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Solar Observations for April 2018

Monty Leventhal OAM taking his regular solar observations

Every morning, when our Sun is shining, our astronomy society president, Monty Leventhal, sets up his two telescopes to make solar observations from his balcony in Maroubra, Sydney. Monty not only observes, he also photographs the Sun and completes a hand-documented map of the Sun, showing filaments, Sun Spot groups and other phenomenon such as coronal mass ejections (CMEs). Monty's observations are then sent to several recipients around the globe to be included in data sets. Here is a summary of Monty's observations for April 2018:

The solar disc was clear of Sunspot from 1st March 2018 to the 12th April when a single Axx (1) spot was seen at 20° North & Longitude 332°. Though it could not be seen on the 5th it could still be observed on the 6th in AR12693.

No Sunspots could be seen on the solar disc until 12th. On that day a Bxi (3) group of 3 spots were observed 8° north & longitude 27° in AR12704 By the next day the 13th it had disappeared. No further Sunspots could be seen until the 18th when a single Axx spot (1) in active region 12706 was observed. By the next day it was gone.

A new single Hsx Penumbral spot was observed close to the NE limb in AR12707. Emanating from it was a small Filament This group grew to a CV of Cki (39) as it rotated with the Sun very close to the Equator. Its position on the 23rd was at 2° north and a longitude of 282°. By the 28th it had disappeared and the Sun was clear of Sunspot to the end of the month.


The most significant Prominences were on the 5th on the SE limb with a Single Arch type reaching a height of 37,000km. It was still visible on the 6th and had grown to a height of 47,000km.

The Sun was completely clear of all activity on the 7th.

A larger Prominence appeared on the SW limb on the 14th reaching a height of about 74,000km and was still visible on the 15th

For the month of April most Prominences remained small and faint.

Prominences were seen on all observing days this month with the exception of the 7th when no activity at all could be seen.


No Flares were seen for the whole month of observations.

For the month of April 2018 all Sunspot activity once again on the Sun remained extremely low.

A total of 20 Observations were made for the month with the remaining 10 days being cloud covered and/or rain.

A total of only 3 groups were observed. This included 2 groups in the north and 1 in the south, comprising of 9 spots in the north and 1 in the south giving a total of 10 Sunspots.

The average Relevant Sunspot number for the month was 5 and the average CV was 1.4 and the Q CV 1

No CMEs were observed.

Monty Leventhal OAM.

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