Labor Day Sun

Click to enlarge

Happy Labor Day here in the USA!  This marks the third consecutive day that I have been able to observe the Sun in white light and take some close up images of the active regions (AR's).  Both AR 1560 and 1564 are rather picturesque sporting many spots both large and small.  At left is an image of the whole disc taken this morning at 1503 UT (8:03 MST) with my Canon T2i through my TEC 140 and Lunt Herschel Prism.

There is something going on in my imaging over the past couple days in that the disc is not illuminated properly.  While the Solar limb should be darker all the way around, there is an obvious light drop off on the right side of the image.  This was closer to the horizon, but I am skeptical that it is atmospheric extinction...I will try and take an image later today with the Sun high in the sky, just to rule out the atmosphere.  Done!!  See the Edit at the bottom of this post-





Using the 2x Barlow, below are crops of AR 1560 and 1564 taken at 1515 and 1520 UT respectively.

AR 1560 - Click to enlarge

AR 1564 - Click to enlarge

EDIT!  I went out to the observatory a few minutes ago and snapped two pictures of the Sun, at an altitude of 56 degrees above the horizon...and the above "shadow" effect on the whole disc is no longer apparent...maybe it truly was atmospheric extinction!?  Image below from 1741 UT:

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