Installation and usage issues about a-track

[yucelkilic]

Dear @ppissias,

First of all, thank you for your great effort. Can you send me 3-4 sample fits files to [email protected] to repeat the problem and to help you better?

Best wishes.

[ppissias]

Hi @yucelkilic
thanks a lot for your reply,
Finally I saw that sextractor was not installed correctly. It seems that using the package manager i.e. sudo apt-get install sextractor does not install it correctly (it seems to install just some documentation and no executable... not sure what the isssue is). I manually installed it and then installed some other missing python packages and finally got it to working correctly!
I have 2 questions:

1. I noticed that it cannot process color images, do you confirm that this is the case? (the initial images I had the error I sent you were from color images, now I got it working with monochrome images).
2. One other question, if the files already have the WCS elements on the FITS header, does the software read them from the FITS header?

Many thanks,
Petros

[yucelkilic]

Dear @ppissias,

Glad you solved the problem. When you using A-Track, I suggest you run it with the "--skip-mpcreport" argument for now. For example;

python3 atrack.py /path/fits_files/ --skip-mpcreport

Otherwise, you may have some problems with the mpcreport part, so you can skip it. On the other hand, A-Track only supports monochrome images, you are right. Actually, the A-Track runs on catalog files produced by the sextractor and can work with all input files that SExtractor accepts. I suggest you set "solve_field = False" and "reject_area = False" in "atrack.config" file.

If you already have WCS in your images, 'ALPHA_J2000', 'DELTA_J2000' information will be extracted by the source extractor and A-Track will be able to read it easily and you should also see this information in the result list of detected moving objects.

I hope I could help. If you have any other problems or suggestions, please write at any time.

Best wishes,
Yucel

[ppissias]

Thanks Yucel,

Regarding WCS data, the images are already "plate solved" using a local astrometry engine or by nova.astrometry.net
and have a header like

SIMPLE  =                    T / Standard FITS file                             
BITPIX  =                    8 / ASCII or bytes array                           
NAXIS   =                    0 / Minimal header                                 
EXTEND  =                    T / There may be FITS ext                          
WCSAXES =                    2 / no comment                                     
CTYPE1  = 'RA---TAN-SIP' / TAN (gnomic) projection + SIP distortions            
CTYPE2  = 'DEC--TAN-SIP' / TAN (gnomic) projection + SIP distortions            
EQUINOX =               2000.0 / Equatorial coordinates definition (yr)         
LONPOLE =                180.0 / no comment                                     
LATPOLE =                  0.0 / no comment                                     
CRVAL1  =        312.584785922 / RA  of reference point                         
CRVAL2  =        44.3796425302 / DEC of reference point                         
CRPIX1  =        739.564693451 / X reference pixel                              
CRPIX2  =        412.081944227 / Y reference pixel                              
CUNIT1  = 'deg     ' / X pixel scale units                                      
CUNIT2  = 'deg     ' / Y pixel scale units                                      
CD1_1   =   -0.000129378038268 / Transformation matrix                          
CD1_2   =    0.000693935921799 / no comment                                     
CD2_1   =    -0.00069486223599 / no comment                                     
CD2_2   =   -0.000129152873537 / no comment                                     
IMAGEW  =                 1522 / Image width,  in pixels.                       
IMAGEH  =                 1125 / Image height, in pixels.                       
A_ORDER =                    2 / Polynomial order, axis 1                       
A_0_0   =                    0 / no comment                                     
A_0_1   =                    0 / no comment                                     
A_0_2   =   -1.26499559714E-06 / no comment                                     
A_1_0   =                    0 / no comment                                     
A_1_1   =   -2.39062436835E-07 / no comment                                     
A_2_0   =   -8.12762702006E-08 / no comment                                     
B_ORDER =                    2 / Polynomial order, axis 2                       
B_0_0   =                    0 / no comment                                     
B_0_1   =                    0 / no comment                                     
B_0_2   =     1.3610757751E-06 / no comment                                     
B_1_0   =                    0 / no comment                                     
B_1_1   =     8.8428680197E-08 / no comment                                     
B_2_0   =     2.5731858321E-07 / no comment                                     
AP_ORDER=                    2 / Inv polynomial order, axis 1                   
AP_0_0  =    0.000105004787597 / no comment                                     
AP_0_1  =    -5.4694811938E-07 / no comment                                     
AP_0_2  =    1.26357249829E-06 / no comment                                     
AP_1_0  =   -3.97035003821E-08 / no comment                                     
AP_1_1  =    2.38950114567E-07 / no comment                                     
AP_2_0  =    8.11809968058E-08 / no comment                                     
BP_ORDER=                    2 / Inv polynomial order, axis 2                   
BP_0_0  =   -0.000114472684206 / no comment                                     
BP_0_1  =    6.04213905525E-07 / no comment                                     
BP_0_2  =   -1.35946156203E-06 / no comment                                     
BP_1_0  =   -3.87567298792E-08 / no comment                                     
BP_1_1  =   -8.84976210267E-08 / no comment                                     
BP_2_0  =   -2.57232933876E-07 / no comment      

Apologies, since I am not an expert on this but would this be enough ?

Thanks!
Petros

[yucelkilic]

Dear @ppissias,

For the astrometric solution of FITS files, I also use local astrometry.net (solve_field). This header will be enough. You can use ds9 to check your WCS header.

Best wishes,
Yucel