Help - how to use platesolving to control CG5

[RobertI]

I have decided to try using platesolving to acquire objects for my video/EAA sessions as I find doing gotos remotely from inside the house is not always reliable and initial alignment is a pain. I have a Celestron ASGT (CG5) which I control from a PC using Stellarium connected to NexRemote software and a long cable connected to the handcontrol. I use a Lodestar camera and Starlight Live software for image capture. 

I have been getting a bit lost with platesolving to be honest, not helped by the lack of information on CG5 mounts, and the options available for platesolving. The questions seems to boil down to:

• What platesolving sofware to use
• How to feed the captured image from Lodestar Live (or other suitable capture software if this is not possible) to the platesolving software
• How to get the platesolving software to position the CG5 mount whilst still allowing planetarium control of the scope 
• What cabling to use

I'd really appreciate some pointers as I am rather lost!! 

Thanks  

 

[furrysocks2]

I think I'm interested in finding a similar workflow.

My last sessions have involved capturing frames in SharpCap, running a script on the command line to solve the most recent snapshot in the output directory and issuing "go to" commands via Stellarium's HTTP-based remote control interface to simply display my location, then manually tweaking RA/Dec handles and repeating the solve to get closer to a target. Integrating two drive motors for goto is my next step, and thereafter trying to work with alignment and solving.

From 

Quote

some tools combine platesolving with iterative goto's that will get you to target by adjusting the next goto to take into account the error between target position and the actual position reported by the plate solve  - alternatively they may issue a sync to the mout driver (which does the same thing) and with EQMOD this can be used to create an aligment model as well ! 

 

I don't know if an "alignment model" is what I think it is (converting equatorial coordinates to mechanical mount coordinates?), but I'd like it to be possible to combine inaccurate goto and plate-solving to iteratively "home-in" on a target and also "learn" the alignment of a mount's axes to improve subsequent goto accuracy - based on the assumption that of course good scope levelling and polar alignment will improve results in all cases (re: field rotation and drift) but given short exposure imaging and live stacking together with "learning", acceptable results can be achieved.

Is this the same goal? If this is just N-star alignment (or a generalised version of the process for arbitrary "solved" coordinates rather than stars), there must be ways and means already.

[furrysocks2]

Not an answer, but relevant background: http://eq-mod.sourceforge.net/docs/eqmod_alignment_models.pdf

[Dr_Ju_ju]

I don't have or know the mount or NexRemote software, but if it has the ability to call external programs to capture an image & then control mount position, it may be worth looking at a local Astrometry.Net server (http://adgsoftware.com/ansvr/)  This works for SGPro, APT etc....

[RobertI]

Thanks for the info and links @furrysocks2 and @Dr_Ju_ju, some useful information. It seems from the link that Astrotortilla and SGPro  are commonly used software for capturing, solving, working out how far away from the target and telling the scope where to go. 

So assuming I choose one of these, my problem is how to get Astrotortilla and SGPro to communicate with the CG5. I assume I need to control the mount via ASCOM, so need to install the "Celestron Unified ASCOM Driver" , but not sure what cabling to use , where to plug it in and what effect this has on use of the hand controller? As I mentioned, I am clueless on this!

I see from the link that @joecoyle and @Thalestris24 use Celestron AVX's so perhaps they can advise if they are watching? 

Thanks

Rob

[Dr_Ju_ju]

First, you'll need to install the Ascom platform (http://ascom-standards.org/Downloads/Index.htm) Then as long as you have appropriate Ascom drivers for each device & the software is Ascom compliant, all should work ok...

The left fileld solution would be to use Linux and the INDILib\KStars etc....

[RayD]

I use SG Pro for image capture and platesolving when I'm imaging away from home (Celestron AVX) and it works perfectly.  I believe it uses the same driver as your mount. I use Pinpoint for the platesolving, but you can use Platesolve2 or Elbrus equally as well.  I think it makes it very easy if you combine the platesolving with the image capture and mount control as it all communicates seamlessly.

With the Celestron you can't use EQMOD for mount control, but the driver will connect with either Cartes du Ciel, which is my preference for the actual imaging, or Stellarium if you prefer.  CdC is more of a star chart and Stellarium more planetarium, so I tend to use Stellarium or SkySafari to plan my session, then CdC to run it as to me it is just easier to use for this.

