Thursday, June 29, 2006
The Antennae galaxy from Chicago
I am guessing that the Astronomy Picture of the Day for tomorrow, with the title "cosmic antennae", is likely to be about the Antennae Galaxy, an interacting pair 63 million light-years away in Corvus the Crow, visible now as a compact quadrilateral to the far lower-right of Jupiter blazing in the south after sunset. So, I'm posting a poor image of them now, because otherwise the APOD gets me every time in posting something I should have posted earlier.
I imaged the Antennae (also known as NGC 4038/4039) on April 26th from Ryerson Observatory. The total exposure time was about 85 minutes. My light-polluted skies overwhelmed the faint antennae structure of stars thrown out of the galaxies during the collision. I can see the individual superclusters of bright blue supergiants formed during intense starbirths from the compression of gas clouds during the collison. The two brightest knots in the galaxy (oriented roughly vertical in my image) are actually the cores of the original pre-collision galaxies.
Any variations in the dark gray background are dust donuts from the telescope, and leftovers of a smoothing feature I used to help get rid of the vignetting. My flats were not good enough to use for this processing.