Rik Hill's observation below, confirmed with another by Jim McGaha at Sabino Canyon Observatory, show that last night's occultation path passed right over Tucson, Arizona. Fulton Wright has reported a miss at his site in Prescott, Ariz. So it appears there was about a 3/4 path width shift from Edwin Goffin's nominal prediction, and I look forward to other reports from southern Arizona; the path must have passed over Phoenix as well, and in Venezuela, closer to Caracas than to Merida. It's unfortunate that we did not have effective astrometry to predict this path so that a larger effort may have been made for it; I hope that the earlier predictions giving a shift into California did not discourage too many Arizonan observers (for that reason, I distributed my last update to them where Jim Hart's new reduction cast great doubt on the earlier- distributed California prediction; I didn't distribute that one to the observers in California). This shows that the nominal predictions for PPM stars are quite good, and I think worth setting up local nets of observers when they are nearby, even in the absence of astrometric updates. In this case, the CAMC-based prediction was wrong because it did not update the asteroid, only the star; and Jim Hart's March 20th observations were just too early; the star and asteroid were not close enough together to get a good prediction. I think that would have been possible only from observatories in Europe and perhaps the eastern USA earlier on March 21 UT, when a prediction could have been generated with a few hours of warning, if CCD observations had been made, reduced quickly, and sent to me by e-mail.
David Dunham, IOTA
I looked for the Campania occultation last night and did not see it. I observed from 8:13 to 8:23 UT with a 12" telescope under good conditions. Fulton Wright, Jr.
Site: My Home 231 Spindlewood Ave. Camarillo, CA Long. 119 deg. 00.6' W Lat. 34 deg. 12.6' N Elev. 140 feet
Transparency Poor (2 mag.), Seeing Good Limiting Mag. through scope: > 9,5
The star 138801 was positively identified by careful comparison with detailed finder charts. A 4" refractor at 104X was used, giving a clear view of the target star and fainter surrounding stars, even though thin clouds limited the naked eye visibility to 2 mag. stars.
Observations encompassed the period from 08:16:09 to 08:23:02. No occultation was observed.
Sincerely, Gary Goodman
Sabino Canyon Obs.
12" SC at 150x
WWV and tape
OUT: 8h 18m 42.0s, IN: 8h 18m 48.1s, no steping in or out
James McGaha
I just bagged my first visual observation of an astroidal occultation. Location: 110.77554 deg. W or 110 deg. 46' 31.9" 32.18006 deg. N or 32 deg. 10' 48.2" elevation = 2875 ft. Conditions: skies clear, seeing 1-2", transperency 4th mag. due to full moon, temp. ~60oF, humidity ~30%, wind 0-5 WSW.
Instrumentation: 10" f/12 Cass, no filter, 152x
Began observing at 0808UT with WWV and tape deck. Star slightly out-of- focus to help reduce fatigue. Disappearance was 08:18:41.0 with a duration of 6.8 sec. clear and unmistakable.
Very exciting after 15 years of attempts!
-Rik
Despite the poor prospects for viewing the occultation, I observed the >> star continuously from before 0817 UT until 082355 UT (with an interruption >> of less than three seconds between 082113 and 082116) but did _not_ see >> any change in apparent brightness. This observation was made from my home >> in southeast Chandler, Arizona, approximate coordinates 111d49m W, 33d18m N, >> elevation 375 meters. I will send a complete report to Jim Stamm as soon >> as I can determine the geographical coordinates to better precision, however >> I wanted to notify you that the path apparently did not cross the southeast >> portion of the Phoenix area unless the event happened significantly earlier >> than predicted. >> >> Best regards, >> >> -- Michael Collins -- >> -- >> mcollins@wdc.sps.mot.com
Last night update
The path of tonight's occultation by Campania will just miss the southern California coast (8:18 UT), passes over northern Baja California, southern Sonora (8:17), just north of Mexico City (8:15), and near Merida, Venezuela (8:11 UT), according to two CCD exposures of Campania and SAO 138801 taken remotely last night by Jim Hart with the University of Iowa's Automated Telescope Facility (18cm APO) and reduced by Hart with GSC 1.2 data. This confirms Martin Federspiel's prediction distributed yesterday that did not include an update for Campania. However, the new prediction could be in error, so observers at least in California, Mexico, and Venezuela are encouraged to try to monitor the star for a possible occultation from convenient locations. The weather satellite image shows clouds covering most of northern and central California, but Arizona and northern Mexico look good. Adding uncertainty to the new prediction is a 6" error in the right ascension of the star for Hart's recent observations (all of the other data are consistent, with the worst scatter being in the observed declination residuals of the asteroid, which are different by 0.20"). For this prediction, I have used earlier observations of the star's right ascension by Hart with the same telescope made on Feb. 20 and Mar. 3.
