Eyepiece Selection for an f/8 Scope

[astro_al]

Hi Everyone,

Up until recently the planets have been my main target for visual observing and because of this I have never really worried much about a large field of view as I use a driven mount. Lately I have started to appreciate viewing objects outside of the solar system through my 18mm ortho which I initially bought for viewing the full lunar disc. I have found that I really enjoy looking at objects in context and this has got me thinking about purchasing an eyepiece with a larger AFOV.

The 19mm Panoptic has been at the top of my list for a while but I am now thinking about the 16mm Nagler and maybe the 24mm Panoptic at a later date. My aim is to own only a few eyepieces (honest) and I already own the 3-6mm Nagler Zoom which takes care of my high magnification requirements. I have had no problem with using eyepieces with tight eye relief (10mm and less but only with up to a 52 degree AFOV) and I don't really want to step up to the 2" eyepiece format. I observe from a fairly light polluted site. As I have already mentioned most of my visual experience relates to high magnification observing so I am new to the whole wide field concept. My telescope is a 100m f/8 refractor.

Any advice would be gratefully received, especially from those of you with a similar setup.

Thanks

AL

[astro_al]

I went for the Nagler 16mm T5 in the end. This gives me 51x, a 1.6 degree TFOV and a 2mm exit pupil. Hopefully I will get to test it out soon.

[dweller25]

I would have suggested a 14mm Pentax XW but the Nagler is also a very fine eyepiece.

You have some excellent equipment that will last a lifetime.

Clear skies to you.

[astro_al]

Thank you. I did consider the 14mm Pentax XW but was put off by reports of noticeable field curvature (plus it was more expensive). If the eye relief of the Nagler turns out to be an issue for me then the Pentax may be the way to go. Shame I couldn't try both before buying.

[great_bear]

I think you frightened everyone away with your Takahashi! All I was going to say, is that with light pollution against you, avoiding 2" is a good idea.

For what it's worth, I think your choice of a 16mm Nagler is an excellent choice for your scope and your conditions, for what you have in mind.

[John]

If you wanted to save some £'s you could opt for a 16mm UWAN instead. I used to own one and "upgraded" to a 16mm Type 5 Nagler - there was little, if any, improvement in performance noticable to me and the eye relief of the Nagler was tighter (10mm v's 12mm). In an F/8 scope (I was using them in an F/6) I doubt there would be any difference at all in performance and the UWAN is £100 less expensive than the Nagler - you could put that towards the 24mm Panoptic

[astro_al]

Thanks John. I almost bought the UWAN but changed my mind at the last minute. With the current Telescope House Bank Holiday discount it wasn't quite as much as £100 difference but the UWAN would still have represented a decent saving. However I have always rated the Televue equipment I have owned in the past so I guess in the end I went with what I knew. Plus the Naglers appear to hold their value quite well.

AL

[John]

Thanks John. I almost bought the UWAN but changed my mind at the last minute. With the current Telescope House Bank Holiday discount it wasn't quite as much as £100 difference but the UWAN would still have represented a decent saving. However I have always rated the Televue equipment I have owned in the past so I guess in the end I went with what I knew. Plus the Naglers appear to hold their value quite well.

AL

I'm a huge Tele Vue fan (my EP's are Nagler T5,s and T6's and the 13mm and 8mm Ethoi) but I have to confess that the UWAN's and the Skywatcher Nirvana's get to 95% or more of Nagler performance and are really nicely made. Their re-sale value is not as good as the TV's though which I guess makes them even better buys used !.

The only area that the Naglers pull noticably ahead is in really fast scopes (eg: F/4.5 or faster).

Can't fault the Nagler 16mm T5 though - it's a darn sharp eyepiece - just a pity that they could not squeeze a bit more eye relief out of it

Watch out for the lowest field lens element - it's very near the bottom of the eyepiece barrel and easy to accidently mark with a finger or when fitting a filter.

[astro_al]

Watch out for the lowest field lens element - it's very near the bottom of the eyepiece barrel and easy to accidently mark with a finger or when fitting a filter.

Thanks for the heads up John. I hadn't noticed just how close it is to the end of the barrel.