Cora»Occultation

2018-10-18 / 4UC 368-177464 / (168) Sibylla

#	OBS	Observer	Occ	Meth.	Instr.	CC	TSRC	UT1	UT2	UT3	UT4	UT2E	UT3E	Dur.	Chrd
1	show	Lionel Rousselot	O+	CCD	M250	FR	NTP	19:23:39	19:30:13.45	19:30:20.97	19:23:38	0.84	2.23	7.52	124.1
2	show	Karel Halir	O+	VID	M507	CZ	GPS++	19:28:30	19:30:53.98	19:30:59.10	19:33:50	1.28	1.28	5.12	84.5
3	show	Stefano Sposetti	O-	VID	M200	CH		19:28:15			19:32:35
4	show	Andrea Manna	O-	VID	M200	CH		19:29:44			19:32:04
5	show	Gregor Krannich	O-	CCD	M350	DE		19:29:57			19:32:59
6	show	Jean-Louis Dumont	O?	CCD	M408	FR	GPS	19:28:25	19:30:05.53	19:30:14.89	19:31:20	0.66	0.51	9.36	154.4

UT1/UT4: Begin/End of observation | UT2/UT3: Begin/End of occultation | Dur: Reported duration in seconds | Chrd: Corresponding chord length in km | More

6 observations found in db: euraster

Available (probably) matching predictions (click on the link to switch):

JPL#71 : b0aa3e65-74ff-46e3-bc02-6cf211854a1b [db: observed]

Using prediction b0aa3e65-74ff-46e3-bc02-6cf211854a1b for map and profile fit

Get observations as KML file (reduced site location resolution)

Ellipse and circular profile fits to the timings (chords)

Auto-Fit Result:
Size = 1950 x 155 km
a',b' = 974.9, 77.5 km
X0,Y0 = -598.5, 420.7 km
Mean diameter = 550 km

From 3 chords (VID,CCD)

You can enter space separated chord numbers (example: 11 4 8) or a method like VIS to ignore all visual timings, or a time source like RAD and NTP (but not GPS).
If the plot disappears, then there are less than 2 chords left (too much ignored, go back with browser).

Check SiMDA for size and mass data.

Check Johnston Archive for satellites.

Map with groundtrack and observer stations

Event Details
Occultation UUID [and DB] : b0aa3e65-74ff-46e3-bc02-6cf211854a1b [observed] Occultation Date + Time : 2018-10-18 at 19:28:10 UT +/- 0.01 min [1] Object Designation : (168) Sibylla Orbit Class : MBA Star Designation : GDR3 4181628267319921664 Star Coordinates (ICRF) : RA = 19 42 42.9451, DE = -16 34 48.546 [2] Star Magnitudes : G = 13.44 mag, RP = 12.87 mag, BP = 13.84 mag Object Magnitude : V = 14.27 mag Estimated Magnitude Drop : 1.3 mag Estimated Max. Duration : 9.0 sec Object Mean Diameter : 148 km (src: astorb) Speed of the shadow : 16.5 km/s Elongation to Moon & Sun : 24° (sunlit = 69%), Sun = 89° Cross-track uncertainty : 1.0 mas = 2 km = 0.02 path-width (1-sig) RUWE and duplicate source : 0.94 mas, dup.src = 0 (0:false, 1:true) Ephemeris Reference : JPL#71 Object is a Gaia mass determination target ! [1] time t0 of closest geocentric approach c/a, [2] including proper motion until t0

Event Details

 Occultation UUID [and DB] : b0aa3e65-74ff-46e3-bc02-6cf211854a1b [observed]

 Occultation Date + Time   : 2018-10-18 at 19:28:10 UT +/- 0.01 min  [1]
 Object Designation        : (168) Sibylla
 Orbit Class               : MBA
 Star Designation          : GDR3 4181628267319921664
 Star Coordinates (ICRF)   : RA = 19 42 42.9451, DE = -16 34 48.546  [2]
 Star Magnitudes           : G = 13.44 mag, RP = 12.87 mag, BP = 13.84 mag
 Object Magnitude          : V = 14.27 mag
 Estimated Magnitude Drop  : 1.3 mag
 Estimated Max. Duration   : 9.0 sec
 Object Mean Diameter      : 148 km  (src: astorb)
 Speed of the shadow       : 16.5 km/s
 Elongation to Moon & Sun  : 24° (sunlit = 69%), Sun = 89°
 Cross-track uncertainty   : 1.0 mas = 2 km = 0.02 path-width (1-sig)
 RUWE and duplicate source : 0.94 mas, dup.src = 0  (0:false, 1:true)

 Ephemeris Reference       : JPL#71

 Object is a Gaia mass determination target !

 [1] time t0 of closest geocentric approach c/a, [2] including proper motion until t0

More Data and Informations

SiMDA \| 3D Asteroid Catalogue \| Johnston Archive \| Star at CDS (Vizier) \| JPL Small-Body Node \| Minor Planet Center \| Wikipedia

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Aladin Sky Atlas

Aladin Lite direct link (has Gaia overlay)

Collaborative Occultation Resources and Archive (CORA)

2018-10-18 / 4UC 368-177464 / (168) Sibylla