2003 YT1 Planning
Background
2003 YT1 was discovered by the Catalina Sky Survey on December 18, 2003.
It will approach within 0.0733 AU (28 lunar distances) on April 30, 2004,
just a few hours before the first Goldstone track is scheduled to start.
Its absolute magnitude of 16.2 suggests that it is within a factor of two of about
1.8 kilometers in diameter. As such, this is probably one of the larger
near-Earth asteroids that we have observed in the last few years at Goldstone.
On April 22, Adrian Galad, Stefan Gajdos, and Petr Pravec reported that 2003 YT1 has
a rotation period of 2.34 hours. The lightcurve amplitude is about 0.15 magnitudes,
suggesting that this object is not very elongated. They observe an additional dip
in the lightcurve that may indicate the presence of a companion.
Otherwise, nothing is known about the physical properties
of this object.
Due to its size and the proximity of its orbit to that of Earth, 2003 YT1 has been
classified as a "Potentially Hazardous Asteroid" by the International
Astronomical Union's Minor Planet Center.
These will be Goldstone-only observations. Arecibo
will be unavailable due to maintenance during dates when 2003 YT1 is visible.
Orbital and Physical Characteristics
orbit type Apollo
semimajor axis 1.110 AU
eccentricity 0.292
inclination 44.06°
perihelion distance 0.786 AU
aphelion distance 1.434 AU
absolute magnitude (H) 16.2
diameter unknown
rotation period 2.34 h
pole direction unknown
lightcurve amplitude ~0.15 magnitudes
spectral class unknown
Last updated: 2004 May 7
Discovery
Discovery Announcement
M.P.E.C. 2003-Y30 Issued 2003 Dec. 19, 12:39 UT
The Minor Planet Electronic Circulars contain information on unusual
minor planets and routine data on comets. They are published
on behalf of Commission 20 of the International Astronomical Union by the
Minor Planet Center, Smithsonian Astrophysical Observatory,
Cambridge, MA 02138, U.S.A.
Supported in part by the Steven and Michele Kirsch Foundation
Prepared using the Tamkin Foundation Computer Network
MPC@CFA.HARVARD.EDU
URL http://cfa-www.harvard.edu/iau/mpc.html ISSN 1523-6714
2003 YT1
Observations:
K03Y01T* C2003 12 18.06049 22 26 25.63 -11 11 29.5 17.8 V EY030703
K03Y01T C2003 12 18.06841 22 26 25.93 -11 11 03.0 18.3 V EY030703
K03Y01T C2003 12 18.07635 22 26 26.29 -11 10 33.9 18.4 V EY030703
K03Y01T C2003 12 18.08436 22 26 26.65 -11 10 06.8 18.0 V EY030703
K03Y01T C2003 12 18.13245 22 26 28.80 -11 07 20.2 17.7 V EY030703
K03Y01T C2003 12 18.13360 22 26 28.83 -11 07 15.7 17.9 V EY030703
K03Y01T C2003 12 18.13476 22 26 28.89 -11 07 11.8 17.8 V EY030703
K03Y01T C2003 12 18.13589 22 26 28.96 -11 07 08.0 17.9 V EY030703
K03Y01T C2003 12 18.15130 22 26 29.69 -11 06 13.8 18.0 R EY030854
K03Y01T C2003 12 18.15791 22 26 30.01 -11 05 51.4 16.5 R EY030854
K03Y01T C2003 12 18.16452 22 26 30.26 -11 05 28.7 18.2 R EY030854
K03Y01T C2003 12 18.70122 22 26 56.48 -10 34 34.6 EY030557
K03Y01T C2003 12 18.70273 22 26 56.53 -10 34 29.4 EY030557
K03Y01T C2003 12 18.70425 22 26 56.61 -10 34 24.2 EY030557
K03Y01T C2003 12 18.70578 22 26 56.68 -10 34 18.9 EY030557
K03Y01T C2003 12 18.70729 22 26 56.75 -10 34 13.5 EY030557
K03Y01T C2003 12 18.72031 22 26 57.25 -10 33 28.6 EY030246
K03Y01T C2003 12 18.72119 22 26 57.34 -10 33 25.3 EY030246
K03Y01T C2003 12 18.72206 22 26 57.40 -10 33 22.2 EY030246
K03Y01T C2003 12 18.72275 22 26 57.42 -10 33 19.5 EY030246
K03Y01T C2003 12 18.72368 22 26 57.46 -10 33 16.8 EY030246
K03Y01T C2003 12 18.72462 22 26 57.50 -10 33 13.6 EY030246
K03Y01T C2003 12 18.72541 22 26 57.55 -10 33 10.6 EY030246
K03Y01T C2003 12 19.07595 22 27 14.33 -10 12 59.2 20.0 R EY030333
K03Y01T C2003 12 19.07792 22 27 14.41 -10 12 52.7 19.6 R EY030333
K03Y01T C2003 12 19.07981 22 27 14.49 -10 12 45.8 20.1 R EY030333
K03Y01T C2003 12 19.14453 22 27 17.39 -10 09 02.2 17.8 R EY030926
K03Y01T C2003 12 19.14571 22 27 17.47 -10 08 58.6 17.8 R EY030926
Observer details:
246 Klet Observatory-KLENOT. Observers M. Tichy, M. Kocer. 1.06-m KLENOT
Telescope + CCD.
