not sure which telescope to buy.

[nivniv]

hey, I don't know what telescope to buy between maksutov 8 INCH vs   8INCH schmidt cassegrain VS C6-RGT Advanced VX.

what are difference between maksutov and Schmidt cassergrain.?

at price of 180mm makustov I can buy apoRefractor

 

[CraigT82]

What do you intend to view the most?  Solar system (moon and planets) or DSO (deep sky objects - nebula, galaxies, globular clusters etc...).  Will you be observing from home or travelling somewhere with darker skies?

What particular 8" maksutov are you looking at?  This is quite a specialised scope, intended mainly for lunar and planetary viewing with it's very long focal length.

An 8" SCT is a pretty decent all round scope, quite a long focal length but not as long as the mak.  Will be good on planets and also on galaxies and globular clusters.

A 6" refractor is a big heavy beast. this will be a good deep sky scope with the widest field of view of the three, and will be pretty good for planets and moon viewing.

[nivniv]

I interested in DSO. in darker skies.

I  talk about sky watcher 180mm maksutov with atlas mount. between nextstar 8 se

[CraigT82]

Then I'd go for the 6" refractor if I were in your shoes.  It's a big long scope but should be fine on an AVX mount.

[nivniv]

yes but what are real difference between maksutov and Schmidt cassergrain

does 180mm MCT has more  light-gathering than 8 inch SCTs?

does 154mm Refractor has more    light-gathering than 180mm MCT?

[Cosmic Geoff]

2 hours ago, nivniv said:

does 180mm MCT has more  light-gathering than 8 inch SCTs?

does 154mm Refractor has more    light-gathering than 180mm MCT?

No, and no.  The 180mm Mak is said to be heavy.

A 154 apochromatic is likely to be very expensive.

Of the three, the 8" SCT should be the lightest and easiest to manage. They are also very popular.

[garryblueboy]

Like mentioned the 8 Schmidt is a good all rounder slight softer image on planets but larger view 

[Handy_Andy]

For dso's your better off with a ed80 or something similar, the mak and Schmidt have long focal lengths which make guiding and polar alignment absolutely critical to any imaging. 

The difference  between the mak and the Schmidt is that the mak has a concave corrector plate in the front which makes it heavy. Schmidts have a thinner flat corrector but use an additional flattener to make a flat field.

Another point is both the mak and the Schmidt are prone to dew problems and have long cool down times.

[nivniv]

'wwwhat difference will have 127mm mak than 180mm?

[Cosmic Geoff]

3 minutes ago, nivniv said:

'what difference will have 127mm mak than 180mm?

The 127mm Maks are a lot smaller and lighter than the 180mm, and easy to handle. The focal lengths are less extreme. I have one. It's a fine instrument, but my 203mm SCT clearly outperforms it all round, so I expect the 180mm Mak will too.

If you want to look at DSO's visually, you need aperture.  (and the 180mm Mak will have a small field of view - it seems designed for planetary work). If you want to do planetary astrophotography, you could use any of the telescopes discussed in this thread. Deep space astrophotography needs totally different kit.

[nivniv]

 what about 150mm/200mm of reflector will be enough for DSO? and its scope is huge less good compare to mak?

[Cosmic Geoff]

1 hour ago, nivniv said:

 what about 150mm/200mm of reflector will be enough for DSO? and its scope is huge less good compare to mak?

A 200mm Newtonian reflector would be enough to show you some DSOs visually, with pleasing results (from a dark sky site). I recommend mounting it on a GoTo mount unless you are willing to spend all night finding a small number of objects.  It's entirely down to you whether you choose a Newtonian (cheaper, and potentially a wider field of view) or a SCT (shorter, lighter, easier to manage).  A Newtonian will require periodic collimation wheras most designs of Maksutov generally don't, and SCT's seem to require little attention to collimation once adjusted.

If you are looking at galaxies and planetary nebulae etc the prime requirement is that the scope be of large aperture and easy to manage.

[nivniv]

I guess computerized goto mount is rather good for planetary than DSO.

I think its hard to use computerized mount for DSO

[Cosmic Geoff]

7 minutes ago, nivniv said:

I guess computerized goto mount is rather good for planetary than DSO.

I think its hard to use computerized mount for DSO

For planets, you just need a mount that tracks. Finding a bright planet is no problem.

With my GoTo SCT, I observed over 60 galaxies in two nights (over 90 counting those I viewed on both nights). There is no way I could have found that many without the GoTo mount.  Hard? You just have to enter the NGC or Messier number into the handset. 

[Louis D]

1 hour ago, Cosmic Geoff said:

For planets, you just need a mount that tracks. Finding a bright planet is no problem.

With my GoTo SCT, I observed over 60 galaxies in two nights (over 90 counting those I viewed on both nights). There is no way I could have found that many without the GoTo mount.  Hard? You just have to enter the NGC or Messier number into the handset. 

Or go with a push-to set of DSCs if you're good with manually tracking.

[nivniv]

my location has a lot of light pollution  Is that OK for 200mm telescope?  Or I need to be in better location. 127mm must be for Astrograph?  Or 100mm and 80mm app OK with planetry without astrography.  

There is no way I get out from city.  

Apo vs mak? 

[nivniv]

Can I dso with 80mm ed? 

[CraigT82]

2 hours ago, nivniv said:

There is no way I get out from city.

If this is the case I suggest you stick to lunar and planetary observing. City light pollution will drown out all but a couple of DSO.... no matter what scope you have. 

For lunar and planetary in the city I'd  recommend a 100mm apo refractor or a 150mm maksutov on a motorised EQ mount. 

[nivniv]

I'm in small city.  And   80mm apo is also good? 

[Cosmic Geoff]

3 hours ago, nivniv said:

And   80mm apo is also good?

For what? People mostly buy them for deep-space astrophotography, which you can't do well from a city.  If you tell us what you want to do, then we can suggest a suitable scope. Otherwise buy a small and modestly priced telescope like a 127mm Mak (with GoTo) and use that till you figure out what you can do, or want to do, from your location.

[nivniv]

lunar and planetary.  100mm apo is also mostly used for dso? 

[spaceman_spiff]

Hi there nivniv,

In my opinion, DSO imaging is possible for light polluted skies but you need to add filters to remove the unwanted light and you cannot expect to capture the very faint detail around some nebulae and galaxies. The LP will simply be brighter that the detail you are trying to image.

Reading your posts, I am not sure exactly what you want to do with a scope...you mention earlier that you are interested in DSO imaging but now you also mention interest in Lunar/Planetary imaging. Perhaps you yourself are not sure...an understandable position, I was also unsure when I started. If that is the case, then you should be looking for a good all-round telescope with decent aperture and a focal length that is not too long (IMO less than 1200mm). Other posters have recommended a 100mm APO/ED doublet telescope. This will perform well for both DSO and Lunar/planetary imaging as well as being easier to mount, move about and collimate compared to a larger Newtonian.

Might I also suggest you look into local astronomical societies and talk to them. Most societies have observing nights and you can see different telescopes in action and talk to their owners.

HTH Dan.

[nivniv]

Should 'nt dso occur in skies full of stars? 

[Louis D]

On 5/6/2018 at 05:27, nivniv said:

Should 'nt dso occur in skies full of stars? 

Yes, if your observing skies are dark enough to be full of stars of all magnitudes, then DSOs should be readily visible.

Could you elaborate a bit more on whether you're more interested in visual astronomy or astrophotography?  It makes a huge difference in recommendations.

[nivniv]

visual astronomy.  I will go with celestron  nexstar  8 se