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Mars again.. LOL :-) Contrast questions

Started by Ron777, 08/25/2003 04:24PM
Posted 08/25/2003 04:24PM Opening Post
Hey, me again!

When you guys are veiwing Mars, how does it look compared to the photo here. ( I edited it to have less contrast but enhaced the polar cap since it seems to stand out when I veiw it. )
This is how the contrast looks in my scopes. I know they always say (who ARE those they ppl?) that Mars takes practice and eye training. This is my first year to really look at Mars, and I do "infer" detail looking at it, but when you are just looking right at it, how is the contrast in your scope compared to this?
Or is it seeing?
Or is this just all the "contrast" you see with an untrained eye and direct vision?


Attached Image:

Ron777's attachment for post 8682
Posted 08/25/2003 04:47PM #1
Close. The way I see it, the polar caps have more defined, brighter/more white, and shaped w/ an appearance of higher altitude. The surface features are a tad darker and the planetary edges are much sharper (probably due to the pixel size of the jpg. The contrast between Mars and the background is similiar to my view through the APO.

Posted 08/25/2003 06:38PM #2
I remember the polar cap as being much brighter... but that was a few weeks ago before the monsoon.


Fort Lewis Observatory: (37.238, -108.052) ~2360m (7744 ft.) elevation.
Darkness - typically 6.5+
Scope - Meade 16" LX200; f6.3 focal reducer
Focus - JMI Smart focus
Camera - SBIG ST-10XE; (~.5"/pixel)
Guiding - AO-8 and/or Meade 5"/DSI/PHD
Posted 08/26/2003 12:02PM #3
Hello Ron,

Your views are about what I get with a 6" f/12 Mak-Cas using a UHC filter at lat 37, except mine is a bit brighter overall. Mars is so bright a UHC or a O-III can be used to bring out details. I tried a raft of colored filters and ND filters but none of them gave me the details I saw with the UHC and the O-III. They will only work when Mars is this bright. Otherwise, they'll dim things out once the planet's magnitude drops below a certain point.

Considering what I was getting as Mars became much brighter these past few weeks, I was very happy to get views similar to yours. And this is after allowing for cool-down time, viewing Mars at the highest point in the sky, focusing on distant stars before swinging over to Mars, testing different EPs for best magnification and "working" the image.

I think the only thing I can do to improve my views, short of getting more aperture, at this point is to seek higher altitude with clear, steady skies.

Clear & Steady Skies,

Posted 08/26/2003 05:46PM #4
If you increase the contrast 50%, up the resolution about the same, and brighten the ice cap you get the view I had Saturday with very good seeing (stable but poor transparency) and my Questar 7.

There are only 10 kinds of people who understand binary - those that do and those that don't