Mars Occultation December 7, 2022

December 08, 2022

It was supposed to be clear. It wasn't. Low clouds and fog stayed around all day and were still present when I got off work after 5pm. All of my close, low-elevation observing sites were under the blanket judging from the satellite images. I needed to go up in elevation to get off the basin floor. Unfortunately, there had been a snowstorm last week, so road conditions over the Cascade passes looked dubious. I needed somewhere I could get to in under an hour. Also, I didn't have a Sno-Park permit. So going west wasn't a great option.

The other clear place on the satellite image was to the northeast. There is a 5000' pass at Bly Mountain, and the roads looked okay. I wasn't sure that I was going to make it up there in time, or exactly where I would set up if I did, but I decided to give it a shot. I already had my scope pre-cooled in the car (from an excellent Mars observing session the previous night), so I threw in the accessory cases, binoculars, camera and tripod and left at 5:40pm, almost exactly an hour before the start of the occultation.

The drive was filled with more clouds and occasional pea soup fog. After 6:15, I caught an occasional glimpse of the Moon but no Mars. At around 6:30 as I climbed the pass the fog finally cleared. There weren't any great pull-outs, but there was a snow-covered side road that seemed like the quickest option. I pulled onto it and stopped where a previous motorist had given up and turned around. Bly Mountain doesn't have the greatest reputation locally, but I figured I would only be there for 15 minutes or so, so not much chance of tweakers showing up in the 18-degree night.

I only had a few minutes to spare, and the snow surface wasn't amenable to setting up my Dob, so I decided to go with the camera and the binoculars. I had planned to set the intervalometer on my camera, but had neglected to pre-set it, and it's a fiddly function. I didn't want to miss the disappearance, so I ended up doing a rather stupid dance of holding down the shutter button with one hand while looking through the binoculars with the other. I did remember to turn off the image stabilization on the lens beforehand in anticipation of using the intervalometer, and I should have turned it back on once I was pushing the button manually. The handheld 8x binoculars weren't satisfying; I'm sure I lost Mars before it merged with the Moon. The camera shots worked out better than they might have.

6:43pm PST. The Moon covers Mars--Mars disappears at around 8 o'clock on the lunar limb.

I wasn't going to stay at the same site for the reappearance. I crested the summit, hit a bit of black ice on the other side, and made it down to a road junction with a pullout that is often used by semis. I had plenty of time to plan for the reappearance, so I set up my Dob, worked out the interval timer and exposure on my camera, and prepared to observe at 104x in the scope while letting my camera and 400mm lens fire away. There was passing fog at times; it wouldn't endanger my scope views, but I worried that it might mess with the photos.

Reappearance started, and the Moon grew a little orange pimple. I watched the Moon creep away from and uncover Mars over numerous seconds. It was a cool view. The only disappointment was that the seeing (atmospheric steadiness) was horrible, and sometimes Mars and the limb of the Moon were distorted. Very little detail was visible on Mars (after such a nice steady night with abundant detail on Tuesday). But, it was better than missing the occultation. The camera worked, despite also catching some of the crazy turbulence.