The Occultation of a 9.6 star by Ophelia, from Carrizo Plain
Sunday evening Nov 15 9:54:50pm PST
This bright star has 6 claimed sites, well spread across the predicted shadow, including mine at my campsite at Carrizo Plain. As Sunday evening that's inconvenient, but I'd love to do a good long trail run to Caliente Peak, which I've not done this year (well, got halfway there in the Spring Astro 25 attempt). So the thought would be to drive out either before dawn on Sunday, or perhaps Saturday evening, camp out, do the trail run, and get back in time to cook some dinner, pack up and take off and get the occultation from just east of Paso Robles, on Estrella Rd, and immediately head home so I can do my Monday morning class. We'll see if that plan is a "go".
The star will completely disappear for up to 12 seconds, so it should be a nice event to video record and get a very solid shape analysis done. It's 36 degrees up, in Taurus near M1 and Eta Tauri in the east.
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This looks like the best site to maximize odds and not step on other claimed chords. I could instead go farther north towards the northern limit... |
I've claimed a second station, in the off chance I get a joiner, and mainly just so I have a choice. This site is a few miles north of Bradley, with the oil jacks right across the street. I believe the offramp will be labelled "Alvarado" but check on the drive down. This site has only an 89% chance of a hit, while the Estrella Rd site has 100% odds. However, it's probably better spacing of sites and also gets me home quicker. I won't be packed up after the occultation till 10:20pm and won't get home till close to 2am from here; worse from Estrella Rd. |
Claimed chords, and the two I put down for. I'll plan to be at the northern one, but the one near the centerline is a backup. |
A magnified view of the northern part of the path, for choosing sites for Kirk, if he can do this one. |
Results:
Kirk and I both observed occultations, near the northern limit. Kirk had a successful recording. I did not. Either the record heads failed, or the tape reached the end and the camcorder did not alert me. However, I watched a 2.5-3 sec long occultation, with the D showing a noticable fade, while the R was crisp. Kirk too had his D look slow while the R was more crisp. My report will have to be estimated times based from Kirk's times.
Kirk's Observations and Reductions
Here's his video, centered on the event, of the 8 second occultation on his YouTube channel
Kirk did his own reductions, using PyMovie, and then PyOTE, in field mode, and at 4x setting. His
PyMovie photometry csv file
and IOTA Report, and his PyOTE csv file
and PyOTE Log file
Richard Nolthenius Observations
I got on target efficiently, then took some time to photo the project variable star fields for my students. I then got the scope in final form, and watched on the camcorder LCD as the star disappeared. I'd guess the event lasted 2.7 sec +- 0.8 sec. The D was gradual, the R was crisp. I didn't play back the tape, but packed up quickly to get back on the road. I knew that I'd have to struggle to keep alert on the long drive home from San Ardo and wanted to get going. Only the next day, when I played it back, did I find it did not record. I think it got to the end of the 60min tape, but then why didn't it stop while taping? From now on, I'll plan to rewind the tape frequently, before it ever gets near the end. I filled out the IOTA report, after taking my interval of D/R and placing it in the middle of Kirk's 8 sec event. Best that can be done.
My IOTA report
Here's the Skyplane plot from IOTA reductions
