Special Ed
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Early Mars Sketch
#3317395 - 09/05/09 06:06 PM
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Hi Folks,
I have posted a sketch and observation report in the SSO forum that can be seen here:
Mars Observation Sept. 5th
It was a challenge--Mars is still pretty small--but I wanted to scrape some of the rust off of my Martian observational and sketching skills. I used erasable color pencils and 2B and 6B graphite pencils. The templates are 2 inch (50mm) circles on Strathmore recycled sketch paper. I might try smoother paper next time. I reversed the drawing digitally to have preceding to the left.
Clear Skies!
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rolandlinda3
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Re: Early Mars Sketch
[Re: Special Ed]
#3317663 - 09/05/09 09:28 PM
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Nice Michael. It is not an easy target to sketch right now. You done good!!
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frank5817
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Re: Early Mars Sketch
[Re: rolandlinda3]
#3317709 - 09/05/09 10:09 PM
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Michael,
Great report and sketch. You do very well teasing out fine details on a target that looks very monotone to me this early in the Mars approach. Always enjoy your skillful treatment of your targets.  
The less time you have the clearer will be the sky.
Frank 
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Sol Robbins
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Reged: 12/01/03
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Re: Early Mars Sketch
[Re: frank5817]
#3317868 - 09/06/09 12:13 AM
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Great sketch Micheal. I echo what the others say.
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kraterkid
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Reged: 03/07/05
Loc: Jacumba, California
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Re: Early Mars Sketch
[Re: Sol Robbins]
#3317909 - 09/06/09 01:01 AM
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Great sketch and observation report of this wonderful mini Mars! 
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Jef De Wit
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Loc: Hove, Belgium
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Re: Early Mars Sketch
[Re: kraterkid]
#3318721 - 09/06/09 03:33 PM
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Michael
What exactly is the limb arc/brightening/haze?
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Special Ed
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Loc: Greenbrier Co., WV 38N, 80W
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Re: Early Mars Sketch
[Re: Jef De Wit]
#3319863 - 09/07/09 09:18 AM Attachment (50 downloads)
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Thanks, everyone--much appreciated.
@ Sol--if you are still looking for a source of planet ephemeris, here is the url for Jeff Beish's WIMP program (it's designed for Windows):
http://www.dustymars.net/Wimp.zip
Quote:
Michael
What exactly is the limb arc/brightening/haze?
Jef, it is the water ice, CO2, and dust in the Martian atmosphere catching the sunlight on the following (morning) limb as it rotates into view. I believe it condenses in the cold Martian night and then gradually dissipates as it approaches the central meridian (Martian noon).
As Mars rotates into night and the surface cools, a limb haze can often be seen on the preceding (evening) limb, too but this is harder to see right now because the surface moves into the terminator before we see the edge of the limb.
The limb arc is usually visible without filters, but the use of a W80A (blue) filter brightens atmospheric clouds and can sometimes help detect them extending out onto the Martian disk. It also can help detect orographic clouds associated with the summits of the Tharsis volcanoes.
Watching the Martian weather is one of the best things about observing the Red Planet. Below is an example of some of the atmospheric phenomena I've described. This sketch was posted on the CMO website which is an excellent resource.
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Jef De Wit
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Re: Early Mars Sketch
[Re: Special Ed]
#3320544 - 09/07/09 03:37 PM
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Michael, thanks a lot for the explenation. I never observed Mars with my big telescope. In my 7cm refractor last year it was a simple red dot without any detail  . But I will pay attention to the haze next time I visite the planet.
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Tommy5
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Re: Early Mars Sketch
[Re: Jef De Wit]
#3320887 - 09/07/09 06:57 PM
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Great sketch of the tiny mars, good idea to catch mars early in the morning when the seeing is very steady,as winter comes good observing nights will get rarer.
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Special Ed
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Reged: 05/18/03
Loc: Greenbrier Co., WV 38N, 80W
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Re: Early Mars Sketch
[Re: Jef De Wit]
#3320893 - 09/07/09 07:01 PM
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Jef, glad to be of help. Try your big Dob on Mars when you get a chance. If the scope is well collimated and the seeing good, you should be able to put enough magnification on Mars to see the main albedo features facing us at the time, the hood covering the North Pole, and the limb arc. Don't expect too much until Mars gets a little bigger, but practice never hurts.
T5, thanks. You're right--we'll be missing these steady (and warm) nights later on, won't we? 
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Kris.
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Re: Early Mars Sketch
[Re: Special Ed]
#3321883 - 09/08/09 11:11 AM
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i seem to actually have got my best views (steadiest seeing) during cold nights/mornings with freezing temperatures...
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Special Ed
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Reged: 05/18/03
Loc: Greenbrier Co., WV 38N, 80W
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Re: Early Mars Sketch
[Re: Kris.]
#3323555 - 09/09/09 06:24 AM
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Quote:
i seem to actually have got my best views (steadiest seeing) during cold nights/mornings with freezing temperatures...
Predicting seeing is tough--you really never know unless you go out and look.
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CarlosEH
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Re: Early Mars Sketch
[Re: Kris.]
#3323587 - 09/09/09 07:05 AM Attachment (50 downloads)
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Michael,
I remember your excellent Mars observation from 2005. Thank you for sharing it with us all once again.
As Michael explains very clearly, the limb brightening (hazes) are a result of scattered light in the Martian atmosphere from dust particles, carbon dioxide (CO2) crystals, and cirrus water-ice clouds viewed at an oblique angle from the Earth. These limb hazes are more easily noted using a Blue (Wratten 38A), Violet (W47), and Blue-Green (W64) filters.
Links;
http://www.dustymars.net/Observing_Mars_5.html (Excellent article on the subject by Jeff Beish)
http://imgsrc.hubblesite.org/hu/db/images/hs-2001-24-a-full_jpg.jpg (HST image of Mars obtained on June 26, 2001 showing limb clouds (hazes))
I have attached an observation of Mars that I made on November 25, 2005 showing limb brightening, especially over the preceding (evening) limb.
Carlos
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Special Ed
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Loc: Greenbrier Co., WV 38N, 80W
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Re: Early Mars Sketch
[Re: CarlosEH]
#3324970 - 09/09/09 09:29 PM
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Carlos,
Thanks for the kind words and also thanks for expanding on my description of Martian atmospheric phenomena. The links are instructive and your drawings are excellent examples of what Martian weather looks like.
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