See a Giant Sunspot!

By: Sean Walker January 19, 2023 0

The Sun as seen by the Solar Dynamics Observatory showing the immense active region AR3190 below center.

If you have a solar filter, check out the sunspot group AR 3190 that’s crossing the solar disk this week.

If you have a solar filter, be sure to have a look at the Sun over the next several days. Sunspot AR 3190, which is crossing our stars central meridian today, is massive — so big, in fact, that you can see it without a telescope by simply holding a filter to your eyes and having a look.

Sunspot group is black on the center of the yellow-orange disk of the Sun — The Sun, as seen by the Solar Dynamics Observatory, shows the immense active region AR3190 (at center).
*SDO / HMI*

Of course, the view is much more rewarding with a properly filtered telescope, as there are more than half-a-dozen smaller groups of spots riddling the photosphere.

Solar activity is rapidly increasing as we head towards the maximum of the Sun's 11-year cycle, which should peak in 2025. Long-time Sky & Telescope contributor Tom Fleming notes he's seen more sunspots this week than any time since Cycle 25 began a few years ago. So if it's clear and you have a safe solar filter, be sure to have a look! Observers with small refractors lacking a solar filter could also see the spot by projecting the image onto a piece of paper. Just be careful not to look at the Sun through the unfiltered telescope.

diagram of solar projection — A simple projection setup made from a cardboard shield and a piece of white paper as a projection surface. A surprising amount of detail can be seen this way.
*Sky &a Telescope illustration*

To read more about safe solar imaging, check out the November 2022 issue of Sky & Telescope.

About Sean Walker

S&T Senior Editor Sean Walker joined the staff of Sky Publishing in 2000 and specializes in astrophotography, solar system observing, and astronomy gear.