Tiny Mars - the eyepiece view

[Don Pensack]

Hmm.
Moon is 30 arc-minutes = 1800 arc-seconds.
Mars on March 4th is 13.6".
Mars = Full Moon to the naked eye size at 1800/13.6 = 132X.
At 225X, Mars in a telescope is close to 3X the area of the Full Moon to the naked eye. It appears small because there is no "context" other than the edge of the field.
But just how big is the full Moon? Everyone overestimates its size. When I hold out my arm, it's 1/2 the size of my little fingernail--tiny. We see it as large because of its context with the sky and horizon (the "Moon Illusion"). Look at the Moon through a paper towel tube, and it appears quite small.
To see anything other than some vague light and dark areas, you need about 10X on the Moon, which translates to 1320X on Mars!
Well, obviously that's impractical.
So we cheat a little bit and use filters that accent certain features:
#82A light Blue and #80A blue to enhance the ice caps, the limb clouds.
#23A Red Orange and #25 red to enhance the dark markings
#15 yellow and #21 Orange to enhance dust storms and lighter areas.
#30 Magenta to see both blue-enhanced and red-enhanced features at the same time (the "Mars" filters made by several companies essentially do the same with dichroic coatings).
Most of the color filters also suppress bad seeing a little by reducing the portion of the spectrum seen.
And last, a simple polarizing filter can help improve sharpness without dimming as much as most color filters.

Yes, Mars is the toughest planet to observe details on (other than Uranus and Neptune, of course) and it's only close every 26 months. But, if you look often between now and early April, you just might catch one of those super-steady nights where Mars seems rock steady and details just pop out. I saw a night like than in 2003 and drew a map of Mars that helped me identify about 50 named features on Mars, with a 5" scope. But that was a 5" scope at 328X in rock-steady seeing.
You won't catch that night if you don't look though.
Best of luck to everyone.
Don

[GeoffMc (Geoff)]

It is not difficult to see surface features on Mars at all...if you consider the other planets (all under optimal conditions). Jupiter: easy, but the level of detail varies enormously; Saturn: I'd say it is about the same ranking as Mars, although you could start to quibble over what the word "features" means. As to the rest... Mercury? I don't think so. Venus? Do phases count as surface features? Probably not. Uranus, Neptune and of course the asteroids are out of the question. In fact when it comes to Mars I think it's astonishing we can see anything at all on that tiny world.

I'd like to endorse the comments made earlier by Dave about the reasons for bothering to look at Mars or anything else in the night sky. John Dobson years ago took it to an extreme when he commented at a public forum in Sydney that astrophotographers have some kind of disease: there are far better photos available from HST and so on that are far superior to anything they could produce (he said, not me!). But he had a point: people want to see things for themselves, otherwise tourism would be a thing of the past now the internet is here.

About 15 years ago I was running an evening Astronomy course and the members of the group wanted to see Uranus through my 8" Dob. I told them they'd see little more than a small dot, but that wasn't the point. They wanted to be able to say they'd seen it with their own eyes and it gave me a thrill to be able to show them. It's a very human, very valid perspective (no pun intended). I am absolutely hooked on exploring the Moon telescopically and buy books (such as Charles Wood's for example) to help me do so. I do not simply sit in a chair and look at photos and I doubt many of you do either. While I don't share Deep Sky observers' interest, I do appreciate their motives and applaud all those sketches louder than the technological triumph of electronic images (although they're extraordinary too!).

Geoff Mc

[Vegeta (Ibrahim)]

Originally Posted by blink138

some very clever AP'er here on IIS posted some amazing pics of one of mars' moons a week ago
check "solar system images"
pat

Thanks Pat

[Jeremy Parker (Jeremy)]

Viewed Mar two nights ago on my 8" sct at 225x.
Just a red blob and could not discern the ice caps.
This is my first view of the Red and I am excited, simply because this is truly my first and at least I know where it is in the night sky.

[mr bruess]

"Many Telescope ads are very misleading. They show huge planets and full colour nebulas and Giant galaxies."
This is so true.
This basically describes the department store junk telescope cover label on the box.
Those photographs are what you'd see from giant observatory class telescopes and from space probes like voyager,pioneer and galileo spacecrafts.
if it gets young kids started in Astronomy then it is better than nothing
:thum bsup:

[Rob_K]

Originally Posted by Geoff Mc

I'd like to endorse the comments made earlier by Dave about the reasons for bothering to look at Mars or anything else in the night sky. John Dobson years ago took it to an extreme when he commented at a public forum in Sydney that astrophotographers have some kind of disease: there are far better photos available from HST and so on that are far superior to anything they could produce (he said, not me!). But he had a point: people want to see things for themselves, otherwise tourism would be a thing of the past now the internet is here.

About 15 years ago I was running an evening Astronomy course and the members of the group wanted to see Uranus through my 8" Dob. I told them they'd see little more than a small dot, but that wasn't the point. They wanted to be able to say they'd seen it with their own eyes and it gave me a thrill to be able to show them. It's a very human, very valid perspective (no pun intended). I am absolutely hooked on exploring the Moon telescopically and buy books (such as Charles Wood's for example) to help me do so. I do not simply sit in a chair and look at photos and I doubt many of you do either. While I don't share Deep Sky observers' interest, I do appreciate their motives and applaud all those sketches louder than the technological triumph of electronic images (although they're extraordinary too!).

Geoff Mc

Well said Geoff!

Originally Posted by Jeremy Parker

Viewed Mar two nights ago on my 8" sct at 225x.
Just a red blob and could not discern the ice caps.
This is my first view of the Red and I am excited, simply because this is truly my first and at least I know where it is in the night sky.

Congrats on your first view Jeremy!

Cheers -

[Scopie (Brad)]

Originally Posted by Rob_K

And 225x is 225x no matter what scope you're looking through, only the width of the field might vary with premium eyepieces. That is, the same view through say a 16" Dob at 225x (using whatever eyepiece) except tiny Mars will be blindingly bright! Your mind is a wonderful thing though, and works to 'compensate' for the tiny size.

Words of wisdom there. I was looking at Mars last night at 400x with a 16 inch dob. I needed a moon filter to cut the glare down and see details- it was still very bright! At 400x Mars is about the same diameter as a biro give-or-take and when the atmosphere steadied, I could see the polar cap slightly larger than the head of a pin. At the bottom of the image some of the dark markings were visible VERY occasionally and I *think* there was a bright triangle on the eastern limb (?cloud perhaps).

I'm about 30kms south of Perth so I get a fair bit of sky glow as well as the unsettled air that comes from being right on the coast.

[naskies (Dave)]

Second night out with my 10-inch dob... Mars was just a blurry, boiling red blob just like the first night out, but I patiently waited and watched. Eureka! I had 5 mins of great seeing in between the clouds and could clearly see the dark regions, the larger polar ice cap, and lots of red dirt. Happy times