The Occultation of an 11.8 (combined) Target by (234) Barbara

Nov 27, 2020 at 4:49:13am Friday

Preston Predictions and global map

The asteroid Barbara is a strongly suspected contact binary, by photometric modelling (ref 6). However, it is possible that a strange shape or albedo distribution is not ruled out. Verifying it as a contact binary would be valuable. Tough timing - this requires a drive to south of Laguna Mtn for high confidence. And it's right after Thanksgiving night. The target is 65 degrees away from the 93% moon, and is at 41 degrees altitude in the west. a little southeast of the Rosette Nebula in Monoceros.

To King City from home is 1h 23m in good traffic as I would have. It's 1h 45min to Lonoak via Hwy 25.

From Coalinga/Hwy25 intersection to Lonoak is 11.2 miles, and 12.46 to my first chosen site just north of the homestead, and 14.3 to my 84% odds site at the two opposite gates which are offset

Results:
Given the exciting possiblity of discovering another rare contact binary asteroid, I signed up right away. And given Kirk didn't have to work on Friday, he also decided to do this. I had Thanksgiving day with friends, and too much wine (we got onto the subject of administrators and bureaucratic systems and capitalism in general - spirit(ual) relief was necessary). I had thought I'd pretty much finished all the charts necessary, but after I got home at 8pm, Kirk had signed on, and I ended up being up till midnight to go through the process of definitely settling on the best, and highest probability of success stations for both of us. No one else in the IOTA group planned to observe this, which was disappointing. So, up till midnight, and I'd set my alarm for 1:45am to enable getting getting on the road at 2:00am. Google Earth had said earlier that it would be a 1hr 23 min drive to Lonoak, but now, even though it was empty roads to the extreme - it decided it would take more like 2 hours to get there. That still got me there by 4:00am and give me 50 minutes which would be plenty.... or so I thought. It was bitter cold. It felt like the high 20's. I worried about my camcorder in such temperatures, thinking of the Australian Outback and our trouble in the Hayabusa Mission. And even just earlier this month, the asteroid occultation at 10pm on the way back from Carrizo Plain, when temperatures were really not that cold, not nearly as cold as it was now, north of Bradley for me, and the failure to record (tape fatigue, now I'm thinking??).

My iPhone 5 guided me to the wide spot on the road called Lonoak well. However, the battery charge read 55% when I unplugged it from the charge cable at home, and then put it on charge again in the car. But now it read only 35%. It seemed not to be charging as I drove, or else the draw from Google Maps and from playing podcasts was more than the charging could deliver, significantly so. I got set up efficiently, the Orion Dynamo Li-Ion battery worked fine, and kept working fine for even another hour after the event, till I shut down. That was something else I worried about, whether temperature-dependence of Li-Ion batteries might help explain the death of my iPhone 6SE at Carrizo Plain. I kept the ZR85 camcorder in its zipped case, and the car had been kept in the high 70's temperature on the 2 hour drive to Lonoak. I used Arcturus and Betelguese as my align stars, and the telescope then swung to the target very well, and ID was easy. I then put in the fitting for the Watec and turned on the camcorder. The camcorder came back with a message - "no card" and refused to do anything, even play back the tape that was in there. That made no sense to me; the card is only needed for photography, not for videotaping. Could it somehow have slipped itself into photography mode?? I went through the menu, saw nothing, tried flipping obscure external switches... then found indeed a switch that had gotten itself into photo mode. Flipping that, and now the camcorder came to life in normal mode. But it was only 7 minutes till the occultation. I did a short test recording, then rewound and verified it had indeed taped. Yes! This was going to work after all! Still, I wanted to video-record the LCD screen using my Nikon D7000 camera in video mode. But lack of memory (sleep deprivation), lack of practice, and I didn't quite the right buttons going, and it clearly wasn't video'ing my camcorder screen. I shut it off and just focused on getting the recorder out of 'pause' and started recording 1 minute before the predicted time. I watched intently... and the star disappeared as the critical time arrived. But my eyes, in the cold, were watering big time, and the view of the stars on the tiny camcorder screen were distorted and dancing due to the tears. And unfortunately the 12th magnitude target star was sandwiched between two other stars about 5x brighter, and so their dancing images made some confusion. Nevertheless, midway or so during the ~5 seconds the star was gone, I thought I saw a good 1 second or so when the star was back, but I'm very unsure it was real due to the bad optics from my tears. All I can say, is that that was my impression. Was it confirmation bias? Don't know. I'll never know.... because after the event, I rewound and played it back, and there was no recording. Again! Damn!! Even the test recording now played back with the tell-tale bars and blocky false colors, and the audio was full of cut-outs. When the time for the real event recording happened, the tape had clearly stopped getting written to, because now what was on the tape was prior asteroid events. I hoped somehow if I could warm up the camcorder, it would show me a good recording. I kept it inside my fleece jacket inside my down jacket until it felt mostly warmed up to the touch. But it didn't help.

By now, Venus had risen and there was a side project to photograph brightening Comet Erasmus. But my sweep with the 10x70 binoculars continued to show nothing as Venus rose and the comet should have been up, but very low and just not bright enough. I never did see it. Then, distant headlights over the hills from the south slowly got closer and it was Kirk, as promised. His report: He got on target and got taping and confident as he had never had a taping fail. I told him I suspected he too had a non-recording as the camcorder I had given him was a ZR45mc, same model I used and trusted for so many years - except for its failure in the record cold of the Australian Outback for Hayabusa I.

Diagnosis of Camcorder failures:
I now think it's a mistake to try to keep the camcorder as warm as possible until the last minutes before the event. Because it will in any case have to be in the ambient cold for at least 15 minutes to have enough time to locate, focus, and prepare for the event. That means the warm air still inside the mechanism will be cooling rapidly during that time and condensation is most likely to occur. I did see a red flashing indicator before the Barbara event which in hindsight I believe was the condensation indicator. Instead, the camera should be put out in the cold first and left their to equilibrate. Then, after equilibration, it should be placed on a jacket-warmed Blue Ice bag and wrapped in a small cloth to help it now RISE in temperature to some extent, at least out of the 30's F. This should cause any condensation to evaporate. I'm thinking too of what happens in the SBIG CCD chamber when I've not baked the desiccant recently, and the frost on the window is worst on cool down, but if you just leave it on cool down, the frost gradually goes away. There are TWO problems at work here -

#1 is that the camera is stated to only be designed to operate at T>32F. It was colder than this, I believe, at our site (note: should get a temperature indicator to mount inside the Occ Box).

#2 is that condensation will also cause failure, and that can happen at any temperature. It is a problem if the humidity is high and the temperature inside the camcorder is falling. Make sure the temperature inside the camcorder is RISING as the final prep's and occultation happen, so that any condensation inside will evaporate before use.

#3 Another issue is the ability of a given tape to re-record over it. You should always test that you can record successfully before the event. And if the problems #1 and #2 don't apply, and you get failure, the tape may not be good. Swap in a fresh unused tape. You can't expect to keep re-re-re-recording over the same tape forever. I think that foiled another attempt, and may have even played a part in this event. I've now as of Dec '20 have a fresh tape in the same recorder (ZR85) as used here, and it tapes fine.

Always take a video recording of the LCD screen during the event. The LCD screen always seems to show what's coming into the camera, regardless of whether it is successfully being relayed to the miniDV tape. Use either the tripod mounted Nikon D7000, or even your small PowerShot.

IOTA report from my station finalized on 12/13/20 and sent to IOTA at that time.