PANSTARRS success from Kentmere

Tuesday 30th April was sunny all day, the last patches of cloud drifting away to the north in late afternoon.  After my previous encounter with humidity and moonlight in Kentmere, it looked like a good opportunity to test this new dark site.

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This is how my setup looks.  Just me, a layby and the EQ3-2 equatorial mount.  At 9.30pm the Sun has already set, but I wanted to leave plenty of time in case it clouded over and I had to dash to another location.  It will be another couple of hours before the Sun is 18 degrees below the horizon, the offical end of astronomical twilight.

Elevation 25 degrees, Sun is 15.7 below horizon.

Elevation 25 degrees, Sun is 16.2 below horizon.

Elevation 25 degrees, Sun is 16.4 below horizon.

These unprocessed frames with the Sun only 15 degrees below the horizon show what a difference that makes to long exposures.

50mm f/2.8, ISO 800, 6 min. 2 X 240 sec. frames stacked in Photoshop.

50mm f/2.8, ISO 800, 8 min.
2 X 240 sec. frames stacked in Photoshop.

Two frames of 4 minutes each, stacked as layers in Photoshop.  PANSTARRS is in the centre, moving from Cassiopeia to Cephus.  The settings of ISO 800 and 240 seconds were inspired by Fred Espinak’s version, using pretty much the same kit.  I guess the difference in our results is an indication that, even on a good night in Kentmere, conditions in Arizona are better.  The thousands of stars in the bottom left corner (Cassiopeia is in the Milky Way) become so indistinct through our 80% humidity that they look like background glow, and any attempt to eliminate them damages the rest of the picture.  On the other hand, it could just be that Fred is much better at this than I am.

300mm f/5.6, ISO 3200, 12 min.
3 x 240 sec. frames stacked in Photoshop

With the 300mm lens, the optimum aperture is f/5.6 so I have wound the ISO up to 3200 to compensate.  Four minutes tracking with the 300mm lens is quite satisfying, with the stars showing no sign of trail.

PANSTARRS is passing close to two nebulae, Cederblad 214 and NGC 7822, between Cassiopeia and Cephus.  While neutralising the background, I notice that I have caught some nebulosity in Cederblad 214 – that’s the reddish glow to the right of PANSTARRS.

The comet itself still has two distinct tails.  The ion tail points away from the Sun (towards one o’clock in this photo) and the dust tail trails behind the comet (towards nine o’clock in this photo).

300mm f/5.6, ISO 3200, 5 min. Single frame of 300 sec.

300mm f/5.6, ISO 3200, 5 min.
Single frame of 300 sec.

Before packing up, I can’t resist an attempt at a five-minute frame.  The tracking seems to hold up well, which promises much for future sessions.

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…