[vsnet-campaign-v838mon 403] V838 Mon and Light Echo Surface Photometry

[DWest61506@aol.com]

On 11/11/2002 11:15 UT I imaged V838 Mon in V and Ic band with my 0.2 SCT + ST-9E CCD + filters.  The photometry was reduced using MIRA and the Henden and Kaitchuck PEP software.  The results have been color transformed.  For V838 Mon:
V=15.9 +/- 0.2, V-Ic = 6.1 +/- 0.2.
The large errors are due to poor signal-to-noise ratio in the V band measurements and the large color correction required.  My filters may also suffer from "red leak", this is common for typical amateur filters and extremely red objects like V838 Mon.  The comparison star used was GSC 4822:3661 V=10.079 and V-Ic = 0.415 per Arne Henden.

I also measured the color of the light echo at the position 07 04 03.77 -03 50 32.9.  For the light echo V-Ic = 1.8 +/- 0.2.  The light echo is much "bluer" than the central star itself.  The photometric inner annulus radius was 6.84" and the outer annulus was beyond the light echo.


Regards,
Doug West
http://hometown.aol.com/dwest61506/index.html

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