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Summer Milky Way There's not much night-time when the Earth is at the Summer Solstice of its annual orbit. But this is the season when we in the northern lattitudes get a glimpse of the center of our galaxy! The bright star clouds and structure to the Milky Way in this region show at the top of this picture. It is important when making time exposures to be sure that the sky is adequately dark. This limits the time to the few hours remaining after the last glow of twilight, but before the onset of early dawn. The sky is dark enought to avoid fogging the film only after what is called "astronomical twilight", a condition where the sun falls below the horizon by 18 degreees. The late sunset, early sunrise and summer ecliptic leave only a few precious hours to make astrophotos. I had gotten a late start on this night. I drove west, watching the sun set, followed by the crescent moon. I was looking for a site away from city lights and the ubiquitous rural security lights. I eventually got out of range of radio towers with their flashing warnings to aircraft, and the nearest farmhouse seemed behind the windbreak trees at the horizon. It was well after midnight. This left only a short time before astronomical dawn (3:30 AM) to make the exposures for this mosaic. Lights are everywhere however, and a particularly annoying one shows behind the trees on the northern horizon (bottom).
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