Astronomical Refractor

by admin on Saturday, April 11th, 2009 | No Comments

$Astronomical Refractor$
Question about telescopes?

I'm looking into buying a telescope.
Of course, budget is a concern,
so I'm wondering...

does anyone know what the minimum decent size is?
I see them ranging from 50mm x 450mm
to 1100mm x 102mm

This means nothing to me.

Also, I see there are Dobsonian, Newtonian, and Gallileo ones.
Assuming these are brands?

More important distinctions I think are:
Tri-centric
Refractor
Reflector
Astronomical (I know what that means)
Terrestrial (I know what that means, too and it's not ET!)
and Equatorial

Any ideas what these mean and why I would want them on my telescope?

Kind of in a rush,
as I'd like to purchase it before Thursday.
(Birthday present)

If I know what these things mean,
then I can maybe find one I want in a price range I can afford.
(the one that has them all is $1,399)

First of all, I think it's a mistake to buy someone something as personal as a telescope without consulting them first. Although it may spoil the surprise, I'd strongly advise including the recipient in the decision-making process. Some of the factors involved are age, amount of technical savvy, physical constraints, and many more. I'll try to give some specific answers:

Minimum decent size: 75mm for a refractor, 114mm for a reflector, but 100mm and 150mm respectively would be better.

Dobsonian is a type of mount, like a cannon. Newtonian is an optical design using mirrors. Galileo is a brand, not a very good one.

Tri-centric: never heard of it in 50 years in astronomy!
Refractor: optical design using a lens
Reflector: optical design using mirrors (same as Newtonian)
Astronomical vs. terrestrial: first good only for astronomy, second good only for birding, etc.
Equatorial: type of mount

This probably has left you more confused than ever, so let me tell you what I would buy: any one of these, depending on budget:

http://www.telescope.com/jump.jsp?itemType=CATEGORY&itemID=9

Finally, where to buy: don't buy from a discount/department/big box store! They don't know anything about telescopes and sell nothing but junk. Buy from a telescope store (look in the Yellow Pages) or online. If you ignore this advice, you're almost certain to get your loved one a piece of crap! Better to delay the gift by a few days, than waste your money.

But please, PLEASE, heed my initial advice of including the recipient in the decision-making process.

Amateur Astronomy for Beginners: Reflectors/Refractors