Eyepieces

[Adrianf]

Is there any advantage getting a 2" eyepiece compared to 1.25"?


Adrian

[Radar]

Hi Tim,

I've been told that 2" eyepieces are better for lower magnification work. And also 2" inch eyepieces can yield wider fields of view as opposed to 1.25 inch eyepieces.

Because the lens elements inside 2 inch eyepieces are larger, using the eyepiece is bigger, the eye cup always seems to be large which means you get better eye relief. You don't have to have your eyeball up against the glass to see things.

So in a nutshell, 2 inch eyepieces are better and of course, more expensive :biggrin:

Have you got something in mind?

Ray

[Mick]

IMHO I don't think there is any advantage ether way I use both. But the best eyepiece that I've used so far was 1.25", It was a Tele Vue Nagler 13mm VI.

[rmcpb]

2" eyepieces allow a wider field of view than the 1.25" lenses because they don't interfer with the light cone coming into the lense. This only becomes important at lower powers which is why Mick's 13mm Nagler can have a ultra wide FOV at 1.25" and explains why its usually the longer focal lengths that go to 2".

I have one 2" a 35mm Panoptic, all the rest are 1.25" even the 19mm Pan.

Cheers

[Mick]

I prefer the 68° FOV eyepieces over the ultra wide FOV's mostly, they seem to fit my eye better. Looks like you may have the same tastes Rob?

[Adrianf]

Would a 2" eyepiece be better for photographing planets compared to 1.25"?
I am trying to photograph saturn (if the clouds ever go away) afocally and have an opportunity to buy a 26mm and a 13mm 2" eyepiece at a good price.

Adrian

[Radar]

Would a 2" eyepiece be better for photographing planets compared to 1.25"?


My first guess would be yes, these 2 incheyepieces would be better for afocal photography, but then other things may come into play. I guess we have to compare what 1.25inch eyepeices they are competing against. Can you give us the make of these eyepeices?

Cheers

Ray

[Adrianf]

The ones I have been looking at are Guan Sheng SUPERVIEW 68° 2".
These ones
http://www.andrewscom.com.au/site-section-10.htm

Just click on the Guan Sheng link

Adrian

[Radar]

I don't have any experience with those particular eyepieces Adrian, but I think Shev has. I'll contact him and see what he says.

Ray

[AstroTasmania]

Hi Adrian,

I bought three of the $49 2" GS eyepieces and for the money, you cannot go wrong. GS products are very good value for money, buy one & try it. They are heavy of course being 2" and a lot of glass, so it you are using a Dobson mounted Newtonian reflector, you may need to compensate with a bit of extra weight at the mirror end.

Their Laser Collimator for $49 looks the same that sells for $120. It has the sloping 45 degree face, (I had to make one for mine originally so they took up on my user recommendation.

Note*
I have no shares nor any other pecuniary interest in GS products, but the people who I have advised ( based on my personal use experience) have not been disappointed. We have at least a dozen GS 8" Newtonian's on Dobson mounts now within the local general & astro community.

Clear skies...
Shevill

[Adrianf]

Thanks Shevill I think I will buy the 2" 26mm eyepiece first and see how I go. I also have a GSO 10" dobsonian I find the scope good but if I had thought it through before I bought it I would probably gone for a smaller more portable scope. Not that there is anything wrong with the 10" scope its just not very portable.
I have just fitted a camera adaptor and camera to the scope and I have to make a counter weight to compensate.


Adrian

[Tenacious Del]

thanks for the info shevill. i will keep these in mind.