Mare Frigoris Page 2 Home

Move your mouse over the picture to see the names of the various features.
For a wider-angle picture of the whole of the mare and a discussion of its possible origin, see Page 1, and for larger-scale mosaics see Page 3.

This is a composite of two images of this area taken when the libration was about as unfavourable as it gets.  Mare Frigoris (Cold Sea) is the northernmost mare on the Moon and is bordered to the south by the Jura Mountains, the Alps, and the Caucasus to the east.  To the north is a rugged area with many large, ancient craters such as W C Bond, Birmingham, and Meton, which date back some 4,000 million years.  Anaxagoras, on the other hand, is very young at less than 1,000 million years.  The difficulty observing this area means that although the sizes of these craters are known (Meton for example is 125 Km in diameter), their depths are largely unknown.  South of the Mare Frigoris lies Plato, 105 Km in diameter but probably only about 1000 metres deep, its floor having been flooded with lava relatively recently.  To the east is the Alpine Valley, a feature 150 Km long and about 8 Km wide.  Down its centre, not resolved in this picture, runs a narrow rille about 700 metres wide.  South of Plato is the northern part of Mare Imbrium with the Teneriffe Mountains and the isolated Mount Pico.  Pico is interesting.  There are craters named Pico A , Pico B etc., but there is no crater Pico––Pico is a mountain, just south of which is a nice little linear mountain with the rather boring name of β.
It is impossible to show realistic scale markers for a picture so near the pole.  The markers are very approximately 100 km long north and east and apply to the region of Plato.  The effect of perspective is clear from the different lengths of these two markers (Plato is circular) and the effect gets dramatically greater as one goes north (Anaxagoras is also circular).  I have marked where I think the North pole is, but it must also be remembered that the lines of longitude will be curved.

The picture was taken with a ToUcam attached to my LX200 on 19th March 2005, when the Moon was 9.1 days old.
Date and Time 19th March 2005 19:40 UT
Camera ToUcam 740K
Telescope LX200 at prime focus
Capture K3CCDTools. High gamma, 1/100", 9% gain, 308 frames
Processing Registax. 74 frames stacked. Wavelet 1-2 = 10



Plato This is a slightly wider-angle picture of the southern part of the picture above.  However the libration was very different.  In the picture above, the libration was -6° 24' in latitude and +0° 53' in longitude, whereas here it is +2° 59' in latitude and -1 51' in longitude.  So relative to the picture above, the Moon is tipped 9° south and 2° west.
The scale markers correspond approximately to 100 Km north and east and apply at Plato.
The picture was taken with a ToUcam attached to my ETX125 on 15th July 2005, when the Moon was 8.5 days old.
Date and Time 15th July 2005 18:30 UT
Camera ToUcam 740K
Telescope ETX125 at prime focus
Capture K3CCDTools. Low gamma, 1/25", 15% gain, 498 frames, infra-red light
Processing Registax. 296 frames stacked. Wavelet 1-3 = 10, contrast 180, brightness -76
Plato This is a slightly narrower-angle picture of the same general area as the picture above.  The libration was fairly neutral, at 0° 57' in latitude and -1° 51' in longitude.
The scale markers correspond approximately to 100 Km north and east and apply at Plato.
The picture was taken with a ToUcam attached to my LX200 on 5th June 2006, when the Moon was 9.0 days old.
Date and Time 5th June 2006 17:51 UT
Camera ToUcam 740K
Telescope LX200 at prime focus with IR-pass filter
Capture K3CCDTools. Low gamma, 1/25", 22% gain, 609 frames, infra-red light
Processing Registax. 122 frames stacked. Wavelet 1 = 10
Plato This is western end of the Mare where it joins Sinus Roris which is a part of Oceanus Procellarum.  It was taken on day 22.7 so the lighting extends to the limb and the crater Pythagoras shows nicely despite an unfavourable libration.

The picture was taken with a ToUcam attached to my LX200 on 18th July 2006, when the Moon was 22.7 days old.
Date and Time 18th July 2006 08:22 UT
Camera ToUcam 740K
Telescope LX200 at prime focus with IR-pass filter
Capture K3CCDTools. Low gamma, 1/33", 22% gain, 481 frames, infra-red light
Processing Registax. 44 frames stacked. Wavelets 1 = 10, 2 = 5, gamma 0.7

This is eastern end of the Mare.  It was taken on day 6.6 so the area is close to the terminator with the light coming from the right.  The scale markers are approximately 100 Km north and west and apply at Hercules, but the picture is not as tipped over as it may appear from the direction of the north arrow.  The camera was a little bit mis-aligned but this is in the far north-east quadrant of the Moon and the north pole is not very far out of the top-left corner of the picture, so the north arrow would have pointed very much to the left even if I had aligned my camera correctly.

The picture was taken with an Atik 1-HS attached to my LX200 on 9th June 2008, when the Moon was 6.6 days old.
Date and Time 9th June 2008 21:01 UT
Camera Atik 1-HS
Telescope LX200 at prime focus with IR-pass filter
Capture K3CCDTools. Low gamma, 1/250", 53% gain, 628 frames, infra-red light
Processing Registax. 342 frames stacked. Histogram 0-175, wavelets 1,2 = 10./td> 
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