This is a short time-lapse of a public star party, July 27, 2019 at the Rothney Astrophysical Observatory south of Calgary, Alberta, attended by about 600 people.
You see the crowd build in numbers, the stars come out, and our laser tour begin, then end, and the crowd numbers thin out. The event went from 10 pm to 2 am.
Telescopes were supplied by the Observatory and by members of the Calgary Centre of the Royal Astronomical Society of Canada.
The evening was the last in a trio of Milky Way Nights held each summer and that are always popular. We began them in 2009 during the International Year of Astronomy.
The 1200-frame time-lapse shows the laser beams from our green laser pointers. Once it got dark I presented a laser-guided tour of the stars and constellations, with the other RASC members assisting by also pointing to the same spots, so all could see. I am standing at right addressing the audience on the hillside and patio.
The camera I set up for the night to capture the event was aimed north away from the Milky Way but toward Polaris and the circumpolar stars, which you see rotating about Polaris. However, light pollution from Calgary also lights the northeastern sky.
Music is "Rise to Success" by Adi Goldstein / AGSoundtrax.com and is used by permission.
TECHNICAL:
The video opens with a "Ken Burns" pan of a panorama shot the night before on July 26. It is an 8-segment panorama stitched with Adobe Camera Raw.
The time-lapse sequence then runs twice, first with the 1200 frames shot that night assembled for a standard movie.
The second version uses stacked frames created by the Advanced Stacker Plus actions in Photoshop to create an intermediate set of accumulating star trails that draw themselves across the sky.
However, in that second clip only the sky comes from the star trail set; the ground comes from the standard time-lapse to prevent the people from blurring and "trailing" as well. So this clip is actually a composite of two movies, masked and blended in Photoshop using its video functions.
The time-lapse camera was a Sony a7III at ISO 3200 with a 15mm Laowa lens at f/2, and with the shutter on Auto-Exposure to lengthen the shutter speed from 1/1600 at the start in twilight to 8 seconds at night.
I processed the frames in Camera Raw and with LRTimelapse to smooth exposure changes and eliminate flickering.
Thanks! -- Alan
Негізгі бет Stargazing at the RAO
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