VV-Cep....il est où le jet?

[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



avec un joli profil



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



et il s'imbrique pas mal avec celui du copain



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

[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

[Gerard Arlic]

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

[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]

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
I will make a spectrograph "Barège" with a network 600 lines
Thank you for your encouragement