Copying from yesterday's message: In case of an occultation, there will be a 4-mag. drop in the brightness of the 8.4-mag. star (the expected central duration is 7.5 seconds), so the event should be easy to observe with any small telescope; however, allow plenty of time to find the star, since it's in a rather sparse part of Virgo and the 93% sunlit Moon 40 deg. away will wash out the fainter stars. A finder chart locating the star is in the Celestial Calendar section of the March issue of Sky and Telescope, with a more detailed one available under upcoming events on our Web site at http://www.anomalies.com/iota/splash.htm (that's the IOTA chart that was distributed with the last issue of Occultation Newsletter).
The new path for the occultation is given below, with a path comparison table at the end. Note that other predictions give a time for the event a few minutes later than Hart's time, which could be in error due to the R.A. problem noted above. Jim will be looking at the data during the next couple of hours, so new reductions might be performed correcting the problem and resulting in a new prediction that would be distributed by e-mail later tonight, as well as posted on the Web site mentioned above and also on the IOTA phone line at 301-474-4945 [that now has Federspiel's prediction, which I will leave (since the new path is only a little more pessimistic than that one) until and if the RA problem with last night's observations is resolved].
Jim Hart says in a message just received that the star was near a corner of the CCD, with no reference stars beyond it, so its R.A. may just be poorly determined from the geometry of the reference frame, and it might not be possible to improve the prediction over what I have already done. His new declinations for the star are in good agreement with the ones from his earlier observations. He will check the situation in detail soon, and I will distribute another message only if the prediction can be improved.
CENTER PATH IS ABOUT 112. KM WIDE AT THE COORDINATES LISTED BELOW
UNIV. TIME Campania SUN MOON
LONGITUDE LATITUDE H M S ALT. AZI. ALT. AZI. ALT.
