Post by Deleted on Jan 2, 2014 4:42:57 GMT
In Tucson, on the Winter Solstice, a marvelous event occurs. The sun sets directly behind the telescopes at Kitt Peak National Observatory (KPNO) when seen from sixty miles away, between mile posts 8 and 9 on the Mount Lemmon Highway at a pull off area. Actually, it lasts for about three days before and after the solstice, it just varies when you get the full array of the scopes as the sun passes behind Kitt Peak. This year I set up the Lunt 60mm solar scope on 12/17 and 12/24. The first session was OK, but the four minute video came out as 7000 frames and 4 GByte since the record feature is at 30 Hz. Taking with Dean Ketelsen, the lead mirror maker at the Univ. of Ariz. Mirror Lab and maker of most of the world's biggest telescope mirrors and the one who first noticed the solstice phenomenon and who leads us up there each year, 1 Hz rate is best. So, wife Susan and I went out to Saguaro National Monument's visitor center fifteen minutes from home and practiced a bit. Instead of record, I used the snapshot function on the computer running the camera.. Here is some narrative about the results and a link to the resulting video from Movie Maker.
This being our third year, it did not do badly, but next year I will probably do simultaneous H-Alpha and full visible on a dual saddle plate.
A preliminary note: the Mallincam Junior PRO video camera I recently added to my basic Mallincam Junior puts out two streams on separate ports; composite (all data in one stream, usually the yellow input on a portable TV, and the only stream out of the camera I used at the Grand Canyon), and S-Video, much more data on multiple channels including one called luminance, which tells the video display how to mix the colors. I used both channels - composite into the monitor, and S-Video into the computer to take snapshots for storage.
Good Points:
1. Alan Strauss, the director of the Mt. Lemmon Sky Center, reminded me what I learned 12/17 when I lost the luminance channel on the S-Video feed due to a connector failure. The sun photographs better in monochrome where more surface details come out. So, since I can't turn that channel off in the S-Video feed, instead I cut the saturation down to below 10%. Some color is available, but not the usual red poker chip. MUCH better detail available.
2. I used manual snapshots during the run on the control software for the Mallincam so I ended up with several hundred PNG pics that easily converted to a movie file using Microsoft Movie Maker. And only about 8 Megabytes.
Baby steps and practice seems to help!
Bad Points
Everything seemed ready to rock and roll early on, but of course that can't be allowed to happen.
1. Since I was in H-Alpha, I have no way to align the camera with the horizon. So clever me, I turned off tracking on the mount and saw where the motion of the image was going, and rotated the camera. But idiot me set it so it was moving vertically, NOT along the ecliptic. So the video has the sun going straight down and KPNO at an angle. Duh. Another lesson learned.
2. For efficient operation I had the monitor I use for focus set a foot away from the scope, and the laptop for recording about three feet away. Both use 30 foot data, power, and control cables provided by Mallincam. All during prep time, the digitizer was back to working in full color S-Video since I laid it gently on the table in front of the laptop. I had put the mount controller right next to the computer so I could turn off tracking when the sun touched the Peak. About 10 seconds before solar contact, reaching for the mount controller, I accidentally pulled the S-Video line out of the digitizer. In the video link below, note the start already has some detail, then a quick jump when I was verifying the connection instead of manually triggering the snapshots. During the fuss, I forgot to turn off the mount tracking so the video follows the sun, not fixed on Kitt Peak. ANOTHER lesson learned. Next year, using a dual saddle with the Lunt and the 90mm refractor, I'll align align the FOV of the two scopes ahead of time on solar surface detail, then bring the two down together to the horizon freeze point to wait with a Mallincam in each telescope.
Bottom line, lots of fun when it works, the people were great, and Dean has patiently taught me a few essential facts that make this all possible.
All in all, the pure visible light is loads easier to do, but the surface detail of the sun in H-Alpha was very striking, more pronounced in the monitor view; but, since KPNO is at 6700 feet and we are sixty miles away at 6000 feet, we are in the shadow but the sun hasn't set, so there is gorgeous backlighting from the sun behind Kitt Peak. All of that is lost in H-Alpha, thus my plan to do full visual band as well as H-Alpha next year.
My video is at:
Also, Dean Ketelsen and Alan Strauss got some great video as well.
Dean K. on 12/17: www.theketelsens.blogspot.com/2013/12/a-great-alignment-and-spectacular-sunset.html
Alan Strauss on 12/17 and 12/24:
lostpleiadobservatory.blogspot.com/2013/12/sunset-behind-kitt-peak-national.html
lostpleiadobservatory.blogspot.com/2013/12/post-solstice-kpno-sunset.html