[AZ-Observing] Re: Aperture comparison

Nice chart, Mike.  And I spose you are forgiven!  Go and err some more.  ;^)



Richard Harshaw
Cave Creek, AZ


-----Original Message-----
From: az-observing-bounce@xxxxxxxxxxxxx
[mailto:az-observing-bounce@xxxxxxxxxxxxx] On Behalf Of Michael Collins
Sent: Saturday, April 26, 2008 3:28 PM
To: az-observing@xxxxxxxxxxxxx
Subject: [AZ-Observing] Aperture comparison

   Probably the second worst thing you can do in email is copy a mailing 
list when you intended a message for a single recipient.  You'd think 
I'd know how to use email after 22 years...

   In an effort to perhaps add more signal than noise, I've put a chart 
on my webspace which might come in handy if you're thinking of buying a 
new telescope or have ever wondered just how much better life would be 
if you could afford that 25" Obsession.

<http://members.cox.net/f7j9jwirjsljejic/aperture_comparison.pdf>

   The chart shows the difference in limiting magnitude (all other 
factors being equal) among a variety of common apertures.  Of course, 
all other things are rarely equal, but the numbers are good to a first 
approximation in most cases, and should be pretty close when comparing 
similar telescope designs.

   What's clear is that it's pretty easy to pick up a couple of 
magnitudes when you start with binoculars or a small refractor, going 
from, say, 4" to 10".  Getting the next two is much more difficult, and 
a three magnitude increase over a 10" scope puts you (literally) off the 
chart.

                                -- Mike Collins --

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