by Ann » Thu Dec 25, 2014 8:29 pm
Chris Peterson wrote:Ann wrote:The tail is thin and mostly gray, with hints of both blue and green. I might have expected the tail to be bluer.
It is quite blue on my monitor.
Is it possible to find out exactly what stars are seen in the background?
From astrometry.net, the image center is 100.430°, -39.214°, the field is about one degree on a side and about south up, the image scale is 2.48 arcsec/pixel.
lj_astrometry.jpg
Thanks a lot, Chris!
The bluest-looking star in the picture is HD 48726. Its apparent B-V index is -0.02, which makes it a bit bluer than Vega. (Vega's B-V index is usually given as either 0.00 or -0.01.) The apparent color of HD 48726 is not nearly as blue as some O- and early B-type stars, however.
Since HD 48726 looks
much bluer than the tail of Comet Lovejoy, even though it's just a bit bluer than Vega, I take it that the tail of this comet is not as blue as the (apparent) color of Vega.
Ann
[quote="Chris Peterson"][quote="Ann"]The tail is thin and mostly gray, with hints of both blue and green. I might have expected the tail to be bluer.[/quote]
It is quite blue on my monitor.
[quote]Is it possible to find out exactly what stars are seen in the background?[/quote]
From astrometry.net, the image center is 100.430°, -39.214°, the field is about one degree on a side and about south up, the image scale is 2.48 arcsec/pixel.
[attachment=0]lj_astrometry.jpg[/attachment][/quote]
Thanks a lot, Chris! :D
The bluest-looking star in the picture is HD 48726. Its apparent B-V index is -0.02, which makes it a bit bluer than Vega. (Vega's B-V index is usually given as either 0.00 or -0.01.) The apparent color of HD 48726 is not nearly as blue as some O- and early B-type stars, however.
Since HD 48726 looks [i]much[/i] bluer than the tail of Comet Lovejoy, even though it's just a bit bluer than Vega, I take it that the tail of this comet is not as blue as the (apparent) color of Vega.
Ann