Tracked and Stacked Galaxies M81 and M82 This is stack of 26 individual frames for a total of 64 minutes of total exposure. The stack increased the signal-to-noise ratio of the image, allowing the contrast to be increased to bring out details in the faint spiral arms of galaxy M81.

M81, at left, is a grand-design spiral that is one of the great showpiece galaxies in the northern sky.

M82, at right, is an irregular starburst galaxy. It has an extremely active nucleus containing regions of rapid star formation in star clusters. The star formation may have been triggered by a close encounter with galaxy M81, which stirred up gas and dust, forming the unusual dark lanes in M82 visible in this photo.

The combination of these two galaxies close together in the sky makes them an amazing treat for both visual observers and astrophotographers.

Individual stars in these images are foreground stars that are located inside of our own galaxy, the Milky Way. Individual stars inside of other galaxies are usually not resolved because of their great distance.

With a visual magnitude of 6.8, M81 is probably the farthest object that can be seen with the unaided eye at a distance of 12 million light years, although this is a most difficult observation. It has been reported on several occasions, particularly by Brian Skiff of Lowell Observatory. He reported glimpsing it as a "threshold" object, detected only 5-10 percent of the time with optimally adapted averted vision under very dark skies at Anderson Mesa in Arizona. At that time, stars down to magnitude 7.9 were visible to the unaided eye. This is an extraordinary observation.

Image Data

• Lens / Scope: Stellarvue SV70ED ED doublet refractor
• Focal Length: 420mm
• F/stop: f/6
• Exposure: Stack of four 5-minute exposures plus twenty-two 2-minute exposures (64 minutes total exposure)
• Mount: Orion Sirius polar-aligned German-equatorial mount
• Guiding: None
• Camera: Unmodified Canon EOS 1000D (Digital Rebel XS)
• Mode: JPEG
• ISO: 1600
• White Balance: Custom, set on sky background
• In-Camera Noise Reduction: Off
• Filter: Lumicon DS filter on the 5 minute exposures, no filter on the 2 minute exposures
• Temp: 22F and 28F
• Start Time: Start 1:52 and 12:18 a.m.
• Date: March 21 and 24, 2009
• Location: Maxwell, NJ
• Calibration: None
• Processing: Standard in-camera JPEG processing. Stacked in Deepsky Stacker. Contrast and color adjusted in post processing.