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Mars 14th december - HELP NEEDED!

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#1 Jef De Wit

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Posted 14 December 2009 - 04:23 AM

Hi Mars-sketchers

I got finaly early out of bed for my first observation of Mars with a 12" dobson. The seeing was excellent: I could magnify to x600 (althoug I didn't see more than with x300).

The big problem was: Mars is too bright to see much detail. Because the only filter I have is a Lumicon UHC, I tried to stop down the aperture with a kitchen towel. :smash: It was a little better...
Then I tried the UHC and that gave the best result. I know he's not made for observering Mars :shrug:

So I think I will by me some filters for Christmas. Is a standard filter-set a good buy for allround planetary use? Or do you suggest other filters?

Is there software for Mars? Something like Virtual Moon Atlas could be interesting to control your observation with reality.

What I certainly saw:
north polar cap, black region south of polar cap (wider from "left" to "right"), a lot of limb haze

What I think I saw:
a small black region at the south, a lighter region at the "left"

Although I'm not quit satisfied with the sketch, here he is. All comments are welcome. I have still a lot to learn.

14/12/2009, 3.30-4.50 UT, 12" dobson @ x300, UHC-filter

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#2 dweller25


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Posted 14 December 2009 - 04:55 AM


Sky and telescope have Mars profiler software.

Also Winjupos is a good free download.

A variable polarising filter may be worth condsidering - you can vary the amount of light transmitted to the eye.

Hope that helps.

#3 Kris.


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Posted 14 December 2009 - 05:50 AM

good sketch Jef,

personnally i'm not bothered with Mars's brightness, certainly not at 300x or above, but you may have to get used to it...

a variable polarising filter works well to cut the glare as dweller says, but you can also use an orange/red filter to bring out more surface details, a green one for ice caps and blue for clouds. a lot of people swear by a magenta filter, but they're tough to find i thought? anyway 12" aperture is more then enough to use these filters.

with this link you can check your observations. choose 4:30 on the right and it shows the side you were faced with tonight. too bad we're probably gonna have some good clear nights this week, but with the blank side facing us. seems to happen a lot more often than when syrtis major is facing us :grin:

instead of using a kitchen towel, i would use filters, or perhaps make your own apodizing mask? helps good with poor seeing and reduces the brightness, i'll bring it with me in January with the presentation so you can see for yourself!



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Posted 14 December 2009 - 06:49 AM

Beau dessin Jef !
Je vais essayer de dessiner Mars cette nuit.

#5 markseibold


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Posted 14 December 2009 - 10:26 AM


You've got a great start here. :bow: :bow: :bow: I have not observed Mars up close for a few years now. I am anxious to get out again as soon as the weather clears here in Portland Oregon.

I used an old Orion Sky Glow Filter as a last resort and they don’t make it that way any longer as they changed the coatings to a pronounced green color where mine has a particular blue transmission wavelength that seems to enhance the Mars surface features without discoloring the view. (You can see my sketches of Mars through my gallery, they were all done from the 2003 ~ 2005 years of the closest approaches. I actually sketched my hand holding the Orion Sky Glow Filter into the work }

A close-up >

But my old 10.1” Coulter Odyssey is probably not as well to produce resolution as your 12 inch Newtonian. The Coulter people had a users manual showing to cut out an off-axis aperture mask that I made then in 1987 when I bought the scope. This is a 4 ½ inch circle to mask the 10 inches down to an effective 4.5 inch f/13. I still have that mask, tattered as it was made from cheap cardboard.

Although Mars is small compared to Jupiter, Saturn, and Venus, keep observing Mars when seeing conditions improve. You will see much in details with continued efforts.

Good luck and I look forward to your future observations, reports and sketches,


PS: Jef- I just found that old pastel sketch that I never posted before- This was Mars observed through a 20 inch Obsession one night with the use of the Orion Sky Glow filter. I have rendered the colors better in this than in my other gallery images. The disc of Mars is sketched at 3 inches in diameter. *Following if that is OK to post here within your post - South Polar Cap is up, the Morth Polar Hood at bottom; I never figured what the green-grey surface features were. -Mark >
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#6 frank5817



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Posted 14 December 2009 - 11:03 AM


Very nice sketch. Another site you may like for all the planets is --- http://space.jpl.nasa.gov/.

At this site make the Mars settings as follows: see image

When finished press run simulator. The Mars image will be North up and the polar cap will not be seen. The other possible albedo features will be seen. You can use this in combination with the Mars Profiler dweller25 mentioned above from Sky and Telescope to ID features. Variable effects like clouds and dust will not show. These are other websites too.

Frank :)

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#7 Jef De Wit

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Posted 14 December 2009 - 01:43 PM


Thanks for the links. I will check them out on a cloudy night. In the shop at my local astroclub they have filters from Meade and Lumicon. What about the quality?

From Meade they have:
Set #1 (#12, #23A, #58, #80A)
Set #2 (#11, #25A, #47, #82A)
Set #3 (#8, #21, #38A, #56)
#3200 Lunar & Planetary Filter Set

From Lumicon they have a lot of different colourfilters and one Planetary Filter set.

What do you recommend?

#8 Tommy5



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Posted 14 December 2009 - 08:49 PM

very nice sketch of mars, i would usse a #21 orange to get the best from the dark maria features.And a blue 80a or green #56or#58 to get views of the caps and clouds.

#9 phxbird


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Posted 17 December 2009 - 12:08 AM

I like the Hirsch filters on e-bay. They seem to be high quality and low cost. There is also a dedicated Mars filter from Orion that is also supposed to be good but I have not used it.

#10 Special Ed

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Posted 20 December 2009 - 06:43 AM

Keep sketching, Jef--you saw quite a bit even with the "boring" side facing you. :)

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