A Partial Nectaris Basin Ring

On a beautiful spring evening with mostly clear, warm skies, I was able to sketch the famous fourth ring of the Nectaris basin, namely, the Altai scarp or Rupes Altai. Sunlight was bouncing off the outermost visible rim of this combination basin ring / fault enhancing its visibility north of impressive crater Piccolomini (88 km.) and beyond for 500 kilometers. Some of the sheer cliffs are 3.5 – 4 km.high and are nicely treated and described in Steve Bounce’s interesting study and profile in Selenology Today #10, June 2008.
What was also eye catching about this view was the fine illumination and shadow on the terraces of crater Piccolomini. The 2 km. tall central peaks of this crater above its smooth floor added to the grandeur of the eyepiece view.

Sketching Information:

Sketched on white paper using graphite pencils (HB, 4B, 6B), blending stumps, white Pearl erasers
10” f/ 5.7 Newtonian riding on an equatorial platform and a 6mm eyepiece for 241x
Date and Time: April 10, 2011, 01:50-02:40 UT
Weather: partly, calm, 65 degrees F (18 degrees C)
Seeing: Antoniadi II-III
Lunation: 6.4 days
Moon 34.8% illuminated

Frank McCabe

6 thoughts on “A Partial Nectaris Basin Ring”

  1. Great incredible work Frank! Wow! You change the technics of drawing?
    Iìm stopped in this moment ,i have exposed my sketch in one Exhibition in Perugia with the support of my friends Astronomy lovers of this town.
    Bravissimo come sempre!
    Ciao Giorgio.

  2. Scott and Giorgio,

    Thank you both for your comments. I don’t sketch the moon in graphite as often as I once did but I was using graphite powder and blending stumps in much of this sketch.
    Giorgio, I’m sure your beautiful sketches are well received.

    Frank 🙂

  3. Frank,

    a realistic view of the moon, 4 well proportioned terrace, it doesn’t matter the technik, you always do great jobs.


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