Saturday, February 12, 2011

Movie Night!

While I enjoy attempting astronomical photography, use of one of the newer DSLRs can be fun, but is ultimately limited by the built-in filters in front of the sensor. While more convenient for a beginner to use, an astronomical CCD system is ultimately much better. But since I travel to dark skies without power and need a portable setup, I continue to use my trusty Canon cameras.

One of the more enjoyable applications is in taking a series of still photos and transforming them into a time-lapse movie. This is an application where the consumer cameras excel, and it is easy to get satisfactory results quickly. All you need is a tripod, and an intervalometer - a device which allows taking pictures at preset intervals. We have a couple Chinese made knockoffs for our cameras that are only $20. We take a series of pictures, import them into Windows Moviemaker (which is included in nearly every laptop computer I've seen), and you can turn out a time-lapse movie in minutes. For years, I used an alternate program that converted the images into animated gifs, but their limited color resolution and small size made them unsatisfactory. Of course, file sizes can be quite large for even a short high-definition movie, but we've found that YouTube is an excellent interface for both display, storage and making your clips available to the public.

For the first example, back in 2006 at the Grand Canyon Star Party, this was one of the first sequences I took. Wanting to show the beautiful Milky Way overhead with telescopes and observers clustered below, I setup near the restrooms, where the red lights dimly lit the foreground. I used a wide-angle Nikon 16mm F/2.8 fisheye, taking a 40 second exposure every 90 seconds, allowing the camera to use it's internal noise reduction for each exposure. The streaks in the sky are mostly airplanes, though there is at least one satellite. The small light dome on the horizon to the right of center is from the town of Tusayan about 8 miles to the south. I thought the video showing 2.5 hours of elapsed time effectively showed the excitement of observers and the beautiful sky conditions. To see this video via YouTube, click HERE.

In an effort to improve upon this effort the next year (2007), I repositioned at a different spot in the parking lot. The earlier date of the event that year allowed catching the Milky Way rise as the sky darkened, so I started a little earlier to catch the end of twilight, and continued for 4 hours. At the start of the sequence, the exposures started out short, but grew to the same 40 seconds and same intervals as above, and the same lens was used too. The shuttle buses were rerouted that year, so we had fewer lights going through the parking lot. The picture at left from the sequence looks to be a space alien, but is in fact a red-illuminated Dennis Young checking out a sky map at his observing desk. The bright object in the Milky Way is the planet Jupiter. There are a few clouds that appear early and late in the video, but otherwise is another fine result. We repeated this sequence a few extra times and we fit it to one of my favorite song standards by Hoagy Carmichael - "Stardust", performed by Nat "King" Cole. Click HERE to see this video on YouTube. I think the song makes it pretty special!

A couple months ago I posted about the real-time video we made of the sunset behind Kitt Peak National Observatory every winter solstice week. In years past I would photograph it every 4 seconds or so, and make a gif of the results. While I enjoy the video we posted in December, I'm including this reprocessed video of those frames. It is the only sunset I recall where sunspots were visible, and are seen in the image to the left just above the 90" Bok Telescope of Steward Observatory. The images were taken with a 6" Newtonian telescope and a Thousand Oaks solar filter. The video on YouTube can be seen by clicking HERE.

And while that last sequence was taken from 60 miles east of Kitt Peak, on another date, I was setup about a mile to the west in the picnic area on the mountain. A radio telescope dish (part of the VLBA Radio Telescope)is located nearby, and it's actively changing objects frequently makes a striking sight with the observatory domes in the background. I started the sequence before sunset, the first exposures about 1/1000 second, lengthening to about a minute exposure every 2.5 minutes. I didn't realize the Pleiades Star Cluster would rise behind the radio dish, but it made it much more interesting! Click HERE to see the video!

The last one presented here is a time-lapse of the tide coming in at Puerto Penasco, Mexico. At the northern end of the Sea of Cortez, the tidal range can exceed 6 meters, so at low tide, the shore can be 200 meters away from the high tide line. These pictures were taken every 2 minutes for over 5.5 hours showing just about the entire incoming cycle. It was almost shocking how fast it came in during it's fastest, and it shows up nicely in the sequence. Check out the video HERE.

So now you know how it is done - easy and rewarding, simple to upload to YouTube for ease of storage and viewing by others. Consider giving it a try!

1 comment:

Anthony Vodraska and Anita Gilbert said...

I sure liked seeing all of those time-lapse videos of the night sky and especially the link for the timer remote.