Saturday, September 1, 2012

Milky Way


Milky Way -- © Dave Spier

Okay, something a little different, something out of this world.  It's the Milky Way, our home galaxy, from Nick's Lake campground on September 20, 2009. This part of the Milky Way is in the "summer triangle," formed by the three brightest (alpha) stars in the constellations Cygnus (the swan), Lyra (the lyre, or small harp) and Aquila (the eagle).  I've marked them on the photo, which is repeated below. Deneb is the tail star in Cygnus, a.k.a. the northern cross, which flies down the Milky Way.  Vega is a very bright star located in Lyra, and Altair is the eye of the eagle flying up the Milky Way. You can download a free star chart for September (or any month) at skymaps.com to help you locate constellations and stars in the night sky. The dark, irregular band through the middle of the Milky Way is an absorption nebula, a cloud of interstellar gas and dust between us and the concentration of stars beyond as we look edge-wise across the galactic plane. The center of our galaxy in the constellation Sagittarius, visible during the summer, is now below the horizon.

A love of stars goes back to my days as an amateur astronomer.  At the time I could have lived in the Adirondacks for no other reason than the dark skies, but no memory tops an October(?) camping trip to Meacham Lake.  On a dry, moonless night, we could see every star visible to the human eye, right down to the southern horizon, but what made it special was the perfect reflection of every star on an unusually dead-calm water surface.  We had walked to the edge of the lake from our campsite in the woods, but alas, had taken no camera (and therefore no tripod either).  It would have been interesting to shoot star trails with their perfect reflections, so there's a suggestion if you ever encounter that situation..


Photo notes: The four-minute (240 second) exposure started at 8:36 pm.  I was using a 17-40mm L zoom lens wide-open at f/4 on a full-frame body.  For landscape photography, I need depth of field and small f-stops, so I no longer own a fast wideangle lens, but it leaves me at a disadvantage on these rare occasions.  To compensate, I shot at ISO 800 with long-exposure noise reduction and then further processed the image using Levels.  The camera was strapped to a small refractor used as a guide scope on an equatorial mount aligned to the North Star. The blur on the trees at bottom results from tracking the stars as the Earth rotates, rather than using a fixed-mount tripod.

Corrections, comments and questions are always welcome at northeastnaturalist@yahoo.com or connect through my Facebook page or photo page. Other nature and geology topics can be found on the parallel blogs Northeast Naturalist and Heading Out.

1 comment:

  1. It's 8:10 pm, September 10th, and just getting dark enough for the first stars to be visible. Directly overhead is bright Vega and the summer triangle is clearly visible through a large break in the trees.

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