HELP WITH VISUAL SPEC

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  • #573991
    Peter Taylor
    Participant
    • 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

    #579290
    Jack Martin
    Participant

    Peter,

    I suggest you try British Astronomical Spectroscopy Software at

    https://uk.groups.yahoo.com/neo/groups/astrobodger/info

    Hope this helps,

    Jack

    Essex UK

    #579294
    Andy Wilson
    Keymaster

    Just 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

    #579299
    Peter Taylor
    Participant

     In  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

    #579306
    Robin Leadbeater
    Participant

    Hi 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

    #579307
    Robin Leadbeater
    Participant

    If 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

    #579311
    Peter Taylor
    Participant

    Hi 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

     

    #579316
    Robin Leadbeater
    Participant

    This 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

    #579318
    Peter Taylor
    Participant

    Hi 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

       

                

    #579321
    Robin Leadbeater
    Participant

    Hi 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

    #579322
    Peter Taylor
    Participant

    Hi Robin, 

                   Yes I was on page 54 not 53 of the manual, must be old age, will try that.

          peter 

                     

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