32 replies to this topic

[areyoukiddingme]

With a C8 Edgehd, the scope presents a flat field with low aberrations, so that any edge issues are likely attributable to the eyepiece.

 

I had the 11", and it was kind of like running my Televue 101, with a flat field and little by way of aberrations of a standard SCT.

 

It would be interesting, for example, to compare an 85 degree Masuyama in an F10 refractor to that in Edgehd. I suspect the F10 in the refractor would be less revealing of aberrations than the Edgehd. Maybe someone has tried . . . 

[SeattleScott]

I doubt there would be much difference. My F9.5 refractor is very forgiving with eyepieces. The point of the Edge is to clean up the inherent coma/FC in the standard SCT design. Basically the point is to make a SCT with a field as flat as a F10 refractor. The refractor won’t have coma/FC to deal with at F10. At least not assuming 1000+mm focal length.

[Scott99]

Thus my answer to your question is that in my opinion, super wide-field eyepieces in general are unsuitable for use at f/10, because of the tradeoffs discussed. There may be exceptions for eyepieces that I am not familiar with. I suspect my opinion is uncommon on CloudyNights.

 

Clear sky ...

This philosophy may be "uncommon" but it's not unheard-of, we do have a significant "minimum glass" contingent here and I'm a card-carrying member

 

To that end I suggest the Masuyama wide fields (85 degree).  With only 5 lens elements they split the difference between traditional orthos & plossls and more complex widefields.  i.e. they give you the contrast & sharpness of the simple ep's with a huge FOV.      At longer f-ratios like f/10 the breakdown at the edges is minimal, I think someone reported it was near perfect at f/12....f/10 will be good. 

 

The optical and build quality is exquisite and they're much lighter than the big hand-grenade eyepieces.  You won't need all that extra glass at f/10.

Edited by Scott99, 19 March 2025 - 01:50 PM.

[areyoukiddingme]

Edgehd works great with 100 degree eyepieces. You maximize the field, and because the scope and eyepieces (e.g., ethos) has good correction, you get a very well corrected field. 

 

Given eyepieces like the Masuyama have astigmatic edges, I would think that you'll see plenty of that in the edgehd.

 

In a regular SCT, I would also imagine a rather hairy experience, but don't have a Masuyama to try out. 

[Procyon]

Masuyama wide fields (85 degree).  f/10 will be good. 

 

The optical and build quality is exquisite and they're much lighter than the big hand-grenade eyepieces.  I think someone reported it was near perfect at f/12....f/10 will be good. You won't need all that extra glass at f/10.

Unfortunately the view through a 32mm Masuyama 85 was blurry looking halfway through it's wide field in my F/10 C11. Having said that, it provided one of the best views ever on many nebulae and is a pleasure to hold, kind of feels like a 22mm Nagler T4 in build and size. 

 

One of the best center fields I've ever seen in an eyepiece followed by one of the worst outer fields. I still wouldn't mind owning one again though. The center is that good. It should work better at F/12 like Scott99 said.

 

100 degree eyepieces work great with regular and edgehd SCT's. Hard to go back to sub 70-80º when you try one that actually fits your face lol. I've been hooked on hyperwide fields of 90º+ ever since I found the right ones for my eyes/cheeks.

 

It's good to have some sharp Orthos, etc or Delos/Pentax for planetary viewing (or other uses), but for deep space views, especially large open clusters, nothing matches the big field eyepieces I find, especially in a larger SCT where you inherit small views off the bat. I get a very sharp, clear and almost a full degree with a 25mm 100, .7 with a 20mm 100 and .62 with a 17mm 100. More if I add the focal reducer. Also, an eyepiece that weights 1-2lbs is usually not a big deal for an SCT.

 

Just my 2 cents, clear skies!

Edited by Procyon, 19 March 2025 - 03:34 PM.

[C. Evangelista]

In the WA-class (+/- 70° FOV), the Nikons NAV SW 5, 7, 10, 14, (not 17.5) are the best EPs, in my experience.

Slightly better than Delos´, DeLites, XWs, LVWs, Mophei etc, in terms of sharpness, contrast, transmission and color fidelity.

However, this experience comes from using and testing the EPs in triplet apos of F6, F7 F8 and F9, but this will hold true of course in SCTs of F10.

The very best one of the series is the 14 because it has "only" 7 lenses, the 17.5 is not good...

In your F10 SCT, the 10 and 14 will work very well.

[Scott99]

Unfortunately the view through a 32mm Masuyama 85 was blurry looking halfway through it's wide field in my F/10 C11. Having said that, it provided one of the best views ever on many nebulae and is a pleasure to hold, kind of feels like a 22mm Nagler T4 in build and size. 

doesn't sound right - I see more like 70-80% of the FOV is sharp at f/9....FWIW
 

[152ED]

Interesting thread; I was just thinking about this.  I have two eyepiece sets - one for the f/5 newtonians and another set for the f/9 refractor and f/10 SCT.

The first set has the naglers, meade uwa's, mwa's etc.  The second set is nothing but old UO konigs, widescans, and a couple meade swa's.

For some reason I prefer the simpler (and much lighter) old school eyepieces in the slow scopes.  I notice a little more brightness and snap at times compared to the heavy and complex eyepieces.  Of course they are too fuzzy at the edge to be used in the f/5 scopes!