Photographs of Comet C/2013 A1 (Siding Spring)

This page contains photographs of the comet C/2013 A1 (Siding Spring) taken with my 12″ SCT telescope from Perth, Western Australia in the southern hemisphere.

The comet C/2013 A1 (Siding Spring) is predicted to transit very close to Mars in October 2014 (October 19th & 20th), so close that if it were Earth it would be well inside the orbit of our Moon. This is a unique situation and so astronomers are paying particular attention to Mars and the comet in the lead up to this event. You can find out a lot more about C/2013 A1 (Siding Springs) and it’s passage past Mars at the wikipedia article. And no, the comet is not expected to hit Mars.

I photograph comets on a regular basis using automation scripts. The scripts are run on any clear night that I have my observatory open. During June, July, August and September 2014 C/2013 A1 (Siding Springs) is in a good part of the sky for observations from the southern hemisphere. The comet rises in the south-eastern sky before midnight and before dawn is of good high altitude for photography before the Sun starts to lighten the night sky.

My automation scripts which track the comet at the theoretical comet tracking velocity mean that my images can be easily 300 seconds in length and show no comet nucleus trailing. It has taken some time to develop these scripts but they are working well in particular for this comet, allowing deeper exposures (longer) which show more peripheral detail of the comet when the comet is at it’s highest altitude late at night (or early morning) when I much prefer to be sleeping than awake. These comet tracking scripts rely on the custom tracking rates functionality of Software Bisque’s TheSkyX software and of course CCDCommander.

Chris Wyatt has written a great document summarising the viewing opportunities for the duo of Mars and comet C/2013 A1. It will help you understand the sequence of events, where Mars will be, what parts of the Earth will be able to see the event during night time, etc. You can download the PDF and have a read via this link: Viewing aspect of C2013 A1 from Walcha – Updated 110814

Some more information about observing the comet including prediction images of it’s visibility above the local horizon (Perth, -31 degrees south) is available via this presentation (available for download as a PDF) I gave to the Perth Observatory Volunteer Group in August. Comet C2013 A1 Siding Spring (short presentation)

Technical details of the photographs (unless otherwise specified) are:

• Telescope optics: 12″ SCT @ F/7.4 (~2200mm)
• Image Scale: 0.84 arc seconds per pixel scale
• Camera: SBIG ST8-XME
• Filter: Astronomik Type II Red filter.

Comet C2013 A1 Siding Spring from Roger Groom on Vimeo.

The photographs above this point are from after he comet C/2014 A1 (Siding Spring) passed close to Mars on the 19/20th October 2014. The pair are setting early in the west which has meant for decreased number of exposures. As such the quality of the above photographs cannot be directly compared to the below photographs which contain more sub-exposures. As the comet continues away from Mars after close approach it appears to be continuing to fade.