SGP - Various Starter Questions

[PhotoGav]

I bow before the Oracle and seek your assistance and knowledge, oh wise ones.

I am looking at SGP as a possible solution to obsy automation (MaximDL is very expensive!) and have a trial version that, this time, I have easily set up plate solving (I tried last year, but failed miserably at this first step) and am just trying to get to grips with it all before setting up with the kit in earnest. I have this list of questions so far:

CCD cooling and warming - I use a QSI 683 and cool it to -20°C, what time should I use for the cool down and warm up periods?

Target Coordinates - What is the best way to populate the target coordinates? I am guessing that something like CdC is essential to slew to a target, unless you have starting coordinates from somewhere else that you can type in directly. You then frame up your target to your satisfaction, plate solve the image you are happy with and carefully type in the resulting coordinates? I am used to using APT which has a similar custom target details area, but with that you can just click a button and in go the current scope coordinates - very easy.

Is there anyone out there who uses the observatory controls in SGP? I am interested to hear your experiences, especially if controlling a dome with this software. Does it do the job properly and easily?!

Finally, for now, autofocus - I don't have autofocus hardware for any of my three scopes yet, but looking at SGP, it seems that the only way to really harness its full potential is by having autofocus. So, what is the best autofocus hardware solution? I have a WO Star 71, an SW 80ED and an EdgeHD 800. Do I need one set of kit for each scope that remains attached to the scope and is simply plugged in when I change scope? With the EdgeHD, I presume that I need to fit a focuser to the optical train that is then fitted with autofocus. I focus with the edge's standard focuser, lock the mirror and then use the other focuser to achieve good focus?

I thank you in advance.

[swag72]

I use a 5 min cool down and warm up time for my QSI and that's down to -15.

For Autofocus I use a Lakeside on each scope. It takes a bit of faffing around to get the V curves. Up until now I've just had one Lakeside control box and a stepper motor on each scope that just plugs in - That works fine if you are just using one instance of auto focus at one time.

[PhotoGav]

Thank you Sara. When you say 'a bit of faffing around to get the V curves', when does it do this? Is it every time you autofocus or just to begin with or how does it work in practice?

[swag72]

The faffing about is only the once to get the settings right for the V curve - Each scope will be different with the number of steps it needs, the increments it needs. Once that's set up, then it runs like a dream. It works very well indeed in practice.

[PhotoGav]

Ah ok, thank you, so it's just when you put the scope on first. Can you then store the settings for each scope or do you have to do it again each time you change scope?

My pockets are being stretched at every turn at the moment, though I have a feeling that I am edging towards a super-dooper complete set up! One other thing - do you know any decent cloud dispersal systems??!

[swag72]

In SGP you can set up equipment profiles so that you store the relevant settings for each scope / camera combo separately

[PhotoGav]

30 minutes ago, swag72 said:

In SGP you can set up equipment profiles so that you store the relevant settings for each scope / camera combo separately

Perfect, so that's where it goes!

[swag72]

Then when you start a sequence you pick the relevant equipment profile to suit... I have an ongoing Tak sequence and an ongoing ODK sequence, that I add to and remove targets from as and when. So I always know what is being done with what combo.

[PhotoGav]

Ah, ok, it's beginning to make some logical sense to me now. Thanks for your help.

What do you do about framing and entering coordinates? Just get on target via another system, frame up precisely in SGP and type in the coordinates I suppose?

[sloz1664]

You can populate your coordinates from website images, such as Astorbin. Find the image and then use the image URL in SGP.

Steve

[martin_h]

1 hour ago, sloz1664 said:

You can populate your coordinates from website images, such as Astorbin. Find the image and then use the image URL in SGP.

Steve

Or just load a random image from the web of the target of your choice, right click on the image and blind solve, it will then ask if you want to use those settings for your target.

[martin_h]

I cool/warm my CCD in over 5 mins, as for driving a dome I should imagine that will depend on the software/hardware installed for that purpose, SGP just integrates it all.

[Steve 1962]

Hi Gav

I also cool down in 5 mins (to -20c in winter, -15c in summer), but I don't actively warm up at the end, I just turn the cooler off.

Like Sara - I use a Lakeside focus motor. It took a bit of tinkering with the settings to start with but now it works every time. My scope needs a refocus every half degree of temperature change and it draws out a very nice V curve

As Martin and Steve have said, you can enter coordinates manually or download an image then plate solve it to input targetting information.....or you can do as I've just done and invest in the Mosaic & Framing SGPro Add-In - it's excellent. You just enter your camera / scope specs (which it remembers in subsequent sessions), search for your target, decide what you want as a FOV and it does the rest for you - it sets the target RA and Dec and creates a sequence for you. It also creates multiple targets if you're doing a mosaic.