333 Desert Eagle Observatory. Observer W. K. Y. Yeung. 0.45-m reflector
+ CCD.
557 Ondrejov. Observer P. Kusnirak. 0.65-m f/3.6 reflector + CCD.
703 Catalina Sky Survey. Observers S. Larson, E. Beshore, E. Christensen,
R. Hill, S. Kolar, D. McLean. 0.68-m f/1.8 Schmidt + CCD.
854 Sabino Canyon Observatory, Tucson. Observer J. E. McGaha. 0.356-m f/10.0
Schmidt-Cassegrain + CCD.
926 Tenagra II Observatory. Observers P. R. Holvorcem, M. Schwartz. 0.81-m
f/7 Ritchey-Chretien + CCD.
Orbital elements:
2003 YT1 PHA 0.022A
Epoch 2003 Dec. 7.0 TT = JDT 2452980.5 MPC
M 298.04124 (2000.0) P Q
n 0.79574600 Peri. 85.54223 -0.38420237 -0.81878784
a 1.1533286 Node 38.14510 +0.29038920 -0.54576821
e 0.3046479 Incl. 43.68181 +0.87639184 -0.17811101
P 1.24 H 16.5 G 0.15
From 28 observations 2003 Dec. 18-19.
Ephemeris:
2003 YT1 a,e,i = 1.15, 0.30, 44 q = 0.8020
Date TT R. A. (2000) Decl. Delta r Elong. Phase V
2003 12 17 22 25.58 -12 12.9 0.828 1.036 69.1 62.6 18.4
2003 12 27 22 33.51 -02 47.9 0.855 0.985 64.4 64.2 18.4
2004 01 06 22 40.88 +06 04.5 0.878 0.936 60.1 65.6 18.4
2004 01 16 22 47.19 +14 24.7 0.892 0.891 56.5 66.9 18.4
2004 01 26 22 51.99 +22 14.0 0.894 0.853 53.7 68.6 18.3
2004 02 05 22 54.77 +29 32.2 0.878 0.824 52.1 70.7 18.3
2004 02 15 22 55.15 +36 17.3 0.843 0.806 51.5 73.5 18.2
2004 02 25 22 53.07 +42 28.7 0.787 0.802 52.2 77.0 18.2
2004 03 06 22 48.79 +48 10.1 0.710 0.812 54.0 81.0 18.1
2004 03 16 22 43.17 +53 35.1 0.616 0.835 56.7 85.1 18.0
2004 03 26 22 37.59 +59 19.1 0.508 0.868 60.5 88.9 17.9
2004 04 05 22 33.87 +66 40.2 0.390 0.910 65.4 91.7 17.5
2004 04 15 22 40.1 +79 00.1 0.272 0.957 72.3 92.0 16.8
2004 04 25 10 06.9 +73 19.5 0.174 1.007 85.2 84.9 15.7
2004 05 05 10 18.47 +22 23.3 0.162 1.058 103.3 68.1 15.1
2004 05 15 10 23.87 -10 31.0 0.251 1.109 106.4 61.0 15.9
2004 05 25 10 30.55 -24 24.0 0.375 1.158 103.3 58.3 16.8
2004 06 04 10 39.11 -31 34.6 0.505 1.205 99.5 56.1 17.5
.
