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6 days after the Venus transit, there is now some activity on the solar disk as up until now there had been none. The left image shows a group of 3 sunspots with clearly defined faculae around the spots. The right image of sunspot group 634, shows an already well developed grouping. I used wavelet processing to enhance the granulation in each image which also clarifies the sunspots, faculae and pores. Also notice how that the sunspots seem to look like depressions in the photosphere because they are close to the limb. This observation is called the Wilson effect.
In 1769 a Scottish astronomer named Alexander Wilson noticed that the shape of sunspots noticeably flattened as they approached the Sun's limb as the Sun rotated. These observations showed that sunspots were features on the solar surface, as opposed to minor planets or objects situated above the surface. Moreover, he concluded that sunspots were in fact slight depressions in the surface of the photosphere.
24th May Moon Mosaic
The Moon is 5 days old in this photo and is a beautiful waxing cresent. This is my first Moon mosaic using the Orion ED80 and I am quite pleased with the result. Final image resolution is 2500x1300 pixels.
M51 : The Whirpool Galaxy
I was intending to image Comet NEAT again but some low cloud changed my mind to the meridian. M51 has been well placed for viewing and imaging for some time. Even though the skies do not get completely dark at this time of year, I found M51 fairly easily (for a change) and started capturing. It was fairly windy though the scope was quite sheltered. I wanted to take alot more frames, but the clouds came over and they didn't look like they were on a flying visit :-( This is my very first image of M51 and I'm fairly pleased with the result. A longer exposure is probably my next goal and higher magnification. This was a very wide field capture and I have only used the central area of the image.
Focusing was my main problem as looking through an optical viewfinder is quite dim compared with an eyepiece. Ideally, I could have gone to a bright star and focused on that and then gone back to M51 without changing focus but it was quite dim to find and would have been impossible to locate again without changing the focus when using an eyepiece. An off-axis guider would be ideal for this job. Instead, I took 20 second exposures and looked at the image at high magnification and adjusted the focus accordingly. This was a very slow method but worked well as I achieved a very fine focus on the dimmer stars.
Venus and the Moon
This sight is always awe inspiring. The 1 and a half day old Moon and Venus in the evening sky.
Comet c/2001 Q4 (NEAT)
I took this image from Slieve Croob. The skies were quite clear with the Beehive cluster naked eye visible. Coma Berenices was visible as a large open cluster. Limiting Magnitude was around 5.5 and I estimated that the comet was around Mag5 coming very near to the limit of naked eye visibility. Unfortunately, the wind was very strong, around 30mph, so I could not take very long exposures without blurring. Still, after some heavy processing in Paint Shop Pro, you can see the nucleus, coma, a bright dust tail and a faint dust tail stretching out horizontally.
Sunspots 609, 608 and 612
The image on the left is of sunspot 609 which split in two to form Sunspots 609 and 608. Notice the very small black sunspots in and around the main sunspots which usually last only a few hours and are called pores. You can clearly see that 609 is split closely in 3 parts and the bridges between are brighter than the surrounding sun surface. I used wavelet processing to enhance the granulation which is caused by convection in the photosphere (visible surface) of the Sun. The dark umbrae are surrounded by the lighter pemumbrae in which you can see a crochet pattern which is quite difficult to image. The right image shows a nearby sunspot, 612 to the far right. Notice that even though the right image was taken only five minutes after the first, sunspot 608 has changed slightly in shape and structure over that brief period.
Yes, OK, so I didn't check the ISO setting before taking the picture. I should have used ISO100 but didn't realise in time to take any more. The final image is a bit noisy compared with last month's image but I thought I would include this to show the Sunspots in context of the full disk.
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