Once you start up from your park position, just move to somewhere with a good star field and use your chosen platesover to do a solve and a blind sync so the system knows where is it pointing.  Using CdC or Stellarium slew to the location you are imaging.  Once in the vicinity of the target you can do a solve and sync, which should get you very close, and if using SGP you can use a centre here function to get your target perfectly framed.

Plate solving if imaging is extremely easy and very accurate as you can even take an image from your last session, solve it and use those coordinates for your current session.

I have just set up a YouTube channel where I am doing videos in really simplified terms showing how to do certain things, and Platesolving is one I have planned for this week, so weather permitting I can add the AVX to this to show it working with the Celestron driver on Stellarium.

[RayD]

With regards to cabling, you keep your handset plugged in and plug a USB cable from the bottom of that to your computer.  You may already have this cable if you are controlling your mount from indoors.

[Thalestris24]

Hi

Thanks for mentioning me!! Yeah, I have an AVX with a NexStar+ handset and cable as above. I use Ascom platform, StellariumScope+Stellarium, APT for image capture, PHD2 for guiding and Astrotortilla for platesolving. The Astrotortilla works fine for me which is why I've never changed it. APT supports Platesolve 2, I think but I've never tried it. It doesn't look like Astrotortilla will be developed any further (though I might be wrong!). Still, it does it's job for now. My workflow is:

Select target in Stellarium

Use Astrotortilla to acquire an image 

Astrotortilla talks to APT and takes an image of the sky through the imaging camera

It uploads the image and does things to it and attempts to platesolve

If it comes back with RA/DEC close to where I want it to be I run AT again and this time slew to target and resolve. Very occasionally AT thinks I'm pointing somewhere else - not good cos it can slew the scope to miles away then everything gets confused! I think miss-solving is usually caused by poor sky conditions/wrong exposure.

Usually my platesolving exposure is set to 2-3 secs. Platesolving, slewing, solving again usually takes less than 30 secs. Centres my target

Hope that's helpful.

Louise

PS I don't use the hand controller as such but make sure the time and other settings are ok. The AVX has a battery so settings are stored. I just switch on the mount, hit enter on the controller a few times and select 'last alignment' or 'quick alignment'. Thereafter, everything is done from the PC.

[RobertI]

Thankyou @RayD very informative and answers a lot of questions. Very useful to confirm the cable arrangment ( thanks for the pic), for some reason I thought the cable had to go directly into the mount and bypassed the handset when using Ascom, but the handset cable is the one I already use, so that's good news. I understand the 'sync' terminology, but not sure which bit of s/w this is done in. I look forward to seeing the video!

Thanks @Thalestris24 , its good to see your workflow, and confirmation of cables, planetarium sofware, etc. I am familiar with Stellarium so will probably use that and Stellarium scope for now.

I think most of the main gaps in my understanding are plugged now, it's just a question of which image capture and platesolving s/w to use. I am assuming I will have to switch from Starlight Live (my main tooll for EAA) to another image capture tool to allow platesolving/slewing and then back again when I have centred the object and am ready to start 'observing'? SGPro seems a bit advanced given that I only need the platesolve/goto functionality (which does not appear to be available in the Lite version), I hear that Sharpcap Pro supports platesolving so might give that a go? Any thoughts on that or any other options?

Thanks again!

 

[Robrj]

Just to reiterate and add to what I mentioned in the other thread. 

You'll need the latest ASCOM (6.3), plus the Celestron ASCOM drivers for the mount (you probably already have that) and the ASCOM driver for Starlight Xpress cameras for use with APT (there's a link on Starlight Xpress' website).

For Sharpcap, you just need to install Astrotortilla, Cygwin and the indexes (all part of the Astrotortilla install).   Astrotortilla doesn't even have to run or be configured.  Sharpcap has it's own settings but needs the Astrometry server to be installed (which is what Astrotortilla's install does).  To plate solve, you slew with Stellarium/Stellariumscope and then click the "GPS" button in Sharpcap's telescope control (bottom right panel).  It will plate solve and then move the mount (the mount has to be aligned first).

For Starlight Xpress cameras using Starlight live I use the setup below.  It's a bit more cumbersome to set up but once it's up, it works great:

Astrotortilla and APT for plate solving, Starlight Live for capture with Starlight Xpress cameras, Sharpcap 3.0 Pro for Polar Aligning (with a different camera), and Stellarium/StellariumScope for finding targets.   

You can use a Starlight Xpress camera to do the Polar Aligning with Sharpcap 3.1 beta's native driver but you'll need to disconnect the camera or close Sharpcap before using Starlight Live as Sharpcap is always collecting from the camera (it will crash if you try to collect with Starlight Live at the same time).

