Extraction trick
figueira wrote on Mar 23, 2008
Hello all!
I want to create a blaze function for my spectroscopic data. To do so I would like to use the apertures and tracing that I did on an object image's order and extract the same pixels from a flatfield. Can I do this using doslit or any similar? If not, could you tell me simply how to sum n adjacent lines from a image and put them into a new image?
Keep up the good work and my most sincere thanks!
Pedro
I want to create a blaze function for my spectroscopic data. To do so I would like to use the apertures and tracing that I did on an object image's order and extract the same pixels from a flatfield. Can I do this using doslit or any similar? If not, could you tell me simply how to sum n adjacent lines from a image and put them into a new image?
Keep up the good work and my most sincere thanks!
Pedro
Mike Fitzpatrick wrote on Mar 23, 2008
Hi Pedro,
I believe there is a way to apply the aperture tracing from one image to another, but Frank is the ninja for that and will have to reply. To simply sum adjacent lines and create a new image see the BLKAVG task and set the 'option' param to sum, e.g.
would sum rows 10-20 to create the 'newspec'. Hope this helps.
Cheers,
-Mike
I believe there is a way to apply the aperture tracing from one image to another, but Frank is the ninja for that and will have to reply. To simply sum adjacent lines and create a new image see the BLKAVG task and set the 'option' param to sum, e.g.
cl> blkavg spec[*,10:20] newspec option=sumwould sum rows 10-20 to create the 'newspec'. Hope this helps.
Cheers,
-Mike
figueira wrote on Mar 23, 2008
Hi Mike,
Thank you very much for your reply. For now that's what I'll use. Still, I would like to know if Frank can repeat the tracing/extraction as I explained.
Thank you again!
P.
Thank you very much for your reply. For now that's what I'll use. Still, I would like to know if Frank can repeat the tracing/extraction as I explained.
Thank you again!
P.
Francisco Valdes wrote on Mar 23, 2008
Hello Pedro,
This is a common task with the APEXTRACT package. If you have run DOSLIT you should have aperture description files in your database subdirectory. To reuse the aperture description on another image use APALL and set the references parameter to be the image name that had apertures defined for it. Because something like DOSLIT may redefine names you may have to figure out what image name to use. But you can fairly quickly figure this out by listing the database directory and looking at the ap* names. You want to specify a name without the "ap" prefix.
Note that you may be asked about resizing, recentering, retracing, etc. You can just say no or turn off parameters for those steps.
I hope this helps.
Yours,
Frank Valdes
</u>
This is a common task with the APEXTRACT package. If you have run DOSLIT you should have aperture description files in your database subdirectory. To reuse the aperture description on another image use APALL and set the references parameter to be the image name that had apertures defined for it. Because something like DOSLIT may redefine names you may have to figure out what image name to use. But you can fairly quickly figure this out by listing the database directory and looking at the ap* names. You want to specify a name without the "ap" prefix.
Note that you may be asked about resizing, recentering, retracing, etc. You can just say no or turn off parameters for those steps.
I hope this helps.
Yours,
Frank Valdes
</u>
figueira wrote on Mar 23, 2008
Great! As you said, it's very easy.
Thank you very much!
Cheers,
Pedro
Thank you very much!
Cheers,
Pedro
Last post on Mar 23, 2008