VV-Cep....il est où le jet?

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Gerard Arlic
Posts: 148
Joined: Mon Jul 10, 2017 10:25 pm

VV-Cep....il est où le jet?

Post by Gerard Arlic »

Bonjour,
avec pour référence le spectre de JP N acquis avec un Alpy 600, j'ai tenté VV Cep
Star Analyser 100 / Atik 383 / T200/1000
je n'arrivais pas à calibrer tout ça, lorsque je me suis apperçu qu'il y avait une étoile A0 juste à côté

Image

avec un joli profil

Image

du coup, j'ai pu retravailler le profil de VV Cep

Image

et il s'imbrique pas mal avec celui du copain

Image

à part que je n'ai pas le pic Halpha :(
et là est mon interrogation:
le Star Analyser ne permet pas de capturer un pic aussi fin?
l'image du copain date de 22 mois, le pic ne serait pas permanent?
désolé si je vous embête avec mes questions de débutant :oops:
Star Analyser 100; Atik 383L; T200/1000
Robin Leadbeater
Posts: 1926
Joined: Mon Sep 26, 2011 4:41 pm
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Re: VV-Cep....il est où le jet?

Post by Robin Leadbeater »

Hello Gerard,

Yes VV Cep H alpha emission is still there
http://www.spectro-aras.com/forum/viewt ... =19&t=1801
I think it still shows in your spectrum but the H alpha line is only ~10A wide. This is narrower than the Star Analyser resolution so it does not look as high.

The focus of Star Analyser spectra changes along the spectrum so you might get a stronger H alpha if you focus on that line. A good emission star to practice focusing on is P Cygni
http://www.threehillsobservatory.co.uk/ ... _annot.png
(Note the spectra here have been rectified (the continuum shape has been removed)

Cheers
Robin
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Gerard Arlic
Posts: 148
Joined: Mon Jul 10, 2017 10:25 pm

Re: VV-Cep....il est où le jet?

Post by Gerard Arlic »

Robin Leadbeater wrote: I think it still shows in your spectrum but the H alpha line is only ~10A wide. This is narrower than the Star Analyser resolution so it does not look as high.

The focus of Star Analyser spectra changes along the spectrum so you might get a stronger H alpha if you focus on that line. A good emission star to practice focusing on is P Cygni
Hello Robin
Thank you for this clear explanation
Soon I will make a spectrometer "Barège" and I can go further in resolution
have a good day
Star Analyser 100; Atik 383L; T200/1000
Peter Somogyi
Posts: 420
Joined: Sun Jul 13, 2014 8:56 am

Re: VV-Cep....il est où le jet?

Post by Peter Somogyi »

Gerard,

The SA100 can be traded flexible between SNR and resolution, especially in case of such a bright object: playing with reducing the f-ratio (either putting mask in front of scope, or putting in a barlow till the seeing allows). Your setup should be capable of capturing even sn2017 eaw, if have no moon up.
Of course, adjusting focus to the wavelength of interest with testing bright emission objects is a must before continuing with the real stuff. (Focusable wavenelgth range at a given quality depends on the f-ratio.)
In case of VV Cep, the blue end having a higher interest at low resolution (till you do the calibrations perfect, you might want to use a 2nd ref star to check).
By the way, congratulations for the good instrumental and other calibrations!

- Peter
Gerard Arlic
Posts: 148
Joined: Mon Jul 10, 2017 10:25 pm

Re: VV-Cep....il est où le jet?

Post by Gerard Arlic »

Peter Somogyi wrote:Gerard,

The SA100 can be traded flexible between SNR and resolution, especially in case of such a bright object: playing with reducing the f-ratio (either putting mask in front of scope, or putting in a barlow till the seeing allows). Your setup should be capable of capturing even sn2017 eaw, if have no moon up.
Of course, adjusting focus to the wavelength of interest with testing bright emission objects is a must before continuing with the real stuff. (Focusable wavenelgth range at a given quality depends on the f-ratio.)
In case of VV Cep, the blue end having a higher interest at low resolution (till you do the calibrations perfect, you might want to use a 2nd ref star to check).
By the way, congratulations for the good instrumental and other calibrations!

- Peter
Hello Peter
sn2017eaw :D
I will make a spectrograph "Barège" with a network 600 lines
Thank you for your encouragement
Star Analyser 100; Atik 383L; T200/1000
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