Comet 17p/Holmes

Acquisition Date: 2007-10-26 01:15:48 UT
Location: Carp, ON
Telescope: Celestron 11" f/10 SCT
Mount: Losmandy G11 with Gemini
Spectroscope: LHIRES3 #36 with 150 l/mm grating and 29m slit
Camera: SBIG ST8XME
Guiding: SBIG Remote Guide Head on slit image
Software: MaxIm DL v4.58 used for acquisition and processing, along with MS Excel for analysis.
Exposure: 9 x 600s, bias and dark calibrated, combined using SDMask mode.


Spectra of comet nucleus. Effective resolution R=490 at center, intensity uncorrected, wavelength calibrated via built-in neon lamp.



Normalized spectra of comet nucleus, divided by polynomial fit to self and halogen lamp flat. H2O and O2 absorption lines are caused by the atmosphere. CN is cyanogen emission and C2 is molecular carbon emission. The three Blamer lines of hydrogen absorption are present, as is the magnesium triplet and the sodium doublet (both unresolved).




Neon calibration plot


Spectra of comet coma (1.3' from nucleus), intensity uncorrected, wavelength calibrated via built-in neon lamp.



Normalized spectra of comet coma (1.3' from nucleus), divided by polynomial fit to self. The forbidden lines of OI are visible in emission, the same lines that produce aurora, especially the red emission at 630nm. The C2 emission lines and emission band around 550nm are very pronounced since they are not overwhelmed by the scattered sunlight that dominates the spectra of the nucleus.