L44: Mersenius

Mersenius is located west of Mare Humorum not far from the moon’s western limb. It is of average size but still rich in detail. The crater walls are broad and terraced; the floor has been flooded with lava and bulges markedly upwards in the middle.

My observation was done under excellent conditions with steady, transparent skies and favorable illumination. The terraces were prominent, especially on the western side (right i sketch). The convex shape of the floor was indicated by a soft shadow tracing the walls in the northern half of the crater. Two lighter rays were also clearly visible on the floor. (After checking up on the observation it seems that the northern and thinner ray, is a rille rather than a ray.) Several secondary craters were also seen, most notably Mersenius H on the southern part of the rim, and Mersenius L adjacent to the crater on the northern side.

xxx
Sketch made on 25 September 2015, UT 21:00, using a SkyWatcher 10″ and a TeleVue Nagler zoom 3-6 mm. Seeing 4-5/5. South is up.
Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s