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Using MILES stars to check spectrum quality

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Robin Leadbeater's picture
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Last seen: 1 hour 43 min ago
Joined: 05/03/2014 - 00:50
Using MILES stars to check spectrum quality

I find comparing the spectra I am producing with professional spectra of the same stars  a good way of checking that my acquisition and data reduction techniques are sound. With the ALPY,  MILES stars are useful for this. For example at this time of year one could use stars in Taurus eg

HD 27819 (64 Tau) A7v  mag 4.8 at 48deg altitude  from here at midnight currently  could be used as the reference star and nearby MILES stars of various spectral types could be measured and compared with the spectrum in the library eg

HD28305 (Eps Tau)     G9.5iii   mag  3.5     49 deg

HD27962 (68 Tau)        A2iv      mag  4.2     48 deg

HD29139 (Aldebaran)  K5iii       mag  0.8     46 deg

 Hopefully the measured and library spectra will be a perfect match !

 

Cheers

Robin

 

Robin Leadbeater's picture
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Last seen: 1 hour 43 min ago
Joined: 05/03/2014 - 00:50
The results are in !

I measured these stars (and added a few more to better cover the spectral classes) on Saturday.  

See the attached report.

I have also attached  the reduced spectra as fits files if anyone wants to play with them. (Note the extension has been changed from fit to fits to be acceptable for upload to the forum. I also tried zipping them together but the forum does not allow zip files unfortunately)

The results are generally very encouraging with typically less than 2% error in relative flux from 4000-7300A.  There are some larger systematic errors below 4000A which seem to be due to a small flux offset and will need further investigation. Extra precautions also need to be taken against scintillation when measuring first magnitude targets.

Cheers

Robin

gasman's picture
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Last seen: 3 weeks 2 days ago
Joined: 05/02/2015 - 20:08
Excellent work Robin!

Great work Robin, shows a very good match on most if not all the stars you tried. Gives you confidence to use the Miles library with Isis.

cheers

Steve