The Comets of Christmas 07

Two bright comets close in the sky were visible during Christmas this year. This page contains some pictures I took from my San Jose backyard the evening of December 26. The moon was still not up, but the comets were located in a very heavily polluted part of the sky. As an example here is a raw frame.

All of the pictures were derived from that glop! These frames are 13 second exposures. Compare this to a 20 second exposure at Mount Lassen.

Click on any of the pictures with a blue frame for a larger version.

Pictures of the Comets

The comets passed close enough that I could capture them both in the same frame

Annotated View

8p Tuttle

Tuttle was zipping through Andromeda that evening. The map above shows the approximate boundaries of the blowup below

Here is an annotated version of that picture.

17p Holmes

This comet has been visible since the end of October. In early November it was visible visually from a dark site. My backyard is anything but dark, but with the aid of photography and heavy reprocessing it still clearly shows

Here is an annotated version of that picture.

Equipment

These pictures were first light on my Seronik tracking mount

This was the mount that Sky and Telescope editor Gary Seronik described in the June 2007 issue of Sky and Telescope. I had the opportunity to use Gary's in Costa Rica.

My camera was a Canon 20Da using a 24 mm f/1.4 lens at ISO 800. Images were processed principally by ImagesPlus, but also with Photoshop. The result was a stack of 10 13 second exposures. Anything longer resulted in milk.

rjh 1/3/08