Repsold on the rim

Repsold crater 

A favourable lunar libration put the crater Repsold at a better
perspective than what one usually finds.  And finding it on the
terminator made it an object for a quick sketch despite the obstacles. 
It was only a few days before a June full moon so the moon was quite low
(from 50 degrees north lat.) even when near the meridian.  Turbulence 
and generally poor seeing kept things from looking sharp for more than
brief  instants.  And the mosquitoes were bad enough that at times they
cast long shadows across my sketching paper.   Sketch done using
graphite pencils,  ink and some not entirely successfull applications of
whiteout.   I usually like to take longer with a sketch but the
mosquitoes kept the viewing short.  North is more or less up and east is
to the left.   Viewed through 150mm f/6 Maksutov Newtonian with
binoviewer, 2x barlow and 23mm eyepieces.

Repsold is a rather large crater at approximately 110 kms diameter that
is known for a prominant rille of the same name that runs through it. 
Some of the unusual highpoints in the sunlight of my sketch might be
part of that formation as they are oriented in an agreeable direction.  
But  being unfamiliar with that extreme limb crater,  I cannot say for
certain.  Sketching limb craters present its own unique challenges and I
find myself thinking more of the three-dimensionality of the crater as
you are no just ‘looking down’ onto the third dimension.

Gerry Smerchanski

3 thoughts on “Repsold on the rim”

  1. Gerry,

    Very nice work. I too like sketching features on the limbs for the reasons you stated. This is a crater that is new to me–thanks!

    Michael Rosolina
    Friars Hill, WV USA

  2. It was a new crater for me too, as staring at an almost full moon can be taxing in its own right regardless of the conditions. But a lack of observing of late got me out looking at the moon and this unfamiliar looking crater seemed to be a natural for a sketch. I should add that the sketch was done around 4:00 UT June 29th 2007. I think sketching craters near the limb should be attempted by all observers as it forces one to come to terms with the distortion caused by the oblique observing angle. I found myself taking much longer to do the initial “roughing in” as I kept making objects far too round and then had to erase and slim them up to get the diminsions more accurate. It was a classic example of how sketching became a real diagnostic process in aiding observing.

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