.
.
Timothy B. Spahr (C) Copyright 2003 MPC M.P.E.C. 2003-Y30
SNR Calculation
Hmag = 16.2
Diameter = 1.8 km (assumes H = 16.2 and an S-class optical albedo)
Period = 4 h (an educated guess)
The SNR estimates below adopt RA, DEC, and delta at 00:00 UTC on each date; actual
view periods may differ, in some cases, substantially.
------------GOLDSTONE---------- -------------ARECIBO-----------
Max Max
Dat Run UTC Dat Run UTC
Date RA Decl Delta Runs SNR SNR Window Runs SNR SNR Window
2004 4 25 61 81 0.112 358 69 4 0:00-24:00 0 0 0 -
2004 4 26 87 78 0.102 391 100 6 0:00-24:00 0 0 0 -
2004 4 27 105 74 0.092 427 144 8 13:54-35:00 0 0 0 -
2004 4 28 116 67 0.084 383 190 11 16:41-33:30 0 0 0 -
2004 4 29 123 58 0.078 339 239 14 18:11-32:53 0 0 0 -
2004 4 30 127 48 0.074 313 274 17 19:06-32:23 0 0 0 -
2004 5 1 131 38 0.073 288 278 18 19:53-32:00 23 2266 497 22:11-22:53
2004 5 2 133 27 0.075 259 248 17 20:30-31:36 58 5042 705 21:23-24:00
2004 5 3 135 17 0.079 228 196 14 21:00-31:11 58 4255 588 21:23-24:06
2004 5 4 136 8 0.085 198 140 11 21:23-30:48 47 2877 451 21:36-24:00
2004 5 5 138 1 0.093 170 94 8 21:48-30:30 25 1195 266 22:11-23:18
2004 5 6 139 -6 0.102 145 61 6 22:06-30:06 0 0 0 -
Goldstone Track Assignments
UT UT Duration Rotations
DOY Date TX Window PST TX Window (hh:mm) (P = 2.34 h)
--- ---- --------- ------------- ------- ------------
122 May 1 0330-0735 2030 Apr 30-0035 May 1 4:05 1.7 CANCELLED DUE TO EQUIPMENT PROBLEMS
123 May 2 0355-0725 2055 May 1-0025 May 2 3:30 1.5 CANCELLED DUE TO EQUIPMENT PROBLEMS
This object may be observable at Arecibo. Here are Arecibo Rise-Transit-Set times
assuming 70 degree horizons (time resolution = 1 minute):
UTC
hh:mm RA (deg) DEC (deg) Delta (AU)
2004-May-01 21:24 *r 132.80315 28.14016 0.0743829168
2004-May-01 22:40 *t 132.90429 27.58250 0.074514397
2004-May-01 23:55 As 133.00273 27.03257 0.0746549771
2004-May-02 21:19 *r 134.69409 18.01173 0.0780726314
2004-May-02 22:42 *t 134.77899 17.45858 0.0783556120
2004-May-03 00:05 As 134.86275 16.90831 0.0786509719
2004-May-03 21:33 *r 136.20483 8.92826 0.0840769921
2004-May-03 22:43 *t 136.26128 8.52552 0.0844141095
2004-May-03 23:53 As 136.31716 8.12564 0.0847591161
2004-May-04 22:06 *r 137.44019 1.12460 0.0920250960
2004-May-04 22:43 *t 137.46423 0.94647 0.0922443819
2004-May-04 23:21 Ns 137.48880 0.76439 0.0924716194
Uncertainties
From Horizons: 2004 March 1, JPL solution #18, # obs: 110 (41 days)
Date__(UT)__HR:MN R.A._(a-appar)_DEC. delta POS_3sigma DOP_S-sig DOP_X-sig RT_delay-sig
2004-Apr-15 00:00 * 341.29208 66.66114 0.2359983844 121.158904 22.97 82.17 0.096480
2004-Apr-20 00:00 *m 351.19978 73.40874 0.1711912425 170.826644 21.26 76.04 0.110665
2004-Apr-25 00:00 *m 60.64683 80.70030 0.1117488088 236.551476 16.06 57.44 0.141680
2004-Apr-30 00:00 *m 127.39755 48.47283 0.0744924572 243.811928 30.44 108.89 0.182237
2004-May-05 00:00 * 137.53648 0.54775 0.0926897348 374.063852 54.07 193.38 0.132730