35.97 W 1.50 8 8 2.7 11.7 262.0 -5.8 89.5 -24.1
44.47 W 1.83 8 8 26.8 20.0 261.3 -14.1 89.2 -15.7
54.65 W 3.20 8 9 11.2 29.6 259.4 -24.1 88.2 -5.7
64.72 W 5.60 8 10 10.7 38.7 255.7 -33.8 85.9 4.1
66.38 W 6.09 8 10 21.9 40.1 254.8 -35.3 85.3 5.7
68.04 W 6.61 8 10 33.4 41.5 253.8 -36.9 84.6 7.3
69.69 W 7.16 8 10 45.3 42.9 252.7 -38.4 83.9 8.8
71.34 W 7.72 8 10 57.4 44.2 251.5 -39.9 83.1 10.4
72.98 W 8.32 8 11 9.8 45.5 250.2 -41.4 82.2 12.0
81.09 W 11.61 8 12 15.9 51.2 242.0 -48.4 76.2 19.5
89.09 W 15.42 8 13 26.7 55.3 230.3 -54.3 66.9 26.6
92.26 W 17.07 8 13 55.9 56.4 224.7 -56.2 62.0 29.2
93.84 W 17.92 8 14 10.6 56.8 221.8 -57.1 59.4 30.5
95.42 W 18.78 8 14 25.4 57.0 218.8 -57.8 56.6 31.7
97.00 W 19.66 8 14 40.2 57.2 215.7 -58.5 53.6 32.9
98.58 W 20.55 8 14 55.1 57.3 212.6 -59.1 50.5 34.1
100.16 W 21.46 8 15 9.9 57.2 209.4 -59.5 47.2 35.2
101.73 W 22.38 8 15 24.7 57.1 206.3 -59.9 43.8 36.3
103.31 W 23.31 8 15 39.5 56.8 203.1 -60.1 40.3 37.3
104.89 W 24.26 8 15 54.2 56.4 200.0 -60.3 36.8 38.3
106.48 W 25.21 8 16 8.9 56.0 197.0 -60.3 33.2 39.2
108.06 W 26.18 8 16 23.4 55.4 194.0 -60.2 29.6 40.1
109.65 W 27.16 8 16 37.9 54.7 191.1 -59.9 26.1 40.9
111.25 W 28.14 8 16 52.2 54.0 188.3 -59.6 22.5 41.7
112.85 W 29.13 8 17 6.4 53.2 185.5 -59.2 19.0 42.4
114.47 W 30.13 8 17 20.4 52.3 182.9 -58.6 15.6 43.0
116.09 W 31.14 8 17 34.3 51.3 180.4 -58.0 12.3 43.5
117.72 W 32.16 8 17 47.9 50.3 177.9 -57.2 9.1 44.0
119.36 W 33.18 8 18 1.4 49.2 175.6 -56.4 6.1 44.4
121.02 W 34.20 8 18 14.6 48.0 173.3 -55.5 3.1 44.8
Detailed central line coordinates across Mexico and just off California
TRACK 0 CENTER FOR 377 Campania SAO 138801 DATE 1997 MAR 21
W. LONG. LAT. W. LONG. LAT. W. LONG. LAT. W. LONG. LAT.
90.000 15 53.1 99.000 20 47.7 108.000 26 8.5 117.000 31 42.7
91.000 16 24.2 100.000 21 22.3 109.000 26 45.2 118.000 32 20.0
92.000 16 55.8 101.000 21 57.1 110.000 27 22.1 119.000 32 57.2
93.000 17 27.7 102.000 22 32.3 111.000 27 59.1 120.000 33 34.4
94.000 18 0.1 103.000 23 7.8 112.000 28 36.2 121.000 34 11.6
95.000 18 32.9 104.000 23 43.5 113.000 29 13.4 122.000 34 48.6
96.000 19 6.1 105.000 24 19.4 114.000 29 50.7 123.000 35 25.5
97.000 19 39.6 106.000 24 55.6 115.000 30 28.0 124.000 36 2.2
98.000 20 13.5 107.000 25 31.9 116.000 31 5.3 125.000 36 38.8
(in case of a 0.15" north shift, the path crosses southern California, as
shown below, but an even larger north shift IS possible)
