Thursday, March 21, 2013


Mare Imbrium 
Just another night, a little bit of haze, a little bit of high clouds and gibbous Moon. So no temptation for deep sky astrophotography, but just a few moments in the backyard for Moon gazing. Well, in fact Moon film making, because imaging of Moon and planets is not just taking pictures. Actually we make a short movie (like 300-3000 frames) and then use dedicated software (like Registax) to select best frames and stack them into one, detailed picture. We do it, because atmosphere turbulences making different parts of image blurred (it is called seeing). But if we take many single pictures, there is a chance of having different regions with high quality in the different frames. Then software start to work - it aligns frames, selects best regions and stacks it into one single picture. 
This is also the way these pictures were recorded. Although my setup is not quite suitable for planetary (high resolution) imaging, I do it from time to time. I use my QHY5 guiding camera, put it into main scope with barlow lens and effective focal length of this system is about 2400mm. I also use infrared filter that passes only infrared light, so this spectrum range is less affected by seeing conditions (Astronomik IR 742). All pictures in this blog entry has scale 1px ~ 750 metres (enlarged).

Rupes Recta in the center
Here are the results of this short session (terminated by solid cloud cover) - you can click every picture to enlarge. The first image is centered around famous Rupes Recta (Straight Wall) that is about 300m high and over 100km long. At the bottom starting from the right are craters: Alphonsus, Alpetragius, Arzachel, Purbach  and many, many others (I recommend current anniversary edition of Virtual Moon Atlas for this kind of studies)

Next image presents Plato crater (101km diameter) filled with lava, so it has relatively flat bottom. You can see crater walls shadow at its bottom. Under Plato there are Montes Alpes  up to 2400m high and famous Vallis Alpes across the mountains. Right part of the photo is covered with Mare Imbrium. At the bottom Cassini and Aristillus craters, and separated Mons Piton above them.

At the top center part of this photo we can see Tycho crater (86km diameter, 4800m depth) coming out from the shadows. 1500m high central mountain in this crater is not yet visible. Many other craters around - you can see different crater generations - younger craters are placed over the older ones. 

 Montes Apenninus (up to 5400m high). To the right Archimedes crater (86km diameter). 

Another Montes Apenninus  picture with Eratosthenes crater at the top left (60km diameter, 3570m height). You can see two of its summits going out of the shadows. 

Clear skies!

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