help to identify sky/light pollution lines
Posted: Thu Jul 15, 2021 10:12 am
Hi All,
In the process of attempting to take a spectrum of asassn-21mk ( Be star maybe?) at dec -71 degrees, and the worst possible hour angle (directly below the pole), I got more signal from sky glow or light pollution than the star. I have been able to identify a few lines, but there is one prominent one which I cannot work out, at around 5517 angstrom.
I think I identify oxygen at 5577 and 6300, and
there are a few street lights in town which are still high pressure sodium (most are LED), so I identify various sodium and mercury lines.
mercury 5461 5769 5791
sodium maybe 4983, 5153 5684 5688 and a hint of the high pressure sodium light wings.
but i cannot identify the most prominent line which seems to be 5517 angstrom.
perhaps my whole wavelength calibration is wrong, but everything else seems to fit. I wonder if the line might be some sort of rare earth from phosphors on the LED lamps?
If anyone has any suggestions, I am all ears!
note: the title on the plot is asassn-21mk because this is the same data but without "don't remove sky background" switch on.
I can't attach the fit file for a forum post but am happy to email it.
Cheers,
Hamish
In the process of attempting to take a spectrum of asassn-21mk ( Be star maybe?) at dec -71 degrees, and the worst possible hour angle (directly below the pole), I got more signal from sky glow or light pollution than the star. I have been able to identify a few lines, but there is one prominent one which I cannot work out, at around 5517 angstrom.
I think I identify oxygen at 5577 and 6300, and
there are a few street lights in town which are still high pressure sodium (most are LED), so I identify various sodium and mercury lines.
mercury 5461 5769 5791
sodium maybe 4983, 5153 5684 5688 and a hint of the high pressure sodium light wings.
but i cannot identify the most prominent line which seems to be 5517 angstrom.
perhaps my whole wavelength calibration is wrong, but everything else seems to fit. I wonder if the line might be some sort of rare earth from phosphors on the LED lamps?
If anyone has any suggestions, I am all ears!
note: the title on the plot is asassn-21mk because this is the same data but without "don't remove sky background" switch on.
I can't attach the fit file for a forum post but am happy to email it.
Cheers,
Hamish