Buying a Telescope, but which one? – This is a tough question but first I need to ask you some questions.
- What do you want the telescope for?
- Do you want to study the planets, deep space or both?
- Do you live in a light polluted city or rural?
- What will your budget allow?
- Will astronomy be a temporary hobby?
Buying a Telescope – OK, did you answer those questions – Good. Now I’ll give you a quick run down on the types of telescopes you will find.
Buying a Telescope – Refractor:
Buying a Telescope – Refractors gather light with an objective lens at one end and focus the light at the eyepiece at the other end. The refractors advantages are their potential for the best images, there is no obstruction in the light path. The disadvantages are some secondary colors called “chromatic aberrations” which are visible in all but the most expensive telescopes.
Buying a Telescope – Reflector:
Buying a Telescope – This uses a parabolic mirror at the end of the tube and focuses the light back at the front of the tube, where the eyepiece sits, after being deflected by a smaller secondary mirror in the light path. The advantage to these telescopes is that they are cheap and more portable. The disadvantage is that their secondary obstruction results in some loss of contrast.
Buying a Telescope – Schmidt-Cassegrain:
Buying a Telescope – Also called Maksutov-Cassegrain and Classical-Cassegrain. These use mirrors and lenses to fold the optical path back onto itself, resulting in a compact tube. The technical term used for this type of telescope is “Catadioptric”. The advantage of these telescopes is that they are the most compact of all telescopes. There is a huge assortment, and they can be totally computer driven. The disadvantage is that they are the most expensive of the three types.
OK, now we have that out of the way it’s back to that big question “which telescope to buy”. Firstly it will depend on your observing habits, and your financial situation. Despite the optical superiority of refractors and the low cost of reflectors, many people buy a Schmidt-Cassegrain as their primary telescope.
And you can understand why, you can buy a 10″ Schmidt-Cassegrain at an affordable price or you can buy an 4.5″ or 6″ reflector which are great beginner telescopes. Many astronomers have more than one telescope and this maybe something to think about. You could start with a 80mm reflector and then in a couple of years balance things out by getting 10″ or 12″ Dobsonian. I’m not going to tell you how many telescopes I own (too many)
Buying a Telescope – I can almost hear you through the internet asking yourself when is she going to tell me which telescope to buy. This question is the one I am asked the most and it is the toughest to answer. But here goes, I would recommend the Dobsonian as a excellent first telescope and if you have read my reviews you would know by now that I am a big fan of the Dobsonian, I have several reason for thinking this.
You get more aperture for your dollar.
The Dobsonian is cheap.
It is a simple telescope to use.
With large aperture you have more objects to view.
Buying a Telescope – The 6″ to 8″ Dobsonian would make a great first telescope. Don’t go much higher than that at first as the larger Dob is hard to move around. I like all the Dosonians from Meade, Orion to Celestron.