Diagonal or Prism

[CowsonConcrete]

Hi,

I've just sold my EQ5 and Skywatcher 130pds and am about to buy a Williams Optics Redcat 51.  The move is for a smaller kit and the fact that the Redcat can be used as a terrestrial lens as well 

Anyways, I kept some EPs and would like some advice as to whether I need a star diagonal or Prism.

The scope/ lens will mainly be used for astrophotography but  I would like to do some viewing as well. My current EPs are nothing special in terms of quality but will be sufficient for what I need (super plossi's etc).

So should I get the WO prism or a £65 Skywatcher diagonal or is there something else.......

 

Thank you

[johninderby]

The Redcat is f/4.9 and prisms work best with scopes over f/7 so you would be better off with a dielectric diagonal.

 

Edited April 13, 2021 by johninderby

[CowsonConcrete]

Thank you, I did not know that.

[johninderby]

One of these would go nicely with the Redcat.

https://www.altairastro.com/125in-lightwave-premium-dielectric-diagonal-red-765-p.asp

[tuckstar]

I have an older Altair dielectric 1.25 diagonal not doing anything. Yours for £30 + postage if you want it. 

[CowsonConcrete]

9 minutes ago, tuckstar said:

I have an older Altair dielectric 1.25 diagonal not doing anything. Yours for £30 + postage if you want it. 

I'll take it. I see you're in Derbyshire, not the Sheffield side are you?

[tuckstar]

6 minutes ago, CowsonConcrete said:

I'll take it. I see you're in Derbyshire, not the Sheffield side are you?

I'll pm you

[Oldfort]

I'm not sure it's possible to get visual focus with a Redcat using a regular diagonal - I certainly couldn't.  WO do make a diagonal specifically for this scope.