2" eyepieces

[Dupertron]

I have a 4.2inch refractor, f/660, focal ratio 6.47, that can take 2" eyepieces. Taking these specs into account is it worth purchasing 2". Generally how good will they be on my scope, will I get better views than normal 1.25" eyepieces?

[John]

Hi,

One of my scopes is a very similar specification to yours and I love iusing 2" eyepieces in it. The benefits are the wide field views that you get from the 2" format. For medium and hihger power viewing I use 1.25" eyepieces as there is nothing really to be gained from the 2" format in those focal lengths.

Obviously you need a 2" diagonal to take 2" eyepieces but these come with 1.25" adapters so you don't need separate diagonals for the different size eyepieces.

With your scope (as mine) being around F/6.5 you don't need really expensive 2" eyepieces to get nice views. Something like the Skywatcher 38mm Panaview would give you a lovely wide, low power view showing around 3.9 true degrees of sky - great for scanning star fields and the really large deep sky objects such as M31 and the Veil Nebula although a UHC filter will be needed to get the best out of that last one.

 

 

 

 

 

[DevonSkies]

If you want the wide field of view that a 2" eyepiece offers, then they are well worth it. 

[Guest]

Hi, I'm new too. I bought a 2inch eyepiece for my Skywatcher Dobsonian.  I knew that it would take 2 and 1.25 inch eyepieces and there was an adapter for the 1.25 inch. However the first time I tried the 2 inch I found that the focuser would not retract far enough to bring it into focus. This meant buying an extension tube. Perhaps you should check to see if you might need one too.  

Steve

 

[Dupertron]

Cheers guys, really helpful

[Alan64]

A 2" 70° 32-38mm will enable the refractor to act as its own finder, and for an improved opportunity in observing the galaxy in Andromeda and the Pleiades in their entireties...

http://www.firstlightoptics.com/skywatcher-eyepieces/skywatcher-panaview-2-eyepieces.html

I have the 32mm myself, and shown here with a 1.25" 50° 25mm...

From the size alone one might get an impression of its observational advantage.

 

This might sound a bit odd, but I missed out on purchasing a full set of Tani orthoscopics in the .965" barrel format, from a 4mm or 5mm all the way up to a 25mm even, and back in the early-to-mid 2000s when they were still available.  However, such would've made for an ideally portable and capable "grab 'n' go" set.  Spilt milk that was, is, and always will be.

[ronl]

The 32mm as shown  above is a very nice  eyepiece it has a twist  up  eyecup which  I like and  gives very nice views.

[Alan64]

I'm almost 100% certain that my 2" 32mm Astro-Tech "Titan" illustrated above is the same as the 2" 32mm PanaView, as they appear identical.  The eye-cup extends out by about 15mm, stops in any position, and for varying lengths of eye-relief; that is, the distance between the eye itself and the eye-lens of the ocular.

[Dupertron]

Cheers guys I've had some amazing feedback on this

[ronl]

Alan it is exactly the same, made by the same manufacturer, but under another name. 

[John]

31 minutes ago, aeajr said:

...You can get 70 degree 1.25s but not in long FL.   I have

a 38 mm and a 25 mm 70 degree  2 inch.o

You can get a 25mm eyepiece with a 70 degree apparent field of view in the 1.25" fitting - the Antares W70 25mm. It's not a particuarly well corrected eyepiece in scopes faster than around F/8 though.

I used to use a Widescan III eyepiece that provided a massive 84 degree apparent field at the 20mm focal length and was still in the 1.25" format. Similar limitations in faster scopes though.