› Forums › Spectroscopy › HELP WITH VISUAL SPEC
- This topic has 10 replies, 4 voices, and was last updated 6 years, 6 months ago by Peter Taylor.
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31 March 2018 at 3:11 pm #573991Peter TaylorParticipant
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Hi all I am trying to do my spectrograph in visual spec but not getting on to good, my visual spec is 4.3.5 and the tutorials are for 3.0.0 and in a mix of French and English are there any tutorials in English and easy to follow, can get to calibrating I follow tutorials but must get wrong sum were as nothing happens.
peter
2 April 2018 at 5:24 pm #579290Mr Jack MartinParticipantPeter,
I suggest you try British Astronomical Spectroscopy Software at
https://uk.groups.yahoo.com/neo/groups/astrobodger/info
Hope this helps,
Jack
Essex UK
2 April 2018 at 7:45 pm #579294Andy WilsonKeymasterJust to note that BASS stands for Basic Astronomical Spectroscopy Software, written by John Paraskeva, and though it started out ‘basic’ it is now much more advanced. You might get some responses, but I think John setup that Yahoo group for his BASS software rather than VSpec. If you don’t get a response from the BASS group then one of the more general spectroscopy groups might be better like Ken Harrison’s Astronomical Specotroscopy group.
https://groups.yahoo.com/neo/groups/astronomical_spectroscopy/info
Though I’ve used VSpec, I am not very familiar with it. It is very versatile and powerful, but I found it would crash on me without warning and I’d loose my work.
Cheers,
Andy
3 April 2018 at 8:48 pm #579299Peter TaylorParticipantIn ALHENA WITH A STARANALYSER last year John gave me a load of info which as bean really useful I am trying to get Vspec going but I cannot make any sense of how to do filtering.
peter
4 April 2018 at 2:30 pm #579306Robin LeadbeaterParticipantHi Peter,
This video on the Visual Spec website goes though all the steps in detail to calculate and use the instrument response
http://astrosurf.com/vdesnoux/video/reponse.avi
Cheers
Robin
4 April 2018 at 3:06 pm #579307Robin LeadbeaterParticipantIf you want to filter the reference spectrum first as i suggested in the tutorial in the other thread “ALHENA WITH A STARANALYSER”
https://britastro.org/node/11586
https://britastro.org/sites/default/files/attachments/Correcting%20for%20instrument%20response.pdf
then the spline filter function in Visual Spec can be found at “Operations”, “Spline Filter”
it is also a good idea to roughly rescale the spectra first before calculating the instrument response so you dont have to deal with very large numbers. You can do this by selecting a region of the spectrum using the cursor (mouse left click and drag), then right click and select “normalize”. The result is the spectrum is averaged to 1 over the selected region
Cheers
Robin
5 April 2018 at 3:20 pm #579311Peter TaylorParticipantHi Robin,
Thanks very much for all your help Robin, I really do appreciate it, I will do as you suggest and get one program going.
peter
6 April 2018 at 1:56 am #579316Robin LeadbeaterParticipantThis video tutorial shows how to do a 2 point wavelength calibration on the reference spectrum
http://astrosurf.com/vdesnoux/wink/calibspectrum_en.htm
(Do not crop the spectrum but use the zero order (entering 0 as the wavelength) and one of the H Balmer lines rather than two Balmer lines as shown there)
You can then use the zero order and the A/pixel dispersion (sampling) to calibrate any other spectrum using the 1 point calibration function. There is not a video tutorial of that but it is described on page 53 of the manual
http://astrosurf.com/vdesnoux/web/help.pdf
Cheers
Robin
8 April 2018 at 3:01 pm #579318Peter TaylorParticipantHi Robin,
The calibration video really simple I wrote it down cant follow video to well, 1, the one on page 53 cant start I cant
find Define in SPECTROMETRY, 2, what dos the first line mean ( replace the base series “ref1” with series “intensity)
I am in intensity and there is nothing in ref1 or ref2 do I just ignore it.
peter
9 April 2018 at 1:27 am #579321Robin LeadbeaterParticipantHi Peter,
Are you on he right page of the manual? This is the one I mean
Select the zero order (with the mouse + left click)
select “spectrometry”, “calibration 1 line”
In the box that pops up:-
enter 0 for “wavelength” (the zero order)
enter the dispersion (A/pixel) that you got from the reference star calibration in “sampling”
Click “apply” and the spectrum of the target star should then be calibrated using the calibration from the reference star
Robin
10 April 2018 at 10:38 am #579322Peter TaylorParticipantHi Robin,
Yes I was on page 54 not 53 of the manual, must be old age, will try that.
peter
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