Last week I saw on Curt’s astronomical prediction page that Theta Ophiachi would be occulted by the 2 day old Moon November 8, 2010. Curt’s predicted time (at Chicago’s Adler Planetarium) was 4:28 PM CST. That time wouldn’t be precisely accurate for me in Northwest Indiana, but it should have been a close estimate. However, the sky was still bright at that time, and I didn’t expect to see the immersion. Anyway, I woke up late, and was barely out the door to pick up Hillary at that time. His predicted emersion time was 5:41 PM, and that I intended to catch.


After a short diversion, I picked up Hillary at 5:20. I would have preferred to have done the observation in her driveway, but the Moon was already hiding among the trees. With most of their leaves gone, the trees weren’t as much of a problem as in the summer, not yet, anyway, but by the time of the emersion they could cause some problems. Instead we tried a more open location near her house, but again, the Moon was about to drop below the treetops. We were going to the monthly meeting of the Calumet Astronomical Society afterward, so running short on time, pulled into a gas station just before the interstate. From there we could complete our observation of the occultation emersion, then get some iced coffee before leaving.




Observing from Portage Indiana, near the I-94 exit.


It was 5:38 by the time I first looked through the telescope, and was a little disappointed that there was already a star visible east of the lunar crescent. I didn’t know exactly what time Theta Ophiachi should pop out from our location, but it seemed reasonable that we had somehow missed it. We weren’t in a hurry to get to the meeting, so I was willing to wait a few more minutes, and get some lunar time while I could. The star I saw seemed too dim for 3rd Magnitude Tet Oph. Maybe it would be worth the wait after all.




My first image. A star was visible in the eyepiece, but not bright enough to show in any of the images.


I started taking pictures of the Moon, and thinking that we’d already missed the emersion, wasn’t paying close attention. I looked again and there was Tet Oph! I missed it! 5:41. Right on time (except maybe it wasn’t; I used the clock in my car, which may not be accurately set). Later I saw that I’d taken 3 images before I even noticed the new star in the eyepiece. (My best guess for the other star, according to my Peterson Field Guide to the Stars & Planets is that was Omicron Ophiachi).






I took these two images without realizing I had my star!


Now we had two stars to the side of the Moon. Very interesting. The telescope pointed at the Moon caught the attention of a lady and her young son. We let them see the Moon, and when asked if there was a special reason to look, I told her that the star she was seeing was hidden behind the Moon only minutes before. They thought it was a cool sight, but I doubt they understood my geekiness for getting excited about it. To me it is evidence of our Moon’s motion through it’s orbit, something not normally appreciably noticeable. Even when not trying to draw attention, we still ended up with an audience, and they learned a little science as well.


After our visitors left, Hillary and I watched the Moon creep further away from it’s stellar companions in the eyepiece. It wasn’t the precisely documented observation I had hoped for, but this was only the second occultation emersion I’ve observed, so it was still an exciting event for me. I wasn’t with Hillary two weeks ago when we saw our first occultation, but I think she was as excited as I was last night to see that bright star next to the Moon only a few moments after it NOT being there at all. I’m already looking forward to my rematch against Mu Geminorum on November 24. It’s occultation of October 27 was itself mostly occulted by clouds. Maybe this time luck will finally be on my side.




Sorry, no precise times. This was roughly 5:41 PM CST.

Below the Moon is distancing itself from Theta Ophiachi.

















Hillary.








Paulie.

Thanks for the detailed occultation report, Paulie. Good work! You’re gorgeous assistant must have been the inspiration. I calculate the emersion time from Portage would have been 17:41:41 CST while at zenith angle 222.7°. The next occultation of significance will be that of Mu Geminorum before dawn on November 24. Graphics for that are already available on my website.

Patrick, you should have had the star visible east of the Moon in all of your images. It's third magnitude though, so probably wouldn't have been visible naked eye from Horner. I'm kicking myself for not trying to catch it naked eye, or even binoculars. I was so wrapped up in watching it at the eyepiece. We were out for fifteen minutes tops, and look how much the Moon changed position. It was like watching the Galilean Moons move around Jupiter, only much faster.