This kind of stuff never gets old! A crisp Sunday morning, a cup of hot coffee, and a glorious sunrise with our friends Venus, who is a morning planet now after passing through inferior conjunction,, and of course a waning crescent moon.
Spring hasn’t quite sprung yet up here on the Hill. This morning the temp didn’t quite break 30 degrees. Strange patch of high humidity came through last night and when I checked the scope after last night’s session there was frost on it! Had to throw out about 75% of the images as a result. But, we did get one hour’s worth of new data on a new imaging project, the galaxy pair M81 and M82. I have never actually imaged these together before. Looking forward to the finished result! Then to top it off I found one of this month’s binocular bright comets, PanSTARRS, making its way through Aquarius now. I caught a glimpse of it about an hour and half before sunrise. Not enough time to do a full imaging sequence but enough to see a tail! Comet Lovejoy, supposedly more impressive is just too low now for me to get a good look at it. We’ll have to revisit these next month perhaps!
Comet PanSTARRS (C/2015 ER61) just passed closest to Earth on April 19 at 109.5 million miles. It should continue to brighten up until May 10 when it reaches perihelion, closest to the Sun. This is just a 1 minute single frame uncalibrated luminance image taken with the 5″ refractor
New project! The galaxy pair M81, M82 are part of the “M81 galaxy group”. There is a third galaxy, NGC 3077 which is interacting with the other 2 gravitationally but not in this field. The interactions have stripped away hydrogen gases from all 3 forming intergalactic filamentary structures called the Integrated Flux Nebula, I hope will be revealed in the final image. This is a single raw uncalibrated 6 minute luminance image taken with the 5″ refractor. Note the vertical lines through some of the stars. This ccd is very sensitive and what is called non-antiblooming, meaning that for these stars the charge in these pixels have exceeded the saturation level and then start to fill adjacent pixels. The sensor is designed to allow for vertical shifting of charge but not horizontal. So yes, this is kind of an “accepted inconvenience” , which has to be processed out of the image at some point, in exchange for higher quantum efficiency and data preservation but perhaps a topic for another day!
Thanks for reading!
Messier 81 or Bode’s Galaxy is a spiral galaxy 12 million light years away in Ursa Major. It is a favorite target for both professional astronomers who study its active galactic nucleus harboring a 70 million solar mass super massive black hole, and amateur astronomers who take advantage of the large size and brightness for both visual observing and astroimaging.
Back in 2007 I took my first image of M81. I was just thrilled to be able to take an exposure longer than 1 minute and capture any detail with round stars! In under 10 years with improvement in equipment and processing techniques, much more information about the structure of this galaxy is now appreciated. In my recently completed image of M81 (full res version can be found on the flickr site- see link to astroimaging) you can see not only Arps’s loop, Holmberg IX galaxy but also some very interesting nuclear structure! This is not processing artifact folks. I have not seen this on any published image thus far and wonder what physical properties give rise to them! We have come to assume that galactic nuclei in visible light are just bright blobs of gas, but clearly this is incorrect!
Image taken in 2007 with a 10″ newtonian and SBIG ST8XE camera
M81 just completed. 10″RC and SBIG STXL6303E. Larger arrows point to the now appreciated “Arp’s loop”. This is a loop of gas emanating from the galactic disc but recently at least some of this is believed to exist in our galaxy as “galactic cirrus”. Halton Arp was an astronomer who catalogued interacting galaxies and galaxies with unusual structure and features. The smaller hatched arrow points to Holmberg IX, a dwarf irregular satellite galaxy of M81 formed only 200 million years ago, the youngest nearby galaxy!
Arrows point to peculiar nuclear structure! The arrow closer to the center points to a strange vertical projection of dust toward the center of the nucleus with a round knob-like top! What is it and what causes it? Who says imaging is not science!