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Some Be stars
Posted: Sun Mar 01, 2015 4:59 pm
by Christian Buil
Some bright Be stars Alpy 600 spectra taken with a small telescope (a Newton 200 mm f/5). A view of the setup (no need of focal reduced, pure achromatic telescope):
beta Lyr:
zeta Tau:
delta Sco:
and some bright stars...
Vega:
Rigel:
Capella:
Christian
Re: Some Be stars
Posted: Mon Mar 02, 2015 6:36 am
by Olivier Thizy
Very nice setup...
It's not clear to me if the limit we see around 3700A is the actual limit of the spectrograph+camera or if this is actually the Balmer serie barrier which drops around 3646A?
Anyway, newtonians are definitively a great option for spectroscopy!...
Cordialement,
Olivier Thizy
Vous ne verrez plus des étoiles comme avant !
http://www.shelyak.com/en/
Re: Some Be stars
Posted: Mon Mar 02, 2015 6:29 pm
by Christian Buil
Olivier, exact, no so clear. Here a detail of my Alpy600 spectrum compared to CALSPEC (see ISIS data base):
The optical quality of Aply600 is good down to 4700 A. For shorter wavelength some chromatism seem visible (of course, the telescope is perfect).
But on Capella spectrum (a UV rich spectrum) the Alpy600 spectral resolution seem correct down to Balmer limit (3646 A) (the resolution of MILES spectrum is adapted to Alpy600 resolution):
Christian
Re: Some Be stars
Posted: Tue Mar 03, 2015 1:50 pm
by Olivier Thizy
Hello,
It looks like the 4700A limit is not an instrumental limit but a typical A-type star Balmer barrier and no more absorption lines below 4700A. On Capella, your spectrum goes down to 4600A!
Well, looks like the Sony chip helps there... and a Newtonian is a great way to go for spectroscopy with an Alpy 600...
Cordialement,
Olivier Thizy
Vous ne verrez plus des étoiles comme avant !
http://www.shelyak.com/en/
Re: Some Be stars
Posted: Tue Mar 03, 2015 2:48 pm
by Olivier GARDE
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Re: Some Be stars
Posted: Tue Mar 03, 2015 2:52 pm
by Olivier GARDE
Olivier,
You mean 3700 A, I think ?
We can use also a CCD camera more sensitive in blue part of the spectrum like this :
http://www.ccd.com/images/alta_f47_sens.gif
Re: Some Be stars
Posted: Wed Mar 04, 2015 2:19 pm
by Olivier Thizy
Oops - I meant below 3700A and the Balmer limit is 3647A (or 3.39eV) as well explained in second week of EPFL on-line MOOC training - very interesting by the way.
For those interested, registration should close any time soon now as first week is going toward the end and exercises should be done by march 7th!
See:
https://courses.edx.org/courses/EPFLx/P ... T2015/info
Cordialement,
Olivier Thizy
Vous ne verrez plus des étoiles comme avant !
http://www.shelyak.com/en/
