I recently learned about this rarely imaged target just a few weeks ago. In addition to the Magellanic Clouds, two dwarf galaxies orbiting the Milky Way visible only from the southern hemisphere, there are many other satellite galaxies of the Milky Way. One of these is an elliptical dwarf that lies about 225,000 light years away in Ursa Minor and is designated UGC 9749. It was discovered in 1955. It is a very old galaxy with no ongoing star formation. This means it has little primordial gas left to form stars or to see. It is a little underwhelming compared to the types of galaxies I normally like to image. The galaxy is the cloud of dim stars around the center of the image.
I had four clear nights in a row, but with a waxing gibbous moon a little low in the sky. Did I tell you about how much I dislike the moon? I was thankfully able to clean up the background a good bit since there wasn’t much to worry about destroying. In total I got about 24 hours of data, which seems like kind of a waste of clear sky given how underwhelming this target turned out to be. Oh, well.
I may not be the James Webb Space Telescope, but all the exposure time lets us go a little deep in this image. Perhaps more interesting than the intended target, a little above the center of the image is a cluster of very distant galaxies. They are pretty dim but unmistakable as galaxies given their redshift,
The orange-looking “stars” near the center of this crop are galaxies, and some of them are annotated in the following image,
The brightest of these is designated SDSS J151058.89+670626.2, and it has a magnitude of 18.78, making it appear 124,000,000 times dimmer than the brightest star in the sky, Sirius. You can find it just a bit above the center of the image. With a redshift z = 0.423, it is moving away from us at a velocity of near 62,000 miles per second due to the expansion of the universe. Assuming a flat model for the universe, this suggests the light from this galaxy took 4.5 billion years to reach my telescope, and the galaxy is now 5.4 billion light years away. This makes this view of these little orange dots about as old as Earth.
