HELP WITH VISUAL SPEC

[Peter Taylor]

• 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

[Mr Jack Martin]

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

[Andy Wilson]

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

[Peter Taylor]

 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

[Robin Leadbeater]

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

[Robin Leadbeater]

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

[Peter Taylor]

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

 

[Robin Leadbeater]

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

[Peter Taylor]

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

   

            

[Robin Leadbeater]

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

[Peter Taylor]

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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