeable difference to the optical performance. The build quality and finish of the ES was a step up but optically the performance was the same.

If you don't want to go to 2 inch eyepieces at this stage these 24mm 68 degree field eyepieces will show you as much sky as a 1.25 inch format eyepiece can show and a bit more than the 25mm Tele Vue plossl can manage:

 

[Ricochet]

I had a 24mm/68° as the lowest power/widest field eyepiece in my dob for a while and found that it wasn't quite wide enough for my liking. Unfortunately, this means buying an eyepiece that needs a 2" barrel and the additional glass will push the price up significantly compared to a similar quality eyepiece in a 1.25" barrel.

[Spile]

I paid £43 for a used 42mm Revelation which is a GSO rebrand with a AFOV 65°. Focal ratio of my telescope is 5.9 

 

[Louis D]

2 hours ago, Spile said:

I paid £43 for a used 42mm Revelation which is a GSO rebrand with a AFOV 65°. Focal ratio of my telescope is 5.9 

 

How well does it perform at f/5.9?  Have you had a chance to compare it to more premium ~40mm 2" eyepieces?

[michael.h.f.wilkinson]

Regarding the MaxVision 24 mm 68 degree EPs, they work well down to F/5, but I tried one in an F/4.2 scope and that showed a lot of astigmatism. At F/4.7 this might also be an issue.

[Don Pensack]

2 hours ago, michael.h.f.wilkinson said:

Regarding the MaxVision 24 mm 68 degree EPs, they work well down to F/5, but I tried one in an F/4.2 scope and that showed a lot of astigmatism. At F/4.7 this might also be an issue.

JOC's eyepieces all have induced astigmatism in the outer field at f/5.  I see it easily in my 12.5" f/5.75 (the coma corrected f/ratio).

The exceptions are the 92° 17 and 12mm