Occultation by (3200) Phaethon, 2019 July 29, sw USA - Updated 2019 July 31
Phaethon is small, but important as it's the source body for the Geminid meteor stream and the main target of JAXA's DESTINY+ mission
Version 9 of the Stations Excel file is posted, the last pre-event version
The occultation occurred within a minute of 11:20.0 UT (4:20 am PDT) Monday morning, July 29. I'm removing most pre-event information from this page. Now that the occultation is past, we will concentrate on how to report observations of the event here. The past page, with all of the prediction information and ideas for observing, as it was at the time of the event, is here. I'm not going to be able to work on the Phaethon occultation during the rest of this week due to other obligations. _______________ REPORTING OBSERVATIONS - OCCULT WATCHER GOOD FOR THAT (updated July 31) *** AND IOTA EXCEL FILE for REPORTING OBSERVATIONS *** *** Time Limit for uploading observation files to SwRI *** Although we didn't use Occult Watcher (OW) for planning our station coverage, we still want IOTA reports for all of the observations, wether positive or negative, and OW is great for that, so you were encouraged to enter at least one of your stations on OW for that purpose. OW generates a pre-populated (with star & asteroid info., etc.) version of the IOTA asteroidal occultation report ExCel file. A copy of the file is here; especially if you don't have it from OW, please download it. It is completed for our track A19 "Dunham2" station. You can copy the file and edit it with the information for your station. The name of the file is important and should be like the example, but change "A19" to your track number, "Dunham" to your last name, and ONLY IF you had an occultation, change "neg" to "pos". When you open the file, it will take you to the "DATA" tab, the page with all of the reporting information. If you are not familiar with the file, from reporting other occultations, read the other two tabs to the left of the DATA one at the bottom of the page, "Introduction" and especially "Directions". The DATA fields are mostly self-explanatory - the gray fields all need to be competed, when appropriate. The light gray fields have fixed information obtained with pull-down menus; click on the item and an error appears on the right side; clicking on it gives the possible options, one of which you should select. On the left side at the top of the form, if you had an occultation, you need to click on the box with "Negative" in it, and select the "Positive" option. Data lines 5 and 7 have the event identification that you don't need to change, but you might change the mm and ss of the predicted time to values appropriate for your location (in California, the event occurred during the 20th minute of 11h UTC, but east of Calif., it occurred during the 19th minute), but that is optional. The yellow fields are all optional. Notice that latitude and longitude can be expressed in the three different formats that are commonly used. Specifying the camera you used, "Detector", from the pull-down menu is very important (note that there are cameras listed ABOVE the RunCam Night Eagle Astro (it's the one sold by Ted Blank for IOTA) option I used as well as below it). Different cameras (and their integration) have different small time corrections that are applied automatically by the spread sheet, so you shouldn't apply any time corrections manually. In the "Method" box (to the right of the Timing box just above "Timing Device"), I have selected "Video, photo, or photoelectric" since all that I have done is view the recording, to tell that no occultation occurred, so this is a preliminary report, not suitable for filing, since we want to generate light curves for all recordings, whether positive or negative. Once a light curve is generated, change "Method" to "Video with frame analysis" and then you will need to specify the tool you used to generate the light curve; for those with positives, we'll help you with that. On line 38, the right side, you need to change "Was this a Miss?" from "yes" to "no" if you had an occultation. For those with occultations, enter the event times in the gray boxes, not the green ones, whose times are generated by the spread sheet from the uncorrected times and the camera time corrections. ** Once completed, the IOTA form should be sent to reports@asteroidoccultation.com but for this event, ALSO to dunham@starpower.net and buie@boulder.swri.edu ** Besides the IOTA report, your OBSERVATION FILES (.avi for video and .fits for those using CCD rather than video cameras) should be uploaded to the SwRI Web site dedicated for this purpose, only for the next 7 days. For this, Marc Buie gives the following information [we want all data quickly so we can do a quick analysis, to better predict the path for an occultation of another star by Phaethon in Japan on August 21]: To those of you with data on the Phaethon occultation, here is the link for uploading your data: https://cloud.boulder.swri.edu/index.php/s/QcE7Ks7oKCMcfnx The password is the name of the object as spelled above followed by the year of the occultation. Please make a sub-folder with your name and track number. For example: A26-Bardecker You can do this by clicking the "+" in theupper left, this gives you a choice of uploading a file or creating a new folder. So, make your directory, change into that directory then upload your files to this folder. I'm using a new (to me) feature of the cloud server so if you have troubles, please email me directly. Don't send your troubles to the list. If there are updates to the process, I'll send a revision to the list. The link will remain active for a week. --Marc email buie@boulder.swri.edu _______________ STATION LINE ASSIGNMENTS (as of July 29) The link to the official SwRI map using the latest JPL 701 orbit for the event is here. It was used for determining station lines following a plan that is here (The lines list with stations assigned to them), but see below; it's compatible with station list version 9. This was the last version that we used before the event, but it was not posted before the event. I discovered a mistake in the last previous versions - line A37 was not covered, and two stations were assigned to A40 (sorry, I don't know how that happened, in some of the shuffling of lines that we had to do). Later, I will post a version of the Lines file specifying what actually happened, as far as I know it, showing the assigned line, the actual line that the station was located, and whether the event was negative or positive, and if the latter, the duration. Some stations failed, which will be noted as "no observation", with a short discription of the reason for the failure. _______________ STATIONS EXCEL FILE - Version 9 (July 29, last pre-event version) is here. This is the 9th and last pre-event version of the file, but it was not posted before the event. This version didn't try to specify which different equipment was used at the specific different stations for those running more than one station, but I would like to sort that out in the post-event version. The Stations file is explained in the pre-event version. _______________ WEATHER - THERE WERE SOME CLOUDS (updated July 31) Although considerable cloudiness was forcast, there were only a few clouds in the distance, not near the target, over the southern San Joaquin Valley and hills to the west, and skies were apparently also mostly clear around Las Vegas and in southern Colorado around I-25. There was a strong patch of clouds over n.w. Arizona and s.w. Utah, causing one lost station and one that had difficulty, but managed to record the target at the right time (partly cloudy). Marine clouds caused F. Marchis to hurriedly move to an inland site where he recorded the occultation from A21 rather than his intended A29. The IR satellite view of the US at the occultation time is here. _______________ David Dunham, 2019 July 31 e-mail: dunham@starpower.net cell phone: 301-526-5590