Looking south west for darkness

Several locations around Kendal are dark enough for good astrophotography, but the one direction that causes problems is south west, where the lights of Morecambe Bay fill the horizon with their orange glow.

About an hour’s drive away is the West Cumbria coastline.  To the south of St. Bees it runs in a straight line from north west to south east, so it faces south west across the sea to the Isle of Man, Dublin or Anglesey (depending where you stand) with no urban lights to spoil the view.

From the car park at the end of the coast lane at Silecroft, the offshore wind farm sits exactly where the Milky Way hits the horizon, so I took the opportunity of clear skies last night to go and take a look. I had expected to find the wind farm illuminated only by starlight, but it was not to be!

Conditions were quite windy, so the mount was set up in the lee of the parked car.

First, the 50mm lens gives a viewing angle of 27º x 18º.

Start with 10 exposures of 10 seconds:

26 April 2014: The Milky Way from Silecroft. 50mm f/4 ISO 800, 100 sec. 10 frames of 10 sec.

26 April 2014: The Milky Way from Silecroft.
50mm f/4 ISO 800, 100 sec. 10 frames of 10 sec.

 

 

Increase exposure to 30 seconds, five frames:

 

26 April 2014: The Milky Way from Silecroft. 50mm f/4 ISO 800, 150 sec. 5 frames of 30 sec.

26 April 2014: The Milky Way from Silecroft.
50mm f/4 ISO 800, 150 sec. 5 frames of 30 sec.

 

 

The 24 mm lens widens the angle to 52º x 36º.

Seven frames of 60 seconds:

26 April 2014: The Milky Way from Silecroft. 24mm f/4 ISO 800, 7min.  7 frames of 60 sec.

26 April 2014: The Milky Way from Silecroft.
24mm f/4 ISO 800, 7min. 7 frames of 60 sec.

 

Moving up from the horizon, the summer triangle of Vega, Deneb and Altair extends almost to the zenith.

Three frames of two minutes per frame:

 

26 April 2014: The Summer Triangle from Silecroft. 24mm f/4 ISO 800, 6 min. 3 frames of 120 sec.

26 April 2014: The Summer Triangle from Silecroft.
24mm f/4 ISO 800, 6 min. 3 frames of 120 sec.

 

Why not stitch those together?

24mm Panorama

Further up the Milky Way, the 50mm lens again, for Cassiopeia looking down on Comet C/2014 E2 (Jacques).

Three frames at two minutes per frame:

26 April 2014: Cassiopeia and C/2014 E2 (Jacques) from Silecroft. 50mm f/4 ISO 800, 6 min. 3 frames of 120 sec.

26 April 2014: Cassiopeia and C/2014 E2 (Jacques) from Silecroft.
50mm f/4 ISO 800, 6 min. 3 frames of 120 sec.

 

Wide angle astrophotography is just as rewarding as going for long exposures at high magnification!

2012 DA14 time-lapse video

This is the edited and processed result of a three hour astrophotography session at the top of the Shap Road, north of Kendal, Cumbria on the evening of 15 February 2013.

Each frame in the video is a large file jpeg (12MP) on a Nikon D90 exposed for 13 seconds at ISO 6400, using a 28mm lens at f/4. I took a total of 323 frames at 4 frames per minute. They are joined and played at 10 frames per second, making the video 150x normal speed.

Asteroid 2012 DA14 is only 30 metres across, and is heading away from the Earth having approached to within 28,000 kilometers. For the whole of the shoot, it was invisible to the naked eye (magnitude 7+ by this time) and moving across the sky at about one degree of arc (that’s about twice the visual diameter of the moon) per minute.

The forecast clear skies turned to clouds, the fog spread from Kendal, the motor drive on my equatorial mount failed, it was about minus 5 celcius and I had forgotten my down jacket, hat and gloves. Apart from that everything went quite well! It was pitch dark throughout. The orange clouds are reflection of urban light, only showing because of the long exposure, wide aperture and high film speed setting.

2012 DA14 is the dot moving from bottom right to top left of the dark panel. I had no idea I’d succeeded in catching anything until I put the video together back home.

Processing details (Photoshop):

-The dark panel is an area where I eliminated all data below a certain threshold. That’s a quick and easy way of reducing the skyglow.

-For each frame in the dark panel I then isolated the asteroid in a small disc-shaped layer. I maximised the contrast within that disc, then increased its brightness to match its background to the surrounding dark panel background, effectively making the disc disappear and increasing the brightness of the asteroid.

Nothing has been cloned or otherwise added to the original data.