In the early morning hours of Wednesday, October 18, 2023, I returned to one of my favorite galaxies, M33 in Triangulum. A member of our local group of galaxies, M33 lies about 3 million light years from Earth, halfway between Aries and Andromeda. On this damp, chilly, moonless night it passed almost directly overhead, nearly bright enough to see without the telescope. My equipment likes the cold weather better than I do - it performed almost flawlessly as I observed remotely, from about 30 feet away in the warmth of the kitchen. At the end of the session, a cold, clammy layer of dew coated all of the equipment out on the deck.

If you view this image at full size (click "original" below), you can see a large area of red nebulosity near the edge of the galaxy at about the 7:30 position. This area is an emission nebula in M33, an area of hydrogen gas ionized by massive nearby stars, and it has been identified by earthly observers in our New General Catalog as NGC 604. It is about 2,000 times more distant, 40 times larger and 6,000 times brighter than the brightest emission nebula in our own Milky Way galaxy visible from Earth, the Orion nebula. It must be a spectacular sight for residents of the Triangulum Galaxy who are far enough away to avoid injury from the intense ionizing radiation that produces the nebula.

Using a different telescope, autoguider and camera, I visited M33 fifteen years ago. This time, the William Optics FluoroStar 91 telescope and the ZWO ASI071MC Pro camera were controlled with N.I.N.A. software. Autoguiding was performed with PHD2 software, using a 60mm guide scope and a ZWO ASI224MC camera. The Orion Atlas mount was the common denominator, but this time the mount was controlled by a new driver, GS Server, instead of the venerable EQMOD driver. I acquired 118 ninety second exposures before trees got in the way. All image processing was performed later that day with PixInsight.