[Chaos-l] Burgess Finders?

[Michael Hrivnak]

Any experience or opinions on the Burgess 8x50 RACI finder?

http://www.burgessoptical.com/Accessories/Finder8x50.html

I realized that I don't use my Orion 6x30 finder very much, and I think it's 
because I just can't see very well with it.  I can barely make out a few 
brighter objects like M13, but it's a real stretch.  My hope is that since an 
8x50 should gather 2.78 times as much light, I'll have a much easier time 
identifying things in the finder, and thus it will be a more valuable tool.  
Does your experience support that theory?  Do you prefer a different size 
than 8x50?

If I have my math right, I think objects in a perfect 8x50 should be about 
1.56x brighter than in a perfect 6x30.  If only to help my own understanding, 
I should quickly run through the math.  The saying is that doubling 
magnification reduces brightness by a factor of 4, right?  I think that can 
be formulated to say that the factor by which brightness will change from one 
magnification to the next is equal to (old magnification / new magnification) 
^2.  In this case, we have (6 / 8)^2 = .5625.  Correct me if I'm abusing the 
laws of physics here.

Then the difference in aperture area = 25^2 / 15^2 = 2.78.

We have two factors by which brightness will change, so we multiply them!  
2.78 * .5625 = 1.5625.

Object should be bigger, brighter, and thus much easier to locate.  What do 
you think?

Thanks,
Michael
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