Solar Section        


May 20, 2016

Carrington Rotation 2176, a short summary

The Rotation ran from 2016-04-12 1857 UT till 2016-05-10 0053 UT.
Submitted images can be viewed at the following URL:
15 Active Regions could be observed during the rotation (AR2529 – AR2543). The rotation started with a total active region area of 880 millionths and 22 sunspots and ended with a total active region area of 210 and 28 spots. The largest region in the previous rotation, AR2529, continued to be the dominant region for this rotation too, and maxed out with an area of 850 millionths. The lowest total area was recorded on April 23rd with 70 millionths. It has been a while since the Sun produced a flare larger than a M5, However early morning 4/18 marks the day/time when it produced an M6.7 flare which did cause an R2 alert to be posted. The highest Wolf Number (86) was recorded for 4/28 with 6 regions and AR2535 showing 9 spots by itself, and the lowest Wolf Number (11) on 4/24 when only region AR2433 was observed with only one sunspot.

The last day of the rotation showed a special event, the Mercury transit which was the subject of the previous summary.  The archive received over 380 submissions for the rotation, with an additional 40 for the Mercury transit.
Thanks to all who spend their time observing the Sun, and submitting their observations.
The ALPO- Solar team.


May 14, 2016

The Mercury Transit, a short summary

As of this writing the ALPO Solar Section received 26 submissions of observations of the Mercury Transit. The transit was well advertised in the JALPO and Solar blog through John Westfall’s article about the transit. In order to accommodate the request to provide a number of images taken exactly at the full hour, a number of submissions were filed which were taken to the second at XX.00 .00 UT. It is our understanding that some of these images have been used by individuals to re-calculate the distance between the Earth and the Sun ( 1 AU). In addition several composite images showed the planet as it tracked in front of the sun and during ingress and egress. Take a look at the archive to see what was submitted:
We’d like to thank all that took the time to observe this event and submit their observations.
The ALPO Solar team.


May 3, 2016

The Mercury Transit, a call for image submissions

Well, it is less than a week until the Mercury transit, and a group of individuals is looking forward to try, based on the parallax shown in images of the transit at the same time, when made from different locations from Earth, to calculate the distance between the Sun and Earth. In order for this to be successful they will need images made at the same time and know the exact coordinates of the location on Earth where the image was made. We are suggesting to not only submit your images of the transit, but if possible also an image of the full sun at exactly the full hour (if possible to the second because Mercury as well as the parallax are very small), so these enthusiasts will have data they can use. If you make an avi, please use the center time of the avi.

In addition, the ALPO’s Transit section will use the data for an extensive report to be published at a future date in the Stolling Astronomer, the Journal of the Association of Lunar and Planetary Observers (the ALPO).

We hope that Solar imagers will consider this request, and submit all their images (also partial Sun images and close ups) attached to an email with the exact time and coordinates of the location addressed to: .

Thank you and wishing you all Clear Skies,


April 16, 2016

Carrington Rotation 2175, a short summary

Carrington Rotation CR2175 ran from 2016/03/16 11:58 UT until 2016-04-12 18:57 UT.
Submitted images and observations are archived here:
The rotation started with a total Active Region Area size of 140 millionths and a Wolf Number of 59. It ended with a total region size of 880 millionths, and a Wolf Number of 42. During the period, the Sun showed 11 Active Regions (AR2519 & AR2521 – AR2530) and it looked for a while that AR2524 would be the dominant region, until four days before the end of the rotation, when AR2529 came around the Eastern limb. The rotation maxed out as it finished on April 12th, when AR2529 had grown to a size of 850 millionths. However, AR2524 still managed to be a key contributor to the highest Wolf number of the rotation of 66 (5 regions and 16 spots) on March 18th. The largest flare, a C3.7, was produced by AR2521 on March 20th, just when it was getting ready to turn to the far side of the Sun.
We are showing three images below which were captured close to the key dates mentioned above. The images were submitted truly by a number of international contributors: Guilherme Grassmann from Brazil, David Tyler from the UK, and Gabriel Corban from Rumania.
As of this writing, ALPO received 226 observations/images for the rotation, and we like to thank all that took the time to submit their images/observations.
The ALPO Team.


