Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Quasar redshift or garbage?

  • Please log in to reply
26 replies to this topic

#26 robin_astro

robin_astro

    Mercury-Atlas

  • *****
  • Posts: 2,567
  • Joined: 18 Dec 2005
  • Loc: UK

Posted 12 March 2024 - 07:22 AM

If the sky lines are in the right place in the QSO spectrum, your calibration must be good so perhaps there is something odd with the pro spectrum you are comparing with. Can you post the file you used and I will compare with the version I have. You could also download my spectrum from the BAA database and try overlaying your spectrum on it.

 

I find once the pixel size has been tuned, the automatic calibration function in ISIS using the NeAr lamp works very well with the ALPY600 but I have not yet found a way to use it with the ALPY200 as the lines are too blended. I still use it though to measure the slant/smile and use the strong 5852.49 line as a fixed reference between observations,  setting the X position in the calibration tab so ISIS uses that to compensate for any shift. (the constant term in the dispersion equation)

 

Cheers

Robin



#27 mborland

mborland

    Viking 1

  • *****
  • Posts: 617
  • Joined: 17 Mar 2020
  • Loc: Tucson

Posted 12 March 2024 - 09:14 PM

Robin,

 

I got the spectrum from here. I clicked "spectra" and downloaded the Author-ASCII version.

 

Here's a comparison of my spectrum to yours and the professional spectrum. Mine is definitely an outlier.

 

comparisonRL.png

 

--Michael


Edited by mborland, 12 March 2024 - 09:33 PM.



CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics