This week we concentrate on Hyginus crater and associated rilles.
The crater was named after Gaius Julius Hyginus, a latin author and astronomer who lived from 64 BC to 17 AD.
It is located north of Sinus Medii, and south of Mare Vaporum, the Sea of Vapours and is about 5 miles (9km) in diameter. It is a non-impact crater and was probably formed by volcanic action.
Its coordinates are - Longitude: 6.23 Latitude: 7.60
The Hyginus rille (known as Rima Hyginus) is about 130 miles (200km) long with the Hyginus crater roughly halfway along its length. The rille is 2 to 4 miles wide (3-6km) and about 1200 feet deep (365m) and is probably a graben.
There are a number of volcanic vents and collapse craters along the rille, Hyginus crater being the largest vent. These eruption craters developed after the formation of Rima Hyginus so this rille is both tectonic and volcanic in origin.
There is a dark halo around Hyginus crater which can be seen when the sun is directly overhead, which has spectral and radar properties of a pyroclastic deposit, another name for volcanic ash.
The following image is by Wes Higgins
and is linked from the lunar photo of the day
(LPOD) for 13 November 2007. It shows the collapse craters along the rille and Hyginus crater in the middle of the two arms of the rille:
Link to LPOD page (for large image and description): http://www.lpod.org/?m=20071113
A colourful map of the Hyginus area from Mare Vaporum Quadrangle
made by Don Wilhelms
Description can be found here: http://www.lpod.org/?m=20071115
The inside of the Hyginus crater appears to be geologically young as there are some depressed areas on the floor of the crater which have no craterlets inside them.
Some of these depressed areas are shown in the next image which was originally posted as "Pork Chop Hill". http://moonzoo.s3.amazonaws.com/v8/slices/000011796.jpg
If you find any images of the Hyginus crater or surrounding area please post them here:Hyginus Crater formationsReports containing Hyginus information (PDF format):
An interesting report titled "Magmatic Origin for Rima Hyginus": http://www.lpi.usra.edu/meetings/lpsc2010/pdf/1129.pdf
Remote Sensing Studies of the Rima Hyginus Region of the Moon: http://www.lpi.usra.edu/meetings/lpsc1987/pdf/1210.pdf
Geologic characteristics of the nine lunar landing mission sites recommended by the group for lunar exploration planning: http://www.lpi.usra.edu/lunar/site_studies/lunarLandingChar.pdf