Caldwell 12 - The Fireworks Galaxy

[Graeme]

This is Caldwell 12 - The Fireworks Galaxy. Which sits on the boundary between the constellations of Cepheus and Cygnus. Its distance from Earth is about 25.2 million light-years. Ten supernovae have been observed in this galaxy in the 20th and early 21st century. This is about ten times the rate observed in our Milky Way galaxy, even though the Milky Way has twice as many stars. For this reason, it is known as the "Fireworks Galaxy".

This image comprises 42 x 4 minute LRGB exposures giving a total integration of just under 3 hours over three nights as I struggled with 95% humidity!

NGC 6946 Fireworks Galaxy_01_03_EL.jpg

My previous attempt at the Fireworks Galaxy was attempted almost 3 years ago on the 5th of November.

Regards

Graeme

[HansV]

It came out really well!

[jstevens]

Graeme,

Keep them coming as they are truly appreciated.

[ChrisGreaves]

This is Caldwell 12 - The Fireworks Galaxy. Which sits on the boundary between the constellations of Cepheus and Cygnus. Its distance from Earth is about 25.2 million light-years. Ten supernovae have been observed in this galaxy in the 20th and early 21st century. This is about ten times the rate observed in our Milky Way galaxy, even though the Milky Way has twice as many stars. For this reason, it is known as the "Fireworks Galaxy".

I am now on my second coffee of the day, and have, as usual, a few questions.

1) Our closest star, in our solar system of course, is Alpha Centurai(?) at about 4 light years(?). Where does Caldwelll12 fit into the scheme of things? Is it our closest galaxy? Third-closest? Which is our closest galaxy?
I realize that this last may be a trick question. If our closest galaxy is in a galactic cluster, then all the galaxies in that cluster (ten? a hundred? a thousand?) will be closer than Caldwell 12.

2) Relax! I am not going to ask about Caldwells 1 through 11, let alone the ill-fated 13.

3) Might the number of stars in a Galaxy inhibit supernovae observations? An inhabited galaxy with a billion billion stars (doesn't exist as far as I know) might have so many stars that their combined brightness would overpower a dim supernovae? Or perhaps the fact that there are so many stars each with its local gravitational field might smooth out gravitational influences so that degradation of a star is less likely than the collision of that doomed star with a close neighbour?

4) I feel that from my childhood I recall a galaxy named PinWheel (USA?) or Catherine Wheel (UK?). Is this the same galaxy? If so, why all the different names? Were astronomical societies so disengaged seventy years ago.

5) To me a photo of a galaxy is just a photo of a galaxy. Pretty. But since about a month ago I have a slightly better grasp of the effort and labour that goes into setting up for data collection, and the data processing that comes after. At this stage in your life, when you decide on a target ("Next Thursday night I'm going to do Caldwell 12"), what proportion of sessions render a result that you consider can be posted publicly. At the level of Eileen's Lounge? At the level of the Royal Astronomical Society?

{later}

6) Supposing you decided to photograph any polar ring galaxy. How would your current set up cope with it? That is, do you suppose it could be done by you? I was tempted to ask "What can't your set up do?", but I think that that type of question is not fair in a scientific context. C

Cheers, Chris