To examine the effect of heating up a Basler acA640-100gm on image dark current noise during imaging, I conducted an experiment where I took multiple longer (~2 min) films (conditions: dark room, cap on, constant ambient temperature) with different frame exposure lengths and observed mean image pixel value at the beginning and end of the test. Frame exposure lengths and film durations are approximately equal to the ones used in planetary imaging with this camera and not suitable for DSO imaging.
Image exposure length
With cooler – mean pixel value
Without cooler – mean pixel value
At the beginning of the test
10 ms
17.8
17.5
50 ms
18.1
18.3
500 ms
26.7
26.0
1000 ms = 1 s
44.7
40.1
In the end of the test, after ~2 min when the casing temperature was constant
10 ms
18.1
18.5
50 ms
18.7
19.4
500 ms
32.5
42.4
1000 ms = 1 s
60.6
96.1
Basler camera with attached DIY aluminium cooler (without any fan), salvaged from an older CPU.
The following graphs show, the change of camera casing temperature over time in comparison to the constant ambient temperature. From the plots it is observable that majority of heat up occurs in the first 30 sec of imaging and remains almost constant after that.
Some of the filaments visible on the surface of the Sun on this day.
Object: Sun filaments Date: 30 March 2014 10:44 UT Equipment: Basler acA640-100gm, Lunt 60 mm + 2xBarlow Capture and processing : FireCapture, AutoStakkert2Object: Sun filaments Date: 30 March 2014 10:31 UT Equipment: Basler acA640-100gm, Lunt 60 mm + 2xBarlow Capture and processing : FireCapture, AutoStakkert2
A few days ago, on New Year’s Day, a sunspot appeared over the western edge of the Sun. AR1944 is huge and actually consist of more than 50 individual sunspots, the largest of them is far larger than the Earth itself. It was possible to observe it using only unaided eye and proper solar filter (e.g. eclipse glasses).
It has been classified as having a beta-gamma-delta magnetic field and these fields are prone to instability that can produce X-class solar flares. During the rotation around the visible limb of the Sun it was quiet and produced only one major X1 flare.
Object: Sunspot AR1944 and AR1946 in the upper right corner Date: 12 January 2014 12:40 UT Equipment: Basler acA640-100gm, GSO 200/1200 Capture and processing : FireCapture, RegiStax6
During imaging the seeing was very poor and was even more obvious while imaging at higher focal ratios.
Object: Sunspot AR1944 Date: 12 January 2014 12:55 UT Equipment: Basler acA640-100gm, GSO 200/1200 + 2xBarlow Capture and processing : FireCapture, AutoStakkert2, RegiStax6
This giant spot is about to rotate off the face of the Sun, this was probably my first and last shot of it. But this is not the only obvious sunspot currently visible on the Sun. I managed to capture a few other.
Object: Sunspot AR1949(left) and AR1953(right) Date: 12 January 2014 12:45 UT Equipment: Basler acA640-100gm, GSO 200/1200 Capture and processing : FireCapture, AutoStakkert2, RegiStax6
Object: Sunspot AR1949 Date: 12 January 2014 12:55 UT Equipment: Basler acA640-100gm, GSO 200/1200 + 2xBarlow Capture and processing : FireCapture, AutoStakkert2, RegiStax6
Jupiter with moon Io emerging from behind the planet, image taken on 2 August 2012 01:45 UT using Basler acA640-100gm, Skywatcher 300/1500 + 3xBarlow lens
Capture and processing : FireCapture, AutoStakkert2, RegiStax6, Gimp
Sunspot AR1476 image taken on 8 March 2012 14.50UT using Basler acA640-100gmSunspot AR1476 image taken on 10 March 2012 13.20UT using Basler acA640-100gm
