Saturday, June 18, 2011

Saturn at higher resolution

This view of Saturn is at twice the resolution of my previous efforts. The red and IR components came out fairly well but the blue and green images were not sharp.

Comparing this image with the one I posted on June 2 makes clear that seeing is more important than resolution.

Image made on 18 June 2011 at 04:30:23 UT

Thursday, June 16, 2011

Vallis Alpes

Vallis Alpes, the Alpine Valley, exposed 10 June 2011 03:55:56 UT through IR filter.

This valley, depression, is 80 miles in length from Mare Imbrium to the SW to Mare Frigoris to the NE, running through the Montes Alpes. Note also the central crack or rille running essentially the entire length. The valley is constricted to the west to form the "amphitheater".

Erastosthenes at Sunrise

 Erastosthenes, 38 miles in diameter, at the end of the Apennines. Note multiple terraces on interior of western wall. The crater floor lies 8,000' below Mare Imbrium to the north and the western wall towers 16,000' above the floor.

This image was made at 10 June 2011 03:51:41 UT through an IR filter.

Wednesday, June 15, 2011

Apennine mountains

In the Apennine mountains we have several interesting features. These include the crater Conon, Mt. Bradley, Rima Bradley and Rima Hadley. Conon has steep internal walls, is 11 miles in diameter, and has no central peak. Mons Bradley rises about 14,000 feet above the floor of Mare Imbrium. Rima Bradley is a long depression, a graben-type rille, caused by land that has sunk between parallel faults. Rima Hadley (Hadley Rille) was most likely caused by a lava flow or collapsed lava tube. 

Go to NASA site to see video made by Apollo 15 astronauts as they flew to Hadley Rille in 1971.

This image was made June 10, 2011 at 04:22:09 UT through in IR filter.

Tuesday, June 14, 2011


Cassini is about 36 miles in diameter with a narrow, relatively low surrounding rim. Note especially on the rectified view below how the shape of Cassini resembles more a polygon than a circle. The exterior slopes shows show a lot of rubble. Why so much debris on the exterior surface compared to the interior surface. Maybe  some interior rubble later cover up by lava flows?

This view was made 10 June 2011 at 04:25:13 UT through a IR filter.

Monday, June 13, 2011


Last night my nephew and his daughters were visiting my wife and me. He told me about live streaming from the International Space Station ( so watched it for a while then went to Heavens Above ( to see where the ISS was at that time. We saw that it was over Australia and heading towards Southern California, my home. Heavens Above predicted it would be overhead in 13 minutes at a maximum brightness of magnitude -3.5 and 70 degrees high. So we took his daughters outside and all watched it arc majestically high overhead. Later that evening the eldest daughter, 10 years old, sent a text to her mother saying that this was the neatest thing she had done on her trip!

A great success for all.

Saturday, June 11, 2011

Alphonsus and Alpetragius

Alphonsus and Alpetragius, a really interesting pair.

The floor of Alphonsus, of course, has these interesting pits with three zones of surrounding dark material. These are recognized as volcanic pits  with surrounding ash. There are at least two such pits in the west, two in the north east and one in the south east. Are such pits found in  other craters? The N-S ridge running through the center of the crater has been interpreted as debris (ejecta) thrown out by the formation of Mare Imbrium to the north. Such debris may also have caused the streaks through the south east of Alphonsus, through it rim and just outside the crater.

And then there is smaller Alpetragius (close in to the lower left, south west of Alphonsus) with it's outsized central peak. What is the story here?

Image made 10 June 2011 at 04:05:52 UT with 12.5" dob, Basler acA1300 with IR filter and 4X Powermate. I used the best 250 of 1000 images.