One of the things I love about SGpro is the integration with various platesolvers - I used to just use a local Astrometry server but nowadays I use Platesolve 2 and fall back to the local Astrometry server (although it's never fallen back to it). Platesolve 2 solves within about  5 seconds every time. I've never had much joy with Elbrus though.

I'm just working on an ASCOM driver for my dome - I'll let you know how it integrates with SGPro when I get it working.

Steve

 

[Barry-Wilson]

I use the observatory controls in SGP - control roof (open/close with parking/unparking) and AAG cloudwatcher for Safety Switch.  All excellent.

As others have said SGP is remarkable quality for the price.  The Framing & Mosaic wizard is all I use now; the latest beta allows copy/paste of co-ordinates from CdC, but the F&M wizard is worth the small additional expense and is truly excellent.  Once you have set up the profile for your scope/ccd combination, it will seamlessly automate your image capture night after night.  There are a number of users familiar with it on SGL to help out if you get stuck.  The forum is very helpful too.

HTH.

[gnomus]

I have SGP controlling a Lakeside focuser on my WO Star 71 - it wasn't that difficult to set up - I just followed the instructions on the SGP help file.  I think you would need a separate unit for each scope (expensive business).  I also have an Edge HD 8" - with a Moonlite focuser screwed on the back.  I'm not sure if a stepper motor focussing unit would work on this, so this is controlled by a DC motor (manually, if you get my meaning) for now.  I don't have roof control set up and may be picking peoples brains about this in the summer. 

[swag72]

You don't need a totally separate Lakeside unit for each scope - Just a stepper motor on each and then you just unplug the cable from the control box and attach it to the other stepper on a different scope ....... if that makes sense

The Framing and mosaic wizard is excellent and I use it all of the time. I often find stuff on AstroBin and as long as it has been plate solved then you can copy and paste the page into the wizard and hey presto it will be there. I have found it totally indispensable for locating and framing smaller targets within the larger ones for the ODK10.... gets it bang on time after time. I don't think I could work without SGP now.

[PhotoGav]

Excellent, thank you both Steve's, Martin, Barry & Gnomus. That is all really helpful. I gave SGP a first go yesterday evening and had much success. I did lose my nerve though as the sky darkened beautifully and I hastily reverted to APT for a few hours capture. I will definitely be giving SGP a full work out next time.

Another question: there is the option to use High or Low gain for each binning with the camera - which should I use, what's the difference? It defaults to High.

Steve 1962, I am very interested to know more about your dome set up. Good luck with the ASCOM integration, please keep me posted! What do you do now for dome rotation? Do you just align manually with the scope and leave it tracking at sidereal rate? Then I suppose you have to realign after a meridian flip? And now the million dollar question - would you recommend a dome?!

[PhotoGav]

Thanks Sara. Looking on IKI, the first complete unit is around £300, with each further bracket and motor being £115. 

Gnomus - why don't you think the stepper would work on a moonlite focuser on the edge?

[gnomus]

45 minutes ago, PhotoGav said:

Thanks Sara. Looking on IKI, the first complete unit is around £300, with each further bracket and motor being £115. 

Gnomus - why don't you think the stepper would work on a moonlite focuser on the edge?

As I got the other question about the focusers spectacularly wrong, I'm a bit hesitant to reply.  

However, in for a penny ......

The focuser on the Moonlight is a Crayford and not a R & P, as they have on the WO.  I don't know if that makes a difference when it comes to being able to return to an exact position.  The Moonlite for SCT has limited travel - so if I put on a Barlow (for planetary work), I need to make a gross adjustment with the coarse focus, before locking up and going on to the Moonlite.  I don't know if this would mess up my settings in SGP.  Finally, there is the mirror flop issue, which I think can still be a problem even with the focus locks clamped down.  

It could be that my conerns are entirely without foundation - it would be handy to have an expert view (I am only 1 year into this addiction).  Sara?

[PhotoGav]

Ah, OK Gnomus, hopefully you are wrong and there is hope for both of us! From what I understand, the autofocus is a fine focus system to keep you in focus through the night, only after you have achieved pretty much perfect focus at the beginning of the session. So large changes required with the original focuser on the edge would be made first and then the autofocus would be used with the moonlite to make the small fine focus adjustments.

