Sunday, 29 September 2013
There was a lovely surge prom visible today using the double stacked CaK filter. The faint CaK spicule line can also just about be seen on the limb. It seems that double stacking in CaK makes the prominences much easier to see compared to the single stack images. I was pushing things today with the low altitude sun, with this shot being taken with the 100mm at 2000mm focal length with the DMK31 camera, but this image is just about usable... It definitely has much promise for when the sun is higher in the sky.
Tuesday, 24 September 2013
Even on a relatively quiet day on the Sun as it was as we passed into autumn there is still plenty to see in CaK wavelengths. This was another outing for the double stack CaK filter, which had been redesigned in its configuration to remove the reflections and ghost images that were present when i first set it up. It is performing very well now with only minimal ghosting at the bottom of the disk which should be fairly easy to remove with a bit of tilting. This was taken with the 40mm @ f20 with the DMK31 camera.
Sunday, 22 September 2013
The sun starts to take on an almost 3 dimensional textured look to it's surface around the limb with the double stacked CaK filter when used with the 100mm at 2000mm focal length. Taken with the DMK31 camera.
The first day of astronomical autumn brought clear(ish) skies on saturday. The sun is quiet at the moment but far from inactive, with smallish active regions, filaments and prominences putting on a show for us.
Saturday, 21 September 2013
After some considerable time searching I finally have bought another second hand CaK PST. The method behind this was simple; to double stack a CaK filter. The CaK PST filter in it's native form has an advertised bandpass of <2.2a, compared to the 2.4a of the Lunt unit. By putting two CaK PST filters in series the bandpass will tighten to an estimated <1.5a. Well what is to be gained from this exercise? Double stacking in Hydrogen alpha wavelengths has the effect of improving the signal to noise ratio by reducing continuum light leakage into the image - in simple terms the contrast should be better. Images of the CaK sun taken with instruments with a tight bandpass, eg spectroscopes or BASS2000 show the disk itself to be much darker, with plage relatively much brighter, but also with tentative hints of prominences and filaments, something I have observed before in single stack CaK on certain occasions. Well when the image above was taken conditions could not have really been any worse; the sun was at <10 degrees altitude in the sky and was imaged through the haze of high cloud. In addition our star was pretty devoid of activity, there was only one or two very small spots, no proms and the filaments that were there were only very small and hairline - not untypical of our star at solar minimum! However, given the cumulative effect of all these factors I am very pleased with the outcome, the image definitely shows more contrast to what I am used to, and the most apparent thing is that the supergranulation cells are easily visible across the whole disk. If I really stretch the original TIFF file I can start to see the filaments that were visible. Typically since getting this setup the weather has been what can only be described as typically autumunal and have not been able to explore with it as much as would hope. Still, as I write this there is high pressure upon us (and cloud!) but there are breaks forecast, add to that the sun has increased in activity and if the clouds do clear then hopefully should have some good results to share!
Monday, 9 September 2013
Taken with the Coronado DS40 at f20 with the DMK31, there wasn't a lot happening on our star this weekend, with only a few small spots visible. Despite the blue skies first thing in the morning it wasn't very long before the clouds and heavy showers took over and solar observing was over for another day.
Sunday, 8 September 2013
Things are VERY quiet on the sun at the moment with very little on the nearside, even this view taken with the DS40 shows sparse detail. Hopefully things will pick up and this isn't a sign of a things to come!
Taken with the double stack PST mod at 2000mm fl with the DMK31, this picture shows double stacking does show some promise, however these images from saturday are all slightly in the wings of the Ha line. The DS PST mod is complicated to setup, and at the moment i'm still working out all the many variables and their innumerable combinations. The problem I do have is a spell of consistent and continuous sunshine to test out properly. Still, with each outing i'm getting a better understanding of how it works and the optimum way to set this combination up.