Une Be faible (pour moi) et une question

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Une Be faible (pour moi) et une question

Postby Gerard Arlic » Tue Mar 12, 2019 8:15 pm

Bonjour,
Samedi soir, j'étais seul au T60 du Pic avec l'Alpy 600 et mon Atik383
d'après la météo j'avais deux..trois heures
j'ai choisi sur Arasbeam la Be [KW97] 26-56 mag 11.5
4*900s en bin 2 + étoile de référence HD 39970
j'ai juste eu le temps de faire 2 poses sur cette dernière pour la réponse instrumentale
le profil Pickles A0I colle assez bien avec HD39970
Image
la réponse appliquée sur [KW97] 26-56 me donne un profil beaucoup plus haut que le seul présent dans BESS, celui de Pierre Dubreuil en 2015
Image
je suppose que cet écart n'est pas normal?
Star Analyser 100; Atik 383L; T200/1000
Gerard Arlic
 
Posts: 148
Joined: Mon Jul 10, 2017 10:25 pm

Re: Une Be faible (pour moi) et une question

Postby Robin Leadbeater » Tue Mar 12, 2019 8:56 pm

Hi Gerard,

The MILES star HD39970 is significantly reddened by interstellar extinction so does not look like the standard Pickles spectrum. See the attached MILES library spectra (Dark blue is the observed spectrum, uncorrected. Light blue is how the spectrum would look without interstellar extinction.) Did you use the uncorrected MILES spectrum or the Pickles spectrum to calculate the instrument response?

Cheers
Robin
Attachments
HD39970_red_dered.png
HD39970_red_dered.png (27.4 KiB) Viewed 1144 times
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Robin Leadbeater
 
Posts: 1286
Joined: Mon Sep 26, 2011 4:41 pm

Re: Une Be faible (pour moi) et une question

Postby Gerard Arlic » Wed Mar 13, 2019 9:20 am

Hi Robin
so I de-reded the profile of the base Miles with the coefficient 0.82
I recorded it in "mybase", and used the result for the instrumental answer
the profile of the Be is a little different
Image
thank you for these valuable indications :)
question: can we do the same with pickles?
have a good day
Star Analyser 100; Atik 383L; T200/1000
Gerard Arlic
 
Posts: 148
Joined: Mon Jul 10, 2017 10:25 pm

Re: Une Be faible (pour moi) et une question

Postby Robin Leadbeater » Wed Mar 13, 2019 11:58 am

Hi Gerard,

You should not deredden the MILES spectrum in ISIS. The MILES spectra in ISIS are the original spectra as measured (including interstellar reddening) These are the correct spectra to use to calculate the instrument response.

If you use your calculated instrument response with your measurement of the MILES star it should match the MILES spectrum in ISIS exactly (not the standard Pickles spectrum.)

You could try reddening the Pickles spectrum but this will only be approximately correct as the exact effect of reddening is unknown and the actual MILES star might no be exactly like the Pickles standard.

Cheers
Robin
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Robin Leadbeater
 
Posts: 1286
Joined: Mon Sep 26, 2011 4:41 pm

Re: Une Be faible (pour moi) et une question

Postby Gerard Arlic » Wed Mar 13, 2019 12:03 pm

OK Robin :)
with Pickles redden
Image
I'm trying now with Miles
Star Analyser 100; Atik 383L; T200/1000
Gerard Arlic
 
Posts: 148
Joined: Mon Jul 10, 2017 10:25 pm

Re: Une Be faible (pour moi) et une question

Postby Gerard Arlic » Wed Mar 13, 2019 12:16 pm

yessss!! acec la réponse calculée sur le Miles
Image
ça avance :)
Star Analyser 100; Atik 383L; T200/1000
Gerard Arlic
 
Posts: 148
Joined: Mon Jul 10, 2017 10:25 pm


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