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Crater Petavius

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#1 frank5817

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Posted 29 May 2009 - 12:53 AM

I have waited more than 2 years for conditions to be just right for re-sketching this magnificent crater. I got set up to observe under what looked to be hopeless circumstances. Although we have been under heavy cloud cover all week, the weather service forecasted clearing and as an added bonus my nearest “Clear Sky Chart” predicted the best possible seeing conditions until midnight. Both of these came true! Alas, heaven on earth.
Petavius crater (180 km.) is one of the best known and remarkable impact features on the lunar surface. It is a walled plain and floor fractured crater with impressive multiple central peaks (1.7 km), beautiful wall terraces, mare patches, volcanic ash regions, a raised floor and remarkable looking ramparts. In addition there is a special feature of this crater called Rimae Petavius. All three parts of this rille system could be seen clearly under the excellent seeing conditions that persisted during the entire observation. Connected to Petavius to the west is crater Wrottesley (57 km). South of Wrottesley the double rim of crater Petavius can be seen. There was so much detail visible in this area I could not hope to capture but a fraction of it.
Although Petavius is 3.8 billion years old it looks younger, stately and better preserved.

Sketching:

For this sketch I used: black Strathmore 400 Artagain paper, (10" x 12") white and black Conte’
pastel pencils and a hard blending stump.
Telescope: 10 inch f/ 5.7 Dobsonian with 6mm (241x) and 4 mm (362x) eyepieces
Date: 5-29-2009 1:20-3:15 UT
Temperature: 13°C (55°F)
Clear, calm
Seeing: Antoniadi mostly I, [ the collapsed lava tube down the center of Vallis Alps would have been easy under the seeing conditions of this night ]
Colongitude 329.5 degrees
Lunation 4.5 days
Illumination 28%
Moon was at Perigee just 3 days ago
Oak Forest, Illinois

Frank McCabe :)

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#2 Uwe Pilz

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Posted 29 May 2009 - 04:37 AM

Great sketch of Petavius! Especially I like your way to sketch the terraced walls.

#3 CarlosEH

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Posted 29 May 2009 - 06:41 AM

Frank,

A fantastic observation of Petavius showing impressive detail. You have captured the central mountains, Rimae Petavius, and the steeped walls very nicely. This is also one of my favorite lunar features to observe. Thank you for sharing it with us all.

Carlos

#4 Tom Machtemes

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Posted 29 May 2009 - 09:20 AM

Frank,

That"s a very nice sketch.

:thanx:

Tom

#5 cildarith

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Posted 29 May 2009 - 10:07 AM

Wow! Another spectacular rendition, Frank! :bow:

#6 frank5817

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Posted 29 May 2009 - 12:18 PM

Uwe, Carlos, Tom and Eric

Thank you guys. The conditions for sketching were the best I have ever experienced. I dulled 10 very sharp white pastel pencils during this sketch.

Frank :)

#7 markseibold

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Posted 29 May 2009 - 06:15 PM

Frank

Beautiful rendering of the crater Petavius. :bow: :bow: :bow: I'm glad to hear the weather finally worked for you.

Yes, I appreciate the dulling of your white pastel pencils; again the pains that artists must suffer so that others can glean from. :question: :tonofbricks:

We had beautifully warm weather here in Portland last night. About 60 F at midnight. I wished I'd gone out to observe and sketch now, after seing your sketch; perhaps tonight again.

Mark

#8 kraterkid

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Posted 29 May 2009 - 06:22 PM

Frank, OMG you nailed it buddy! :bow: :rainbow: :bow: The beautiful almost intertwined or woven look of the ancient glacis is rendered with remarkable clarity and accuracy. Remarkable job capturing the rilles! Magnificent sketch! :waytogo:

#9 frank5817

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Posted 29 May 2009 - 08:32 PM

Mark and Rich,

Thank you both very much. I have been waiting about a week for the clouds to leave and the moon to appear in the West. I was toying with the idea of taking a new tact to starting a sketch. I tried this once before and gave up prematurely. Instead of applying Conte' crayon to the sketch area first and blending it. I decided to do the entire sketch with sharpened Conte' pencils. Instead of applying pressure I used the weight of pencils of different length to apply the features. To create a brighter feature I just used a longer (heavier) pencil, a not so bright feature a shorter (lighter) pencil. The direction of the pencil helps create the feature. A basket weave motion created the terraced walls in the sketch. I did do some blending and used some pressure to speed thing along but I think I could do an entire sketch this way. It seems to work well on 400 Artagain paper.
Is this obvious and I am just slow to catch on? It was an Aha moment for me. Thanks again guys.

Frank :)

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#10 Tommy5

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Posted 29 May 2009 - 11:04 PM

Great sketch of this interesting lunar feature,glad to see you are still trying out different ways to sketch.

#11 Special Ed

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Posted 30 May 2009 - 06:27 AM

Frank,

That's an incredible sketch--the best I've seen of Petavius since Carlos posted his. :bow:

#12 JimPie

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Posted 30 May 2009 - 11:52 AM

Another incredible luner sketch Frank. :waytogo: :bow:

#13 Sol

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Posted 30 May 2009 - 05:50 PM

Thats an amazing and well observed sketch Frank, thanks for adding the sketch technique info. too, very useful to see other methods for shading features.

Mark

#14 frank5817

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Posted 30 May 2009 - 06:32 PM

Tommy5, Michael, Jim and Sol,

Thank you all for your kind words. I will not soon forget what a perfect observing night it was.

Frank :)

#15 rolandlinda3

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Posted 30 May 2009 - 10:49 PM

Great sketch. As soon as I saw your title I went to the thread. It is such a wonderful lunar target and your work on it is really good. Care to post your first sketch beside this one? I really enjoy seeing two sketches at different times to see how they compare and what I may have emphasized on one or the other. Would love to see yours side by side. Roland

#16 frank5817

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Posted 31 May 2009 - 09:42 AM

Roland and Linda,

Thank you. :thanx: Just for you folks. The sketch attached at the bottom is from the third week of March 2007. The lighting was similar on both days. Both are sunrise sketches.

Frank :)

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#17 Tom Machtemes

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Posted 01 June 2009 - 01:39 PM

Frank,

The both sketches look different to me, I think the top sketch looks, better.

:thanx:

Tom

#18 frank5817

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Posted 01 June 2009 - 05:12 PM

Tom,

Thank you. :thanx:
Yes there are differences. The lunar librations and shadows were different and the top sketch was made under much better seeing conditions. I also didn't rotate them to match orientations. So here you can compare them a little better below.

Frank :)

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#19 rolandlinda3

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Posted 01 June 2009 - 08:08 PM

Excellent. thanks for the trouble of posting both. I find it fascinating to see the subtle differences due to moon position, time, weather, etc. Great work. Would make a real nice side by side frame or example for people you teach to sketch...a challenge to see differences in a target that is affected by various things. thanks

Roland

#20 frank5817

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Posted 02 June 2009 - 09:22 AM

Roland,

Thanks again and for the suggestion to post them together.

Frank :)

#21 Dee

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Posted 02 June 2009 - 06:34 PM

SO totally FRANK with all the trimmings :-)
Brill

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#22 frank5817

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Posted 02 June 2009 - 10:13 PM

Dee,

Thank you much. :thanx:
May the sun shine all day and the moon and stars glow all your nights.

Frank :)






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