Choice of EQ mount for Astrophotography

[mcmalloy]

Hello community! 

For the past year I have been slowly getting into astrophotography. Unfortunately a few things had set me back along the year (terrible weather, lots of work, and a broken mirror).

I recently sold my first mount, the Advanced VX to a friend who also wants to start this hobby. I did this because I wished to get a bigger and better mount, since I have had some minor reliability issues with the AVX.

As we all know EQ-G's aren't the cheapest thing on this planet, and when spending 1000+ Euro's on a mount, you better make the right choice!

So I am asking for your assistance with choosing a mount between the many different models in my price range. Currently I have set my budget to a mount anywhere between 1500-2000€.

I have an autoguider, as well as an OAG, that can be used to help guide the tracking.

Currently I am using a very small scope ( the TS Imaging Star 71m F/4.9 APO , 347mm focal length ), that weighs only 2kg's. In total it weighs about 3-3.5kg's when I have my accessories added on to it. I like the idea of getting a mount, and then piggybacking the APO on a medium-field scope ( RC or possibly SCT ? ).

So what model should I consider in regards to achieving long exposures in the 1500-2000€ price range? Also if you have any suggestions for a second scope that would be very helpful! Thanks a lot - Mark

[ollypenrice]

My shortlist would be very short on this budget. It would be a list of one. http://www.firstlightoptics.com/skywatcher-mounts/skywatcher-az-eq6-mount.html

This mount isn't perfect and will not necessarily be painless to get into full working order at very fine pixel scales. (Long focal length and/or small pixels.) But if there is anything else that will get you into the same probability of success then I haven't heard of it.

Don't become too obsessed with weight. Obviously a mount cannot be overloaded but this often masks the real issue which, at fine pixel scales, is accuracy.

Olly

[sbooder]

You are basically looking at one of the following with your budget: The Celestron CGEM GOTO, The Skywatcher NEQ6 Pro or AZ-EQ6-GT or AS-EQ5-GT if you want to have a mount that will take bigger scopes in the future.
 

But if you want a mount to take what you have now, you can throw in the Vixen Sphinx SX2 in there too.

[mcmalloy]

Thank you for your fast reply Olly! Would you say that the mount would be an improvement over the AVX? At the moment I had been looking into some of Orion's mounts ( Atlas EQ-G) or IOptron. Do you know how they would compare to the Skywatcher?

[ollypenrice]

Thank you for your fast reply Olly! Would you say that the mount would be an improvement over the AVX? At the moment I had been looking into some of Orion's mounts ( Atlas EQ-G) or IOptron. Do you know how they would compare to the Skywatcher?

I think Orion and Skywatcher are the same thing. I have my doubts over iOptron because I think they are too quick to release new products and use the customers as Beta testers. I wouldn't insist upon this point by any means and would suggest a good trawl round netland on the matter. I really can't offer any useful comparison with the AVX which I've only seen once, I think. You have to remember that with mass produced mounts the luck of the draw comes into it. But then, so it does with some rather expensive ones, too...

Olly

[sbooder]

I think overall I would agree with Olly, the AZ EQ6 is probably the best value for money.  I believe it is already belt driven and will save the belt mod the NEQ6 benefits from and has a better alt adjustment than the EQ6 so no need for the wedge upgrade.  I think if I had the budget again, I would go with the AZ EQ6.

[sbooder]

Oh yes, I think it has encoders as standard?

[r3i]

Thank you for your fast reply Olly! Would you say that the mount would be an improvement over the AVX? At the moment I had been looking into some of Orion's mounts ( Atlas EQ-G) or IOptron. Do you know how they would compare to the Skywatcher?

As Olly said, the Atlas is a badge engineered version of the NEQ6 for the USA market in much the same way as your TS Scope is the same as a WO Star 71.

As a happy owner of an NEQ6 for around 5 years I can highly recommend the mount.

[mcmalloy]

As a happy owner of an NEQ6 for around 5 years I can highly recommend the mount. 

