Category: Solar log
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
the Baader Astro Solar Screen ND5 and the Baader Continuum Filter. The overview image below shows four major groups of sunspots. On the western limb (to the right) lies group 671. Between the centre and the western limb lie two groups, 667 (the round group) and 669, an elongated group of sunspots. On the eastern limb you can see group 672.
The detailed image above shows a big group of sunspots (number 672) that seems to consist of three different elements, a big umbra/penumbra, with a smaller spot to the left, and some smaller spots on towards the limb itself. There are some huge faculae around group 672 (white areas). The image was shot using a 20mm Vixen Lanthanum, the Baader Astro Solar Screen ND 3.8, and the IR/UV cut filter, Fringe Killer and Contrast Booster, all from Baader. This image was stacked out of 10 images 1600x1200, shot with the Nikon Coolpix 4500, shutter speed 1/2000, f 9.2, ISO 100, and 4x optical zoom. The image was processed using Keith’s Image Stacker.
The view through the eyepiece was better than all the images you see above, especially with the Baader Continuum filter. This filter blackens the umbras and penumbras, giving them much more contrast than on the images.
On the image above you see the other three groups of sunspots. On the limb lies group 671, and in the centre of the image you can see 667 and 669. Sunspot group 667 has a big round sunspot with a beautiful umbra, which is divided in two by a light-bridge. With the 12 mm Vixen Lanthanum (83x) I can see an arc of 4 to 6 little spots turning away from the big sunspot towards the centre of the solar disk.
Group 669 has a larger spot showing an umbra/penumbra to the right. the southern side (bottom) of the group shows 6 or 8 smaller spots looking like a wedge. The tip of the wedge points to the east. The image was shot and processed exactly as image number 2.« Collapse
On September 9 2004 I tested the Photographic and the Visual Baader Astro Solar Screen while shooting some images of the sun. All images where shot with the Nikon Coolpix 4500, mounted on the TAL 100RS 4-inch refractor and
a 20mm Vixen Lanthanum eyepiece.
There where several groups of sunspots visible as you can see on the overview image below. Near the western limb you can see sunspot group 671. just left of the centre are two groups visible, 667 and 669. On the eastern limb you can see sunspot group 672 just on the edge. The image was shot with a shutter speed of 1/1000 second and the ND 5 Baader Astro Solar Screen.
On the image below shows a more detailed view of the western limb. This image was shot with a shutter speed of 1/2000 second and the ND 3.8 Baader Astro Solar Screen. Near the limb you can see sunspot group 671. To the right you can see two groups of sunspots, 667 being the lower, round sunspot and 669 the upper, more elongated sunspot.
The last two images where shot with 4x optical zoom. The first image was shot with the Baader Astro Solar screen ND 5 and the second with the ND 3.8. The image taken with the ND 5 needed a shutter speed of 1/125 second. Otherwise the image would be to dark. The image taken with the ND 3.8 ND 3.8 was shot with a shutter time of 1/2000 second! This shows that with the Baader Astro ND 3.8 you can use much shorter exposure times, even when you zoom in at a relatively small area on the Sun’s surface.
On September 4 2004 I observed the sunspot group 667 from 08:00 UT until 10.30 UT with the four inch refractor, the Baader ND5 full aperture filter, and three other Baader filters, the Fringe Killer, Continuum and Contrast Booster. Again with a
magnification of 33x (Plossl 32mm) the granulation of the Sun was visible at once. On the eastern half of the Sun (left of the image below) sunspot 667 was visible with a huge area with faculae between the sunspot and the eastern limb of the sun. At higher magnifications (80X to 100x with Vixen Lanthanum eyepieces 12mm and 10mm) the big sunspot of group 667 seemed to bet into 4 pieces by three light-bridges. A hint of these light-bridges can be seen on the detailed (green) image of the Sun.
