Plate solving advice needed

[konstantinos75]

Plate solving is an advanced technique where the telescope will slew to exactly where it previously was to line up with the stars in a shot perfectly, so as to continue a shot or start again a new night, or multiple nights etc

I have at my disposal

·        Skywatcher HEQ5 synscan Pro mount

·        MaximDL

·        Sky 6 professional software bisque

·        Software bisque Tpoint

This is how I set my equipment for astrophotography.

1)      Power on the mount; set skywatcher Synscan hand controller to “PC direct mode”

2)      Start Sky 6 connect to the telescope with EQMOD ASCOM

3)      Insert Tpoint in Sky 6 and map 6 bright stars near my target

4)      Perform goto to the target

5)      Use joystick to center my target

6)      Start autoguiding and capturing with MaximDL

Imagine this; I take a fit image of M45 on the first night let’s call it “image1.fit”. Then I park the scope and don’t dismantle anything. The second night I want to slew the telescope exactly to M45 as it was previous night. Plate solving technique will help me do this. I capture “image2.fit”.

“Image1.fit” and “image2.fit” should be perfectly aligned to each other.

How I can do plate solving without get rid of my current software? I have heard about CCDautopilot but I am not sure… Also I have heard about Sequence Generator Pro… also not sure… All I am asking is to make plate solving in a easy way, like push here dummy ,  and make use of my current software.

Any advice is welcomed!

Thank you very much

Konstantinos

www.albireo.gr

[PatrickGilliland]

Ok here is how I do it and its a doddle.

See you have maxim DL so that's the trick to it.

First complete all your normal alignment processes including polar align.  Get this as accurate as is possible as per normal and then complete your focus procedure.

Next load the image you wish to solve into Maxim DL.

Analyze>Pinpoint Astrometry

Click solve (if set up correctly with correct catalogues) it will now solve.  If it does not plenty of guides available - note I purchased the full version of pinpoint so am assuming to works with the free version to but can not confirm.

Once analysed press close button.

Next in maxim open observatory control options and goto telescope.

Ensure auto expose after slew is set up (bottom right I think).

Next to ensure it works click on arrow next to goto button and select the option to refine exposure after slew, here I normally select the filter I am focused on and auto-dark - I set exposure to 5-10 seconds dependant on conditions and object targeted.

Close form and press arrow again the select load centre of solved image - you will see co-ordinates update.

Press goto - if all working it will slew to position take an exposure as per your settings compare and then make a final adjustment slew.

Ready to go!

This process takes 2 minutes once you are used to it and works everytime for me without fail.

Any questions give me a shout.

Paddy

[IanL]

Might be an idea to take a look at AstroTortilla:

http://sourceforge.net/p/astrotortilla/home/Home/

It plays very happily with EQMOD and apparently it works with MaximDL (though I have only used it with APT).  There is a good tutorial on setting up and using it here:

http://lightvortexastronomy.blogspot.co.uk/2013/08/tutorial-imaging-setting-up-and-using.html

Not at all sure about using TPoint with a HEQ5, seems to me a bit like hiring an F1 driver to work at the local taxi firm  To be honest, if you get plate solving working for you and use the EQMOD 'append on sync' option, you can do away with anything else designed to improve your mount's goto capabilities.  With AstroTortilla I can just finish polar alignment, slew to my first target and have the software capture, solve, sync and recenter and it'll be spot on target every time.  (Plus it builds the EQMOD pointing model for you as you move from target to target).

Should also say that you can load a previous image, have AT solve it and slew the scope to centre exactly on it, which is great for multi-night imaging.

[Merlin66]

have a good look at AstroArtV5 - does plate solving much quicker than AT....also pretty good at guiding ;-)

[D4N]

17s is normal for my AT plate solves, it will depend on how you have it set up mind, it's got lots of fiddly options.

Sent from my iPad using Tapatalk

[konstantinos75]

Hi all

I have created this short tutorial which describes the steps I must follow to shoot the same target on multiple nights with a CCD camera. This tutorial is based on our discussion with Pinpoint.

Could you have a review of it? I need to test this on the field.

https://www.dropbox.com/s/cuen709sagfh4vw/Pinpoint_guide.doc?dl=0

Last but not least, I have noticed PinPoint sometimes takes a long time to plate solve a fit image. I have to abort the operation. Any idea why this happen?

Thanks

[NOMH]

I have used Maxim DL for about 2 years and used the plate solve as described above. It works great and the plate solves can take a bit of time. Try adjusting exposure times to speed up the process and always use the luminance filter.

I recently tried the trial for SGP and I purchased after only a couple of weeks. After two nights I had full automation going and a few nights after that I made all of the minor adjustments to get everything running all night with no problems. Best $99.00US I've spent in this hobby.

JB

[PatrickGilliland]

SGP?

[lensman57]

All this plate solving sounds fine but more often than not I find that I really don't want my target in the center of the image so it is back to square one with taking a test exposure and then slewing to the correct position.

A.G

[pietervdv]

SGP: sequence generator pro. I fully agree, best money I have ever spent in imaging.

Pieter

[ian_bird]

Hi all

Last but not least, I have noticed PinPoint sometimes takes a long time to plate solve a fit image. I have to abort the operation. Any idea why this happen?

Thanks

Hi

If the recorded RA Dec in the FITS image is too far off to begin with - plate solves can take a lot longer or even fail as they have to start a spiral search.

