Category: Solar log
Saturday, March 29, 2008
Prominences and filaments
Today I went outside with my Coronado PST to do a little solar observing. I observed for about one and a half hour and from 13.50 until 14.20 local time I made a sketch of the Sun using different Red, Yellow, Orange and Grey soft pencils. The paper I used was black sketching paper. I also used three different erasers. As a smudging tool I used my finger. The technique I used was adapted from the book "Astronomical Sketching" by Handy et al. The picture below shows the result I got from my observing session. Overall I counted three groups of three prominences each. One on 3 o'clock, another on 4 o'clock and the last between five and 6 o'clock. On 9 o'clock I detected a lonely prominence. On 3 o'clock I saw two prominences that were completely detached from the solar disc. The same goes for two prominences at almost six o'clock. In the 4 o'clock group and the six o'clock group I saw two prominences looking like a mushroom. I think they are called "hedgerows" by official classification. I also found two filaments. One was a dark "S" formed structure about 1 o'clock; the other was a small half circle around a much lighter pelage at 5 o'clock. The sketch was made using a low cost 15 mm Ultrawide (66 degrees) eyepiece with long eye-relief from Sky watcher. The picture was much clearer and showed more detail than my 15mm Vixen Lanthanum. The latter is absolutely darker, and much more expensive (about 5 times the price of the Skywatcher 15mm). Other eyepieces that were used during observing were the 21mm Denkemeier, 12 mm Nagler T4 and the 9mm Ultrawide from Skywatcher. I hope the Sun will start showing a little more details in the H-Alpha band in the next few months. I really enjoyed the H-alpha sketching. It makes you look very careful for details.
Sunday, September 10, 2006
Observing the Sun in different wavelenghts
Yesterday I observed some interesting active regions on the Sun, especially AR 908. I used the 4-inch refractor and the Baader Herschel Wedge (with the Baader Continuum and ND 3.0 filters) for "white light"? observing and the Coronado PST for the H-Alpha line. I tried different eyepieces with the 4-inch TAL: the Vixen LV's, the Zeiss vario zoom-eyepiece and a 32mm Televue Plossl. The best overall view I got was from the 32mm Plossl. At a magnification of 30x the granulation was at its best, even better than in the Zeiss zoom. I noticed that the granulation gradually fades away with increasing magnification. I also compared the Zeiss zoom eyepiece (25-10mm) with the Vixen LV's (20, 15, 12, 10, 9, 7 and 5mm). Although the views through the high quality Zeiss zoom were slightly sharper and clearer than through the Vixen LV's, I still prefer the LV's for their great eye-relief of 20mm. With the Coronado PST I only used the 15mm LV. This eyepiece showed me the most pleasant view, and higher magnifications added almost nothing.
The visual impression you get from Sunspots with the Baader Herschel Wedge and the 4-inch refractor is hard to describe. No image I shoot comes near the sharp and detailed view I get live at the eyepiece, but I always shoot a few images to document the observing session in my observing log. The image below was shot with the Nikon Coolpix mounted on the Herschel Wedge using the 32mm Televue Plossl. The camera settings were 100 ISO, f 5.1, 1/125s and 4x optical zoom.
Click to enlarge!
In the centre of the image you see the active region 908. The more or less pear-shaped group has an area with a few umbra’s that seem to form one large umbra in the form of a cloverleaf. To the left of this almost circular feature lie several smaller dark umbra-like areas, divided by one or two light-bridges, I detected at a magnification of 100 times. The whole group is surrounded by a penumbra, which is also breached by the Lightbridge’s. The Lightbridge’s are not very clear on the image, but visually they where absolutely visible, as where the inner and outer bright ring around some parts of the umbra / penumbra. There where no faculae around AR 908 or on any other part of the Sun.
In H-alpha, the darker umbra’s where very easy to see, but I detected no bright patches in the AR 908 area (plages or flares). I did see two large bright areas around AR 907 and AR 909 (the two smaal groups towards the right edge of the image). Between 907 and 908 I detected a long, snakelike bright area. There where only a few smaller prominences visible. Between AR 908 and the edge of the solar disk I detected two dark filaments.
Monday, October 10, 2005
Three prominences
On Sunday 9 October 2005 I observed the Sun for a while with the Coronado PST. (In white light there was absolutely nothing visible). Along the solar limb there where 3 major areas that showed some very delicate prominences (see image 1 and 2). Also one really large filament was visible (see first image). The Sun was low in the sky and there were some very thin clouds that obstructed the view every now and again. The two images below where the best I could get (click to enlarge).
