Cosmic Geoff

Lots of people here use the Celestron C8 and it is well regarded. There is a choice of mounts if you are buying a package. The AVX seems good , but for pure visual may be heavier and more fiddly to set up than you want.  The SE GoTo mount is one of the cheapest, and just about adequate for visual only use. It has the advantage (shared with some of the other mounts) that you can pick up the whole OTA/mount/tripod outfit and carry it outside. 

Mostly, the OTA is held to the mount by a standard dovetail so that you can mix and match between brands of scope and mount.  But changing the mount on a C8 is going to be expensive, so I'd advise you to be sure of which of the several alternatives you want before investing.

39 minutes ago, danielpiasecki said:

Ok, so if my intention is to look at moon, saturn rings and some galaxies, would i be better off with a long focal length or shorter one?

a bigger aperture will always be better than a smaller one or not necessarily?

Again, my advice is to try this sort of thing for yourself, without committing to a £2K outlay.  The whole moon will just fit in the field of view of my C8 with the minimum magnification.  Saturn is small and a long focal length scope will likely be better.  Galaxies - it all depends. Some actually cover a lot of sky, but visually all you can usually see is the brighter core, so a narrow field scope will work fine. And the vast majority of galaxies are rather small.

A bigger aperture is a big advantage for deep-sky objects.  For planets, rather less so, as if the conditions are poor a larger aperture is more severely affected.  But I'm told the most impressive views of the planets are obtained with big scopes under perfect conditions.  I have never gone in for 'stopping down' and found that on the whole my C8 is the most effective instrument of my collection for looking at planets. 

21 minutes ago, danielpiasecki said:

Would you elaborate why the mount is so important?

 

Also, will i be able to see  saturn ring, moon craters, and nebulea with any telescope of 6 inch aperture ? or the focal lenght, mount, magnification, lenses have something to do it too?

Mounts are what make the telescope pleasant to use or even usable. Especially for deep space astrophotography, where it has to be rigid and track perfectly.

I can see all the above mentioned objects with my 127mm Maksutov.  Any smallish telescope will suffice. The brighter planets and Moon are easy targets for anything that claims to be an astronomical telescope.

Somewhere on this Forum you should find a "What can I see with..."

43 minutes ago, danielpiasecki said:

I was aware that dobsonians are not good for astrophotography, but i thought the skywatcher refractor pro ed would be. Is that right?

It might be, but the experts will tell you that a smaller apo refractor on a massive mount would be better.

The Celestron vx8 (I assume this a C8 on a AVX equatorial mount) would be good for planetary photography but the field of view will be on the small side for some other objects. 

Calling GoTo 'very handy' is an understatement. Without it, you could find locating fainter objects represents either an evening's entertainment to locate one or two, or too much like hard work, depending on your tastes. I saw Venus and Mercury this afternoon. Try doing that without a GoTo.

I suggest that you not spend the £2K right away, but acquire a small and easy to manage instrument first.  Otherwise you may conclude after a while that you have spent £2K of an instrument that you don't much like and which is a pain to use.  The instruments you cite all have their merits and you won't know which is best for you without trying them (or a smaller and cheaper variant). 

Things to consider:  How portable do you want it to be? Are you interested in deep-space photography (in which case scrap that list and start again)?

What mount? For visual, there is a case for having an alt-azimuth GoTo.  But if you want to do planetary astrophotography, an equatorial GoTo might be better (ask the experts). 

If I was spending £2K, I'd probably get a 8" Celestron SCT on one of the more expensive alt-azimuth GoTo mounts.   

If the GoTo is working fine, why do you want to upgrade it? What problems is the upgrade meant to fix? I would leave well alone unless you actually have a problem.

Engineer's old saw: "If it ain't broke, don't fix it."

43 minutes ago, Dave1 said:

Do you still have your Ross telescope? I'd be very interested in seeing it? 

Yes. Here's a picture of it on the AZ-4.

I have a vintage Ross, London (genuine, not replica) 70mm terrestrial refractor with a long focal length. I have not been able to unscrew the erector lenses which expand the focal ratio even more, but both with the original eyepiece and with a modern 20mm Plossl (the latter giving a very high magnification), the performance is first rate.  I clamped a dovetail bar on it and occasionally give it an airing on a AZ-4 or EQ-5 mount (the minimum required).  I have had nice views of Saturn and epsilon1/epsilon2 Lyrae with it.  Apparently an earlier owner got it from Charles Frank of Glasgow along with an equatorial mounting and surveyor type wooden tripod, which I saw but did not acquire.

