Another Thursday Night Mars: February 18, 2010

Posted 20 February 2010 - 02:07 AM

Conditions were much improved over those of last Thursday for observing and sketching the planet Mars. The air column above me was mostly steady with temperatures just a degree above freezing.
Mars is now growing smaller in the eyepiece at 13.0" of arc and 0.72 A.U. from us. 98% of the disk is illuminated and shining at visual magnitude -0.9. The central meridian of Mars was centered around 269° at the time of the sketch.
The north polar cap is clearly diminishing in size and visual brightness. In addition to the major features such as: Syrtis Major, Hellas, Mare Australe, Utopia/Casius, Mare Cimmerium and Mare Tyrrhenum; I was able to see clouds over the Elysium volcanic field and the albedo feature Nodus Alcyonis also appeared during moments of very steady seeing.
Before beginning this sketch I spent 30 minutes looking at Mars through red, green and light blue filters to assist with locating low contrast features.


Sketching:
The eyepiece sketch is the one on top in graphite pencil. The second color sketch was made indoors.
White sketching paper 8" x 11"; HB graphite pencil, blending stumps for blending orange, brown and yellow Crayola pencil shavings.
Date 2/19/2010 – Time 3:00-3:35 UT
Telescope: 13.1 inch f/5.9 Dobsonian and 9mm eyepiece 218x
Temperature: 1°C (34°F)
clear, calm
Transparency 4/5
Seeing: Antoniadi III

Frank McCabe

Attached Thumbnails

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Posted 20 February 2010 - 04:13 AM

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Posted 20 February 2010 - 04:41 AM

I like, when I can compare bw with color one, nice

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Posted 20 February 2010 - 11:33 AM

Jef and S1mas,

Thanks for your comments.
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Jef - I agree using filters while sketching would certainly alter the colors visible but I actually used filters before I sketched. The black and white sketch was done at the eyepiece but I was not using any filters when I made the sketch. When I made the color drawing I was indoors and not at the eyepiece.

Frank

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Posted 20 February 2010 - 11:37 AM

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Posted 20 February 2010 - 12:31 PM

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Posted 20 February 2010 - 12:36 PM

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Posted 20 February 2010 - 01:14 PM

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Posted 20 February 2010 - 05:01 PM

Frank

Very nice sketches and your concise detailed report is excellent as always

I was at one of the largest astronomy stores on the west coast last night- Sean's Astronomy Shop in Battleground Washington. They have much in reduced price now as I am sorry to see they are going out of business soon. (A Daystar state of the art h-alpha .4 angstrom solar filter, originally $8,000 for $5,600, w/adjustable bi-fringe range and will adapt to any focal range telescope.)

I coaxed them to set up a 6 inch f/8 Galileo refractor(they are letting go for $600 with Celestron German Eq motorized tripod!? A Meade 12" Cass like new for only $3,000!?) as I wanted to see Mars; maybe do a sketch as I took my art materials but seeing conditions were not good.

Mark

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Posted 21 February 2010 - 01:51 AM

dweller, Uwe, mathteacher, Tommy5 and Mark,

Thank you all for your comments.
We still have some time left to get in those observations as we slide on past Mars.

Frank

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Posted 21 February 2010 - 12:43 PM

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Posted 21 February 2010 - 03:47 PM

Jay,

Thanks. I must agree with you about the b/w sketching for me. I feel I am twice removed for the eyepiece when I'm indoors trying to re-draw the sketch in color. It is also difficult to hold the colors in mind to be able to put them to paper. I additionally end up with too much contrast.
Those that sketch electronically on portable tablets have many advantages when sketching in color at the eyepiece.
Mars will be too far away before I have the speed and courage to try color sketching at the eyepiece.
Thanks again.

Frank

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Posted 22 February 2010 - 03:12 PM

Frank,

, very nice sketches .

,

Tom

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Posted 22 February 2010 - 07:21 PM

Tom,

Thank you, we are once again shut off from the sky by clouds. You must be ready to see winter go away too.

Frank

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Posted 23 February 2010 - 03:39 AM

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Posted 23 February 2010 - 04:17 AM

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Posted 23 February 2010 - 12:06 PM

Mark and Carlos,

Thank you both.
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Mark- I'll need to go shopping for color pastel chalk, I currently don't have any. I would need to practice for a while too. Thanks for the suggestions.

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Carlos, Thank you for labeling my sketch so well. You are making me look good.

Frank

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Posted 04 March 2010 - 10:18 AM

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