Sunday, September 25, 2005
The Sun is "on fire"
On Wednesday the 21st of September the Sun was on fire. It is hard to explain in words what I saw. Early in the morning I pointed the Coronado PST at the Sun. Large parts of the solar limb seemed to be alive with large prominences, and on the solar disk I could detect a large active region, AR 0810 and a few filaments. AR 0810 was visible as a sunspot (dark, black), with a large bright area (plage). There was also a large filament between the active region and the limb of the Sun. The most spectacular features where the large prominences. One of them was completely detached from the Sun and seemed the hover in space. It is amazing what you can see with the PST. I shot the image below later that day. It should give you an idea of what I saw, but I have to admit that the image doesn't come near to what I actually saw through the small solar scope. The filaments looked like very fine threads and I cannot capture them as I visually saw them. But that goes for a lot of objects. I once observed M 13 under very good conditions with a superb telescope. There is no single picture that comes even near to what I saw that night. Any camera cannot beat the eye-brain combination. I'm sure of that.
Anyway, here's the best image I could shoot (and process) of this "flying" prominence. It was shot with the Nikon Coolpix 4500, image size 2272 x 1704, highest quality, iso 100, 1/8 second, f / 8.2. I used a 15mm Vixen Lanthanum eyepiece (magnification is about 26x) and 4x optical zoom. Image processing: level adjustment (in different color channels), brightness/contrast, hue/saturation (only in magenta) and unsharp masking.
What I also learned that day, is that there are probably two factors that are very important for getting good images: get the image focussed as good as possible and shoot a few series, so you can catch a moment of good seeing. I shot a few series in the morning, and I didn't get one good image. Around 12 O'clock local time I shot another series, with the same equipment and settings. I got significantly better images than a few hours before. Only two things could have changed: I re-focussed the camera and probably got lucky with moments of good seeing.
Enjoy
Tuesday, September 20, 2005
Painting and the Sun
This week the weather is ideal for touching up the paintwork around the house. The sun was still warm and there was almost no wind. Between the painting sessions, I rolled out the EQ-6 with the PST and the TAL 100RS to observe the Sun every now and again. The PST just amazes me every time I use it. There where many details visible on the solar disk. In active region 0810 the sunspot and a large plage was clearly visible. There where two or three filaments on the solar disk. At the edge of the sun things where spectacular as you can see on the images below. There where two large groups of prominences. A fantastic sight. 
Click on images to enlarge
The images where shot with the Nikon Coolpix 4500, a 15mm eyepiece, full optical zoom, exposure 1/30s, ISO 100, f / 5.1, 2274x1704 pixels. Processing: level adjustment, contrast and brightness, hue/saturation and unsharp masking.
I also had the chance to have a look at the Sun in “white light” with my new Herschel Prism mounted on the TAL 100RS. On the image below (taken with the Coolpix 4500, a neutral density 3.0 filter and a Baader Continuum filter, ISO 100, exposure 1/500s, f / 2.6, 2272x1704 pixels. Processing: Contrast/brightness and unsharp masking) you can see active region 0810 in white light. The green color is caused by the Continuum filter. I didn’t find the time for more detailed images, because…. a lot of paintwork was still waiting.
Friday, July 29, 2005
First H-Alpha pics!
Yesterday morning the seeing seemed to be good. The Sun revealed a great number of details in the PST. There where filaments, prominences, plage's, and active regions visible. I also had a chance to use a wide array of eyepieces ranging from 20mm to 5mm (all Vixen Lanthanums. The different views were fascinating. I also shot some images with the Nikon Coolpix 4500, which I include in this observing report. I also fiddled around with adjusting the images in different colour channels. It produced some interesting results that form a base for future improvements. 
Sunday, May 01, 2005
Sunspots 756 and 757
This morning I observed and photographed two groups of sunspots, NOAA 0756 and 0757. After months I got a chance to have a look at some sunspots with the refractor. It was very hot (28 degrees Celsius); there where no clouds, and the sunspot group 0756 was large and impressive. I noticed while shooting the images that with higher magnifications and/or optical zoom the exposure times get longer, and the seeing gets more disturbing on the images. I hope that the new Herschel prism from Baader (still waiting on it) will give me more light at higher magnifications and much shorter exposure times.
The first image was shot with the Nikon Coolpix using the TAL 100RS 4-inch refractor and a Televue 32mm eyepiece with 1x optical zoom. The second, more detailed image was shot with the same telescope and camera, but with a 20mm Vixen Lanthanum eyepiece and 4x optical zoom. The big sunspot group is NOAA 756 and the smaller group to the right is NOAA 0757.
Monday, November 08, 2004
Sunspots 667, 669, 671 and 672
In the early morning of September 10, about 09.00 hrs UT I started my solar observing session. The sky was deep blue and transparent. For my visual observing I used the TAL 100RS 4-inch refractor and the 32mm Televue Plossl eyepiece. The filters I used were
