The crater Hipparchus can be found near the center of the Moon on the nearside. To its immediate south is the large crater Albategnius and to the southwest is Ptolaemeus. The nearest basin is Sinus Medii (Central Bay) to the northwest which forms the origin of the Moon's coordinate system. The crater is named after the famous Greek astronomer, Hipparchus. Hipparchus was arguably one of the most important astronomers in antiquity and worked throughout the 1st Century BCE. He invented trigonometry, calculated the Earth's precession, invented the astrolabe and compiled one of the first comprehensive star catalogs. Armed with his knowledge, he may have been one of the first astronomers to calculate the recurrence of eclipses.
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| Hipparchus (Image Credit: NASA LRO) |
Hipparchus is a large crater with a diameter of 151km and a depth of 3,300m.
Observation
My abbreviated observation record can be found below:
My abbreviated observation record can be found below:
| Date | 2020-05-29 |
| Time | 23:33 |
| Sky | Clear |
| Telescope | 8" Reflector (1200mm F.L.) |
| Eyepiece | 10mm (2x Barlow) |
| Magnification | 240x |
Comments
The first thing I noticed about Hipparchus was that it was missing a semicircular section of its southwestern rim. Also, just outside of its southeastern rim was four successively smaller craters running from west to east. Hipparchus is noticeably flooded with a very low rim that is partially eroded. The crater contains several other craters within. I would speculate Hipparchus is very old. The ill-formed Hipparchus X was seen just northeast of the missing semicircular rim and was noticeably eroded. Horrocks in the northeast was prominent and found within the walls of Hipparchus.
Location
To help you locate this object a map has been provided from the Royal Astronomical Society of Canada's Observer's Handbook. It is object #55, highlighted below.
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| Hipparchus (Crater) |
Another great view is from the Apollo 16 mission. This is looking northward from Halley (in the foreground) with Sinus Medii in the background at the top left.
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| Hipparchus (Image Credit: NASA Apollo 16) |
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