April 6, 2016

Carrington Rotation 2174, a short summary

CR2174 ran from 2016-02-18 04:08 UT till 2016-03-16 11:58 UT. We received 222 images/observations for this rotation. This is the first time again since April 2011 that we were able to archive over 200 submissions for one rotation.
The rotation started with a total Active Region Area size of 300 millionths and a Wolf Number of 60. It ended with a total region size of 180 millionths, and a Wolf Number of 57. During the period, the Sun showed 22 Active Regions (AR2497 plus AR2501 – AR2522). The highest total Active Region Areas size was 300 on the first day of the rotation, which was mostly contributed to the size of 220 of AR2497, which was turning that day to the far side of the Sun. For the rest of the rotation, the total areas size maxed out for on February 26, at 260 millionths. The largest region during the rotation except for AR2497, was AR2505 which measured 180 millionths on February 22nd. The daily Wolf number reached its maximum on March 5th at 95, which was mainly caused by an increase of the number of areas for one day, rather than spots. The observations/images below, were submitted by Gabriel Corban, Dave Tyler and Howard Eskildsen.
Thanks to everyone for their contributions to the archive.
The ALPO team


March 30, 2016

The 2016 Mercury Transit

Have you already made any plans for the Mercury Transit which is coming upon us very fast?  Dr. John E. Westfall, the Coordinator of the Venus and Mercury Section wrote a marvelous article in the Spring Journal of the ALPO about the transit which is to happen on May 9th.  We are encouraging everyone to read this in order to become familiar with what to expect, and if you actually observe or image the event, we always appreciate your submissions for our archive via email to .

In addition, those who might take on the challenge to calculate the length of the Astronomical Unit (distance between the Earth and the Sun), might research the Solar Section’s archive the days after the event to look for the right images captured by individuals separated far enough from each other to extract the data they need for this effort. Follow the link here to download Dr. Westfall’s article.


March 27, 2016

ALPOSS – A report on CR2166 thru CR2168

Do you still remember how active the Sun was in the Summer of last year?   ALPOSS Acting Coordinator and Scientific Advisor Richard Hill published his detailed report on Carrington Rotations CR2166 thru CR2168.  The report was published in the 2016 Spring version of the JAPLO and can now also be accessed on ALPOSS’ Solar Observations & Reports page, or by clicking on the following picture:



March 3, 2016

Carrington Rotation 2173, a short summary

Carrington Rotation CR2173 ran from 2016/01/21 19:58 UT until 2016-02-18 04:07.
The rotation started with a total Active Region Area size of 180 and a Wolf Number of 59. It ended with a total region size of 260 millionths, and a Wolf Number of 260. During the period, the Sun showed 17 Active Regions (AR2484 – AR2501). There were 5 days where the total Active Region Areas reached, or exceeded 500 millionths. The rotation maxed out for the total region areas on February 9th, when the daily region area jumped from 460 to 650 millionths and the next day back to 350, mainly because of activity in AR2497. However, AR2497 also managed to produce the largest solar flare of the rotation on February 13th, an M1.8.
A smaller peak in total area of 540 millionths was noticed earlier on January 29th, when the largest sunspot of the rotation, AR2489, covered 300 millionths and registered a Dko on the McIntosh scale. The daily Wolf number reached its very pronounced maximum on February 6th at 113, which was the only day in the rotation where the Wolf number was above 100, but the spot area was only 400. The observations/images below, which were made on some of the key dates, were submitted by Monty Leventhal, Mike Borman and Theo Ramakers.

As of this writing, ALPO received 155 observations/images for the rotation, and we like to thank all that took the time to submit their images/observations.
The ALPO Team.



February 1, 2016

Carrington Rotation 2172, a short summary

Carrington Rotation 2172 came to an end on January 21 2016. So take a look at over 100 images and observations submitted by our observers during this time period.
This rotation ran from 12/25/2015 1152 UT until 01/21/2016 1958 UT. During this time the Sun showed 16 Active regions (AR2470 to AR2487) of which the largest region became AR2173. This region grew to an Fkc on the McIntosh scale with 38 spots on 12/27, and the size of the region maxed out at 590 millionths on the same date. The region also produced the largest Flare, an M2.4, which maxed out at 00:10 UT on January 2nd.  Here the image of AR2173 on December 27th by Rik Hill and an image submitted by Monty Leventhal of the M2.4 flare on 2016-01-02 ten minutes after the maximum.





Thanks to all contributors to this Rotation: Monty Leventhal, Tony Broxton, Gabriel Corban, Dave Tyler, Rik Hill, and Theo Ramakers.

The ALPOSS Team.


January 5, 2016

Solar Ephemeris Information For 2016

The ALPOSS has provided Solar Observers for many years with solar ephemeris data to help them with their solar observations. This year is no exception, and we have posted the ephemeris data for 2016 in .pdf format on our Solar Ephemerides and Rotations Page . The data can also be downloaded for off-line access. This data has been created using the WIMP program which can be downloaded from the Computing Section webpage . Interested parties can install the program on their PC for off line access. The program was updated with more accurate calculations in the fall of 2015. So if you have not installed the latest version of WIMP we urge you to do so.

Good Observing and Clear Skies,
Your ALPOSS team

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