This is part of the double star cluster in Perseus taken tonight (in the bitter cold) while there was thin high cloud and the moon was rising. The less than perfect conditions meant a lot of processing, which is why some of the stars are a little “clumpy”.
What you are looking at is a genuine collection of stars about 7000 light years away. The stars are very young – only 5 million years or so – and are still close together since they formed together in a great cloud of gas and have not yet had time to move fully apart. Most of the stars in the cluster are hot and appear blue but some have already used most of their gas and are expanding into red giant stars – very obviously different in colour to the blue stars.
This was made of 20, one-minute exposures, (Atik 16ic on 6-inch SCT) combined using “Astro Art” and further processed in Photoshop. The diffraction patterns on the brighter stars are courtesy of the “StarSpikesPro” plugin by Pro Digital.
The one-minute (rather than 30 second) exposures follow me updating the software on the mount for the telescope and then making a very careful polar alignment. The scope will keep an object in the field indefinitely now – visually, things stay where they started. This means that the telescope very accurately tracks the movement of the earth. However, photographically some one-minute exposures show movement while others show none at all. This is called “periodic error” and is because no mechanical system is perfect. The only answer is to guide the mount, using a camera and computer to immediately correct any movement while it is happening, and I will be experimenting with this over the next little while. I want to be able to do exposures lasting several minutes each to capture even dimmer and more subtle objects such as galaxies.