The overview image below was shot with the TAL 100RS 4 inch refractor and a 32mm Televue Plossl eyepiece, Nikon Coolpix 4500 and the following settings: 1600x1200, Image Quality: fine, shooting mode S, Focus Mode: Auto, shutter speed 1/250, aperture 3.8, ISO 100, optical zoom 2x, matrix metering. Filters: IR/UV cut, Fringe Killer, Contrast Booster and full aperture Baader ND5 Solar Screen.
The image was stacked out of 20 images using Keith’s Image Stacker. With Photoshop unsharp masking was set to 192% (amount) and 3.0 pixels (radius), contrast +12, brightness -7.
On the detailed image below you can see the largest member of sunspot group 667 with the faculae between the sunspot and the sun’s limb. You can also see the granulation. You can also see a hint of the three light-bridges that cut the umbra of this sunspot into 4 parts. I couldn’t get a better image, but visually these light-bridges where very easy to detect.
The detailed image below was shot with the TAL 100RS 4 inch refractor and a 15mm Vixen Lanthanum eyepiece, Nikon Coolpix 4500 and the following settings: 1600x1200, Image Quality: fine, shooting mode S, Focus Mode: Auto, shutter speed 1/60 aperture 5.1, ISO 100, matrix metering. Filters: Baader continuum filter and full aperture Baader ND3.8 Solar Screen.
The image was stacked out of 19 images using Keith’s Image Stacker. The image was processed using Keith’s Image Stacker with the following settings: align 3, sort by difference, laplacian pyramid sharpen 1:67, 2:25, 3:41, 4:19, 5:8, 6:3, DC:1, Cutt-off:0. Adjust histogram levels: black 1270-4950.
On August 22 I observed the Sun for an hour from 14.15 UT till 15.15 UT. For visual observing I used the 4 inch TAL refractor with a full aperture ND 5 Solar Screen, the Fringe Killer and the Contrast Booster. Before shooting the images I added
the IR/UV cut filter. At 32x the suns granulation is at its best. It can be seen all across the surface of the sun. As you can see on the image below, there are 5 major groups of sunspots visible. In 661, the biggest sunspot visible, a lightbridge is clearly visible.
The image below was shot using the TAL 100RS, Baader ND 5 full aperture solar screen, the Baader Fringe Killer, IR/UV filter and Contrast Booster, and a 25mm Vixen Lanthanum eyepiece. The image is stacked out of 30 images that where shot with the Nikon Coolpix 4500 and the following settings: image quality fine, shooting mode S, focus mode Auto, shutter speed 1/500, aperture f 2.7, ISO 100, optical zoom 1, Metering matrix.
The 30 images where stacked, using Keith’s image stacker with the following settings: align 3, sort by difference, unsharp masking with radius 5 / intensity 10.4 and cut-off 0, adjust histogram levels red 0-8593, green 0-8121, blue 0-8256.
During the last few days I have been observing sunspot 656. I also shot some images. While processing the images I noticed that I really miss a good observing form for the sun as well as a registration form for the image data (how where the images shot and processed). Yesterday I created the some forms to log all the relevant data of the images I shoot. This should help me to get a better evaluation of the images. Anyway, here are a few nice shots I took. The first image, a close up of sunspot 656, was shot on Wednesday the 11th of August; the second was shot on Sunday the 15th of August. On the second shot you see sunspot 656 near the limb of the Sun.
The images where shot using the 4 inch TAL 100RS refractor. On Sunday I compared the views of the 4 inch refractor with the 8 inch Klevtzov Cassegrain. The images through the 4-inch where definitely sharper and had more contrast. A small sunspot, nr 657, was invisible with the 8-inch, while the 4-inch clearly showed this small dark spot. The 8-inch had much more trouble with the bad seeing conditions.
Yesterday there was a very big group of sunspot visible (nr. 0652). In the early morning while the sun was rising through the mist it was even visible to the naked eye (use eclips-shades!). The group looks spectacular through the telescope at all magnifications!
Later that day I shot some .....follow this link to read the full story