 

[gnomus]

Yes that is correct.  SGP moves the focuser to a series of positions from out-of-focus one way to out-of-focus the other.  It measures the half star diameters at each of (I have set) 9 points and plots these on a graph.  If you start from reasonable focus you get a 'V' or 'U' shaped curve, the bottom of which is the point of best focus.  SGP then returns from an out-of-focus position to that point.  What I don't know is whether the return to that point is repeatable with a Crayford as opposed to a R&P focuser.  

It is a pure joy to watch SGP in action with the Lakeside on my WO - I have it set up to refocus: every hour; if the temperature changes more than 1 degree; and on filter changes.  This is perhaps excessive.  (One day I will get around to calculating accurate filter offsets.) 

I can recommend the Lakeside unit with the WO Star 71.  It is slightly fiddly getting the coarse knob off the focuser (you would have to do this whichever focuser you choose, of course).  One has to line up a small hole with two tiny hex screws.  Slacken the screws but do not do this too much or you might get one jammed in the collar (I know because this happened to me).  Read the instructions carefully.

[martin_h]

I use the Sharpsky Pro system http://www.sharpsky.net/ in conjunction with SGP and my Star 71, works a treat, with the added bonus of a 4 port dew heater built in.

[Steve 1962]

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Steve 1962, I am very interested to know more about your dome set up. Good luck with the ASCOM integration, please keep me posted!

Hi again Gav - I have a 2.2m Green Pulsar dome which is coming up four years old....and I love it.  The dome has a DIY azimuth and shutter system that has provided me with hours of entertainment.

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What do you do now for dome rotation?

The dome azimuth rotation and shutter are driven by 2 x 24V stepper motors controlled through M542 motor controllers by a DIY arduino based controller which currently reads the Baader dome azimuth figures pumped out by my 10 Micron mount..and amazingly it works well at keeping the slot where the scope can see through it. The controller is monitored and "managed" by a bit of appalling self written VB code. I say this works well, but not being an ASCOM driver - SGPro can't talk to it, so I need to get my finger out and finish the ASCOM driver

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Do you just align manually with the scope and leave it tracking at sidereal rate?

If only if it was that simple!  That approach won't work.

The positioning and movement of a dome slaved to a GEM is quite a complex affair because the scopes optical axis is offset one way or the other depending on the side of pier that it's on - and the sky doesn't always move at sidereal rate as far as the dome is concerned.  As an example of the difficulty - the dome will generally move at sidereal rate for a southerly object tracking East through South to West - that's fine and quite easy to see, but now picture the scope pointing northwards and tracking a circumpolar target. Because we are facing north, the sky appears to rotate anticlockwise around Polaris .... so a target which is between Polaris and the North horizon will move from West to East and the dome will follow it. However, as the target travels Eastwards, it'll climb up around Polaris and, as far as the dome is concerned, its azimuth will slow to a stop when the target is due East of Polaris before reversing back Westwards and stopping again if the target reaches due West of Polaris before reversing again Eastwards..and so on. 

The point is that this is all mind numbingly complicated to me, so I let the mount do the sums for me at the mo, and then I'll let the ASCOM driver do them when I get round to it.

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Then I suppose you have to realign after a meridian flip?

No need to - the mount pumps out the correct azimuth based on the scope side of pier, as does the ASCOM Dome "hidden under the bonnet" hard sums bit included in the driver by the nice ASCOM peeps..

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And now the million dollar question - would you recommend a dome?!

Yes I would, but there also some nice Roll Off solutions that avoid all of the above hassle- but then again, they suffer from Dew which I've never had in my dome.

I can't be far down the road from you, so PM me if you want to come and have a look any time.

Steve

[PhotoGav]

Brilliant Steve, thank you for all of that. Indeed, complex stuff! I see that SGP offers the slave capability for the dome and has data entry fields for the offset values to figure out the geometry. So it should be simple for the user with all the difficult stuff dealt with by the software... 

Thank you, that's a very kind offer to visit your dome and one that I really might take you up on. You have exactly the dome I am considering so it would be invaluable to see one for real.

[Starflyer]

This is a cracking thread, lots of great info.

I'm just starting out with SGPro myself and the main reason for doing so was after finding that none of my Baader filters were truly par-focal.  I was focusing with a mask after every filter change and it was a right pain having to slew to a bright star, get focus with the mask and then frame the target again.

I went for the Lakeside system and after a couple of evenings out with it I have it generating good V-curves, it's making imaging pleasurable again.

I was going to go with Pinpoint for plate solving, but Plate Solve 2 just works, is simple to set up and best of all it's free.  I have a few sequences set up and ready to try, I've used Astrobin to define my targets and can't wait to give it a proper go now.

Here's my first rough and ready image using SGPro, it's noisy, the guiding isn't great, but the focus is pretty good.