Comet 19P/Borrelly

[Ross Wilkinson]

This comet was discovered by Alphonse Borrelly in 1904 and became only the 19th periodic comet to have its orbit determined.

It was visited by the Deep Space 1 probe in 2001, but although it has a period of just under seven years, I've never managed to see it before.

Unfortunately, it currently appears low in the West, where my view is blocked by the house. However I worked out that around 8pm I might be able to catch it through the gap between the houses - although it meant using a minimalist setup squashed between the kitchen door and the hedge:

The bright light at the top right is an LED streetlamp just across the road, but I managed to use our neighbours' side fence to shade the camera from its direct light!

My imaging system comprised an old Starlight Xpress Hx916 camera, fitted with a Pentax 200mm telephoto lens, on a Celestron LCM (alt-az GoTo) mount.

I did manage to track the comet (just above the fence) for about half an hour, although it was a mere 15 degrees above the horizon. As well as the scattered light from the streetlamp, I also had to contend with clouds of vapour from our neighbours' central heating exhaust which kept blowing across my field of view!

Nonetheless, here is my first view of comet 19P,  processed from 44x 30-sec exposures:

I didn't see any field-rotation effects with 30-sec exposures on the alt-az platform , and as well as my "invisible comet" stacker, the Gradient Removal tools in IRIS proved invaluable in the post-processing.

[Ross Wilkinson]

Now that this comet is higher in the sky, I managed to catch it with my main set-up half-way down the garden - so that I had a view clear of the houses up to 9pm.

This is a stack of 60x 60-sec with my Mx716 camera on the C8 operating at f/3.5.