Grimaldi and Riccioli Home

The most interesting aspect of this picture is historical.  The craters Grimaldi and Riccioli were named after two 17th-century, Jesuit priests who were responsible for many of the names that we give to features on the Moon today, and for the scheme of this nomenclature.  They named these two large, but battered craters after themselves.  Grimaldi is the larger at 230 Km in diameter and is covered in lava making it more like a mare than a crater.  Riccioli is 150 Km in diameter and largely filled with debris coming from the formation of the Orientale basin, an event dated at 3,840 million years ago.  So Riccioli has to be older than this.  The northern part of Riccioli and all of Grimaldi have been inundated with lava (hence the darker colour).  Riccioli's lava has been dated by counting craters as 3,480 million years with the lava in Grimaldi a little younger at 2,500 to 3,250 million years.

Move your mouse over the picture to see the names of the various features.

Grimaldi I am somewhat doubtful if I have imaged the D'Alembert Mountains;  the picture was taken a day before full Moon and the western edge is the terminator not the limb.  However the libration was favourable, so some of the highlights may be the mountains.
The scale markers are approximately 100 Km north and east and apply at Grimaldi.
The picture was taken with a ToUcam attached to my LX200 on 24th March 2005 at 21:28 UT when the Moon was 13.9 days old.

Date and Time: 24th March 2005 21:28 UT
Camera: ToUcam 740K
Telescope: LX200 at prime focus (FL 2500 mm) with IR-pass filter
Capture: K3CCDTools. High gamma, 1/100", 0% gain, 548 frames
Processing: Registax. 94 frames stacked. Wavelets 1-3 = 10, Histogram 20-200
Grimaldi And here we have the same area imaged at Day 26.3 so that the light is coming from the opposite direction.  This, together with the low gamma that I used on the camera, gives a very different view.  Indeed Riccioli has almost disappeared.  The libration is somewhat less favourable here too.
The scale markers are approximately 100 Km north and east and apply at Grimaldi.
The picture was taken with a ToUcam attached to my LX200 on 31st August 2005 at 04:20 UT when the Moon was 26.3 days old.
Use the Back button on your browser to return to the darker image.

Date and Time: 31st March 2005 04:20 UT
Camera: ToUcam 740K
Telescope: LX200 at prime focus (FL 2500 mm) with IR-pass filter
Capture: K3CCDTools. Low gamma, 1/25", 36% gain, 399 frames
Processing: Registax. 74 frames stacked. Wavelets 1-3 = 10, gamma 0.7, contrast 115
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