 

Would it be unrealistic of me to expect exposure times at 300s or above with an autoguider?

[steppenwolf]

For me it would have to be the Sky-Watcher NEQ6 or AZ EQ6 GT. From a performable point of view, there is little to choose between them but the AZ EQ6 GT is better 'finished' and has the advantage of an altazimuth mode but if looks and altazimuth don't particularly appeal then the NEQ6 would be great within your budget. Consider also driving it with the excellent EQASCOM driver and a suitable EQDIR adaptor - a great combination.

[Jokehoba]

Would it be unrealistic of me to expect exposure times at 300s or above with an autoguider?

As an NEQ6 user, 300s is my normal exposure length. On occasion I have used 600s and 900s when imaging a wider FoV. But for my set up and urban location, there is no advantage beyond 900s but the mount is certainly capable.

John

[ollypenrice]

You can't usefully discuss exposure lengths without specifying the pixel scale. The guiding requirements at 0.5 arcsecs per pixel are 7 times more exacting than those at 3.5 arcsecs per pixel. I'd expect an EQ6 to handle 1.5 arcsecs per pixel (and above) out of the box without too much cajoling. With some cajoling or some good fortune it ought to go below that but, to be honest, I personally would want a more inherently accurate mount for the finer pixel scales. I like an easy life, mount-wise.

You can find your pixel scale with this calculator. http://www.12dstring.me.uk/fov.htm

To give you a specific and popular example of the kind of thing I wouldn't get involved with, take an 8 inch SCT and a DSLR. This will probably be working below 0.6"P/P and for that I'd rather have a Mesu, Avalon, 10 Micron, AP, etc etc. You really do need serious guiding accuracy and excellent seeing to make this worthwhile.

Olly

Oh, a quick PS. The power supply socket on the NEQ6 is rather flimsy, meaning a cable wrap can trash the mother board. The first time this happened it would cost you most of the difference in price between the NEQ6 and the AZ EQ6 which has a much improved socket.

[mcmalloy]

You can't usefully discuss exposure lengths without specifying the pixel scale. The guiding requirements at 0.5 arcsecs per pixel are 7 times more exacting than those at 3.5 arcsecs per pixel. I'd expect an EQ6 to handle 1.5 arcsecs per pixel (and above) out of the box without too much cajoling. With some cajoling or some good fortune it ought to go below that but, to be honest, I personally would want a more inherently accurate mount for the finer pixel scales. I like an easy life, mount-wise.

Well currently I am using a Canon 700D. With my current wide-field setup I will have a resolution of 2.56''/pixel . I would expect that with a wider FoV it will be easier to minimize star streaking in long exposures. However I do plan on getting a scope in the 1000-1650mm focal length range ( 0.89'' to 0.54'' resolution )

[ollypenrice]

Well currently I am using a Canon 700D. With my current wide-field setup I will have a resolution of 2.56''/pixel . I would expect that with a wider FoV it will be easier to minimize star streaking in long exposures. However I do plan on getting a scope in the 1000-1650mm focal length range ( 0.89'' to 0.54'' resolution )

OK, an EQ6 should have no trouble whatever with 2.56" P/P.

But, ouch, 0.89 to 0.54 is out of the comfort zone of the budget mounts. It would be silly to say it couldn't be done because folks have managed it, but it is not likely to pop out of the box and work at that precision. Our Mesu proved very reliable at 0.66 but that's a much more expensive mount and has zero backlash, being roller drive.

Be aware that a combination of fine resolution and slow focal ratio (which may apply to the larger scope?) is going to mean long exposures which may mean a high mortality rate in your subs. DSLRs do work much better at fast F ratios.

Olly

[tony210]

My old EQ6 managed 1" per P/P with care and my EQ8 0.8 - there is nothing wrong with aspiring to good guiding with mounts like these but they will need coaxing and care but then with so many variables this is the nature of the hobby I think- Tony

[iapa]

To throw in to the conversation, I was looking at the CGEM GOTO or the AZ EQ6 GT to take my 200P-DS with around another 4-5lbs additional load (DSLR, guide scope/cam, and other odds and sods)

This is currently around 90% of the AVX payload. Payload wise, both quote 40lbs imaging, so, I am going to be quite well within 75% of load limits.

