Plate Solve Error?

[admin]

Hi,

the 'sigma' setting is one that comes from ANSVR and it is a measure of how strong the signal of a star needs to be for the star to be allowed. Sigma=50 means that the star must be at least 50 times as bright as the noise level of the image, sigma=200 means 200 times as bright, etc. Setting it too low will lead to noise being detected as stars (maybe values below 20 or so might cause this). Too high means only the brightest stars will be detected, which might cause issues if there are not enough of them.

I have checked again and as far as I can tell closing the window does stop the plate solving. However in older beta builds the orange notification bar would remain on screen even though the plate solving had stopped. I have now fixed this in the latest beta build. Hopefully that was the issue.

cheers,

Robin

[rac19]

Hi Robin,

The attached images show the problem that I am seeing. Images capture, caprure1 ... capture5 show the original CPWIl GoTo followed by four calls to Plate Solve and Resync then a final CPWI Goto. The original CPWI GoTo is quite accurate having been previously adjusted by a SharpCap Plate Solve and Resync.

I think that e problem is that there is no error after the first Plate Solve and Resync but it detects an error and corrects by that amount. Successive Plate Solve and Resync calls add to the error.

The final CPWI GoTo returns the target to the centre of the image. Throughout all this, the CPWI model synching remains correct, but the SharpCap centering gets progressively more inaccurate.

The images were captured with the previous beta but the problem remains with the beta made available on June 13th.

If you want to the log file, please let me know.

Best regards
Richard

Note: The images are displayed in reverse order. Please start with the last image.

[rac19]

Hi Robin,

The attached images show the problem that I am seeing. Images capture, caprure1 ... capture5 show the original CPWIl GoTo followed by four calls to Plate Solve and Resync then a final CPWI Goto. The original CPWI GoTo is quite accurate having been previously adjusted by a SharpCap Plate Solve and Resync.

I think that e problem is that there is no error after the first Plate Solve and Resync but it detects an error and corrects by that amount. Successive Plate Solve and Resync calls add to the error.

The final CPWI GoTo returns the target to the centre of the image. Throughout all this, the CPWI model synching remains correct, but the SharpCap centering gets progressively more inaccurate.

The images were captured with the previous beta but the problem remains with the beta made available on June 13th.

If you want to the log file, please let me know.

Best regards
Richard

[admin]

Hi Richard,

what are your settings in the 'plate solving' tab for the second dropdown - 'After solving from Telescope Controls/Solve and Sync Menu'? Do you have 'offset the mount to recenter' selected there? If that's the case then what you are seeing is expected - when that setting is enabled you can only perform the solve and sync once after the GOTO of the target and get correct results. Performing the sync multiple times will cause drift as you are seeing because the second attempt sees the offset co-ordinates from the first attempt as the target and so on.

That doesn't explain why the first puts the star off center, and the log would be interesting from that point of view to see if I can work out what is going on there.

cheers,

Robin

[rac19]

Hi Robin,

It appears to be on the correct setting.

[rac19]

It looks like Sync is working well but it is offsetting instead recentering.

[rac19]

I temporarily changed to the Offset Centre option and that seemed to double the error. I changed back to Synch so that the correct should have been definitely written to the config and the pattern returned to "normal". It seems that one offset is permeant and a second offset is added. when the Offset option is selected.

I would send the log file except that I can't remember where it is.

PS The Brook dismissal was interesting.'

[admin]

Hi,

poor chap - he clearly had no idea where the ball had gone... If he'd have known he could have kicked it or hit it or just stood in the way quite legitimately...

The plate solving issue is equally strange Even if there was somethink like a JNOW/J2000 issue, that should give a constant offset, not an increasing one. Can't think of how any backlash effects could give the observerd results either.

The logs folder is easiest to find by restarting SharpCap, going to the log and then pressing the 'Locate on Disk' button. It will launch Windows explorer showing the current log, but the other logs will be in the same folder. Sometimes explorer comes up behind SharpCap.

cheers,

Robin

[rac19]

Thanks Robin,

I will send the log today. It's strange how the offset error is only on the RA axis. Dec corrections is accurate and stable. I have an Evolution 8 mount on a wedge, by the way.

I really want to get Plate Solve, Synch and Recenter working because either CPWI or PHD2 has a bug that prevents me from using Auto Guiding. It works for a while but after receiving multiple slow, small slew requests (as in guiding), the mount starts to "snap back" when receiving guide commands, making it useless.

I have been using using a Sharpcap Sequence that pauses every 10 minutes to Plate-solve and Recenter.It was working reasonably well but recently it has a been having a negative effect,

Actually, I don't understand why simple tracking at sidereal speed isn't enough to keep the target on centre, especially on the RA axis, but apparently not.

As for the unusual dismissal, I don't think that anyone knew where the ball went.

[rac19]

Hi Robin,

The logs are attached.

I am beginning to wonder if there should be a sequence step to GoTo Target to GoTo Saved Coordinates, without a Plate Solve. I will try it as a manual sequence when I get a chance, maybe tonight.

Best regards,
Richard