celestron NexStar 127 SLT or NexStar 130 SLT

[lostboys]

Hi

I am new to this forum and looking for advice about these two telescopes. celestron NexStar 127 SLT or NexStar 130 SLT.

which one is best for seeing more than just planets ie (galaxies and nebula) and also one i can mount a camera too.

i have looked up both on the internet but its far from black and white which one will get greater deep space items , rather than just planets.

i do understand that these are not 6 to 12 inch scopes and i understand there limitations, but would like to know what i can actualy see with these and which is best for my needs.

Any advice would be good.

[umadog]

These are both 5" telescopes so not terribly different from what you'd see in a 6". Obviously significantly different from what you'd see in a 12". Given that they both have the same size objective size, both telescopes will show you the same level of detail as regards deep space objects.

There are two major differences between the two telescopes:

1. The 127 mm in a Maksutov (Google the term if you don't know what it is). This means that it's got a closed tube. The 130 mm is a Newtonian, which has an open tube with a secondary mirror supported by a 4-vane spider. The Newt will show diffraction spikes but the Mak won't. The impact of these is really just aesthetic. They won't degrade contrast. The open-tube design will cool faster than the closed-tube and it more resistant to dew formation. You will need a dew-shield and maybe a heater to keep dew from forming on the front corrector plate of the Mak. The Mak will need little or no alignment prior to each use. The Newtonian will need alignment prior to use. Alignment isn't hard and it shouldn't be an impediment to owning a Newtonian, but a lot of beginners allow it to influence their choice. This is fine, of course.

2. The real difference, in my eyes, is that the Newt is f/5 and the Mak is just under f/12. This affects the magnifications you can usefully achieve. Both telescopes will reach their highest useful power so you can, in practice, magnify equally with both scopes. It's just that you'll need to use shorter focal length eyepieces or a Barlow lens to achieve this with the Newt. This is no problem. At the lower end, however, you will get much wider fields of view with the Newtonian. This will make the larger star clusters more pleasing to the eye. However, the Newtonian will display an aberration known as coma at the edges of the field of view. This will make the edges blurry. Cheaper eyepieces will also display astigmatism (blurry field edges, basically) in the Newt but will do so to a much lesser degree in the Mak. The upshot is that you will tend to get wider fields in the Newt, but these will show some degree of blurriness unless you spend a lot of money on correctors and more expensive eyepieces. The Mak will have a sharper field and more pin-point stars. This gives the perception of greater contrast. The downside is that the field of view will be smaller. It won't be obscenely narrow by any means, just more narrow than the Newt.

It's really a case of horses for courses. Both are probably good telescopes for starting out. The Mak may give more pleasing views more easily, so I would perhaps consider that more carefully. I would also forget about connecting a camera to either of these scopes. Astrophotography a very involved thing and you probably won't get good results with those mounts. Start off with visual then thinking about photography later.

[lostboys]

Hi

Thank you for your reply, will either of these see any forms of DSO or am i just waisting my time with a goto and should just bite the bullet and get a sky watcher 200p with a eq5 mount/tripod, i take it it would see a heck of a lot more deep sky/DSO and eventualy be suitable for astrophotography.

thank you.

[umadog]

If you want to see DSOs, I think a 8" or 10" Newtonian is hard to beat. Even if you get a monster scope later, a Newtonian in that size range is always useful. On EQ mount, yes, it may eventually be suitable (if the mount is heavy enough). If you're interested in doing AP "eventually" then I'd suggest your best course is to buy an 8" or 10" Dobsonian now and forget AP. If you're still interested in AP in a year or two then get yourself a fast refractor on an equatorial mount. The reasons are that a mount suitable for AP with a largish Newtonian is going to be heavy and expensive. Those things have fairly long focal lengths so you will need good tracking to get nice images. A fast refractor will give you nice wide panoramas and won't magnify too much, so it will be easier to get sharp shots. Its light weight means that a lighter mount will be acceptable. I think you'll get better results more cheaply and easily in the long run by having a dedicated imaging scope and a dedicated visual scope. A good imaging Newtonian is fast and has an over-sized secondary. You don't want a over-sized secondary for visual observing. It's better not to ask two conflicting things of the same instrument: never works out best at either. By waiting for the imaging, you'll have a chance to learn the sky and read up about AP so you can make a well informed choice. Incidentally, a lot of people start out with a dSLR on a tracking mount. Another option to consider.

[lostboys]

Hi

Thanks for reply, I will take your advice on board and get the skywatcher 200p and concentrate on learning astronomy then look at ap at a later date.

[umadog]

I hope it all works out! I should point out: please don't take my suggestion as discouragement of AP, which I think is a fine pursuit. It's just that there's a lot see, do, and learn in this hobby and if you try to do too much, too quickly, and with sub-optimal kit, you may become discouraged. There's lots to see visually, as you will see if you head over to the DSO and planetary fora.

[lostboys]

Thank you for the advice, no it has not put me off, i just have one of those minds that never stops (was a presicion engineer and also spent my entire life either building or cad designing with computers) so love science. i have ordered my skywatcher 200p and will be here tomorrow, i think it will be a good place for viewing the night sky as i live near the mountains in cumbria.