Question about telescopes?

Question

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)

Answer 1

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.

Answer 2

For starters, let's just say 'Happy Birthday' ///
What do you want to look at? Planets, distant galaxies? Dim nebulas?
All?
You're going to want a scope that will actully get used, no matter what bells and whistles it may have.
As a rule, the larger the aperture, (the size of the lens or the main mirror) is what determines how deep you may peer.
Keep in mind, though, you don't want a first telescope SO big that you'll not want to lug it in and out from the house.
If you are primarily concerned with highly detailed images of the planets, a 5- or 6- inch refracting telescope may be the one for you. It's a pretty hefty scope, but it won't kill you to move it.
If you want to look at deep- sky objects, then a large aperture telescope is what you want. A scope in the range of 8" to 10" will show you some beautiful sights. A Dobsonian or Newtonian reflector would be ideal.
Consider, too, the cost of eyepieces. You'll need a few good ones. Start with a 40mm Plossl for wide- field views, a 20mm Plossl for mid- field, and maybe a 10mm or 8mm for high- magnification seeing.
It's good that you are asking questions about telescopes, but I would urge you to do research on them (before Thursday!) to decide what you really need.
Good Luck!!!

Answer 3

Galileo is a brand.
Dobsonian and Newtonian are types of telescopes.
50mm x 450mm means a 50mm diameter lens with a 450mm focal length. (2 inch diameter)
1100mm x 102mm means 1100mm focal length and 102mm diameter lens (4 inch). They have the diameter and focal length switched on that one. The focal length is always larger than the diameter.

The diameter is the important number, and bigger is better. 50mm is too small. 102mm is maybe OK but still small by modern standards.

Try one of the ones in the sources. The first 2 sources are mail order though, which is bad if you are in a hurry. The last source is Frys.

Answer 4

Geoff is 100% correct, as usual.
Here is a way you can involve the other person and still keep it a surprise:
Find an Astronomy club in your area !!
they have "star parties" which are events open to the public and are free of charge.
Make plans to attend their next party and take the person you want to surprise along.
you will get a chance to look through lots of different telescopes of all sizes and get an idea what's involved in setting them up and operating them. You will also get a very good idea of what things look like through the different Telescopes. plus you will easily get lots of answers to tons of questions.
You will learn more in an hour at one of these star parties than you will in a month of reading about it.
And trust me.... The folks at the club will love to have you attend one of their parties. I don't know a single Astronomer who doesn't love to share his views of the skies with another person. So, "get thee to a star party".
But do it soon, because in the colder parts of the country they usually stop having them in late fall because of the cold weather.

Adolph

Answer 5

Well the first thing you need to do is get some smarts about telescopes. Try this link to get spun up:
http://f1.grp.yahoofs.com/v1/gNsCR-A38rklKJn-13qb-V-9VD41w-qi1YoZfw2I6QUUbhQhxZL7RiTtP76bAHPxBUYEhyXJExlwDFqyvdbu/So%20You%20Wanna%20Buy%20a%20Telescope.doc

After you got smarts, then signup with Astromart.com to look for really good deals on used, well cared for advanced amateur equipment.