Telescopes

[Dreaming]

my sister wants to get a telescope for her hubby for christmas. Can anyone tell me what the difference is between a Refractor or a Reflector as that only seems the difference but the Reflector is �50 more. Sorry if I seem a bit dim, just reading off leaflet she gave me.

[Tim B]

Refractors use lenses to focus at the base of the tube where the image is viewed. Reflectors use a mirror at the base of the tube which converges (like a shaving/make up mirror) the light back up the tube to a prism/mirror which reflects it sideways to the eyepiece.

Because refractors have more lenses they absorb more light (less likely to see dim onjects) and suffer from chromatic (colour) and other (spherical) distortions, they are not as good.

The bigger the mirror in your refractor the more light gathering power is has (not necessarily a higher magnification) so's you can see dimmer objects clearer.

Given the choice go for a reflector every time.

[Narolines]

I'm no expert, but as far as I am aware a refractor is a simple instrument, the same basic type as the old-fashioned sailor's telescope, where you look through an eye-piece and see directly through the objective lens whatever the telescope is trained on. A reflector incorporates a mirror, so you look into the side of the instrument and see a reflected image of whatever you're looking at. The advantage of the reflector is that the image can be bounced about inside the telescope and progressively enlarged, so that you get better magnification in a smaller telescope. By and large the reflector is considered the more professional instrument and you will get better reults than from a refractor of comparable size. I'm sure there's more to it than that, and somebody knowledgeable will expand or put me right. Hope this helps!

[Dreaming]

Thanks Tim for your answer, will try and explain all this to my sister, but can I just ask, do you think �100 is about the right price for a telescope for an absolute novice?

[Dreaming]

Thanks Narolines for your help too.

[Dreaming]

Or you Narolines, if you can offer any help. Would appreciate it.

[mibn2cweus]

For the money refractors give sharper details, reflectors gather more light. Refractors can be easier to care for since they are somewhat sealed internally from dust/dirt. They also suffer less from light polution. If your hope is to enjoy the telescopic experience than I hope you enjoy selecting a good telescope as much as using it. I found this crucial to the end result. Happy hunting, stars and all!

[Dreaming]

thanks Mibn

[Dreaming]

Mibn should she go for the Refractor at 50 quid, or the Reflector at 200 quid. Appreciate your advice

[SteveD]

What does he want to use the telescope for? There is a difference between astronomical and terrestrial telescopes.

[Dreaming]

My sister says he wants to look at the stars with it. I am just asking on her behalf.

[mibn2cweus]

For general star gazing I recommend a good pair of 7X50 binoculars to any telescope of equal price. They provide a wide field of view that makes locating what your looking for/at easy to find and you can see a lot of it at once. This, and a good binocular/astronomy book is the best way I know to become familiar with the night sky.
Of course this will leave you wanting more but it may provide encouragement to due the necessary research and invest the necessary money to get a telescope that you will be happy with.
Stars under any magnification remain points of light, you just see more of them. If you have some binoculars I encourage you to go have a look at the night sky. I keep a pair of binoculars handy when I�m using my telescope and rarely use my telescope to look at stars.

[Dreaming]

Thank you very much Eddie and Mibn for all your help and advice. Much appreciated.

[Dreaming]

Thanks Eddie, I do think it may be a craze my sisters husband is going through. Think I may be more interested and invite myself round. But thank you very much for all your help

[mibn2cweus]

Nebula (and the occasional comet) also show up well in photos but I believe you need to track these for a timed exposure.