Lovejoy and ISON under clear sky

Only nine days from perihelion, ISON is lower and lower on the eastern horizon.  On Monday night (Tuesday morning, of course) I set the alarm for 3.30 and went out to chase it down at a new location, about a mile south of Killington Reservoir, east of Kendal.

It turned out to be a perfect location for looking east, with almost no urban glow on the photos.

Comet C/2012 S1 (ISON) 300mm f/5.6, ISO 400 150 seconds. 5 frames of 30 seconds.

Comet C/2012 S1 (ISON)
300mm f/5.6, ISO 400 150 seconds.
5 frames of 30 seconds.

It is almost impossible to process out the combination of moonlight and early twilight, while retaining the detail in ISON’s tail.  The angular separation of ISON from Spica (top right corner) is about 4 degrees, and others have photographed ISON with a tail in the region of 6 degrees.

Comet C/2012 S1 (ISON) 300mm f/5.6, ISO 400 420 seconds. 7 frames of 60 seconds.

Comet C/2012 S1 (ISON)
300mm f/5.6, ISO 400 420 seconds.
7 frames of 60 seconds.

A little more tail detail comes out from this stack of 60-second frames.  I am using ISO 400 to avoid completely burning out the centre of the comet.

Comet C/2013 R1 (Lovejoy) 300mm f/5.6, ISO 400 180 seconds. 12 frames of 15 seconds.

Comet C/2013 R1 (Lovejoy)
300mm f/5.6, ISO 400 180 seconds.
12 frames of 15 seconds.

Well above the horizon, and unaffected by the twilight, is Comet Lovejoy.  This was a particularly pleasing result, given the bright moonlight.

ISON outburst

ISON observers had begun to report an “outburst” that might have increased  the comet’s brightness by up to two orders of magnitude.  While it is advisable to temper one’s enthusiasm with the knowledge that Cumbrian skies don’t always play ball with astrophotography, my trusty forecaster App indicated that there might be a short window this morning between ISON’s rising at 04:04 and the development of an overcast dawn from twilight at 05:34.

Alarm set for 03:30, swap texts with Stuart Atkinson at 03:40, load the kit in the car and off we go towards Farleton, east of Kendal, to get away from urban lights.

Remember that Cumbrian skies don’t play ball?  Well, there was a stubborn bank of low cloud on the eastern horizon (Stuart’s wider angle photos give a much better context of our session) but suddenly, in the gaps…

Comet C/2012 S1 (ISON) 300mm f/5.6, ISO 800, 30 sec. Single frame.

Comet C/2012 S1 (ISON)
300mm f/5.6, ISO 800, 30 sec.
Single frame.

Amazing for a single shot, compared with the stack of 20 frames from the previous outing.  Note also that this is 30 seconds at ISO 800 whereas the previous outing was 20 x 60 seconds at ISO 1600.  I have stretched the histogram in PixInsight, and rebalanced the colour to get rid of the more extreme red glow in the clouds.

The 12MP frame can even stand cropping to enlarge it to 6x the original…

Comet C/2012 S1 (ISON) 300mm f/5.6, ISO 800, 30 sec. Single frame, cropped.

Comet C/2012 S1 (ISON)
300mm f/5.6, ISO 800, 30 sec.
Single frame, cropped.

Eddington and comets

Members of the Eddington Astronomical Society met at Kendal Castle early on Sunday morning (was that really only yesterday?), to have a look for comet ISON.  There was a good turnout, which meant my photography session wasn’t quite the lonely vigil it usually is. I guess that was down to the presence of the Discovery Channel who are making a documentary about comet hunting, organised through our society Secretary the tireless astronomy outreacher Stuart Atkinson.  To be honest, I was really only there to boost the numbers, as I didn’t think the seeing would be too good – the forecast was well over 90% humidity.

But the humidity wasn’t too bad, especially in our elevated position up Castle Hill, and it was great fun to be staring at the sky with friends for a change!

For the most part, it made sense to stick with the 6 x 60-seconds at ISO 1600 on the new 300mm lens at f/5.6.  I have the dark frames and flat frames for this combination already on file.

First up, comet Lovejoy, very easy to find at an elevation of 54 degrees, well above the mist, and just north of the Beehive Cluster in Cancer.

Comet C/2011 W3 (Lovejoy) 300mm f/5.6, ISO 1600, 6 x 60 sec.

Comet C/2011 W3 (Lovejoy)
300mm f/5.6, ISO 1600, 6 x 60 sec.

 PixInsight allows stacking on the comet centre, so the starts are slightly trailed.

Then on to ISON, by star-hopping from Regulus through Mars straight down the ecliptic.

Comet C/2012 S1 (ISON)
300mm f/5.6, ISO 1600, 6 x 60 sec.

ISON doesn’t present as well as Lovejoy, owing to its position nearer the horizon.

That went well, so a quick trip over to LINEAR, rising next to Arcturus.

Comet C/2012 X1 (LINEAR) 300mm f/5.6, ISO 1600, 6 x 60 sec.

Comet C/2012 X1 (LINEAR)
300mm f/5.6, ISO 1600, 6 x 60 sec.

LINEAR doesn’t look anywhere near as good as last week’s capture.

After that, I left the camera running, for twenty more frames of ISON.

Comet C/2012 S1 (ISON) 300mm f/5.6, ISO 1600, 20 x 60 sec.

Comet C/2012 S1 (ISON)
300mm f/5.6, ISO 1600, 20 x 60 sec.

These have processed quite well in PixInsight to remove most of the sky glow. I might return to these frames and see if I can’t eliminate more of that background colour. I’d also like to try putting the comet back onto a set of frames stacked on the stars.