taskGNU Astronomy Utilities - Tasks: task #16282, Include ICRS equatorial coordinate...

 
 

You are not allowed to post comments on this tracker with your current authentication level.

task #16282: Include ICRS equatorial coordinate type

Submitter:  Mohammad Akhlaghi <makhlaghi>
Submitted:  Mon 24 Oct 2022 05:27:49 PM UTC
 
Should Start On:  Sun 23 Oct 2022 11:00:00 PM UTC Should be Finished on:  Sun 23 Oct 2022 11:00:00 PM UTC
Category:  Libraries Priority:  5 - Normal
Item Group:  Enhancement Status:  None
Privacy:  Public Percent Complete:  0%
Assigned to:  None Open/Closed:  Open
Effort:  0.00

Mon 24 Oct 2022 11:06:06 PM UTC, comment #1: 

A nice review of ICRS in relation to FK5 and J2000 is given in Feissel and Mignard 1998. In their Figure 1, they show the pole positions in relation to each other.

We should be able to use these pole positions to convert ICRS to 'eq-j2000' and from that, to all the other coordinate systems that are currently recognized.

Some other references:

Mohammad Akhlaghi <makhlaghi>
Project Administrator
Mon 24 Oct 2022 05:27:49 PM UTC, original submission:  

As of Gnuastro 0.19, we still don't recognize the "International Celestial Reference System" or ICRS (which is the IAU approved coordinate system; unlike FK5; that we do support!).

This stems from the fact that in lib/wcs.c we have used NED for the conversion of coordinate system information and NED doesn't have ICRS!

We should find the conversions (possibly from the link above, or other places) and implement them in the WCS library because many surveys like SDSS, J-PLUS or J-PAS use this equatorial coordinate system.

You can reproduce the problem like below:

$ sdssurl=https://dr12.sdss.org/sas/dr12/boss/photoObj/frames
$ wget $sdssurl/301/3716/6/frame-r-003716-6-0117.fits.bz2 -Or.fits.bz2
$ bunzip2 r.fits.bz2
$ astfits r.fits -h0 --wcscoordsys=eq-j2000
astfits: gal_wcs_coordsys_identify: the 'ICRS' value for 'RADESYS' is not yet implemented! Please contact us at bug-gnuastro@gnu.org to implement it

Mohammad Akhlaghi <makhlaghi>
Project Administrator

 

(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

No files currently attached

 

Depends on the following items: None found

Items that depend on this one: None found

 

Carbon-Copy List
  • -email is unavailable- added by makhlaghi (Submitted the item)
  •  

    There are 0 votes so far. Votes easily highlight which items people would like to see resolved in priority, independently of the priority of the item set by tracker managers.

     

     

     

    No changes have been made to this item

    Back to the top

    Powered by Savane 3.9