[Chaos-l] Another idea.....pls advise

[michelle s]

Well, I finally made a decision (it's returnable within 30 days for a full refund) and went with the Celestron NexStar 130. If it's a mistake I will know it after using it. I get the whole aperture idea (and I might be making a mistake) but really would prefer a lighter weight telescope and also one that helps us find out where things are. I might be exchanging it for the xt8 later in the month, but at least I will be paying for return shipping on an 18 lb. item, as opposed to a 40+ lb. scope. 
You have all been helpful and I will be referring to these emails if and when I decide I don't like the Celestron. Free shipping, and it should be here on Thursday! So....by Sunday, hopefully we will have spotted something :)
Michelle


________________________________
From: Jim Pressley <binovision at gmail.com>
To: michelle s <shellytex1 at yahoo.com>
Cc: chaos-l at rtpnet.org
Sent: Monday, May 23, 2011 10:46 PM
Subject: Re: [Chaos-l] Another idea.....pls advise


Michelle,
The Celestron Nexstar 130 telescope's mirror is ~5" in diameter, with a focal length of 650 mm.   The 8" Dobsonians discussed earlier are about 1200 mm in focal length.    There will be performance differences here...almost an apples and oranges situation...that might better be discussed and explained in person at a club meeting.    
 
For example, although the step between a 5" and an 8" mirror may seem relatively small, their respective surface areas are 20 square inches (6") and 50 square inches (8").   That equals an almost 2.5X increase in light grasp.   In most cases, brighter is better.
 
It may come down to deciding which is more desirable...a 2.5X brighter image or computer control to find objects.   Certainly, computer controlled telescopes have merit...many of us use them...but you can enjoy learning the sky by star hopping with a finder and star charts.  In fact, this is a great way to learn the sky and can be a very satisfying pastime.
 
It might be best to simply hold off purchasing anything until you and you son can attend an observing session and see first hand the differences in various types of telescopes.    It's not easy to make an informed decision without understanding the many options offered with today's modern telescopes.
 
As several others have said, I too would go with aperture over features, but everyone has to find out what they want for themselves.
 
Jim
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