Time & Date: 12/17/09, 4h 24m UT
Telescope: Meade LXD75 SN6
Camera: Meade DSI Pro III
Grating: Star Analyser 100
Luminance: 15x10sec, saved as FITS
RGB: None
Guide scope: Meade DSX-90, PHD
Software: Envisage, Autostar Image Processing, Photoshop, Excel, KaleidaGraph

This is a full-frame image taken of the same field as the photometric image, but this time through the Star Analyser 100 in the filter slide in place of the V photometric filter. Note that in the photometric image the nearby 9.50 magnitude GSC3735:480 is brighter than R Aur, but in this image the 0th-order image of the stars shows that R Aur is much brighter than GSC3735:480, an indication that R Aur is shining strongly outside of the green passed by the V photometric filter. Another indicator is that most of the stars in this field show a long tear-drop shape pointing towards the 0th-order image of the star, indicating most of the radiation is towards the blue end of the spectrum. Finally, the spectrum of R Aur shows a lot of structure in the form of several prominent absorption bands, a characteristic common to cool red stars. As it turns out, GSC3735:480 is a yellow G0 star, making it a nice main sequence star similar to the Sun (which is a G2 if I recall right). Comparing the spectrum of R Aur and GSC3735:480 shows that R Aur is indeed very, very red, emitting most of its radiation in the IR. It’ll be neat to watch as this star brightens towards maximum over the coming months and how this process expresses itself in the emission spectrum.

-John