TRACK 150 NORTH FOR 377 Campania SAO 138801 DATE 1997 MAR 21
W. LONG. LAT. W. LONG. LAT. W. LONG. LAT. W. LONG. LAT.
90.000 18 22.1 99.000 23 22.3 108.000 28 48.5 117.000 34 27.2
91.000 18 53.8 100.000 23 57.5 109.000 29 25.8 118.000 35 4.9
92.000 19 26.0 101.000 24 33.0 110.000 30 3.3 119.000 35 42.5
93.000 19 58.6 102.000 25 8.8 111.000 30 40.8 120.000 36 20.1
94.000 20 31.6 103.000 25 44.8 112.000 31 18.4 121.000 36 57.5
95.000 21 5.0 104.000 26 21.1 113.000 31 56.1 122.000 37 34.8
96.000 21 38.8 105.000 26 57.7 114.000 32 33.9 123.000 38 12.0
97.000 22 12.9 106.000 27 34.5 115.000 33 11.6 124.000 38 49.0
98.000 22 47.5 107.000 28 11.4 116.000 33 49.4 125.000 39 25.7
Detailed central line coordinates across South and Central America
TRACK 0 CENTER FOR 377 Campania SAO 138801 DATE 1997 MAR 21
W. LONG. LAT. W. LONG. LAT. W. LONG. LAT. W. LONG. LAT.
35.000 1 30.7 49.000 2 18.4 63.000 5 7.2 77.000 9 52.5
36.000 1 30.0 50.000 2 26.5 64.000 5 23.8 78.000 10 17.2
37.000 1 30.0 51.000 2 35.2 65.000 5 41.0 79.000 10 42.3
38.000 1 30.6 52.000 2 44.5 66.000 5 58.7 80.000 11 8.0
39.000 1 31.8 53.000 2 54.4 67.000 6 17.1 81.000 11 34.3
40.000 1 33.6 54.000 3 5.0 68.000 6 36.1 82.000 12 1.0
41.000 1 36.1 55.000 3 16.1 69.000 6 55.6 83.000 12 28.3
42.000 1 39.2 56.000 3 27.9 70.000 7 15.7 84.000 12 56.1
43.000 1 42.9 57.000 3 40.3 71.000 7 36.4 85.000 13 24.4
44.000 1 47.3 58.000 3 53.2 72.000 7 57.7 86.000 13 53.2
45.000 1 52.3 59.000 4 6.8 73.000 8 19.5 87.000 14 22.5
46.000 1 57.9 60.000 4 21.0 74.000 8 41.9 88.000 14 52.2
47.000 2 4.1 61.000 4 35.8 75.000 9 4.9 89.000 15 22.4
48.000 2 11.0 62.000 4 51.2 76.000 9 28.4 90.000 15 53.1
Prediction Comparisons
MIN. GEOCENTR. Shift from S&T
U. T. SEP. Time Path
h m " min. " Widths
8 16.2 2.88N 0.0 0.00 0.0 Goffin nominal (p. 73 of Feb. S&T)
8 17.0 2.65N +0.8 0.23S 3.3S Federspiel's CAMC star update
8 14.9 2.56N -1.3 0.32S 4.6S Hart's March 20 data, early star RA
Earlier data
Martin Federspiel has updated the prediction for Friday morning's occultation by Campania using improved positions for the star from the Carlsburg Automated Meridian Circle (CAMC); the new path is two path widths southwest of my nominal prediction using Edwin Goffin's data, with the time 3/4 minutes later. This path goes over the southwestern coast of California (San Luis Obispo, Santa Barbara, Ventura, southwestern Los Angeles, coast of Orange County, San Diego), I think over San Pedro Martir Observatory in northern Baja Calif., over Sonora and just north of Mexico City, and over parts of Venezuela (closer now to Merida, farther from Caracas).
But MUCH UNCERTAINTY REMAINS, since Campania itself has not been updated; the actual path could still be the nominal path, or even northeast of it, so observers throughout California, southwestern Nevada, Arizona, Mexico, and Venezuela should plan to at least monitor the appulse from convenient locations to possibly time an occultation. In case of an occultation, there will be a 4-mag. drop in the brightness of the 8.4-mag. star (the expected central duration is 7.5 seconds), so the event should be easy to observe with any small telescope; however, allow plenty of time to find the star, since it's in a rather sparse part of Virgo and the 93% sunlit Moon 40 deg. away will wash out the fainter stars (try to find the star on a previous night, if weather permits). A finder chart locating the star is in the Celestial Calendar section of the March issue of Sky and Telescope, with a more detailed one available here.
Jim Hart has obtained some GSC 1.2-based positions of Campania. These might show a northward shift of the path that could counteract the southern shift caused by the star (that is, return the path to E. Goffin's nominal path across northern Calif., Arizona, and Caracas), but this is far from certain, since the GSC 1.2 and CAMC systems could be a little different. A more accurate prediction will be possible if CCD observations reduced with GSC 1.2 stars are made of both objects on the same frame, but that will not be possible until the day before the event, so such an update will likely not be available until a few to several hours before the occultation. Astrometrists should send any observations to both of my e-mail addresses: David_Dunham@jhuapl.edu and dunham@erols.com. Martin Federspiel's message is below. Note that in his table of positions in the new central line, longitudes west of Greenwich are negative.
David Dunham, IOTA
>Dear Martin,
>
>Here is the CAMC J2000 position for the star SAO 138801 for the Mar 21
>event.
>I hope to get a position for PPM 195395 (Mar 30) a few days before that
>event also.
