| 21. | Perihelion presently occurs around January 3, while aphelion is around July 4.
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| 22. | Four days after perihelion, the Sun's normal apparent motion resumes.
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| 23. | Perihelion Software produced an operating system for the INMOS processor or another one.
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| 24. | Its previous perihelion passage occurred on December 23, 2004 at 9h00 UT.
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| 25. | Its next perihelion will be on 18 July 2018.
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| 26. | Around perihelion on 12 January, it was visible worldwide in broad daylight.
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| 27. | Mars passed an aphelion in March 2010 and its perihelion in March 2011.
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| 28. | CN ( cyanide ) was not detected until the comet was near perihelion.
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| 29. | The preliminary orbit shows the next perihelion passage to be around January 2024.
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| 30. | During the 2004 perihelion passage the comet brightened to about apparent magnitude 11.
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