Re: [APML]: DW-2 6x Finder for F2

["Philip Perkins" <philip@astrocruise.com>]

The Astro-Photography Mailing List
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>   I paid $300 for mine and believe it is worth every penny.  
> When using the F2 at prime focus, it is like looking through a 
> regular eyepiece.  You can see messier objects in the 35mm framing 
> area.  It makes focusing and framing a pleasure... well, almost.

Mike,

I very much agree with your views about the F2 / DW-2 combination. I was
amazed at how much faint detail becomes visible once the pentaprism is 
removed. Nebulosity in Messier objects becomes visible actually on the 
camera focus screen, many more faint stars are visible, and focusing / 
composing becomes so much easier. This is such an elegant solution too, 
because it provides right angle viewing and removes the light loss 
associated with the pentaprism in one go. 

The only problem is that the DW-2 is very hard to obtain.  While some have
made their own version from the 8x Peak Loupe, I decided to make one using
the 6x Linen Tester magnifier available from Edmund Scientific. This is a
very sharp 2-element magnifier with excellent eye relief and overall
performance which is remarkably close to the Nikon DW-2. Since it is 6x
(like the real DW-2), the entire frame may be comfortably viewed without
moving the eye around.  A photograph of my home-made DW-2 may be seen at:
http://www.astrocruise.com/guide.htm

I also have the real Nikon DW-2 (thanks to Jerry who found one for me) but I 
use it only as a backup. My home-made DW-2 works every bit as well and has 
the advantage that it is so light that it can be kept in place on the camera 
while the exposure is in progress. I also have a home-made 15x direct screen 
magnifier which I use only for focusing.

Regards
--Philip

Philip Perkins  --  philip@astrocruise.com
51 27'N 1 36'W  --  Wiltshire, UK
43 54'N 5 32'E  --  Luberon, France
Astrocruise     --  http://www.astrocruise.com