Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Equilibrium_E on 09/10/2016 11:39:56

Title: Can I tell the colour of a star, if I have the u,g,r,i,z, colour index?
Post by: Equilibrium_E on 09/10/2016 11:39:56
So I have the Colour spectral breakdown of a number of stars (sdss data) and I was hoping there was a technique or process I can conduct/run in order to tell the actual appearance (as it might seem to someone viewing them), as it might seem to an observer? an example of one of the lines/observations is:
ra                     dec                           u         g                  r         I                 z
2.111125647   -0.935711213   22.04581   21.63591   21.73088   21.47245   21.43542.

Anybody who as any kind of experience dealing with this data, I'd be genuinely delighted to hear from, or in fact,
anybody who as any thoughts at all on it!
Thanks in advance,
E_E
Title: Re: Can I tell the colour of a star, if I have the u,g,r,i,z, colour index?
Post by: yor_on on 01/11/2016 12:32:34
I'm not sure you can?
Maybe, seems to be some conversions made?

The SDSS Data, processing the Data (http://cas.sdss.org/dr7/en/sdss/data/data.asp)

Photometric Flux Calibration (http://classic.sdss.org/dr7/algorithms/fluxcal.html)

And from that to Ugriz colors.

Potential colors for studying stellar
populations. (http://www.google.se/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0ahUKEwiM7fOgxofQAhXGApoKHfHCBwsQFgg3MAI&url=http%3A%2F%2Fjournals.cambridge.org%2Farticle_S174392130700782X&usg=AFQjCNFXwWy31Amoa40sWNfRFNRwwAx0dg&bvm=bv.137132246,d.bGs)

Transformations between SDSS magnitudes and UBVRcIc (and ugriz ) (http://classic.sdss.org/dr7/algorithms/sdssUBVRITransform.html)

The u'g'r'i'z' Standard Star System: (http://www-star.fnal.gov/ugriz/)
==

As for how a star looks to the naked eye?
White, yellow, red I'm not really sure what you're after here?

This? SDSS Filters (http://skyserver.sdss.org/dr1/en/proj/advanced/color/sdssfilters.asp)

Actually I think most stars would look 'white' to me, (except possibly red ones), in space outside a atmosphere? I'm not sure though?