Astrophotography by Torsten Mueller


The Arp Project

I can´t remember the exact reason, but when observing the first galaxies more in detail, i was looking for some more scentific project approach. I´m not the pretty picture photographer, every integration more than several hours is just too long for me and the short nights under the week. Then i stumbled across Halton C. Arps work about the morphological classification of galaxies (1966). His work resulted in a catalog of galaxies, sorted by specific classifications. He used the Palomar Telescope to get images, that means, the catalog is limited to mostly northern sky objects down to magnitude 17. In sum, the catalog contains 338 objects, all within the reach (more or less) of my telescope (regaring brightness and size) So, i decided to try to follow Halton Arps footsteps and photograph each object by myself!

Here is some shortend goals of the project:

In preparation, i aquired some detailed information about the objects. I created some python scripts to calculate the best visibility of each object over the next years.
That means, the object should be more than 10° over the horizon, or more than 30° if its in the eastern sky. Additionally, it should be more than 90 degree away from the moon.
I quickly noticed, that more than 80 objects will never get hight enough to be see at the given location. This was quite disappointing because then i have to take these photos somewere else. I will come back to this point later.
Most galaxies are visible in winter, when the centre of the milky way is not in the sky. That means the best observation time ranges from december to april. (Remark: In a moonless late january night, all Arps become visible at proper locations!) Taken the disturbing moonlight each month and the weather in germany into account, the usable nights are quite few. Each object needs at least 20 minutes integration time, better about 1 hour to get proper signal. That means, it takes long time for me to do all the images. The project will take at least 3 years, probably 4 years.

Overall integration time for the Arp project: 9.38h