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Clavius Suspended Over the Terminator

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#1 frank5817

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Posted 04 April 2009 - 12:59 AM


At about 3:00 universal time April 4, 2009 the large well known crater Clavius (225 km.) was suspended over the terminator in a remarkable way I don’t get to see often enough. I was observing with a 4.25 inch f/5 Newtonian using a 4mm eyepiece 135x. I felt compelled to grab a quick sketch of this remarkable view. After 40 minutes this is what I came up with. The craters on the central floor of Clavius, namely D and C were visible during the entire session and sunlight was spreading across the crater floor around these craters as I worked. For sketching I used 3 graphite pencils (2H, B and 6B) and a sheet of copy paper. The final sketch was adjusted in brightness +2 and contrast +2 after scanning. The sky was clear and cold 3.3°C or 38°F. Seeing was below average Antonialdi IV. The moon at the time of the sketch was 8.4 days old.

Frank :)

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#2 CarlosEH

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Posted 04 April 2009 - 05:50 AM

Frank,

An excellent observation of Clavius on the terminator. This large crater present interesting terrain, especially mixed in with shadow. Thank you for sharing it with us all.

Carlos

#3 vennard

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Posted 04 April 2009 - 08:32 AM

Excellent sketch! On my screen it appears that there is a textured background, is that on purpose or a result of the brightness and contrast adjustments?
MikeV

#4 frank5817

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Posted 04 April 2009 - 09:55 AM

Carlos and Mike,

Thank you both for the kind words. :thanx: Mike, the sketch is small about 3" x 3" and I was not working as carefully as I usually try to do. I had a lot of graphite smudged all over the paper so instead of trying to erase it all, I just blended it into the background. I should have used a 4B instead of a 6B pencil.

Frank :)

#5 Tommy5

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Posted 04 April 2009 - 10:57 AM

Excellant sketch of this large crator in interesting light. The moon was sky high last night, too bad the seeing wasn't better.

#6 markseibold

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Posted 04 April 2009 - 10:58 AM

Frank

Beautiful rendering of Clavius at the terminator! :bow: :bow: :bow: I can really appreciate that you were working with a small format of only 3" X 3".

I too was staring at this region last night in a public courtyard restaurant through a Nexstar 5i with excellent seing conditions at 5:30 UT (10:30 PDT), allowing a couple dozen patrons to view it at 180X through a 9.7mm Plossl. I was kicking myself for not doing at least a rough pre-sketch or at least take a photo of it with my hand held digital camera.

You have inspired me today to at least work from memory and others photos and sketches. I want to work up an imaginary large 20" X 25" format pastel sketch of 'Standing on the moon at Clavius in the Terminator' with an eyepiece rendering in triptych similar to a previous work, before I do a lecture for astronomy students soon.

Thanks for sharing this image and your techniques,

Mark

#7 frank5817

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Posted 04 April 2009 - 12:02 PM

Tommy and Mark,

Thank you both for the kind words.:thanx:
We just need to make the best of these opportunities. It is always so wonderful when everything comes together but those times are rare in my estimation.
--
Mark, as you know Clavius always looks great in any light but catching it with illuminated crater rims and a black floor is very special but it will happen again.

Frank :)

#8 rolandlinda3

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Posted 04 April 2009 - 03:15 PM

Great timing to get the detail of those inner craters. Nice sketch.

Roland

#9 frank5817

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Posted 04 April 2009 - 09:19 PM

Roland,

I would call my timing lucky. When I pointed the scope at the moon I could see Clavius sticking out from the southern terminator. I ran back in the house and grabbed a few pencils, my light, some higher powered eyepieces and clipboard. It looked much better than my sketch. Oh and thanks :thanx:

Frank :)

#10 varmint

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Posted 05 April 2009 - 11:34 PM

Frank,

Nicely done. It almost looks like the crater floor is sloping up in the middle gently.

All that detail on 3x3. Bravo.

I sure admire your spontaneity.

#11 frank5817

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Posted 06 April 2009 - 12:00 AM

Jim,

Thank you. :thanx: Yes the central floor of Clavius does have a little uplift and low central peaks. When I began sketching only the secondary crater rims were illuminated in the middle of the view but by the time I finished the floor of Clavius was beginning to take sunlight.

Frank :)

#12 Tom Machtemes

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Posted 06 April 2009 - 10:22 AM

Frank,

Nice sketch, keep them comming.

:thanx:

Tom

#13 rodelaet

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Posted 06 April 2009 - 04:25 PM

Frank,

Great sketch and excellent timing!!

I like it how you depicted the central floor, it seems to rise from the dark.

#14 frank5817

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Posted 06 April 2009 - 09:36 PM

Tom and Rony,

Thank you both guys for the kind words. :thanx:
I was lucky to catch the crater at this moment time.

Frank :)

#15 emersonv

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Posted 07 April 2009 - 04:50 AM

Just beginning crater sketches, having tired of earthly scenes. I like the contrast you achieve with what must be careful eraser skill for the highlit rims. I also appreciate the difficulty of balancing sketching and other observing equipment simultaneously. It's easier for me to work in daylight, when possible, less wear and tear on the iris. Thanks for the inspiration.

#16 frank5817

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Posted 07 April 2009 - 09:43 AM

Emerson,

Welcome to the Sketching Forum and thank you for the compliment. :thanx: I have a collection of filed and shaped plastic type erasers and sometimes use an eraser shield. Unlike deep sky sketching you can use as much light as you want during a lunar sketch. I used a clip board to hold the paper and kept the drawing small so I could finish before the scene changed too much.

Frank :)

#17 janehoustonjones

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Posted 07 April 2009 - 11:56 AM

Nice sketch - I too was out doing 100 Hours of Astronomy public outreach on Friday night, and this view of Clavius was shared with 200 people in Old Town Pasadena. I couldn't sketch, because there were dozens in line for the 3 hours we were doing the sidewalk astronomy. But it sure was pretty! The straight fault was also easy to show people that night.

Saturday also offered another good sketching opportunity - sunrise on Sinus Iridum, but alas for me, also a public 100 hours event so no sketching but it was a winning view that amazed the public!

#18 frank5817

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Posted 07 April 2009 - 08:53 PM

Jane,

Thank you for the response.:thanx:
That is great work you are doing out there in Pasadena. My hat is off to you for the sidewalk astronomy and sketching.
I remember those sketches you and Dee posted on line. :bow: :cool:
I have a second of the season Open Viewing scheduled at a local community college in about 1.5 weeks. They are always worth the effort and the public's reaction is usually very positive. Clear skies to you.

Frank :)






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