List of asteroids/121301–121400

|| September 8, 1999 || Socorro || LINEAR
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121303 - || || September 8, 1999 || Socorro || LINEAR
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121306 - || || September 8, 1999 || Socorro || LINEAR
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121309 - || || September 8, 1999 || Socorro || LINEAR
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121312 - || || September 4, 1999 || Anderson Mesa || LONEOS
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121315 - || || September 7, 1999 || Socorro || LINEAR
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121318 - || || September 6, 1999 || Kitt Peak || Spacewatch
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121321 - || 1999 SH || September 16, 1999 || Višnjan Observatory || K. Korlević
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121322 - || || September 30, 1999 || Socorro || LINEAR
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121325 - || || September 30, 1999 || Catalina || CSS
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121328 - || || September 29, 1999 || Catalina || CSS
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121331 - || || October 4, 1999 || Prescott || P. G. Comba
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121334 - || || October 6, 1999 || Modra || L. Kornoš, J. Tóth
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121337 - || || October 13, 1999 || Ondřejov || P. Kušnirák, P. Pravec
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121340 - || || October 10, 1999 || Xinglong || BAO Schmidt CCD Asteroid Program
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121343 - || || October 4, 1999 || Socorro || LINEAR
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121346 - || || October 4, 1999 || Socorro || LINEAR
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121349 - || || October 4, 1999 || Socorro || LINEAR
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121352 - || || October 4, 1999 || Kitt Peak || Spacewatch
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121355 - || || October 6, 1999 || Kitt Peak || Spacewatch
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121358 - || || October 6, 1999 || Kitt Peak || Spacewatch
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121361 - || || October 7, 1999 || Kitt Peak || Spacewatch
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121364 - || || October 8, 1999 || Kitt Peak || Spacewatch
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121367 - || || October 9, 1999 || Kitt Peak || Spacewatch
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121370 - || || October 11, 1999 || Kitt Peak || Spacewatch
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121373 - || || October 11, 1999 || Kitt Peak || Spacewatch
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121376 - || || October 15, 1999 || Kitt Peak || Spacewatch
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121379 - || || October 2, 1999 || Socorro || LINEAR
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121382 - || || October 3, 1999 || Socorro || LINEAR
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121385 - || || October 4, 1999 || Socorro || LINEAR
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121388 - || || October 4, 1999 || Socorro || LINEAR
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121391 - || || October 4, 1999 || Socorro || LINEAR
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121394 - || || October 4, 1999 || Socorro || LINEAR
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121397 - || || October 6, 1999 || Socorro || LINEAR
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121400 - ||