This telescope totally outperformed a 70mm supermarket refractor which I also owned at the time.

56 minutes ago, Dinoco said:

But when scopes are usually this cheap sometimes they don’t perform that well.

Be reassured that the scope by all accounts is adequate optically, though an eyepiece upgrade may improve things.  The cost savings come in the mount. The mount in your case costs almost nothing to manufacture, wheras other outfits may come with an all-metal mount head and tripod, with various 'bells and whistles' adding hundreds of pounds to the cost.

40 minutes ago, martinl said:

That said, sending poorly designed products back might be the only way to make manufacturers realise that there is a problem. 

Quite right. The altitude range on these mounts is restricted. They should really have a 90 deg gear sector and worm gear to adjust the altitude. It wouldn't kill the manufacturers to do the job properly.

If you don't care at all what it looks like, the colored plastic caps from supermarket 500ml milk bottles are just the right size to cap the eye end of common Plossl eyepieces from Celestron, etc.

Will certainly serve till you order the proper ones from abroad.

Somebody may be missing a chance to import some caps cheaply from the source (China) stamp his business logo on them and then give them away to potential customers (like a lot of companies do with ballpoint pens).

1 hour ago, Jimmystargazer said:

Assume this is a better value option?

http://www.365astronomy.com/Dew-Shield-Lens-Shade-with-Dew-Heater-for-Celestron-8-Schmidt-Cassegrain-Telescopes-with-Controller.html

I use a home-made cardboard dew shield, and no heater. Your money, your choice.

There has been discussion elsewhere about what kind of diagonal is best, and comparative surveys can be found. You can chase it up, but with a long focus telescope like a SCT you can use a prism diagonal which offers high contrast (low scatter) and has no coating to deteriorate.  Any mirror diagonal should have sufficient wavelength accuracy, but more expensive ones may offer higher reflectivity and less scatter of light.

I have a SCT of the same aperture and focal length. I use 25mm, 15mm and 8mm eyepieces with it. All are 1.25". You only want 2" eyepieces for lowest power/widest field as the 1.25" are cheaper and more widely available. Plossl types are good enough at 25mm and 15mm unless you have exacting requirements or deep pockets. I have not invested in any lower power (wider field) or 2" eyepieces as I have other scopes for that.  For my scope the cost of a 2" visual back, 2" diagonal and 2" eyepiece adds up to an off-putting sum. But if you have no other scope you may feel it's worth it.

You will need to get the finder (finders) to work and be accurately aligned before you can proceed to aligning and using the GoTo electronics, as the field of view of the main scope is fairly small. Assuming the hardware works as it should, you will scarcely need the finder once the GoTo is set up, and you should be able to find large numbers of objects.  While GoTo systems differ, there is usually a choice of alignment modes e.g. One Star or Solar System object - quickest and least accurate, Two Star - more accurate , Three Star - most accurate and the most fiddly.

Even if the mount has an equatorial wedge (and corresponding settings in the software) you should get used to using it strictly in alt-azimuth mode (mount base horizontal) first - that may prove challenging enough to start with. The equatorial wedge is principally for astrophotography.

I'm not sure how your Meade is powered, but if it uses internal dry cells, think about getting an external power pack for it soon.

Celestron do a 127mm Mak, which seems to be the same as the Sky-watcher except for the paint. This does not exhaust the list of brands. I assume they are all made in the same Chinese Synta factory, and if the specs are the same, they should perform the same. So you can choose on the basis of preferred brand and after-sales service.

Needless to say, I think my 127 Celestron Mak is great.

On 5/7/2016 at 23:29, noah4x4 said:

Sky Portal (off-line) once told me; having correctly set its time/date & location in my Android device; that the Andromeda Galaxy was one of 'Tonight's Best'. My HC time/date/ location was set correctly too. But when I tried to GoTo using the HC it rightly warned me "will exceed slew limits". I am hence nervous about attempting this equivalent GoTo when under solely Android control. How can an object be in both "Tonight's Best" and yet "beyond slew limits'?  

While testing my brand new Starsense with my 127mm Nexstar GoTo, I commanded it to find the Andromeda Galaxy (overhead) , and got that "will exceed slew limits"  message. I persisted, but the galaxy was outside the eyepiece FOV. Everything else I told it to find last night was in the FOV. Strange.

Is this a good telescope? No idea.

See this earlier post "Problem with lens"

https://stargazerslounge.com/topic/281633-problem-with-lens/#comment-3083201

in particular the review link from 'John', and also click on the Danubia RET50 link above, and get a Google translation into English. Then draw your own conclusions.