I set up Astrotortilla using this tutorial:  http://www.lightvortexastronomy.com/tutorial-setting-up-and-using-astrotortilla-for-plate-solving.html

It's important to follow all the steps for Astrotortilla.  You'll need to figure out the field of view so you can choose the right indexes and set the correct parameters.  The tutorial walks you through it.  I would download all the indexes and move the ones you don't need to another location. It speeds up the plate solving if you only use indexes in range of your camera/telescope but ensures you still have any index available to copy in case you use a different camera or a different telescope.  It will take a while and uses quite a bit of space.  Once you have a camera/scope set up, save that profile so you can easily load it if you have more than one camera/scope combination.   I also have an Excel spreadsheet that can quickly calculate the settings and indexes you'll need for various cameras and scopes.

I'm doing this from memory so it may need a slight tweak.  I have a new laptop coming in a week so I'll be running through the setup again so I'll be able to ensure it's all correct.  For APT, I just use it for plate solving so you only need the free version, though I don't think the paid version is very much.  To connect the Lodestar to APT, assuming the ASCOM driver for the Lodestar is installed, just press <SHIFT> and click the "Connect" button near the top right.  You'll get the ASCOM driver dialog.  Select the Starlight Xpress Cameras from the CCD ASCOM Camera box.  Select Properties.  Click the "Enable USB Parameters" checkbox.  That will make the PID editable.  You'll need to set the PID to 507 for the Lodestar (it may already be set to that by default).  For an Ultrastar, the PID is 525.   Then select "OK".  You can have Starlight Live and APT both connect to your camera.  Just make sure to pause Starlight Live if you plate solve or it may lock up the programs (they can't both access the camera while it's capturing).

When StellariumScope is installed, there's an option to automatically set up Stellarium.  Click the "Update Stellarium Configuration" button.  You'll use StellariumScope to connect to your mount to the ASCOM Telescope.  Select "ASCOM Telescope" and then Celestron Telescope, set the appropriate COM port in the properties and click "Connect" after the scope is aligned.    Stellarium should work at that point.

Start up APT and connect your Lodestar as above (<Shift> and click "Connect").  Check the binning in APT as mine defaulted to 8x bin (1x bin is sufficient for the Lodestar).  Then start Astrotortilla.  Connect it to the telescope (again, ASCOM Telescope and then Celestron Telescope driver).  You shouldn't have to set the COM port again unless you put it in a different port.  Set the camera to "APT" (you don't need to do anything to the "Setup").  On the right, select "Sync Scope" and "Re-Slew to Target".  Re-Slew is what moves the telescope once it plate solves.  They'll be grayed out if the scope is not connected or while it is plate solving.

That should be it.  Select your desired object in Stellarium and hit <Ctrl>-1 to move to that object.  Once it stops, in Astrotortilla, click "Capture and Solve".  You should see something in APT's dialog stating it's running the Astrotortilla capture.  You'll hear a "Gong" from APT when it's gets the image and then Astrotortilla should start trying to plate solve it.  It will display the progress at the bottom of the Astrotortilla program.  It will show the number of objects detected and then start running through the indexes.  You want the number of Objects detected to be greater than 40, preferably above 50.  If it's too small, it won't plate solve.  To get the number of objects higher, either increase the "exposure" time in Astrotortilla (10s should be sufficient) or adjust the sigma number down (default with the setup is 70).  Be careful not to wipe out the "Custom options" line when you edit it.

 

[RobertI]

@Robrj That's fantastic stuff thank you so much Rob. I was just downloading Astrotortilla when your post landed so will complete that first and get it working and then move on to the image capture (probably APT to start with) and work my way through your instructions. Will let you know how I get on (will probably take several days!). Looking forward to getting this working. 

[Jkulin]

On 11/27/2017 at 14:57, RayD said:

I have just set up a YouTube channel where I am doing videos in really simplified terms showing how to do certain things, and Platesolving is one I have planned for this week, so weather permitting I can add the AVX to this to show it working with the Celestron driver on Stellarium.

Hi Ray, Have you got a link to your Youtube Channel?

