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kiloran

GoTo - AltAz or EQ?

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I'm researching options for a mount for both imaging and observing and thinking of going down the GoTo route. I'd really wanted to learn how to find objects manually but an impatient 7yo is making that difficult. I don't want to kill off his passion for astronomy with too many more failed observing sessions. Its not helped by the current mount being utterly rubbish (too light, slow motion controls tricky to use).

Budget is £500 but can be pushed if needed. I'm guessing an AltAz mount is going to be quicker to set up - we can't observe from home due to light pollution so setup time is important.

I'd like to do some imaging with it, direct mounting my DSLR. Primarily wide-field DSOs initially. I know AltAz isn't best for imaging but thinking it might be good enough for what I want to do - relatively short exposures and stacking frames.

Current scope is a beginner's Bresser 70/700 refractor- which will be upgraded if the astro bug really bites the aforementioned 7yo. 

So both scope and camera are relatively light payloads.

I don't really know what's out there but have looked at the Skywatcher Star Discovery AltAz and EQ Pro 3 mounts. Any other options out there?

I'm not looking to get into using a laptop for scope control but somewhat intrigued by the option to use my Android phone - been reading about the Virtuoso app and Bluetooth modules. Advice on those also appreciated.

 

 

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You might pick up a second hand Skywatcher AZ-EQ5 for that budget, perhaps a little more. It would give you the convenience of Alt-Az with the ability to switch to EQ mode if the imaging bug takes hold.

I have its big brother, the AZ-EQ6, which is by far the best tracking mount I have owned and people here have given the AZ-EQ5 great reports.

Edited by DRT

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You are starting out with a good budget. I'm hoping this is just for the mount.

i'd get a second hand HEQ5. Equatorial but relatively easy to set up once you know what you are doing, and as long as your observing sote isn't 1000 miles away from home you won't need to do anything more fancy than plonk it down and line it uo with magnetic north and then just do a star alignment. I wouldn't bother with a polar alignment ifyou are planning mostly visual stuff, a plonk it down and pointing north (with latitude previously set) will do. When you want to do 5 minutes subs widefield with the dslr this will be the perfect mount and you can get the polar alignment much tighter.

you'll need a power source too - threads everywhere about that.

if you are starting out wanting to do a. It of DSO imaging with a DSLR then make life easier from the start and go equatorial. 

James

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8 hours ago, jambouk said:

if you are starting out wanting to do a. It of DSO imaging with a DSLR then make life easier from the start and go equatorial. 

James

All good recommendations on this thread, but whether an EQ mount will make life easier is questionable. At the end of the day it all rather depends on where you think you'll want to end up. Make no mistake, if it's serious astro imaging, it'll be serious money!

Have look at the 'No EQ challenge' thread (https://stargazerslounge.com/topic/228101-the-no-eq-dso-challenge/) and the 'The EQ3 Challenge' thread (https://stargazerslounge.com/topic/279039-the-eq3-dso-challenge/#comment-3054192) to see what's achievable using Alt-Az and EQ3 mounts.

Ian

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'Easier' is a relative term :) [I'm sorry for my awful typing in the last post, this is what you get for typing on an iPhone in bed when very tired]

I think DSO imaging with a roughly aligned equatorial mount is easier (quicker and gives better results) than DSO imaging with an alt-az mount. I think if you had the opportunity to sit down with someone who understands how equatorial mounts work and how the celestial sphere works then you could get your head around the concept of equatorial mounts and polar alignment in an hour. I think once you are at that stage setting up a roughly aligned equatorial mount is about the same time as setting up a well aligned alt-az tracking mount; but the benefits of the former in terms of results out weigh the apparent simplicity of setting up the latter.

Yes if you get into this in a serious way you need to then start doing bang on polar alignments and get more advanced kit, but I'd still say if you are going into this thinking 'I want to image DSOs' then I'd go for an equatorial mount, but find buddes near by who can help. Make sure you go along to your local astronomical society / club.

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An Alt/Az is likely quicker to set up, but maybe not, they all take some time. But if imaging is a factor (as stated) the it will have to be an Equitorial. Alt/Az mounts just do not move right.

Additionally for imaging a goto is again preferable, motors are usually better.

If there are 2 people I will say that a manual mount has it's limitations: You find something, center it and get the other person to have a look and the object can have moved out of view. Tracking is a really useful thing.

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The mount doesn't "have" to be equatorial for DSO imaging, but if not you'll be limited to subs of 5-30 seconds depending on focal length, position of the target in the sky, accuracy of set up and tracking, and all other factors not necessarily unique to an alt-az mount (light pollution and sky glow, neighbours security lights etc). Though having said that, unless you are guiding and/or have spot on polar alignment and good tracking motors and depending on the focal length of your scope, you may still be limited to 30 second exposures with an equatorial mount.

james

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Going back to you said we can't observe from home and a 7 yard old. So the easier it is too grab kit and go out to observing location in our weather the better.

Will you be walking or driving to observing location?

EQ mounts are a tripod, head and weights, the bigger the eq mount the less likely you can carry everything at once and are very likely to need two or three trips, tripod with head, telescope, weights with other gubbins like battery.

Taking the star discovery it has freedom find this is very useful because it means the mount will work with no power. With power the mount can track and be goto. It has a vixen style dove bar so can take telescope off and fit other telescope or just a camera with lens. You have budget left for a couple eyepieces and battery power pack. The 150p is a decent size for general all viewing planets and DSO (they view as grey smudges you won't see glorious colour). (I've ignored imagining with the telescope that comes with the mount as it won't reach focus).

Funny enough I've just thought of one member who has both mounts star discovery and eq3-2 @Nigel G might be able to comment on weight/setup speed differences.

Edited by happy-kat

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As above, if you want to share the view with a small child then motors and tracking are essential. Losing the object you can see by the time the child is at the eyepiece will be a real problem with manual mount.

If you are travelling to a remote site and want a quickish setup then I agree with happy-kat, the 150p skywatcher star discovery is good value and will allow you to keep objects coming to keep the child interested.

As for photography, I know nothing about it except I think you need to make a decision whether you are visual or photography and then move on from there. Maybe accept that one scope cant do everything and use the scope as a learning/proving ground so you can jump in "all for yourself" when the child has grown up into their own interests and leaves you to get on with yours?

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Thanks - as to setup we can drive to a very secluded car park that's dark save for a few distant house lights. Good views all around so it will be our observing site of choice for pretty much everything (only low north-north-west slightly obscured).

You're right about tracking - that's one of our limiting factors as one of us finds something and by the time we've swapped over its moved.

I'm familiar with how to do PA - and as we'll be observing from the same site most of the time I can set the wedge once and have half the job done. I might even be able to mark out the alignment as there are concrete areas (old airfield).

The existing mount can be used as an EQ but my son prefers Alt-az movements - more logical to say up/down left/right I think at his age.

For now I think we'd use the existing telescope as he's quite attached to it so I'm just looking for the right mount. Having said that the 150p on the Star Discovery mount is a great deal at the moment - particularly as the mount seems to be unavailable on its own at present.

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For your information,

The EQ3 weight is a bit heavier than the Star discovery mainly because of the counter weights. But good for a field mount, not too heavy or big.

I have marked 3 points on my patio and leave the tripod in its levelled position but bring it in after a session, I also park the mount. The next sessions setup is about the same as the Star discovery, very minor polar adjustments and a 3 star align. With the marks on my patio and the tripod already levelled setup is around 5 - 10 minutes.

1 point is that with the EQ3 I never have to walk around the mount moving cables or the battery pack which I had to with the star discovery when it decided to do a 360 degree turn on alignment or going to a DSO, sometimes pulling a cable out of the camera or power to the mount, quite annoying.

Good luck.

Remember the star discovery 150p scope will not focus with a DSLR without a barlow or serious modifications to the focuser or ota.

Nige.

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If I were in your shoes and my children were still that age I would forget DSO imaging for the moment.  I would get a GoTo Alt/Az mount and decent planetarium software (Sky Safari) to keep you both occupied out at night and enjoying visual observation.  I would then look at doing some Lunar imaging which will be fine in Alt/Az mode.  Get a copy of 'Turn Left at Orion' too, its a great resource and gives a real feel what can actually be observed.

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1 hour ago, Owmuchonomy said:

If I were in your shoes and my children were still that age I would forget DSO imaging for the moment.  I would get a GoTo Alt/Az mount and decent planetarium software (Sky Safari) to keep you both occupied out at night and enjoying visual observation.  I would then look at doing some Lunar imaging which will be fine in Alt/Az mode.  Get a copy of 'Turn Left at Orion' too, its a great resource and gives a real feel what can actually be observed.

Thanks - we're already quite a way into observing Venus/Mars and the Moon. Also Jupiter a couple of times including once with the ISS zooming overhead. We're just missing Saturn - which is great as he's learning that the sky changes with the seasons and he needs to be patient! Turn Left at Orion is helping locate possible targets.

My slight problem is that unlike me at his age his expectations of DSOs have been spoiled by Hubble images - trying to explain why M42 isn't a riot of blue and magenta through a scope is proving tricky. First time he saw it he was hugely disappointed. I think some quick and dirty imaging might help with that - not expecting him to be involved that much in the imaging workflow but he'll be happy if he ends up with an image to take to school to say "I took this". They're not doing planets until next year - I've already warned the school that he'll probably end up teaching the class :)

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For me it is not the small grey smudge, but that the small grey smudge is x millions of miles away, that the light looks xx time to get to us, that there are x number of stars in the cluster etc. and this is what it looks like

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On 21/02/2017 at 19:50, happy-kat said:

For me it is not the small grey smudge, but that the small grey smudge is x millions of miles away, that the light looks xx time to get to us, that there are x number of stars in the cluster etc. and this is what it looks like

Me too - teaching the scale of the universe to a 7yo  not the easiest thing to do though :)

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To close out this thread I ended up buying a 150P Star Discovery Alt-Az. Not using the OTA yet but finally after a month of cloudy skies I got to use the mount with my son's Bresser refractor.

I had some concerns over the Skywatcher approach to GoTo alignment (compared to Celestron's bells and whistles approach) but I have to say I found it easy and reasonably intuitive. Also quicker than doing a Celestron three-star align. Yes you need to have some rudimentary knowledge of the skies but I'd warrant in these days of smartphone sky atlases pretty much anyone can find Rigel or Sirius. I got my first alignment (Betelgeuse & Arcturus) done in 10 minutes and was pleasantly surprised to find the mount went on to track M42 unattended for 45 minutes whilst I put my son to bed. It was also spot on when I did a GoTo tour of several objects.

Now I just need to wait for a properly clear night on a weekend so we can stay up later. Shame about spring arriving (and that's the first time I've ever not looked forward to the clocks going forward!

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A great update and hope you get much enjoyment from your mount and nice to read you attached the faved telescope you already had.

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