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Old 09-02-2013, 07:59 AM
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pvelez (Pete)
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Some nights you are the windscreen... - Plate solving

and others you are the bug.

Last night I was the bug.

I've been struggling with guiding/flexure/collimation issues this week - posted elsewhere - again, eggy stars. Nothing I tried worked.

Oh well, best then refine my PA as its been a bit off. So started a TPoint run to check my adjustments. Would TSX plate solve - No!

Does anyone else find plate solving in TSX temperamental? Last week it wouldn't solve anything. I changed settings, dense images, simple images with only a few stars. Nothing.

Next day, load an image - BLAM instantly solved. Ran a 170 point session of auto calibration without any problems. Each image solved between 5 - 15 seconds.

This week - it wouldn't play again. Restart TSX after restarting the computer and it all runs smoothly. Last night, there was nothing I could do to coax it into solving anything.

All of this with no change to any settings. Same stock images.

Has anyone else seen this?

Pete

Last edited by pvelez; 09-02-2013 at 11:50 AM.
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Old 09-02-2013, 08:09 AM
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pvelez (Pete)
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Can you believe it?

Just switched on the puter - plate solved the first image from last night in TSX within 20 seconds!!

Damn!

Rant over for now

Pete
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Old 09-02-2013, 11:50 AM
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Plate solving!

I think I understand what is going on...

When starting my TPoint run, I delete the previous TPoint model. Mistakenly, I have not been syncing on a star first before getting started. So when I take an image with the Camera Add On the RA and Dec are not added to the FITS header. So Image Link has no means of actually doing a plate solve and it fails.

When I image with Maxim, if it is not connected to TSX, again there is no RA and Dec written to the FITS header and plate solves fail. However, when Maxim is connected, it writes the RA and Dec from TSX based on where TSX thinks it is pointing. So Maxim has something to work with and plate solves.

Here is the trick - which is what has confused me leading to odd results. When Maxim late solves, it writes the RA and Dec to the FITS header. TSX now has something to work with and obediently (and quickly) plate solves the image. So TSX will plate solve images taken with Maxim but not its own images - because the pilot clearly has no idea how to fly this particular plane!

I tested it this way. I had an image taken with Maxim without it being connected to TSX. Neither TSX nor Maxim would plate solve. I then manually entered the RA and Dec for the image into the appropriate field in the Astrometry tab in Maxim and solved it. Opening the image in TSX, it then happily plate solved.

Does this make sense?

If I am right, the take away for others is - sync in TSX first before trying to image and plate solve it.

I can't wait to test this - its no fun stuffing up, but I feel much better about it when I solve the puzzle.

Pete
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Old 09-02-2013, 01:54 PM
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Octane (Humayun)
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Yep, I've had the same thing before, trying to solve something using PinPoint LE that had no RA/DEC approximations. I now make sure that my RA/DEC is written to the FITS header. No problem.

H
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Old 09-02-2013, 03:05 PM
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Good tip and yes I have found T-point models fussy and prone to failure. I had it working with Marcus Davies help with the Sky 6 and PME. There it just required a larger databasae of stars (speaking of which I asked for and received from the US Navy astronomy department a free star database they will give out if you ask).

With PMX and Sky X there were a number of things I had to be careful of. In the end I am not sure which of the many things I adjusted made it go but it did.

But syncing first makes a lot of sense and I'll make sure I do that next time.

It makes me reluctant to delete the existing model and create a new one as I am not confident it will just work but I could probably get it going but how long would that take away from limited imaging time?

There's a lot to be said for a bullet proof polar scope!

Greg.
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Old 09-02-2013, 04:11 PM
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Quote:
Originally Posted by gregbradley View Post
Good tip and yes I have found T-point models fussy and prone to failure. I had it working with Marcus Davies help with the Sky 6 and PME. There it just required a larger databasae of stars (speaking of which I asked for and received from the US Navy astronomy department a free star database they will give out if you ask).

There's a lot to be said for a bullet proof polar scope!

Greg.
Agreed Greg - its a fussy thing. When its working, its great and when its not...it is so frustrating.

It drove me mad trying to work out what was responsible for the inconsistent results. Little did I realise that by examining the images in Maxim, I was actually changing the images and therefore clouding the issue.

I'm keen to get it just right and then to leave it alone.

Pete
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Old 09-02-2013, 05:07 PM
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Glad you sorted it Pete.
I use TSX, PME with tpoint and camera addon for all my auto callibration runs, personaly i would say it works flawlesly for me, it just works as it is designed to. Plate solves in a matter of seconds and will complete 650 points in a few short hours. Thanks to Software Bisque. Make sure before you start a new run, and syncing on an image link (as said before), you delete the syncronisation history in TSX.
I have noticed than when Pollar aligning, getting down to 30" of error in PA from the refracted pole for your location, the PA report will move to and fro after trying to improve on that figure. I believe there is a lot to be said for a single large (150 point) tpoint run at this stage, and then only moving ALT / AZI, half the recomended movement. The question is, is it worth getting any better?

Josh

Last edited by Joshua Bunn; 09-02-2013 at 09:18 PM.
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