Which Telescope?

Question

Hi all, new to astronomy so sorry if any of my points are typical/stupid etc....but please, any input would be really appreciated - thanks! I am hoping to purchase a telescope which will last me for a reasonable time, without being excessively pricey. I am keen to have a GO-TO feature as I am not very confident in my knowledge of the sky. Having said this, I would still like to aim for good quality optics etc... Currently I am looking between the Celestron NexStar 130 SLT (£270) and the Celestron Nexstar 4 SE (£340), I have also seen the NexStar 102 SLT ((£300) Both of these 'scopes fit well into the top of my budget range.However, I understand that they all use different optical systems - the 130 a Reflector system, the 102 a Refractor and the 4 SE a Maksutov-Cassegrain system.Apertures are different- 130 5" and the 102 and 4 SE 4" (I think). What I am really hoping for is some advice, whether to steer me between these or to choose an entirely different one.

Any input is good!

Thanks so far - just for further information my main use is observing in a relatively rural area with a little terrestrial use as well.

My main question now however is (in addition to 'what should I go for' : Do the different optical systems make up for the slightly larger/smaller aperture? - I saw a comparison somewhere relating to the fact that 'a 4" refractor is roughly equivalent to a 5 or 6 " reflector - is this at all accurate and where does the 4 SE or similar telescopes come?

Really what I want to know is which of these will give me the best viewing, and is there anything else equivalent I should be looking at around the same price that is better? (Since many of the other features of these telescopes seem similar - GO-TO system etc...!?)

Thanks for the response so far - great advice - thanks! (I don't mean at all to doubt the answers so far from the above!)

I'm afraid I doubt I can afford a Hubble though!!!

Answer 1

A refractor will gather more light than a reflector of the same aperture, however, unless they are apochrmatic, refractors suffer from chromatic aberration, which can be very annoying.

The NexStar 102, though a hefty 4", is not apochromatic. It is multi-coated. This will reduce, but not eliminate noticable chromatic aberration. This would not be a bad telescope to have if you had another "main" telescope, and you wanted something sturdy that was an easy "pick up and go" scope, but as a main telescope I'd want something else.

The Maksutov Cassegrain was designed to address the issue of coma, a problem that reflectors sometimes suffer from. Coma can distort the shape of object, namely stars, which are near the edge of the field of view. It can be an annoyance if you are looking for undiscovered comets or deep sky objects, or if you are doing astrophotography of star clusters or star fields, so this is where Maksutov Cassegrains have an advantage. They also have long focal lengths so it's easy to reach suitable magnifications for planetary viewing.
The pros of these telescopes, however, are overshadowed by their small aperture and relatively high cost. I don't recommend them often, and at 4", I don't recommend this one.

I guess that leaves the Celestron NexStar 130 SLT. At f/5 it will have a noticable degree of coma near the edges of the field of view but it probably won't be anywhere near as annoying as the color aberration that the refractor has.

To be perfectly honest though, I wouldn't buy any of these. You see goto is nice, but in small telescopes, such as those under 8", there are maybe less than 70 or so objects that the telescope will get a nice view of so the rest of those 40,000 objects in that data base are either stars, which all look the same, or things that are to dim for your telescope to see. You'd be better off getting something with larger aperture without goto and learning the sky yourself. It really isn't that difficult to do and you will eventually become familiar enough with your favorite objects that you will easily be able to point the telescope in the general direction and locate the object quickly.

Answer 2

Hi I recently purchased my first telescope. I bought a used Celestron Nexstar 8. I got it for about 1/2 of what they are new. Personally I don't find the GOTO to be all that great. The mount on the Nexstar setup is not all that sturdy, so if you have even a little wind it will tremble the entire time.

I am not going to tell you what to do, but if I could do it over again I would buy a Celestron Schmidt Cassegrain on a manual equatorial mount (without GOTO), and I would get the biggest possible aperture (sp?) I could find.

If I had to chose between a little mirror with GOTO or a big mirror without I would take the big mirror. Good luck and take your time!

Answer 3

Look, people will tell you that it's a child's toy, and in comparison to telescopes some of us have used or built, it is. But it is far better than the naked eye. I would say if you are thinking about a telescope that size, you might consider a pair of binoculars. I don't know what price range you are talking about, but you should be able to find some decent second-hand ones with at least 50 mm lenses for the same price. Check it out on e-bay some time. I have seen lots of them there.

Answer 4

You should buy the largest size you can afford. By that I mean the largest diameter objective. The difference in what you can see will depend dramatically on the size and hardly at all on the design of the optics. That is assuming the optics are well made. If the optics are poor quality, no design will really work well.

And I may be old fashion, but I think getting some star charts and learning the sky is a good thing. It will really save you money too, because the go-to feature will make the telescope much more expensive.

Answer 5

area resonance type w mul/radio dimension features might be a long term goal, however for a med. budget the schidt/ cassegrain type or newtonian might be feasable i have seen reasonable items on eBay that have good features, if the 130 5" will give greater aperture ambience, the 4 SE would most likely have slightly more refined optics, celestrons are notable for rationally good/exeptional performance for their price, good luck w/ don't forget to check out Meade telecopes/ and viewers

Answer 6

As I have told before, the best option would be a Hubble-like telescope. Just consider how many kind of pollution there are in present days in Earth's atmosphere.