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Solar Observations for April 2017

Image and copyright Monty Leventhal OAM ©


A solar flare is an intense burst of radiation coming from the release of magnetic energy associated with sunspots. Flares are our solar system's largest explosive events. They are seen as bright areas on the sun and last from mere minutes to several hours.Scientists classify solar flares according to their x-ray brightness. There are 3 categories: X-, M- and C-class. X-class flares are the largest of these events. M-class flares are medium-sized; they can cause brief radio blackouts that affect Earth's polar regions. Compared to X- and M-class, C-class flares are small with few noticeable consequences on Earth (NASA

Activity on the Sun continued to be very low during the month of April 2017. The image above is photograph I took of the giant sunspot AR1302 taken through a 10-inch (25-cm) Meade telescope with a hydrogen alpha filter in September 2011 (Image and copyright Monty Leventhal OAM ©, all rights reserved).

Due to bad weather no observations were made until the 3rd April where 3 groups were observed, a Cso group in AR12644, an Esi group in AR12645 and a Dso group in AR12648. On the 4th only 2 groups remained, both in the southern hemisphere, regions 12645 and 12648. Both groups remained on the solar disc until the 6th. Region 12645 was about to rotate round the western limb while region 12648 had reduced in size to a single Axx spot. No Sunspot groups could be seen on the 7th or 8th and bad weather prevented further observations until the 12th. On that day a single Axx spot was seen in AR12650 and also on the 13th. From the 14th to the 16th incl. the solar disc was again clear of Sunspots.

Due to bad weather no further observations were made until the 19th & 20th. On these days a single Csi group could be seen in AR12651.

Due to cloud cover no observations were made until the 22nd when a new group in AR12653 could be seen near the eastern limb in the south. The two groups continued to remain on the solar disc with no other groups until the 29th though both had reduced in size to Hsx.

All that remained on the 30th was a single Hsx spot in AR 12653.


For the month of April most Prominences were again very small and faint. On the 15th a Hedgerow Prominence was observed stretching across the NE limb for approximately 214,000km and reached a height of 47,000km. On the 24th a Colum type Prominence reached a height of about 84,000km on the NE limb and on the 28th a very faint incomplete Arch Prominence reached a height of approximately 84,000km.

Though Prominences could be seen most days of the month, as mentioned, most were very small and faint.

No Flares were seen during my watch.

You can see how I document my observations in the sun map below. This type of diagram is distributed to a number of organisations every day I make an observation.

Every Month I summarise my observations. You can find out more about me and how I make my solar observations on a previous blog post.

Monty Leventhal OAM



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