Sunspot AR3354

July 7, 2023 Rory Glasgow Sun

During the last week of June 2023, a friend of mine alerted me to the fact that the largest sunspot group of this solar cycle was passing across the face of the Sun. I wanted to take some pictures of it.

My rig is not ideally suited for solar imaging, but I do have a white-light filter that works well with the AT72EDII telescope. The trick, though, is polar alignment.

My solution was to set up the mount the night before, level, balance, and polar-align it, and then mark the pavement with chalk to show where to put the tripod the next day.

Three chalk circles on a paved driveway. — The chalk circles marked where to put the feet of the tripod.

Telescope and mount sitting in place on a paved driveway. A white light solar filter is attached to the objective end of the scope. The scope is covered with a heat shield. — A reflective shield helped protect the scope and camera from the heat. The truck in the background was my portable “air-conditioned office” for the computer that controlled everything.

I don’t know if the two images above convey it, but it was HOT out there. The heat index was probably around 110F.

Stacked image of the Sun with AR3354 visible. — AR3354 is the group of dark spots in the upper-right of the solar disc. This processed version of 15 combined images brings out detail of the sunspot group at the expense of the Sun’s surface detail.

A single subframe of the Sun with AR3354. — The granulation of the Sun’s surface is a little more visible in this single image, but the sunspot detail is less due to atmospheric distortion. Look carefully and you might see solar plages (bright filaments) on the solar surface, especially near the edges.

It worked pretty well, overall.

I haven’t gotten the hang of taking good white light solar images, but I think that these turned out OK. The whole process went smoothly and only took a few minutes. I actually spent most of the time talking to my neighbor.

And yes, I got a sunburn.