Maxim DL 6 (The new version) has a link to the Sky Online which will  rapidly get you in the ball park before the final solve. Works a treat. It only gives you the center of the image and image scale - but that is enough for the plate solve to complete in seconds.

Cheers

Ian

[Gina]

I use AstroTortilla (free) for plate solving though I have AstroArt 5 which I might try.

[PatrickGilliland]

All this plate solving sounds fine but more often than not I find that I really don't want my target in the center of the image so it is back to square one with taking a test exposure and then slewing to the correct position.

A.G

A.G. - framing is an issue and has to be done manually for best results. 

But if you want to pick up the image sequence on a number of nights then you need to solve your image (taken on previous evening) and plate solving will get it spot on. 

Paddy

[lensman57]

A.G. - framing is an issue and has to be done manually for best results. 

But if you want to pick up the image sequence on a number of nights then you need to solve your image (taken on previous evening) and plate solving will get it spot on. 

Paddy

Very true but honestly I can not remember the last time that I had two consecutive clear nights for imaging . More like two nights in a 2 or 3 weeks nowadays. Anyway with a mobile set up I just do what has to be done.

A.G

[konstantinos75]

Hi 

I have have upgraded to full version of PinPoint.

I have found the reason why PinPoint takes long time and finally will not plate solve the FITs image.

After examining the FITs header I see RA/DEC parameters are missing.

This is because when I captured the image via MaximDL, I did not enabled the link to the telescope in the Observatory Control window of MaximDL. So the program did not put this info in FITs header.

After manually inserting it, now plate solving works fine and very fast using PinPoint.

Regards,

Kostas

[Merlin66]

It's funny you should mention not wanting the target exactly in the middle of the frame....

We are investigating semi-remote spectroscope operation and usually the entrance slit sits away from the guide field centre..

Fabio at AstroArt and John with his ObsMgr script (https://groups.yahoo.com/neo/groups/AA5ObsMgr ) are working on possible solutions to allow the target star to be plate solved then "nudged" to another X-Y location within the frame...

We're not there yet but testing continues.

[IanL]

For your initial set-up you might solve based on catalogue coordinates for a target, but you may not get good framing depending on field of view, camera rotation and where the recorded centre of an object is (i.e. may not be the "interesting" bit). It will get you close but then you may have to re-frame.  Personally I try to use software to plan the framing beforehand - had to write my own to do what I wanted - see link below.  That will let me know the required camera rotation and RA/Dec of the centre of the desired frame, then I head off to a planetarium to find a catalogued star closest to the centre of the desired frame.  You can pick that, slew the scope there and then use plate solving to ensure you are centred (you can just type the coordinates of course, but I find it much easier to enter a short catalogue number, search and slew to it - especially if you have to keep slewing away to focus and the go back again).

For subsequent nights you just need a previous image and tell the plate solver to re-centre - again you need to ensure the camera rotation is correct.  If the software relies on WCS coordinates in the FITS header of an image then I guess it could well be off target, but using AT it first solves the example image and then slews/captures/solves/re-centres to match so there should be no possibility of error - well it works for me anyway.

[lensman57]

For your initial set-up you might solve based on catalogue coordinates for a target, but you may not get good framing depending on field of view, camera rotation and where the recorded centre of an object is (i.e. may not be the "interesting" bit). It will get you close but then you may have to re-frame.  Personally I try to use software to plan the framing beforehand - had to write my own to do what I wanted - see link below.  That will let me know the required camera rotation and RA/Dec of the centre of the desired frame, then I head off to a planetarium to find a catalogued star closest to the centre of the desired frame.  You can pick that, slew the scope there and then use plate solving to ensure you are centred (you can just type the coordinates of course, but I find it much easier to enter a short catalogue number, search and slew to it - especially if you have to keep slewing away to focus and the go back again).

For subsequent nights you just need a previous image and tell the plate solver to re-centre - again you need to ensure the camera rotation is correct.  If the software relies on WCS coordinates in the FITS header of an image then I guess it could well be off target, but using AT it first solves the example image and then slews/captures/solves/re-centres to match so there should be no possibility of error - well it works for me anyway.

Hi Ian,

This is more or less what I do using CDC and a bit of juggling.

A.G

[Ibbo!]

I find it works much better if you are well focused

[ChrisLX200]

With SGPro I simply power up the mount (after Parking it the previous session), no alignment run at all I just 'goto' the target. I select Center Target to plate solve and position the object precisely (Elbrus solves each pass in a few seconds usually, unless it needs to fall back to a blind solve - which is very rare). Then calibrate PHD2 immediately after the plate solve, and then run the autofocus (a manually triggered focus run so I can check the seeing etc). Finally I re-start the sequence from where it left off last time.

For Framing I use SGP's Frame and Mosaic Wizard - brilliant, it will download a 4x4deg chunk of DSS data and you just draw a small square on it (for a single frame) and drag it around until you're happy with the framing. Using DSS data means you see exactly what you will get, not some green outline or icon on a star map. If you want to get fancy you can use SGP's 'Manual Camera Rotator' which will indicate which way to turn the camera in the focuser and by how much in order to get the orientation you desire, then plate-solve and offer a correction if needed. It's an iterative process. If you have a motorised rotator of course you'll use that instead. Mosaic is the same - just draw a larger square and the wizard will calculate the overlaps needed and create the sequence needed for all the panels. Again, the panels are positioned using the plate solver.

SGPro may not be a fully robotic capable, but it's all you need to make data capture easy.

ChrisH