Thanks

[stash_old]

 

For what its worth :-

I use APT with my DSLR but I have a Skywatcher AZEQ6 which enables me to use EQMOD however as long as you have a Ascom driver and can connect to your kit APT will also connect to your mount via Ascom which if you use Astrotortilla or All Sky plate solver will automatically centre your desired object in your FOV(well nearly 95% of the time).  I use a Serial to USB adapter(buy one your OS recognises without downloading a driver - e.g. a real FDTI)  to connect to the mount as this is faster(and easier than Network/TCP/UDP)

I have used both Astrotortilla and All Sky Platesolver and have found that with a semi fast set up (SSD,8GB and I5 proc) I normally get platesolving done (per plate solve) in about 7secs if you put the Indexes on the SSD drive - this of course may have to be repeated(automatically) until you are within your set ups parameters (mine is set at 20 pixels with dead centre of target).  This also assumes your Polar Alignment if "fair" else i will take longer.

If you set up your Obsys in your PC and have either W/less or wired ethernet you can use RDP/REALVNC etc to connect from a warmer place. I have ,for demo purposes,a smart Android TV device (£25 from fleebay bu most Smart TV's should allow this) which allowed me to download RDP as an Android APP which means I can (and have)  viewed/controlled all my kit from the lounge (Not allowed too - gets in the way of Come Dancing - so I use my Office and just use Windows RDP).

A word of warning if using Windows PC for your obsys - make sure you NOT Microsoft control updates as the automatic feature is a pain and again seems to do it when I am in the middle of Astro work

For me All Sky Platesolver is great (I prefer it to Astrotortilla as i seems faster!) as it comes with an installation process which helps you to choose and download the  correct "Index files" which can be very large in total (30GB plus)- luckily you dont need all of them as the tutorial mention above by Rob explains why.

I also use CDC rather than Stellarium(and of course Stellarium Scope???) as I have found that the latter tends to crash and because of he very good graphics appears to be memory/CPU hungry especially when using RDP/VNC remotes - usually at the most inconvenient point but that my preference and I know many dont get on with CDC. CDC works in conjuction with APT so any moves you make ,either from APT Stars database or CDC(for e.g.), is reflected in both automatically (Part of APT Settings - please remember to back up your APT settings - its a pain to redo them!). Of course you cant do Goto's on both(APT and CDC) at the same time as this would not make sense. 

I admit it might seem lazy to use Platesolving and remote control but being in a nice warm place wins hands down every time plus getting objects dead centre of FOV helps with my poor telescope optics (coma etc at the edge is bad)

Sorry  but my "t" key doesn't always work.

 

 

[RobertI]

Thanks for the info @stash_old, useful to have some other platesolvers up my sleeve.

I have not had any success with Astrotortilla yet, I have installed and configured as per Light Vortex Astronomy website, connected the Ascom Telescope Simulator and loaded one of my images file to platesolve (which successfully solves on Astrometry.net) but  I always get a not solved in between 5 and 10 seconds. The log file appears completely empty. I'm pretty sure I loaded the correct index files but not convinced it finished correctly so have uninstalled entire application and trying again. Fingers crossed. 

[Thalestris24]

Hi Robert

You shouldn't need to uninstall/reinstall anything. It's usually just a matter of getting settings correct. If you'd like to post a jpg I can check it for you with my Astrotortilla, if you also let me know your fov

Louise

[RobertI]

4 minutes ago, Thalestris24 said:

Hi Robert

You shouldn't need to uninstall/reinstall anything. It's usually just a matter of getting settings correct. If you'd like to post a jpg I can check it for you with my Astrotortilla, if you also let me know your fov

Louise

What a good idea, thanks! Image below.....I believe the FOV is 20' width.

[Thalestris24]

Will take a look

[RobertI]

Thx. ?

[Thalestris24]

Can't get it to solve yet though it finds ~189 stars. Are you sure about your images covering only 20' square?

 

[RobertI]

Well I’m pretty sure that’s what astrometry.net said when it solved it, and my setup is generally around that, sometimes a bit more depending on reducer spacing, I may be having a dumb moment though......?

[Thalestris24]

I'm just downloading the index files to cover it. I see there's a 0.8 pre-release Astrotortilla but I've not downloaded it - yet.

[Thalestris24]

Hi I'm not having much luck with your image... Do you have another - maybe with sharper stars, preferably little or no egginess... Can be resized but not cropped - say about 30% the size of the original.

Louise

[furrysocks2]

Pushed it through nova.astrometry.net...

19.8 x 15.3 arcmin

Field 1: solved with index index-201-00.fits.

 

[Thalestris24]

No worries - got a solve in the end  Here are settings I used: