Digital Astronomy from Scratch - The Sun

25 October 2003

Both giant spots are easily visible without a telescope (with just a solar filter). Here are some closeups. I was getting some darkening on the Sun because I set the f-stop too small(?) on the camera, but I was able to obscure most of the problem with the closeups :-).

23 October 2003

Sunspot 484 is huge, and it looks like 486 is going to be just as big. There was an X5 class solar flare, but alas I see no aurorae from brightly lit Silicon Valley. Still, the sunspot is amazing. 4 frames taken with a Canon PowerShot G3, then stacked with Keith's Image Stacker and laplace sharpened. Then I flipped it and rotated it in Adobe Photoshop so it would match the orientation of the image at Spaceweather.com. Click for the full-sized image.

9 March 2003

Just wanted to take another picture of the sun and there happened to be a couple decent sized sunspots. The big spot in the upper right is 296 and the bottom one is 306 with 308 just barely visible below it. The cluster in the middle left is 305. Click for a larger view. Taking solar pictures really shows how I should clean my eyepieces (especially visible in the larger view).

31 March 2001 - There's a big sunspot causing solar flares; The San Jose Mercury News is calling it the biggest sunspot in a decade. Spaceweather.com says it has the surface area of 11 Earths and is the biggest since 1991, but still small compared to the great sunspot of 1947. I can see the sunspot without glasses (with a solar filter, of course). The last time I can remember seeing a sunspot without any visual aid besides a solar filter was before I had glasses! Here's a picture I took with the ETX at 9am PDT.

25 December 2000 - Christmas morning partial eclipse! Canon PowerShot G1, holding the camera over the eyepiece.

Click for a larger version

View Large (252K) or Medium-size (68K) image.

15 October 2000 I had a chance to take my ETX outdoors today and get a look at the sun. There had been a good sunspot about a week ago, so I was hopeful that something similar would be there. I was a little disappointed, but I suppose this is a great day compared to times of solar minimum. Four groupings of sunspots is nothing to sneeze at (and I have a cold today). It took a while to figure out the designations of each group because for much of today I was unable to find another photograph of the sun that had the sunspots labelled. I could find a chart with numbers, and I could find a photograph that looked just like mine (only more detailed, and without the dust spots messing up the image) at a Nasa site. I eventually found the diagram I was looking for at http://www.spaceweather.com/. Cool site! This image was taken with a Canon PowerShot S10. I enhanced it in PhotoShop LE using the Unsharp Mask, then turning down the brightness and turning up the contrast. Then I flipped it and rotated it so it matched the other images I found on the web. My solar filter is from Orion, and it works great! I took the picture in the late afternoon - not the best time for solar observation. I used a ScopeTronix digital camera adapter to hold the PowerShot over a Meade 26mm Plossl eyepiece. I used the timer feature on the PowerShot so that the mount would steady by the time the picture was taken. I focussed by looking at the picture in the LCD on the back of the camera. It's really just a process of experimenting and seeing what happens.

10 June 2000 Larger Image, Annotated Larger Image (30K) Single image, enhanced in PhotoShop 5.0 LE

These images of the sun were taken with my Meade ETX, a Canon PowerShot S10 and a new digital camera adapter to hold the camera steady over the eyepiece without having to use a separate tripod. The adapter came from ScopeTronix. You can clearly see three groups of sunspots, some granularity around the edge of the sun and (unfortunately) some out-of-focus dust on the eyepieces (or somewhere in the optics). I know the "donuts" are optical artifacts because they appear in different spots on different images of the sun. For example, in the image on the right, which is a composite of two pictures taken close together in time, the "donut" has shifted slightly in relation to where the sun shifted in the eyepiece. Notice that the edges of the sun appear dimmer than the middle. This is the phenomenon known as "limb darkening". Pictures taken between 2:05 and 2:08 PM PDT on 10 June 2000. The sun is pretty much at the peak of its 11-year cycle, which means that there are more sunspots than usual. I just found a great site with images of the Sun. I reoriented my image to match the one on that site.

Composite Image at maximum resolution (120K) The faint figure eight in the upper left half of the image is a "double donut" artifact. The bottom left in the limb-darkened region shows some nice texture.

15 November 1999 - The transit of Mercury across the Sun:

The above pictures are three separate attempts at capturing the transit of Mercury across the Sun on November 15, 1999. They were taken through my Meade ETX with an Orion solar filter, 26MM Televue Plossl and a Hi8 Videocamera. I now have my ETX mounted on an Orion SkyView Deluxe equatorial mount with a clock drive. This leads to much better vieweing at high magnifications than I was getting with a straight tripod. Video capture was done on a PC with ZipShot parallel capture device, then moved over to my Macintosh for processing. I took three successive captures and combined them in Adobe PhotoDeluxe (a wimpy version of Photoshop) using layers and the "overlay" feature. I eyeballed the correct placement of each of the three layers (actually, the first of these is four layers) turning visibility of the layer on and off until they fit as closely as I could make them.