frank5817
Carpal Tunnel
Reged: 06/13/06
Posts: 2996
Loc: Illinois
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Craters Messier and Messier A
A long while back I had a correspondence with Kraterkid( Rich Handy) in which he was explaining to me that when you are sketching the moon in graphite you are drawing the shadows rather than the visible surface of the moon. Ever since then I began to think about how we sketch the deep sky objects. If you use pencil to capture a star cluster or galaxy at the eyepiece what you do is invert the sketch to show the stars as light against a dark sky background. Has anyone ever tried drawing the moon surface in graphite leaving the dark shadows light then inverting the sketch like we do for deep sky? I hunted around for an answer but could not find anyone inverting a graphite lunar sketch. I am sure someone else has tried this. Anyway I thought I would give it a go. Now for my old brain this was an exercise in mental gymnastics. I’m looking at the moon through the eyepiece and thinking if it is bright I'll make it dark on paper and if dark I'll not sketch it. I had to start over once because I forgot what I was doing and reverted to the usual way of drawing moon shadows in graphite. My targets are familiar ones the craters Messier and Messier A on the floor of Mare Fecunditatis. The first drawing is the graphite sketch and the second one is the inverted sketch.
Sketching:
For this sketch I used: White CPP sketching paper, 9”x 12”, HB graphite pencil, a blending stump, plastic eraser and an eraser shield. After scanning and copying, the image was inverted and decreased in brightness -2.
Telescope: 10 inch f/ 5.7 Dobsonian and 6 mm eyepiece 241x
Date: 8-19-2008 4:30 - 6:10 UT
Temperature: 20° C (68° F)
clear, calm
Seeing: Antoniadi III
Co-longitude: 124.0°
Lunation: 18.0 days
Illumination: 93.0 %
Phase: 329.5°
Observing Location: +41°37' +87° 47'
Frank McCabe 
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CarlosEH
Post Laureate
Reged: 01/19/05
Posts: 3067
Loc: Pembroke Pines, Broward County...
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Frank,
A wonderful observation of this interesting pair of lunar craters over Mare Fecunditatis. This pair of craters with their "comet-like tail" has always attracted me to them as well. Your inversion technique is a very interesting one. Thank you for sharing it with us all.
Links;
http://www.lpi.usra.edu/resources/cla/info/e4/
http://www.lpi.usra.edu/lunar/missions/apollo/apollo_11/images/messier_lg.gif
Carlos
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markseibold
sage
Reged: 01/19/08
Posts: 430
Loc: Portland Oregon
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Frank
Very nice rendering and I find your inversion process intriguing- I may try it soon. After three days of 100 + F degress here in Portland Oregon, we now have constant rain and clouds with only 70 F for a high and quite cool at night.
As soon as it clears, maybe tonight, I might try your technique. I have inverted my other artwork, photography, oil paintng, etc out of curiosity through Photoshop over the years but not with purposful intenensions as with the moon sketched in graphite.
Now you've got me going!  thanks!
Mark
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frank5817
Carpal Tunnel
Reged: 06/13/06
Posts: 2996
Loc: Illinois
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Carlos and Mark,
Thank you both for the kind words.
Mark, If you have charcoal that may actually work better. I find graphite a bit more difficult to blend than charcoal although I am messy with charcoal.
Frank
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Tommy5
Pooh-Bah
Reged: 03/28/04
Posts: 1382
Loc: Chicagoland
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Very nice lunar sketch, i like you way you explained your thought process and inverted the sketch, sketching not only improves your seeing ability but makes you think about how and what you are seeing,great post.
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frank5817
Carpal Tunnel
Reged: 06/13/06
Posts: 2996
Loc: Illinois
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Tommy5,
Thanks for your kind words.
Frank
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rodelaet
Carpal Tunnel
Reged: 04/28/06
Posts: 2625
Loc: 50°56' N - 4°58' E (Belgium)
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Frank,
I like the 'positive' sketch very much! 
For me, it's the best of the two.
The inverted sketch reminds me of a 'science oriented' approach, as some positive subtle floor features appear more prominently on the negative version. 
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Rony
My Astronomy Sketches
My Binocular Sketches
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frank5817
Carpal Tunnel
Reged: 06/13/06
Posts: 2996
Loc: Illinois
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Rony,
Thank you. I actually thought this would be easy. The only thing easy about it was it was easy to make a mistake. Just sketching the moon straight forward would be the easy way but it was a fun exercise.
Frank
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jonbosley
professor emeritus
Reged: 10/19/05
Posts: 540
Loc: Texas
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Great Sketches Frank! It’s surprising how positive and negative image can show new aspects. I just recently did this two some of my lunar CCD pictures & you caught it very well. Thank you for sharing.
Jon
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C11 XLT Celestron
Atlas Goto Mount on Concrete Pier
WO 66 SD Doublet APO Refractor
Philips SNC900NC Webcam
Faymax FC-1000m Webcam with cooling fan
Orion Star Shoot Deep-Space CCD
POD Observatory
www.whitedwarfobservatory.com
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frank5817
Carpal Tunnel
Reged: 06/13/06
Posts: 2996
Loc: Illinois
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Jon,
Thank you. I know I can see distant galaxies better when the colors are inverted in CCD images, why wouldn't some lunar features look different when inverted.
You have an excellent web site. Great images. 
Frank
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mickmrn1
member
Reged: 05/18/08
Posts: 25
Loc: Mesa, Arizona
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Frank,
Very nice sketches of graphite and inverted craters.
Very nice job as usual!
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Michelle D.
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frank5817
Carpal Tunnel
Reged: 06/13/06
Posts: 2996
Loc: Illinois
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Michelle,
Thank you. I hope your monsoon season ends soon so you can get out under the stars.
Frank
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