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
From Horizons (2004 March 16): JPL solution #19, #obs = 113 (63 days)
2004-Apr-15 00:00 * 341.29344 66.66152 0.2360018375 53.2934548 14.73 52.69 0.042927
2004-Apr-20 00:00 *m 351.20245 73.40911 0.1711947187 76.0149697 13.79 49.31 0.048050
2004-Apr-25 00:00 *m 60.65056 80.69954 0.1117525543 108.255874 10.87 38.89 0.060577
2004-Apr-30 00:00 *m 127.39604 48.47324 0.0744963156 121.662420 14.36 51.35 0.078050
2004-May-05 00:00 * 137.53549 0.54960 0.0926919119 167.442543 25.74 92.07 0.058233
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
From Horizons: 2004 March 22, JPL solution #20, #obs = 116 (95 days)
2004-Apr-15 00:00 * 341.30054 66.66709 0.2360281906 8.96618360 7.79 27.86 0.011892
2004-Apr-20 00:00 *m 351.21778 73.41617 0.1712228499 13.4134191 7.16 25.61 0.011387
2004-Apr-25 00:00 *m 60.71186 80.69896 0.1117855797 21.3598508 5.22 18.67 0.011681
2004-Apr-30 00:00 *m 127.40115 48.47634 0.0745349232 31.8422687 3.22 11.53 0.012863
2004-May-05 00:00 * 137.53709 0.56830 0.0927177535 32.4141052 9.01 32.23 0.011153
2004-Apr-25 00:00 *m 60.71186 80.69896 0.1117855797 21.3598508 5.22 18.67 0.011681
2004-Apr-26 00:00 *m 87.13097 78.36800 0.1015446692 23.4689079 4.52 16.16 0.011898
2004-Apr-27 00:00 *m 105.05926 73.61702 0.0923253279 25.6738216 3.70 13.24 0.012167
2004-Apr-28 00:00 *m 115.96354 66.85616 0.0844693197 27.8757260 2.90 10.36 0.012460
2004-Apr-29 00:00 *m 122.81858 58.36752 0.0783926395 29.9632129 2.56 9.15 0.012720
2004-Apr-30 00:00 *m 127.40115 48.47634 0.0745349232 31.8422687 3.22 11.53 0.012863
2004-May-01 00:00 *m 130.64171 37.75124 0.0732486904 33.3915570 4.58 16.38 0.012809
2004-May-02 00:00 *m 133.04144 26.98108 0.0746659897 34.3696348 6.05 21.66 0.012538
2004-May-03 00:00 * 134.88611 16.92762 0.0786380316 34.5151588 7.34 26.24 0.012109
2004-May-04 00:00 * 136.34818 8.07380 0.0848024360 33.7908707 8.32 29.75 0.011619
2004-May-05 00:00 * 137.53709 0.56830 0.0927177535 32.4141052 9.01 32.23 0.011153
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
From Horizons: 2004 April 21, JPL solution #23, #obs = 130 (119 days)
2004-Apr-25 00:00 *m 60.70543 80.69762 0.1117874402 6.67333743 2.84 10.16 0.006779
2004-Apr-26 00:00 *m 87.12226 78.36719 0.1015463386 8.05616808 2.37 8.49 0.006559
2004-Apr-27 00:00 *m 105.05149 73.61679 0.0923267683 9.81452967 1.79 6.41 0.006266
2004-Apr-28 00:00 *m 115.95722 66.85640 0.0844704844 11.9520433 1.10 3.95 0.005875
2004-Apr-29 00:00 *m 122.81342 58.36812 0.0783934771 14.3232583 0.61 2.17 0.005372
2004-Apr-30 00:00 *m 127.39681 48.47718 0.0745353903 16.5505803 1.21 4.32 0.004780
2004-May-01 00:00 *m 130.63798 37.75219 0.0732487694 18.0917546 2.21 7.90 0.004191
2004-May-02 00:00 *m 133.03816 26.98200 0.0746657027 18.5431535 3.18 11.38 0.003756
2004-May-03 00:00 * 134.88317 16.92842 0.0786374353 17.9235894 4.00 14.29 0.003590
2004-May-04 00:00 * 136.34551 8.07443 0.0848016028 16.6032212 4.61 16.49 0.003674
