Chiron.20140919; September 19, 2014

³Measured position corresponds to RA offset of –0.0599 and Dec. offset of –0.2340.

⁴All "offsets" are defined in the ("corrected" – "reference") or ("observed" – "calculated") sense. The offsets should be added to reference positions to get the measured positions, which we use to calculate the prediction.

⁴Data analyzed using UCAC2 reference network. A weighted average of the data from the two telescopes was used to calculate the RA and DEC. The errors given are 1 standard deviation.

⁵The reference positions for Haumea are those given by JPL Horizon's ephemeris (Chiron source file: JPL79; Earth center source file: DE405).

⁶Data from the USNO 61-inch, SMARTS 0.9m, and Lowell 42-inch telescopes over the span of 4 years were reduced with respect to stars in the UCAC2 catalog. A model was developed to fit the residuals obtained from our measured positions compared to that of the object's JPL ephemeris. All residuals obtained from the different telescopes were consistent with the model. The model includes the first-order effects of errors in the orbital elements of Chiron: (i) constant offsets in RA and Dec, (ii) linear (in time) offsets in RA and Dec, and (iii) sinusoidal terms with the Earth's orbital period. The model was propagated to obtain the predicted position and error of the KBO at the time of the occultation. The errors listed for the KBO are 1 standard deviation.

Table 1: Prediction Details
Chiron Geocentric Mid-time (yyyy month dd hh:mm:ss)	2014 September 19 00:33:08± 00:00:33¹ UT
Chiron Minimum Geocentric Separation	0.316± 0.061¹ arcsec
Position Angle (Chiron relative to the star; measured north through east)	–25.15 degrees
Geocentric Velocity	23.36 km/sec
Occultation Star USNOB R magnitude	16.36²

Table 2: Reference Star Position
Reference star position: (USNOB, at epoch of event)	RA (h:m:s; J2000)	Dec (d:m:s; J2000)	Notes
Chiron.20140919 Catalog	22 55 39.3947 ± 0.0470	–01 19 02.280 ± 0.079
Chiron.20140919 Measured³	22 55 39.3906 ± 0.0140	–01 19 02.514 ± 0.006	From 5 Lowell 42-inch frames
Table 3: Projected KBO Offsets from Reference Ephemeris at the Time of the Event
Body	RA (arcsec)	Dec (arcsec)
Chiron	0.0043 ± 0.0639	–0.329 ± 0.060	See Notes 5 and 6
³Measured position corresponds to RA offset of –0.0599 and Dec. offset of –0.2340. ⁴All "offsets" are defined in the ("corrected" – "reference") or ("observed" – "calculated") sense. The offsets should be added to reference positions to get the measured positions, which we use to calculate the prediction. ⁴Data analyzed using UCAC2 reference network. A weighted average of the data from the two telescopes was used to calculate the RA and DEC. The errors given are 1 standard deviation. ⁵The reference positions for Haumea are those given by JPL Horizon's ephemeris (Chiron source file: JPL79; Earth center source file: DE405). ⁶Data from the USNO 61-inch, SMARTS 0.9m, and Lowell 42-inch telescopes over the span of 4 years were reduced with respect to stars in the UCAC2 catalog. A model was developed to fit the residuals obtained from our measured positions compared to that of the object's JPL ephemeris. All residuals obtained from the different telescopes were consistent with the model. The model includes the first-order effects of errors in the orbital elements of Chiron: (i) constant offsets in RA and Dec, (ii) linear (in time) offsets in RA and Dec, and (iii) sinusoidal terms with the Earth's orbital period. The model was propagated to obtain the predicted position and error of the KBO at the time of the occultation. The errors listed for the KBO are 1 standard deviation.

Site	East Longitude	Latitude	Site Altitude⁶ (km)	Distance⁷ (km)	Velocity (km/s)
CTIO	-70 48 17	-30 10 02	2.198	4954 S.	23.62
DCT	–111 25 18	+34 44 41	2.337	1622 N.	23.39
Llano del Hato Nat. Ast. Obs.	-70 52 20	+08 47 10	3.600	926 S.	23.65
Santiago, Chile	-70 32 10	-33 23 45	0.903	5298 S.	23.61
Stockholm	18 03 57	+59 19 24	0.	234 N.	23.51
SVH	–74 56 45	40 57 41	0.220	1569 N.	23.57
Wallace	–71 29 06	42 36 36	0.107	1579 N.	23.57
Williams	–73 12 06	42 42 42	0.215	1620 N.	23.57
Geocenter	----------	---------	center of Earth	3880 S.	23.35

Site	KBO Immersion (UT)⁹	UT Mid-Time	KBO Altitude	Solar Altitude⁹	KBO Emersion (UT)⁹
CTIO	-----------	00:36:42	36	-----------	-----------
DCT	-----------	00:35:25	1	10	-----------
Llano del Hato Nat. Ast. Obs.	-----------	00:35:50	41	-----------	-----------
Santiago, Chile	-----------	00:36:41	35	-----------	-----------
Stockholm	-----------	00:30:07	22	-----------	-----------
SVH	-----------	00:34:20	26	-----------	-----------
Wallace	-----------	00:34:06	27	-----------	-----------
Williams	-----------	00:34:10	27	-----------	-----------
Geocenter	-----------	00:33:08	-----------	-----------	-----------

Chiron.20140919 Occultation September 19, 2014