Rheita Valley, Messier and Pickering

[Fraunhoffer]

2020-02-11
Playing hide and seek with the clouds this evening. I started to look at the two lonely craters Messier and WH Pickering where the impact debris from Messier washed either side of the older WH Pickering crater.
A band of clouds came over so I went inside for a cuppa, expecting to clear up afterwards. Fell asleep in the chair and woke up an hour later to a lovely clearing sky.
Struck by the strangeness of the Rheita Valley I reached for the sketch pad and started again. So much detail, I was wondering if I had bitten off a bit too much and this took me much longer than expected.
After seeing the Venus crescent and Mercury as a dot in the early evening after sunset, it all turned out quite nice after all.

 

 

[paulastro]

Personally, I think anyone who attempts to draw the Moon is really brave.  A good quality telescope, certainly of 80mm or more,  will show so much really fine detail it really is impossible to record it all.  Even if this was attempted by the best draftsman, it would be daylight before they were finished!  In reality, observers have to be selective what to include:  experience and deciding what are the important features to show will be paramount.  Of course, not taking on too much of an area is helpful, and you many only include part of a feature if it shows what is necessary.  I think what you have produced is very good, look forward to seeing more.

[Mike JW]

Paul - wise words. All too often I get bogged down in detail.

Fraunhoffer - Rheita Valley - tricky to sketch this area as the valley does not readily stand out. Yet careful scrutiny reveals subtle features. I have only attempted the sketch once. Good to see your interpretation.

Messier craters - nice and easy. Your naming has me confused. I thought the pair are now called Messier and Messier A. Pickering crater is elsewhere on the lunar surface. I think I remember reading that originally the Messier Pair were Messier and Pickering but somewhere along the route they got renamed and Pickering was used to name some other crater. Must track the info down.

[Fraunhoffer]

1 hour ago, Mike JW said:

Paul - wise words. All too often I get bogged down in detail.

Fraunhoffer - Rheita Valley - tricky to sketch this area as the valley does not readily stand out. Yet careful scrutiny reveals subtle features. I have only attempted the sketch once. Good to see your interpretation.

Messier craters - nice and easy. Your naming has me confused. I thought the pair are now called Messier and Messier A. Pickering crater is elsewhere on the lunar surface. I think I remember reading that originally the Messier Pair were Messier and Pickering but somewhere along the route they got renamed and Pickering was used to name some other crater. Must track the info down.

Yes, you are right. I was looking at my 1960's edition of A Field Guide to the Stars and Planets moon maps.
My more recent Turn Left at Orion shows Messier  and Messier A. 
Wonder why it was renamed.

[Mike JW]

Hi, I have just found my Messier sketch and thought I would add it for comparison and also the notes I made to go with it and extra info about the change of name.

Messier and Messier A are low angled impact craters as shown by oblong shape. It is likely that they struck at the same time. “A” is a double crater, the smaller one is older and thus mostly obliterated by the impact. The rays stretch for about 120km. Some folk have suggested it was one asteroid that did a rebound but the generally agreed suggestion is that a grazing impact of 1 to 5 degrees coming from the east excavated Messier and another part of the projectile ricocheted downrange to form Messier A and its rays. The craters are about 6 Km apart.

Messier A was originally named Pickering, after the astronomer William H. Pickering. The name was changed to Messier A  by the International Astronomical Union in 1964. They considered that Pickering's rather odd ideas about lunar plant life, in particular in the crater Eratosthenes, ruled him out to have a crater named after him. The crater Pickering near Hipparchus is actually named after William Pickering's older brother Edward Pickering. 

 

I must re-visit this pair.

Mike

 

 

[des anderson]

What sketches, all very good and something I would never achieve. So well done. Des