PANSTARRS in Casseopeia

First attempt, a fairly optimistic shot over the garden fence on 19 April.

Casseopeia with PANSTARRS

18-200mm @ 65mm f/5.6, ISO 1600, 6 min
12 x 30 sec frames stacked in DSS

The clear sky had tempted me to set up the kit, but the urban glow catching the moisture in the atmosphere defeated any serious attempt to produce a reasonable photo. I thought that stacking several frames would help edit out the glow, but it doesn’t work that way.

Out to a new site on 20 April, in a layby part way up the Kentmere Valley.

C&P4x30

50mm f/2.8, ISO 800, 2 min
4 x 30 sec frames stacked in Photoshop

Skies were forecast to clear for an hour or so around midnight, but the waxing gibbous moon spread light throughout the sky. There were a few wisps of low cloud on the northern horizon. These 4 frames were stacked as layers in Photoshop.

My intention was to assess the suitability of the site for views to the north. Having escaped the street lights of Kendal, the next town north from Kentmere Valley is Penrith, some 19 miles away over mostly uninhabited countryside. It was pleasing to see there was almost no discernible urban glow in the northern sky.

C&P4x2

50mm f/4, ISO 800, 8 min
4 x 2 min frames stacked in Photoshop

Finally, four reasonable frames of 2 min each, relatively cloud free. Given that I was able to write notes by the moonlight, and the humidity was high enough for cloud inversion to begin settling in the valley (see bottom right corner of the photo), this is a pleasing result. Certainly I will visit this site again around the New Moon in about a fortnight. Cloud permitting…

M31 and PANSTARRS

When the Cumbrian skies cleared on 1 April we had the opportunity for several nights of catching PANSTARRS in glorious juxtaposition with the Andromeda Galaxy M31.

First up, some test frames on 1 April which turned into a nice capture that I’d had in mind for some time.

50mm f/5.6, ISO1600, 2min 4 x 30-sec frames stacked in DSS

50mm f/5.6, ISO1600, 2min
4 x 30-sec frames stacked in DSS

With a standard 50mm lens and some judicious cropping, this letterbox format shows Mirach (one of the guide stars used when finding M31: “from Mirach, hop right one star, then again, then down to the fuzzy blob”) with M33 faintly visible on the left, M31 on the right and PANSTARRS making its way in from the bottom.

Quite a windy evening, so I cranked up the ISO to 1600 and took just four good frames at 30 seconds.

On to the following night…

200mm f/5.6, ISO 1600, 15 min. 30 x 30 sec. frames stacked in DSS.

200mm f/5.6, ISO 1600, 15 min.
30 x 30 sec. frames stacked in DSS.

Quite breezy again, so I kept the exposures down at 30 seconds, but on the 200mm lens.  30 frames stacked for a 15 minute total exposure.

PANSTARRS is only about 7 degrees above the horizon here.  That presents a whole new set of problems.  At this angle, the line of sight goes through about ten times as much atmosphere as at zenith, multiplying the effect of water vapour on the incoming light.  From this location, Helsington Church, the view North-West also passes over the lights of Windermere and Ambleside, giving a street light skyglow to the bottom of the frame.  One of the beautiful features of PANSTARRS is its fan tail, glowing by reflected sunlight, so any attempt to process out the skyglow tends to eliminate the tail too.

300mm f/5.6, ISO 400, 40 min. 20 x 120 sec. frames stacked in DSS.

300mm f/5.6, ISO 400, 40 min.
20 x 120 sec. frames stacked in DSS.

Another shot I had framed in my mind, estimating there would be just enough room in the 300mm frame to put both M31 and PANSTARRS.  As the wind had dropped, I could get exposure up to 2 minutes, and grabbed 23 frames of which 20 were acceptable.

Finally on 3 April…

200mm f/6.3, ISO 200, 60 min 12 x 5 min. frames stacked in DSS

200mm f/6.3, ISO 200, 60 min
12 x 5 min. frames stacked in DSS

The birthday fairy brought me a polarscope this year, which dramatically reduces the time taken to polar-align the EQ3-2 equatorial mount.  In  a couple of minutes I can align more accurately than I used to get from 30 to 40 minutes of drift alignment using the camera.  Certainly it is good enough for 5 minute exposures at up to 300mm.  I must find time to test the alignment with longer focal length.  Anyway, this stack of 12 frames at 5 minutes each has cropped nicely.  M31 is not as clear as I would have liked (see M31: up to 200mm) but it was too low in the sky for that.

There was another very pleasing alignment on 5 April but the Cumbrian clouds had closed in.