Comet C/1983 H1 (1983d) Iras-Araki-Alcock

Comet IRAS-Iraki-Alcock passed very close to Earth (0.0312 AU or 4.7 million km). Here are the positions at hourly intervals. It was a small comet with only the faintest if any tail, total mag about 2 or so , but with a 2-3 degree coma rather hard to spot from the usual urban or suburban environment (data by Tony Beresford). 
Date           Distance(AU)       R.A.           Dec
11 May 1983    0.0336            10h 28m 49    +60d 31'
11 May 1983    0.0333            10h 21m 32    +59d 07'
11 May 1983    0.0329            10h 14m 40    +57d 41'
11 May 1983    0.0326            10h 08m 10    +56d 11'
11 May 1983    0.0323            10h 02m 01    +54d 38'
11 May 1983    0.0320            09h 56m 12    +53d 03'
11 May 1983    0.0318            09h 50m 41    +51d 25'
11 May 1983    0.0316            09h 45m 28    +49d 44'
11 May 1983    0.0315            09h 40m 32    +48d 02'
11 May 1983    0.0313            09h 35m 52    +46d 17'
11 May 1983    0.0312            09h 31m 28    +44d 31'
11 May 1983    0.0312            09h 27m 18    +42d 44'
11 May 1983    0.0312            09h 23m 23    +40d 56'
11 May 1983    0.0312            09h 19m 41    +39d 07'
11 May 1983    0.0312            09h 16m 12    +37d 18'
11 May 1983    0.0313            09h 12m 56    +35d 29'
11 May 1983    0.0314            09h 09m 50    +33d 40'
11 May 1983    0.0316            09h 06m 55    +31d 53'
11 May 1983    0.0318            09h 04m 09    +30d 06'
11 May 1983    0.0320            09h 01m 33    +28d 21'
11 May 1983    0.0323            08h 59m 03    +26d 37'
11 May 1983    0.0326            08h 56m 41    +24d 55'
11 May 1983    0.0329            08h 54m 25    +23d 15'
11 May 1983    0.0332            08h 52m 15    +21d 37'
Hartmut Frommert [contact]

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