I created a series of images featuring comet C/2025 M2. I used the latest comet data file from the MPC. However, ASTAP does not annotate the comet. When I run the same image sequence in Tycho, the comet is detected — along with a few others.
Using other comet image stacks they were annoted. Maybe something with M2 wrong.
Last edit: Waldhör 4 days ago
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1) The comet is currently magnitude 26.6. Nobody will be able to image such a faint comet. Enter as limit in the ctrl+R window as the limiting magnitude 27 or higher. See screenshot.
2) PinPoint (?) put in an old date format:
DATE = '06/08/25' / [old format] UTC date of exposure start
TIME-OBS= '17:03:05' / [old format] UTC time of exposure start
UT = '17:03:05' / [old format] UTC time of exposure start
This is very old style and confuses ASTAP which expect the standard format. Remove the three aboves lines from the header in ASTAP, save the fits and reload. Or correct in the ctrl+R window the date format.
The annotation is extended with the word "obsolete" when your database is a few months old. Just update the database and the word obsolete will disappear.
I assume the MPL comet file you can download is not fully up to date. I assume it is updated every few months only. Using this file the calculation will result in an magnitude of 26.7.
Does this line:
DATE = '06/08/25' / [old format] UTC date of exposure start
comes from Tycho? Please check because it should not be there and I like to contact the software author.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
I created a series of images featuring comet C/2025 M2. I used the latest comet data file from the MPC. However, ASTAP does not annotate the comet. When I run the same image sequence in Tycho, the comet is detected — along with a few others.
Using other comet image stacks they were annoted. Maybe something with M2 wrong.
Last edit: Waldhör 4 days ago
With the missing attachment.
There are two problems
1) The comet is currently magnitude 26.6. Nobody will be able to image such a faint comet. Enter as limit in the ctrl+R window as the limiting magnitude 27 or higher. See screenshot.
2) PinPoint (?) put in an old date format:
DATE = '06/08/25' / [old format] UTC date of exposure start
TIME-OBS= '17:03:05' / [old format] UTC time of exposure start
UT = '17:03:05' / [old format] UTC time of exposure start
This is very old style and confuses ASTAP which expect the standard format. Remove the three aboves lines from the header in ASTAP, save the fits and reload. Or correct in the ctrl+R window the date format.
The old date format is obsolete since 1999 and should not be used for dates after 1999!
https://heasarc.gsfc.nasa.gov/docs/fcg/standard_dict.html
The annotation is extended with the word "obsolete" when your database is a few months old. Just update the database and the word obsolete will disappear.
Han
Last edit: han.k 4 days ago
I think it was Pinpoint which added the old style date. Can you confirm this? If so we better ask Bob Denny to update his software.
The limiting magnitude of the image is about 17.8.
Hi, thanks. Curiously JPL says:
2025 M2 C/2025 M2 (PANSTARRS) 11:26 (10:26) 15:43 (14:43) 20:01 (19:01) 08:35 21:26:03 -16 45'36" 19.8T for magnitude. I checked it with my tool:
http://www.waldhor.com/astronomie/ephemworker/jplabfragesmallobjects.html (MPC Q71)
I assume the MPL comet file you can download is not fully up to date. I assume it is updated every few months only. Using this file the calculation will result in an magnitude of 26.7.
Does this line:
DATE = '06/08/25' / [old format] UTC date of exposure start
comes from Tycho? Please check because it should not be there and I like to contact the software author.
I update the comets every time before I plate solve.
DATE - seems to be problem/bug in the software of the camera . Images made with iTelescope.
Last edit: Waldhör 2 days ago
I will add some code that ASTAP gives an error or ignores this DATE. Weird that this format (abandoned in 1999) is in the header.
It looks like the original code already ignores the obsolete date later. But I will still add an additional check.