Spectroscopy with the SA100 - A little rusty

[johnb]

Hi

So its been about a year and no astronomy but life has changed and i now have time, so im somewhat rusty (please forgive the questions)

I captured Vega with a QHY5 and then used registax to produce a tif image which I then loaded into RSpec (latest version) I used the 2 point calibration method using the star and 4861 HB line

Images show the complete spectrum and the second image I simply cropped off the star

So I think im on the right track - oh It says 13.6 for Angstroms/Pixel

So assuming the above is correct for this spectrum I can use the save profile as say call it Vega and today's date and at any time in the future I can load it and I will always have calibrated spectrum I created today ?

So if I now capture another A type star I can now use 1 point calibration as I know my setup is 13.6 for Angstroms/Pixel

Im aware there is an instrument response but lets leave that, want to walk before I run

Thanks in advance

regards

John Berman

[Gasman]

Looks fine to me John! I have been told anywhere between 6 and 21 angs/pixel is fine so you are right on the button there.

My own value at the moment is 11.18 although I have been recommended to take fresh reference spectra for each nights images. I have tried this a couple of times but not much variation from 11.18 with my setup.

Steve

[robin_astro]

Looks fine to me John! I have been told anywhere between 6 and 21 angs/pixel is fine so you are right on the button there.

My own value at the moment is 11.18 although I have been recommended to take fresh reference spectra for each nights images. I have tried this a couple of times but not much variation from 11.18 with my setup.

Steve

Hi  Steve,

The dispersion will be pretty stable from night to night with a Star Analyser type setup unless you change something deliberately but if you are using the reference star for instrument response it is a good idea for best accuracy  to take a reference on the same night. This is because the instrument response includes the effect of the atmosphere so will depend to some extent on the particular atmospheric conditions on the night. (Also try to chose a reference star close by at a similar altitude if possible for the same reason)

Cheers

Robin

[robin_astro]

So if I now capture another A type star I can now use 1 point calibration as I know my setup is 13.6 for Angstroms/Pixel

Hi John,

Not just an A type star but you now have what you need to wavelength calibrate a spectrum of any object. Indeed you ca n also use this spectrum to correct the spectrum of any object for instrument response. (but see the caveat in my post to Steve)

You Vega spectrum looks excellent with a nice set of Balmer lines 

Cheers

Robin

[johnb]

Thanks, so where possible get an A type star on each session as a reference.

Thanks

John B