Cora»Occultation

2025-09-07 / UCAC4 638-022171 / (98) Ianthe

#	OBS	Observer	Occ	Meth.	Instr.	CC	TSRC	UT1	UT2	UT3	UT4	UT2E	UT3E	Dur.	Chrd
1	show	Andrea Manna	O+	VID	M200	CH	GPS	23:57:50	00:01:44.1	00:01:47.9	00:04:27	1.300	0.600	3.80	82.5
2	show	Stefano Sposetti	O+	VID	M280	CH	GPS	00:00:15	00:01:45.07	00:01:49.1	00:02:45	0.120	0.200	4.03	87.5
3	show	Gregor Krannich	O+	VID	M350	DE	GPS	23:59:55	00:01:53.090	00:01:57.732	00:03:56	0.229	0.229	4.64	100.7
4	show	Joachim Siegert	O+	VID	M203	DE	GPS	00:01:01	00:01:59.300	00:02:04.300	00:03:01	0.600	0.600	5.00	108.5
5	show	Sven Andersson	O+	VID	M360	DE	NTP	00:01:45	00:02:14.233	00:02:17.237	00:02:45	0.170	0.170	3.00	65.1

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

5 observations found in db: sodis

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

JPL#125 : 6a9b1f30-ddb7-11f0-547e-3f75aa5b64e6 [db: observed]

Using prediction 6a9b1f30-ddb7-11f0-547e-3f75aa5b64e6 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 = 124 x 84 km
a',b' = 62.1, 42.1 km
X0,Y0 = 2139.9, 23.4 km
Mean diameter = 102 km

From 5 chords (VID)

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.

Sky projection (artificial light) for occ. time: 2025-09-07, 00:01 UT (JD = 2460925.501)

DAMIT	Q	P (h)	λ, β	JD0	JD-JD0	φ0	Version	Modified	Vol-equiv D	Cmnt
# 1088	None	16.480	286°, 18°	2.446854e6	14071.5	0.0°	None	None	not scaled	2016-01-04

Q: model quality flag (0-5, 5=highest) | P: rotation period | λ,β: ecl. lon. and lat. of spin axis (J2000) | JD: initial time (epoch) | φ0: initial rotation angle for JD0

Image size: 300px. Transparent image background for copy & paste

Map with groundtrack and observer stations

Event Details
Occultation UUID [and DB] : 6a9b1f30-ddb7-11f0-547e-3f75aa5b64e6 [observed] Occultation Date + Time : 2025-09-07 at 00:03:40 UT +/- 0.0 min [1] Object Designation : (98) Ianthe Orbit Class : MBA Star Designation : GDR3 0186592311556117760 Star Coordinates (ICRF) : RA = 05 07 30.8553, DE = +37 27 17.437 [2] Star Magnitudes : G = 14.05 mag, RP = 13.38 mag, BP = 14.54 mag Object Magnitude : V = 14.14 mag Estimated Magnitude Drop : 0.8 mag Estimated Max. Duration : 4.8 sec Object Mean Diameter : 104.5 km (src: astorb) Speed of the shadow : 21.7 km/s Elongation to Moon & Sun : 104° (sunlit = 99%), Sun = 86° Cross-track uncertainty : 0.7 mas = 1 km = 0.01 path-width (1-sig) RUWE and duplicate source : 1.2 mas, dup.src = 0 (0:false, 1:true) Ephemeris Reference : JPL#125 Note : FP:true [1] time t0 of closest geocentric approach c/a, [2] including proper motion until t0

Event Details

 Occultation UUID [and DB] : 6a9b1f30-ddb7-11f0-547e-3f75aa5b64e6 [observed]

 Occultation Date + Time   : 2025-09-07 at 00:03:40 UT +/- 0.0 min  [1]
 Object Designation        : (98) Ianthe
 Orbit Class               : MBA
 Star Designation          : GDR3 0186592311556117760
 Star Coordinates (ICRF)   : RA = 05 07 30.8553, DE = +37 27 17.437  [2]
 Star Magnitudes           : G = 14.05 mag, RP = 13.38 mag, BP = 14.54 mag
 Object Magnitude          : V = 14.14 mag
 Estimated Magnitude Drop  : 0.8 mag
 Estimated Max. Duration   : 4.8 sec
 Object Mean Diameter      : 104.5 km  (src: astorb)
 Speed of the shadow       : 21.7 km/s
 Elongation to Moon & Sun  : 104° (sunlit = 99%), Sun = 86°
 Cross-track uncertainty   : 0.7 mas = 1 km = 0.01 path-width (1-sig)
 RUWE and duplicate source : 1.2 mas, dup.src = 0  (0:false, 1:true)

 Ephemeris Reference       : JPL#125
 Note                      : FP:true

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

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