2004-May-05 00:00 * 137.53463 0.56877 0.0927167532 15.0076610 5.04 18.04 0.003900
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
From Horizons: 2004 April 26, JPL solution #25, #obs = 145 (126 days)
2004-Apr-25 00:00 *m 60.70000 80.69732 0.1117890402 2.55272994 2.17 7.76 0.005986
2004-Apr-26 00:00 *m 87.11683 78.36735 0.1015477823 3.58393701 1.79 6.39 0.005828
2004-Apr-27 00:00 *m 105.04733 73.61739 0.0923280058 5.02194999 1.30 4.64 0.005605
2004-Apr-28 00:00 *m 115.95414 66.85736 0.0844714527 6.90505944 0.69 2.48 0.005283
2004-Apr-29 00:00 *m 122.81104 58.36937 0.0783941053 9.14835871 0.23 0.82 0.004829
2004-Apr-30 00:00 *m 127.39490 48.47864 0.0745356132 11.4464715 0.96 3.43 0.004227
2004-May-01 00:00 *m 130.63639 37.75371 0.0732485499 13.2949399 1.83 6.53 0.003507
2004-May-02 00:00 *m 133.03678 26.98346 0.0746650483 14.2453228 2.63 9.42 0.002770
2004-May-03 00:00 * 134.88195 16.92970 0.0786363962 14.2028872 3.30 11.81 0.002160
2004-May-04 00:00 * 136.34442 8.07550 0.0848002511 13.4268571 3.81 13.61 0.001814
2004-May-05 00:00 * 137.53363 0.56962 0.0927151610 12.2839360 4.16 14.88 0.001762
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
From Horizons: 2004 April 29, JPL solution #27, #obs = 154 (131 days)
2004-Apr-25 00:00 *m 60.69884 80.69740 0.1117912894 1.17413324 1.95 6.98 0.002969
2004-Apr-26 00:00 *m 87.11572 78.36758 0.1015499761 1.43391166 1.60 5.71 0.002908
2004-Apr-27 00:00 *m 105.04650 73.61781 0.0923301161 1.85409934 1.15 4.10 0.002836
2004-Apr-28 00:00 *m 115.95353 66.85800 0.0844734381 2.48078546 0.59 2.12 0.002744
2004-Apr-29 00:00 *m 122.81057 58.37027 0.0783959085 3.31331994 0.21 0.75 0.002619
2004-Apr-30 00:00 *m 127.39452 48.47980 0.0745371674 4.25906194 0.90 3.22 0.002451
2004-May-01 00:00 *m 130.63607 37.75509 0.0732497944 5.12480936 1.69 6.03 0.002247
2004-May-02 00:00 *m 133.03650 26.98494 0.0746659500 5.70346591 2.41 8.63 0.002033
2004-May-03 00:00 * 134.88170 16.93118 0.0786369604 5.90488069 3.01 10.78 0.001846
2004-May-04 00:00 * 136.34420 8.07690 0.0848005139 5.78774541 3.46 12.38 0.001717
2004-May-05 00:00 * 137.53342 0.57090 0.0927151727 5.47876776 3.77 13.50 0.001651
Setups
We expect a bandwidth of up to several tens of Hz,
so we will use the following
setup on the first track:
TX polarization RCP
RCV polarization LCP
Frequencies: 2
Dwell: 30 seconds
Bandwidth: 4000 Hz
Sampling interval: 2500 x 0.1 usec
VME FFT for PSD files: 1024 for 3.906-Hz resolution
Possible ranging setups:
---------------------------------------------------------------------------
127 x 64 10-usec single sample
baud 10 usec
code 127
gates 127
FFT 64
CLT 11
ncoh 2
bandwidth 394 Hz
resolution 6.15 Hz
TXOFF +60 Hz -> echo will be centered at +9.75 bins or in bin 32+10 = 42
incoh sums 64 => 10.4 sec/record
---------------------------------------------------------------------------
127 x 64 11-usec single sample, 5.6-Hz resolution.