I'm taking a longish view at the moment so taking the view to a purchase that will cover me for at least the next 5 years (LP and other limitations mean I'm unlikely to be able to warrant much in the way of heavier load).

With the 0.85 arcsec/pixel that the online FOV calculator says I can get, with the 20P-DS and Canon 70D would either of these mounts be capable of tracking at that.

Or, should I be better considering the CGEM DX with it's 50lb limit and, I think (still working it out) improved tracking wrt the AZ EQ6 GT.

The next step up EQ8 or CGEMPro are in the area where there is currently no appetite for the expenditure.

[Owmuchonomy]

Olly beat me to it. As an owner of the AZ EQ6 GT, and previous owner of other EQ mounts I would wholeheartedly say that so far it is the best SW mount for the money. It is very well thought out, nicely finished, performs well and in your budget. The only thing I will say is that it is my second mount of this type. The first had  a blindingly obvious periodic worm drive anomaly, This was immediately rectified by the dealer and I'm sure you know the value of a good supplier.

[aparker]

FWIW I have had good luck with my CGEM but have not tried unguided subs over about 60 sec.  I previously owned an iOptron mount and can't recommend it.  Lots of software reliability problems.

[aparker]

On October 31, 2015 at 06:07, ollypenrice said:

You can't usefully discuss exposure lengths without specifying the pixel scale. The guiding requirements at 0.5 arcsecs per pixel are 7 times more exacting than those at 3.5 arcsecs per pixel. I'd expect an EQ6 to handle 1.5 arcsecs per pixel (and above) out of the box without too much cajoling. With some cajoling or some good fortune it ought to go below that but, to be honest, I personally would want a more inherently accurate mount for the finer pixel scales. I like an easy life, mount-wise.

 

To ask a possibly naive question, unless one had truly spectacular seeing conditions, AND large aperture, what would be the point of shooting at 0.5 arcsec/pixel?  My seeing is rarely more than average, and my CCD's 1 arcsec/pixel is seemingly overkill.  I can't see much or any difference in resolution when I bin up to 2 arcsec/pixel, but the improvement in speed is very noticeable.  

[ollypenrice]

7 hours ago, aparker said:

To ask a possibly naive question, unless one had truly spectacular seeing conditions, AND large aperture, what would be the point of shooting at 0.5 arcsec/pixel?  My seeing is rarely more than average, and my CCD's 1 arcsec/pixel is seemingly overkill.  I can't see much or any difference in resolution when I bin up to 2 arcsec/pixel, but the improvement in speed is very noticeable.  

In many cases it probably wouldn't be worthwhile. However, there are imagers who've shown that 0.5"PP can be done at the right site and with the right gear. I wasn't advocating it, though. I was just making the point that exposure lengths are related to pixel scale. In the majority of threads on mounts there is, in my view, too much talk of payload and not enough attention given to accuracy.

Although I've imaged at 0.66"PP I'd happily settle for an arcsecond as being a good compromise from my site. (It's fairly high at 900metres.)

Olly

[johnrt]

On 08/04/2016 at 22:06, Owmuchonomy said:

Olly beat me to it. As an owner of the AZ EQ6 GT, and previous owner of other EQ mounts I would wholeheartedly say that so far it is the best SW mount for the money. It is very well thought out, nicely finished, performs well and in your budget. The only thing I will say is that it is my second mount of this type. The first had  a blindingly obvious periodic worm drive anomaly, This was immediately rectified by the dealer and I'm sure you know the value of a good supplier.

I suffered a similar out of the box fault with my AZEQ6 which was rectified by the retailer (FLO) without question or fuss. The second one works without issue and routinely delivers at 0.97"/pixel on exposure times of up to 20 minutes.