The Sun Solar System: the Moon Planets observing logs

February 23th, 2004: Lunar observing log

On February the 23rd in the late afternoon (17.29 UT) I shot this picture of Venus and the 3-day-old moon from my backyard. This picture was shot with a handheld Nikon Coolpix 4500 using "auto-mode". Image size 2272x1704, shutter speed 1/2 second, aperture f 5.1 and ISO 246. The flash was switched off. I really enjoyed the view of these two bright objects together. Before observing the Moon with my telescope, I had a look with my 15x80 binoculars. The view with two eyes was stunning. I saw the crescent Moon lit by the Sun, but also the rest of the Moon looking like a greyish globe, caused by earthshine (light reflected by the earth brightening the dark part of the Moon).

Overview of a three-day-old moon

After taking some pics from Venus and the crescent moon I got out my telescope. The Moon was only three days old, but there where a lot of details to observe. (The picture below shows the Moon with the north up and west to the left, the same orientation as in the Rukl). What first strikes me when looking at the 3-day-old moon is the eastern part of Mare Crisium (Rukl 26/27/37/38). The mountains around Mare Crisium are beautifully lit by the Sun. On the smooth floor of Mare Crisium you can see some darker "lines" oriented north-south. They look like "waves". These are Dorsum (Wrinkle Ridges) or Dorsa (Wrinkle Ridge systems). In the southeastern corner of Mare Crisium you can see a sort of "cape" in the "sea", Promontorium Agarum (Rukl 38). Just to the west of this feature you see Dorsa Harker running in north-south direction. In the northeastern corner of Mare Crisium you can see a wrinkled ridge system, Dorsa Tetyaev (Rukl 27). Just near the terminator you can see another "structure" in north-south direction. This is probably Dorsum Termier (Rukl 38).

High up in the north you can see a large elongated feature. This is Mare Humboldtianum (Rukl 7) with a diameter of 160 kilometres. To the southwest of Mare Humboldtianum lies the crater Mercurius (Rukl 15). Between Mercurius and Mare Crisium lie 4 craters more or less lined up. The first one is Messala (Rukl 16) which is almost completely visible. The other three, Germinus, Burckhardt and Cleomedes (Rukl 16/26) lie on the terminator, their western rim lit by the sun. To the east of these craters, near the edge of the Moon you can see a large, elongated crater, called Gauss (Rukl 16). On the edge of the Moon, to the east-southeast of Mare Crisium you can see an elongated darker area. This is Mare Marginis (Rukl 27/38)

Now have a look at the southern part of the crescent Moon. You will notice four "larger" craters lying in north-south direction just to the east of the terminator. The first one is Langrenus (Rukl 49) with it's twin peaked central mountain. Langrenus is about 132 kilometres in diameter, and named after Michiel van Langren, a Flemish Mathematician, member of a globe- and mapmaking family, who drew the first map of the moon with names for the different lunar features and formations on it. To the south of Langrenus lies Vendelinus (Rukl 60). The two craters look very different. Langrenus is a young uneroded crater with an elevated rim. The terraces are easy visible. Vendelinus is an old eroded crater. The walls are low and partially missing. In the northeastern part of the rim you see the crater Lame, which overlaps the rim of Vendelinus. There is no central peak. A bit further south there is another young crater, Petavius (Rukl 59), with huge central mountains. Even at low magnification you can see a very dark feature running across the floor of Petavius, from the central mountain into southwestern direction. This is one of the Rimae Petavius. This is definitely the most spectacular of the four large craters south of Mare Crisium! On the eastern rim of Petavius you can see a long elongated shape form by the crater Palitzsch and the Vallis Palitzsch. The total length is about 151 kilometres. To the south-southeast of Petavius you can see two craters Hase and Hase D. On this image they seem to form the figure 8, with Hase the brighter half and Hase D the darker part. To the southwest of Petavius lies the crater Snellius. Now we go to the southernmost of the four larger craters, Furnerius (Rukl 69). This one looks more like Vendelinus, incomplete walls and no central peak. On this image you can see one small crater, Furnerius B, on the crater floor. At the southern edge of Furnerius you find the Crater Fraunhofer. A little more to the south lie two elongated craters alongside each other, probably Vega and Peirescius (Rukl 68).

This image is stacked out of 10 images made with the Nikon Coolpix 4500, using a TAL 200K f/10 2000mm Klevtzov-Cassegrain. The eyepiece used is a 32mm Televue Plossl. I used just a little optical zoom from the camere. The camera was attached to the eyepiece using a ScopeTronix adaptor. The size of the original pictures was 2272x1704, shutter speed 1/30 second, aperture f 2.6, ISO 100, flash switched off. The pictures where stacked with Keith's Image Stacker. The stacked image was processed (unsharp masking, auto-color, etc.)

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