[ask] how to get spesific wavelength with rspectext
Andreas Liudi Mulyo wrote on Jul 01, 2010
hi all ,
i have spectrum (gacrux.fits) which cover spectrum in visible wavelength (400 nm - 800 nm). I want to get wavelength from 580 nm - 620 nm.
First, i convert gacrux.fits into ASCII text (I used WSPECTEXT) with header and two columns (wavelength and intensity). From its ASCII text file, i select spesific wavelength which i want to get (580 nm - 620 nm) and delete rest wavelength with its correlated intensity (I used RSPECTEXT). The result was error message,
"Premature EOF seen in rt_rfpixels"
I tried to see the result, using SPLOT. There was spectrum with weird result.
I tried another way. I didn't print its header (option in wspectext) and then rspectext. It was worked, but its wavelength was not like it used to be. For example, it wavelength should have value 580 nm - 620 nm with intensity about 30,000 - 50,000 (gaussian pattern), but i get in .fits file value of wavelength was from 1 nm - 40 nm with with intensity about 30,000 - 50,000 (gaussian pattern). Maybe it because i delete its header which contain spectrum database?
I think intensity value is right, but how about wavelength? How i solve my problem?
Any help would be appreciated!
Thank you
Andreas
i have spectrum (gacrux.fits) which cover spectrum in visible wavelength (400 nm - 800 nm). I want to get wavelength from 580 nm - 620 nm.
First, i convert gacrux.fits into ASCII text (I used WSPECTEXT) with header and two columns (wavelength and intensity). From its ASCII text file, i select spesific wavelength which i want to get (580 nm - 620 nm) and delete rest wavelength with its correlated intensity (I used RSPECTEXT). The result was error message,
"Premature EOF seen in rt_rfpixels"
I tried to see the result, using SPLOT. There was spectrum with weird result.
I tried another way. I didn't print its header (option in wspectext) and then rspectext. It was worked, but its wavelength was not like it used to be. For example, it wavelength should have value 580 nm - 620 nm with intensity about 30,000 - 50,000 (gaussian pattern), but i get in .fits file value of wavelength was from 1 nm - 40 nm with with intensity about 30,000 - 50,000 (gaussian pattern). Maybe it because i delete its header which contain spectrum database?
I think intensity value is right, but how about wavelength? How i solve my problem?
Any help would be appreciated!
Thank you
Andreas
Mike Fitzpatrick wrote on Jul 01, 2010
Have a look at the SCOPY task as a way to pull out a specific wavelength range. I think your problem is due to the FITS headers not being updated with new NAXIS or wcs keywords after you edit the ascii file.
Andreas Liudi Mulyo wrote on Jul 01, 2010
fitz
Have a look at the SCOPY task as a way to pull out a specific wavelength range. I think your problem is due to the FITS headers not being updated with new NAXIS or wcs keywords after you edit the ascii file.
Thank you! It's been solved! :D
Last post on Jul 01, 2010