>
>
> RA = 12 27 59.770
> Dec = -07 34 5.05
> V mag = 8.26
> Epoch = 1997.19 (6 observations)
>
>Regards,
>Bob
With this position and Goffin's (1996) orbit published in MPC 27886 I
get the following central line for that favourable occultation which
is shifted about two path widths to the southwest compared to the
Sky & Telescope map (February 1997, p. 73):
Central line for an occultation by (377) Campania
(377) Campania occults SAO 138801 (RA 12 27 59.770 DE -7 34 5.05)
orbit: Goffin 1996 (MPC 27886), star position CAMC
Minimum geocentric distance:
date: 1997 3 21 time: 8 16 58.UT; d=2.65", PW=30.55 deg, pi=4.74",mu=33.68"/h
substellar point on earth (lat., long.), PA of least distance:
-7.55 -116.16 30.55
Lat. Long. hh:mm:ss UT StarAlt0 StarAzi0 SunAlt0 SunAzi0
2.71 -36.18 8:10:10. ! 11.3 261.7 -5.4 89.4
2.87 -42.64 8:10:27. ! 17.6 261.1 -11.8 89.1
3.26 -47.38 8:10:44. ! 22.1 260.5 -16.5 88.7
3.78 -51.34 8:11: 1. ! 25.8 259.7 -20.3 88.3
4.36 -54.81 8:11:18. ! 29.1 258.9 -23.7 87.7
5.00 -57.96 8:11:35. ! 31.9 257.9 -26.7 87.1
5.67 -60.86 8:11:52. ! 34.5 256.8 -29.5 86.4
6.38 -63.57 8:12: 9. ! 36.9 255.6 -32.1 85.6
7.12 -66.13 8:12:25. ! 39.1 254.2 -34.5 84.7
7.88 -68.56 8:12:42. ! 41.1 252.7 -36.7 83.7
8.66 -70.89 8:12:59. ! 43.0 251.1 -38.9 82.6
9.47 -73.13 8:13:16. ! 44.8 249.3 -40.9 81.3
10.29 -75.30 8:13:33. ! 46.4 247.4 -42.8 79.9
11.13 -77.40 8:13:50. ! 47.9 245.4 -44.6 78.4
11.99 -79.45 8:14: 7. ! 49.2 243.1 -46.3 76.7
12.86 -81.45 8:14:24. ! 50.5 240.8 -47.9 74.9
13.75 -83.41 8:14:41. ! 51.6 238.2 -49.4 72.9
14.65 -85.33 8:14:58. ! 52.6 235.5 -50.8 70.7
15.58 -87.22 8:15:14. ! 53.5 232.7 -52.2 68.4
16.51 -89.09 8:15:31. ! 54.3 229.7 -53.4 65.9
17.46 -90.94 8:15:48. ! 54.9 226.6 -54.5 63.2
18.43 -92.77 8:16: 5. ! 55.4 223.4 -55.5 60.3
19.42 -94.59 8:16:22. ! 55.8 220.1 -56.4 57.2
20.42 -96.39 8:16:39. ! 56.0 216.7 -57.2 53.9
21.44 -98.20 8:16:56. ! 56.1 213.2 -57.9 50.5
22.48 -100.00 8:17:13. ! 56.0 209.7 -58.4 46.9
23.54 -101.81 8:17:30. ! 55.9 206.2 -58.8 43.1
24.61 -103.62 8:17:47. ! 55.5 202.7 -59.0 39.3
25.71 -105.45 8:18: 3. ! 55.1 199.3 -59.1 35.3
26.83 -107.29 8:18:20. ! 54.5 195.9 -59.0 31.3
27.97 -109.15 8:18:37. ! 53.8 192.5 -58.8 27.2
29.14 -111.04 8:18:54. ! 52.9 189.2 -58.4 23.2
30.33 -112.96 8:19:11. ! 52.0 186.0 -57.9 19.1
31.56 -114.92 8:19:28. ! 50.9 182.9 -57.2 15.1
32.81 -116.93 8:19:45. ! 49.6 179.9 -56.4 11.2
34.10 -118.99 8:20: 2. ! 48.3 176.9 -55.4 7.4
35.42 -121.13 8:20:19. ! 46.9 174.0 -54.2 3.7
36.79 -123.34 8:20:35. ! 45.3 171.2 -52.9 360.0
38.20 -125.65 8:20:52. ! 43.6 168.3 -51.4 356.4
39.66 -128.07 8:21: 9. ! 41.7 165.5 -49.8 352.9
41.18 -130.64 8:21:26. ! 39.8 162.7 -48.0 349.4
42.76 -133.38 8:21:43. ! 37.6 159.8 -46.0 345.9
44.43 -136.33 8:21:60. ! 35.3 156.8 -43.9 342.3
46.18 -139.57 8:22:17. ! 32.8 153.7 -41.5 338.7
48.05 -143.18 8:22:34. ! 30.0 150.3 -38.8 334.8
50.06 -147.31 8:22:51. ! 26.9 146.6 -35.8 330.7
52.27 -152.20 8:23: 8. ! 23.4 142.3 -32.3 326.0
54.75 -158.35 8:23:24. ! 19.1 137.0 -28.2 320.2
57.73 -167.06 8:23:41. ! 13.6 129.5 -22.7 312.4
62.80 170.75 8:23:58. ! 1.9 110.0 -10.8 292.6