A question about calibration

[lensman57]

Hi,

This maybe a hypothetical question but is it posscible to enter the spetral class of any star in a softwarle ike PI for example and then let the software colour calibrate the image rather than the awkward way of searching for G2V class stars to do the calibration with?

Regards,

A.G

[ollypenrice]

I asked a similar question a while back and Harry said they were thinking about it at PI. It has to be a good idea in principle.

I don't know what the professional spectroscopists do about the reddening effects of dust, though. Some care would be needed here. I suspect that they will calibrate it out and give the real spectral class, somehow, irrespective of the apparent colour. This is a guess, though. 

I think it's always worth checking a few stars in an image, though, against their spectral classes. In my case I do this using SkyMap Pro which gives spectral classes down to improbably small magnitudes.

Olly

[IanL]

Take a look at Excalibrator if you haven't already (http://bf-astro.com/excalibrator/excalibrator.htm).  You need three FITS images (one for each colour plane) and you also need to plate solve one of them to add a WCS solution to the FITS header, but after that it will do the hard work of finding appropriate stars and calculating the correction factors which you can then apply in PI.

[lensman57]

Hi,

Great info and suggestions, thanks. I got the itch to ask the question a couple of nights ago while trying to see how M1 would look in my imaging scopes using CdC. The nearest bright star is HD37202 with a spectral class of B1IVe but I guess some clever people had already thought of this idea. I think that for hobby people like myself this would be very useful  as most popular DSOs have at least one bright star nearby and this could be made good use of in colour calbration.

Regards,

A.G