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Old 02-10-2006, 01:09 PM
astropat
Astropat

astropat is offline
 
Join Date: Oct 2006
Location: Brisbane
Posts: 5
Questions: Buying Telescope

Hi All,

I’m a beginner in telescope (although I’m a phd student in physics and once participated in astronomical research). I’m thinking of getting a portable telescope (approx 10kg or less including mount weight, and preferably short tube), so that I can hand carry it around to nearby darker locations. I have a budget of around AUS$700 or less. The reason for buying a telescope is that I’ve been doing naked eye astronomy for years and really want to learn more about operating telescopes and astronomy and seeing more. I read quite a few books and I know that I should get one with a big aperture and sturdy mount, and also one that I can use often (in this case, a very portable one). Now my first question is:

Any recommendations on what telescope I should get?

After searching on the web, I found that the biggest aperture telescopes with weight less than or about 10kg are 114mm diameter + EQ1 mount short tube reflecting telescopes. There are 3 telescopes that I have been thinking of with different f/ratios:

Orion StarBlast 4.5 EQ Reflector (f/ratio=4.0)

http://www.telescope.com/shopping/pr...dd=yes#tabLink

Tasco Galaxsee 46-114375 (f/ratio=5)

http://www.tasco.com.au/Default.aspx...tID=94&cid=209

Celestron FirstScope 114 EQ Compact (f/ratio=8.77)

http://www.celestron.com/c2/product....ID=6&ProdID=19

I know that smaller f/ratio telescopes are better for viewing deep sky objects, but I also heard that it is near impossible to collimate a f/ratio <= 5 telescope. So my second and last questions are:

Is it really near impossible to collimate a f/ratio <= 5 reflecting telescope? And what tools (if exist) do I need to overcome the difficulties?

If it is not too difficult to collimate a f/ratio <= 5 telescope, then which of the 3 telescopes above should I get?


Thanks,
Patrick
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