Which 2" 38mm Eyepiece for f5 ?

[gfletcher]

Hi Guys

I am hoping to acquire a secondhand 2" 38mm eyepiece to use in my 80ED and my 250px.

Which 38mm eyepieces would be more suited to the f5 newt?

Graham

[Stephen]

That's near on an 8mm exit pupil isn't it? Hope you have young eyes!

[gfletcher]

mmmmm good point.

Maybe i should be content with my Panaview 32mm ?

[John]

I'd agree that 30mm - 32mm would be as long a focal length as it's worth using in an F/5-ish (the 250PX is F/4.7 I think) scope.

From my moderately light polluted back garden I find 20mm gives noticeably darker background skies so I don't often use my 31mm with my 10" F/4.8 newotnian.

[RikM]

My favourite widefield eyepiece for my 10" f/4.7 is a 20mm as well.

[swamp thing]

^^^^^Same as. My 20mm 82deg eyepiece is my default one in my 10" f/4.5 Dob. It's in there so much I think it's taken root.

[Moonshane]

Almost the same with me too. my 16" is f4 and focal length of 1840mm (with the paracorr) . I prefer my 26mm Nagler with that scope (70x). just under 6mm exit pupil if assuming f4.5 with the paracorr.

[Andrew*]

I'm going to go against the grain and suggest you try it if you can. If you have a site reasonably free of local light pollution (e.g. Streetlight shining on your observing spot) you may be fine with a 38mm. If you get a dark cental patch, the exit pupil is to big. If not, you're laughing, and will enjoy the very low power views. It sounds like you want something lower than the 32 you already have..

[Mark at Beaufort]

I have the same scope and to be honest I rarely use my 26mm Nagler preferring the 20mm Nagler.

I have seriously considered selling both Naglers and buying the 20mm Explore Scientific 100 degree EP.

Mark

[cs1cjc]

I have a 38mm SWA which is unlabelled but was sold as an Adler Optik model. It works well as a wide angle finder eyepiece and my first view of M81 and M82 through it was a real *wow* moment. The dark shadow of the scope secondary fades once my eyes are fully dark accommodated, but the focal field is very curved and at my age I cannot hold the edge and centre in focus at the same time. I have to focus on an object well offf centre and the edge is still blurred. I use it with an Altair Astro (aka Astro-Tech, GSO) coma corrector so coma is not a problem and my scopes are effectively 10% longer at about f/5.

However I use my 24mm ES68 more. I would like a better long focal length eyepiece but it is still not at the top of my buying list. If I were to get one, it would probably be a Baader Hyperion Aspheric 36mm.