Cassiopeia Observatory logo

Sunspot AR2396, Daytime Thin Crescent Venus

Posted: 9 August 2015

Monsoon season cloudy skies returned on Wednesday, 5 August 2015. Thursday and Friday, the 6th and 7th, had considerable thunderstorm activity in the area, with severe thunderstorm, flash flood, and dust storm warnings during much Friday afternoon, but only a trace of rain fell here during the daytime. However a storm that came through before midnight dropped 0.48" rain in a couple of hours, with frequent lightning. Saturday, 8 August, dawned stormy, with more lightning, but no rain here. Sunday, 9 August, surprisingly dawned clear. Storms were still in the forecast though and some cumulus clouds began appearing mid-morning. I decided to try to image the large sunspot AR2396 and the very thin crescent of Venus late morning before the cloud cover increased.

Open: Sunday, 9 August 2015, 1049 MST
Temperature: 104°F
Session: 855
Conditions: Mostly clear

Some cumulus clouds were visible to the south of the observatory:


Fortunately, they were not yet up to the Sun's or Venus's position in the sky.

Mounted the Orion full-aperture solar filter on the Meade 8" LX200-ACF. Used the "Sun as Asteroid" technique to GOTO the Sun. 1059 MST: viewed the Sun, 83X. Active Region 2396 was very impressive. Two other much smaller sunspots were visible.

Mounted the iPhone 5s on the telescope for afocal imaging using the MX-1 Afocal Adapter at 77X. This full disk view shows the size of AR2396:


Switched to 222X and did some single frame and slo-mo (120 fps) imaging of AR2396. Seeing was very bad. None of the videos were stackable, but one photo was acceptable, as seen in this cropped version:


Switched back to 77X, slewed to Venus, and then removed the solar filter. Wow, impressive view of a very thin crescent against the bright blue sky. Unfortunately, the poor seeing made imaging difficult. I did some slo-mo videos at 77X and 222X. Tried to stack the videos but that didn't work out. I was able to find a single video frame at both 77X and 222X that showed the crescent phase reasonably well. This is at 77X:


And at 222X, highly edited to remove most of the atmospheric blurring:


1123 MST: final look at Venus, 83X. As the seeing was so bad, ended the session.

Close: Sunday, 9 August 2015, 1132 MST
Temperature: 94°F
Session Length: 00h 43m
Conditions: Partly cloudy

I have updated my review of NightCap Pro to discuss version 7 of this amazing app.

Check out this new video highlighting the "big brother" to my observatory, the SkyShed POD MAX. Wow!

Comments are welcome using Email. If you are on Twitter you can use the button below to tweet this report to your followers. Thanks.

Previous report

Cassiopeia Observatory Home Page

Back to Top

Copyright ©2015 Michael L. Weasner /