View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0000938 | SkyChart | 1-Software | public | 12-01-25 11:28 | 12-03-04 19:25 |
| Reporter | James Dietrich | Assigned To | Patrick Chevalley | ||
| Priority | normal | Severity | minor | Reproducibility | always |
| Status | closed | Resolution | fixed | ||
| Product Version | 3.5 SVN | ||||
| Target Version | 3.6 | Fixed in Version | 3.5 SVN | ||
| Summary | 0000938: statusbar and information window show different RA | ||||
| Description | When I select a star, the status bar shows the RA and Dec, as well as other information. When I then click on the star's label to bring up the information window, the RA shown is different than the one in the status bar. | ||||
| Steps To Reproduce | Set the time to 2012 January 11 16:52:20 UT. Set FOV to 5' and position to south celestial pole. Click on the star circled in the screenshot in the attached zip file. This is star nmd 0000-0000184. Now the statusbar says that the RA of this star is 24h00m00.00s (Shouldn't that RA be 0h instead of 24h?) Click on the star's label and the information window comes up. For Apparent coordinates, it says that the RA is 0h00m00.486s Clicking other stars nearby shows similar discrepancies. It seems to me that the RA shown on the statusbar and in the information window should be the same, except for the fact that the information window shows an extra decimal place of precision. To take it a step further: The information window says that the Astrometric J2000 RA is 11h48m22.071s Now I go to Setup -> "Chart, Coordinates" and change "Type of cooordinates" to "Astrometric J2000" Then I click on the same star again and the statusbar says that the RA is 11h48m22.15s, and the information window says that the RA is 11h48m22.147s. These two values are the same, but they don't match the Astrometric J2000 RA that was given in the information window before. | ||||
| Additional Information | I'm using 32-bit Debian, version svn2079. Attached is a zip file with my skychart.ini, an image showing which star I referred to above, and a small extract of the NOMAD catalog to make it easy to test. Thanks for looking at this, and please let me know if there is any other information you need. | ||||
| Tags | No tags attached. | ||||
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This is fixed by revision 2081. This was because of rounding error when computing J2000 position back from the apparent position. This is solved by saving the original J2000 position. This effect is normally not visible but it is amplified here because of the high declination. For this star a change of 1 second in RA represent only 0.005 arcsec in the sky (instead of 15 arcsec at the equator, the reason it as one decimal place more than declination). So do not give too much importance to the last digits of RA for the stars near a pole. It display 24h00m00.00s because it round 23.999999. I also change it to display 0h00m0.00s in this case. http://svn.origo.ethz.ch/viewvc/skychart?view=rev&revision=2081 |
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Thanks for fixing this. The coordinates all seem to match up properly now. Just a little question: I was looking at the diff for revision 2081 here: http://svn.origo.ethz.ch/wsvn/skychart?op=comp&compare[]=/@2080&compare[]=/@2081 And I saw these lines added to cu_catalog.pas: if rec.star.id='0000-0000184' then begin rec.star.id:='0000-0000184' ; end; It doesn't look to me like those lines would actually do anything. Do they need to be there, or is this something left over from your testing? |
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Thank you to notice that! Yes this was temporary code to put a breakpoint when processing your star. I miss to remove it. This is removed by 2091: http://svn.origo.ethz.ch/viewvc/skychart?view=rev&revision=2091 |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 12-01-25 11:28 | James Dietrich | New Issue | |
| 12-01-25 11:28 | James Dietrich | File Added: 1.zip | |
| 12-01-25 15:14 | Patrick Chevalley | Note Added: 0001919 | |
| 12-01-25 15:14 | Patrick Chevalley | Assigned To | => Patrick Chevalley |
| 12-01-25 15:14 | Patrick Chevalley | Status | new => resolved |
| 12-01-25 15:14 | Patrick Chevalley | Resolution | open => fixed |
| 12-01-25 15:14 | Patrick Chevalley | Fixed in Version | 0.3.0 => 3.5 SVN |
| 12-01-25 15:14 | Patrick Chevalley | Target Version | 0.3.0 => 3.6 |
| 12-01-30 11:31 | James Dietrich | Note Added: 0001925 | |
| 12-01-30 11:31 | James Dietrich | Status | resolved => feedback |
| 12-01-30 11:31 | James Dietrich | Resolution | fixed => reopened |
| 12-01-30 11:51 | Patrick Chevalley | Note Added: 0001926 | |
| 12-01-30 11:51 | Patrick Chevalley | Status | feedback => resolved |
| 12-01-30 11:51 | Patrick Chevalley | Resolution | reopened => fixed |
| 12-03-04 19:25 | Patrick Chevalley | Status | resolved => closed |
