Celestron Nexstar 102 or Skywatcher Startravel 102

[igriggs]

Hi all,

Some advice please. Im looking to get a reasonable refractor to do imaging. Im told refractors are best for imaging. Is that correct? I want it computer controlled and would look at one of the above. Are these reasonable choices? Is there another you would choose around £350-£400? Which one would you get?

Second part of question. Im looking at the Celestron Neximage 5 CCD. Would this be a good choice for moon and deep space imaging? Again, what would you get for £250-£300?

Any comments appreciated please.

Many thanks.

Ian

[Tiago]

Well, the limiting factor for imaging is not the optics so much as the mount. Even though you can do *some* imaging on an alt-az mount, it's not in the same league as a proper setup, which requires a heavy, accurate EQ mount, plus autoguiding - this kind of mount and autoguider alone exceeds your total budget, and you'd still have the camera and optics to consider.

DSO imaging requires specialized cameras or a DSLR. Apart from very bright DSOs and using a lot of image stacking / de-rotating by software, you'll need an EQ mount as above. However, do not let that discourage you - I've seen some lovely photos taken with affordable Alt-Az refractors (such as the Nexstar 102, which I considered buying) - they just require a lot more pictures, with shorter exposures.

For moon imaging, pretty much any kind of mount, telescope and a DSLR will do, as exposures are quite short, so no tracking is needed.

For planetary imaging, a specialized CCD as you mentioned is a possibility, or you can mod a £5 webcam and get some fairly decent results - see the imaging subforum for images people get with those. These will also do for moon imaging, but the resolution is far below a DSLR for that.

Sorry if this is a bit more confusing than enlightening,,,

[igriggs]

Thank you Tiago. Both scopes above have computer GOTO and tracking. I think I will abandon this idea then and buy separate EQ mount and scope.

i appreciate your help. Regards. Ian

[RikM]

Both the Nexstar 102 and Startravel 102 are achromatic telescopes, so not really suitable for astrophotography. When people recommend refractors for imaging they are talking about ED or Apochromatic scopes. About the cheapest you can get is http://www.firstligh...ds-pro-ota.html and you need one of these http://www.firstligh...l-reducers.html to go with it.

A separate EQ mount is very good idea. It all starts with the mount either http://www.firstligh...ro-synscan.html or http://www.firstligh...nscan-goto.html would be okay for an ED80 and you could add an autoguider if you want exposures longer than 2-3 minutes. (you will want exposures longer than 2-3 minutes )