M81 & M82 (May 2023)

 

This is a data set from OMI Astro.  It's 11.4 hours of R-Ha/G/B.  This is actually one of my favorite parts of the sky.  These two galaxies are very bright.  In my 10", they look like a whirlpool and a wave, about of equal size.  I can almost squeeze them in the same field of view with the eyepieces I use.  It's quite a sight to come across these very bright objects.  In the telescope view, they have no color at all because they are so dim, even though they are about as bright as galaxies appear at the eyepiece.  Leave it to the camera to pick up colors. OMI collected the data with a Takahashi TOA 150.  I was hoping to work with data collected with a refractor, and that's a good one.

M82, M81

The big spiral galaxy on the left is M82.  The much larger one on the right is M81.  To the right of M81 is another dim spiral galaxy, PGC 28731, probably a satellite of M81.  On the bottom right is NGC 3077, classed as a spiral but looking quite elliptical.  Other, smaller galaxies abound.  Just below M81 is Holmberg IX, a small satellite of M81.  Just below and to the right of M82 is PGC 3097961, magnitude 17.60 smudge of an elliptical.  Between M82 and M81 at the very top of the frame is UGC 5247, a faraway spiral.

Just above and to the left of M82 is a congregation of tiny smudges that constitute a cluster of galaxies.  The brightest members are dimmer than 17 magnitude: PGC 2732102 and PGC 2732338.

Scattered throughout the area are clouds of dust in our own galaxy.  Galactic cirrus, we call them, but they are relatively local.

The M81-82 group we suspect is about 12 million light years away.  The galaxy clusters above and left of M82 may be hundreds of millions of light years away.

This image is 68x900" of Luminance from the dark, dark skies of Deep Sky West.  The image has been re-sized to 50% less to handle the blog format.

M81 (March 11 & 12, 2013)

Full resolution image here.

M81 is roughly 12 million light years away.  We see it in the constellation Ursa Major.  In fact, it sits just west of the Big Dipper's bowl.  M81 is the largest of a group of nearby galaxies called, with affection, the M81 group.  The galaxy just below (west of) M81 in the image is PGC 28757 or Holmberg IX, an irregular dwarf satellite galaxy of M81.  There are other, more distant galaxies in the image, too, but I have no idea what names they carry, or if they do.

This image was taken from skies darker than my normal location.   Distant galaxies are always better seen from darker skies.  The image is shrunken slightly for noise reduction.

If you look closely at the image above, you will see there are clouds to the left of M81 running from the top to the bottom of the image.  These are probably clouds of gas and dust within our own galaxy and have earned the name "Galactic Cirrus."  See here and here.  These clouds are very dimly lit.  They are more easily seen in this inverted version:

Telescope: Astro-Tech AT111EDT and William Optics AFR-IV (eff. at f/5.6)
Camera and Exposure: SXVF-H9 (29x900"), Alnitak Flat-man flats
Filter: Astronomik CLS
Guiding: SX Lodestar and SX OAG
Mount: Takahashi NJP
Software: Nebulosity, Maxim DL, Photoshop CS3
Location: SHSU Observatory near Huntsville, TX; Starry Nights Bed and Breakfast near Wimberley, TX