View Issue Details

IDProjectCategoryView StatusLast Update
0002301SkyChart1-Softwarepublic20-03-22 10:35
ReporterHugo52 Assigned ToPatrick Chevalley  
PrioritynormalSeverityminorReproducibilityhave not tried
Status feedbackResolutionopen 
PlatformPCOSWindowsOS Version10 64bit
Target Version4.4 
Summary0002301: Comet tracking, value is wrong
DescriptionThe comet tracking corrections for PHD2 for comet c/2019 Y4 is wrong RA 99,, I changed it to -199
TagsNo tags attached.

Activities

Patrick Chevalley

20-03-17 15:49

administrator   ~0006393

A possible explanation to the problem can be that PHD2 do not want the RA motion multiplied by the cosine of declination as CdC actually do.
This can make a big difference because of the high declination of this comet.

But 99/cos(66°) = 243 , not 199. Are you sure of the new value you set?

Also what version of CdC and PHD2 do you use?

Patrick Chevalley

20-03-17 20:32

administrator   ~0006394

I look at PHD2 source code and see it also multiply the RA rate by the cosine of declination.
So this correction was done two time and is the reason for this error.

This is fixed by:
https://github.com/pchev/skychart/commit/9497f53889744d5b304d9a30b33891936ca078c8

You can download a test version from this location until the fix is in the beta version:
https://vega.ap-i.net/tmp/skychart/

For tonight it show a RA rate of -253.

Please tell me if this work better now.

Patrick Chevalley

20-03-19 10:16

administrator   ~0006397

Last edited: 20-03-22 10:35

Last night I have clear sky for testing.
The attached image is 10 x 5 minutes stacked without alignment. The result is very good so I think now the computation is right.

There is still a difficulty with the sign of the declination movement. I need more testing to clarify this point.

I am very interested if you can confirm this behavior with your mount.
20200318-c2019y4.jpg (233,194 bytes)   
20200318-c2019y4.jpg (233,194 bytes)   

Patrick Chevalley

20-03-20 17:05

administrator   ~0006398

I do more testing last night.
My conclusion is PHD2 current version no more need the declination inversion that was previously necessary.
The fix I previously introduce for that must be removed, whatever the side of the meridian the calibration is done.
I make a new test version:
https://vega.ap-i.net/tmp/skychart/
With this one it give me perfect comet tracking.

Issue History

Date Modified Username Field Change
20-03-16 22:10 Hugo52 New Issue
20-03-17 15:47 Patrick Chevalley Project CCdciel => SkyChart
20-03-17 15:49 Patrick Chevalley Assigned To => Patrick Chevalley
20-03-17 15:49 Patrick Chevalley Status new => feedback
20-03-17 15:49 Patrick Chevalley Category General => 1-Software
20-03-17 15:49 Patrick Chevalley Product Version 0.9 =>
20-03-17 15:49 Patrick Chevalley Target Version => 4.4
20-03-17 15:49 Patrick Chevalley Note Added: 0006393
20-03-17 20:32 Patrick Chevalley Note Added: 0006394
20-03-19 10:16 Patrick Chevalley Note Added: 0006397
20-03-19 10:16 Patrick Chevalley File Added: 20200318-c2019y4.jpg
20-03-19 13:03 Patrick Chevalley Note Edited: 0006397
20-03-20 17:05 Patrick Chevalley Note Added: 0006398
20-03-22 10:35 Patrick Chevalley Note Edited: 0006397