baud 11 usec
code 127
gates 127
PRP 1397
FFT 64
CLT 11
ncoh 2
bandwidth 357.9 Hz
resolution 5.59 Hz
TXOFF TBD
-------------------------------------------------------------------------
127 x 64 11-usec single sample, 11.2-Hz resolution
baud 11 usec
code 127
gates 127
PRP 1397
FFT 64
CLT 11
ncoh 1
bandwidth 715.8 Hz
resolution 11.2 Hz
TXOFF +60 -> echo would be centered at +5 bins w/perfect ephemeris
-------------------------------------------------------------------------
127 x 64 7-usec single sample
------------------------------
baud 7 usec
code 127
gates 127
PRP 889
FFT 64
CLT 11
ncoh 1
bandwidth 1124.9 Hz
resolution 17.6 Hz
TXOFF +60 -> echo would be centered at +3.4 bins w/perfect ephemeris
-------------------------------------------------------------------------
127 x 64 1-usec single sample
------------------------------
baud 1 usec
code 127
gates 127
PRP 127
FFT 64
CLT 13 & 14, about evenly divided
ncoh 15
bandwidth 525 Hz
resolution 8.2 Hz
TXOFF +50 -> echo would be centered at +6.1 bins w/perfect ephemeris
-------------------------------------------------------------------------------
0.125-usec ranging
------------------
setup JX1XS001
baud 0.125 usec
code 127
gates 127
FFT 64
ncoh 1968
bandwidth 32.008 Hz
resolution 0.5001 Hz
TXOFF 6 Hz = 12 cells, => cell 44
incoh sums 4 looks=> 8 sec/record => expect records per run ~ RTT/8
CLT gate 34.8
_____________________________________________________________________
POSSIBLE RANGING SETUPS: (code=127, FFT=64, single-pol'n)
These are from JX, w/ max-band (min-acc) options from Ray Jurgens.
Currently configured for 5-sec records.
_______________________________________________________________________
Setup Baud RP 1-acc 1-acc
usec m usec band res acc band res
_______________________________________________________________________
JX1XS110 11.000 1650 1397.0 715.8 11.2 2 358 5.6
JX1XS070 7.000 1050 889.0 1124.9 17.6 3 375 5.9
JX1XS020 2.000 300 254.0 3937.0 61.5 12 328 5.1
4 984 15.4
JX1XS010 1.000 150 127.0 7874.0 123.0 41 192 3.0
8 984 15.4
JX1XS005 0.500 75 63.5 15748.0 246.1 123 128 2.0
15 1050 16.4
JX1XS002 0.250 37.5 31.75 31496.1 492.1 492 64 1.0
30 1050 16.4
JX1XS001 0.125 18.75 15.875 62992.1 984.3 1970 32 0.5
60 1050 16.4
____________________________________________________________________
Instructions
NOTE: Data should be moved to the appropriate subdirectories in
stealth:/export/data0/rosema/2003YT1/raw/
2003 YT1 POINTING:
OSOD and initial predicts will be set-up at
Goldstone on stealth:
/export/data2/osod/ops/2003yt1/PRDX.OUT.s??
/PUNCH.OUT.s??
/EPH.OUT.s??
NOT AVAILABLE YET
POINTING
TX Offsets
Date (UTC) DOY hhmmss RA Dec Macro LHA Dec RTT OSOD
NOT AVAILABLE YET
PRDX.OUT.s??
TRANSMITTER: STATION #14, RECEIVER: STATION #14
RECEIVER U.T. RANGE DOPPLER LHA DEC RA EL
NOT AVAILABLE YET
GOLDSTONE MASTERLOG
MASTERLOG
==============================================================================
RCV
file setup runs start -stop osod OFFSET TX Poln
------------------------------------------------------------------------------
May 1
------------------------------------------------------------------------------
May 2
==============================================================================
Dr. Lance A. M. Benner | PHONE: (818) 354-7412
Mail Stop 300-233 | FAX: (818) 354-9476
Jet Propulsion Laboratory | email: lance@reason.jpl.nasa.gov
Pasadena, CA 91109-8099 | Plan: To live long and prosper
Asteroid Radar Astronomy