The Planet that Won't Go Away

http://science.nasa.gov/headlines/y2...sep_goaway.htm

The Planet that Won't Go Away
NASA Science News
September 8, 2003

Mars' closest approach to Earth was on August 27th--but the red planet is
even easier to see now.

"Tony, it's still there. I can't believe how bright it is!"

That's what my mother said to me on the phone last night.
She had just stepped outside for some fresh air and was
startled by an orange star hanging over her house: Mars--so
intense it was worth a phone call.

Like millions of other people, she saw Mars for the first time
on August 27th when the red planet made its closest approach
to Earth in 60,000 years. It was dazzling, but ... "isn't Mars
supposed to be gone now?"

No, Mom. In fact, Mars is even easier to see now than it was
two weeks ago.

Consider this: Mars is receding from Earth at about 6,000 mph
(2.8 km/s). Maybe that sounds fast, but on the vast scale of
the solar system it is not. Mars was 34,647,397 miles
from Earth on August 27th. Today it is 35,532,907 miles
away--not much different.

That's why Mars remains dazzling. It's still nearby. In fact,
during the whole month of September Mars will be as close to
Earth as it's going to get for the next 15 years.

Best of all, Mars getting easier to see. Why? Because it's up
before bedtime. Like all stars and planets Mars rises about
4 minutes earlier each night. (This is a result of Earth's
orbital motion around the sun.) Back on August 27th, Mars was
barely above the horizon at sunset; you had to wait a while
for it to rise. Now, though, Mars is higher in the sky when
the sun goes down. People are noticing the red planet without
even trying.

Eventually, of course, Mars is going to fade. By late September
it will be only half as bright as it is now, and by mid-October
only 20%. The fading quickens because Mars is receding a little
faster each day. Only 6,000 mph now, the pace will increase nearly
3-fold to 16,500 mph (7.4 km/s) by the end of this month.

All these factors add up to one thing: September is a good time
to observe Mars.

Even a modest backyard telescope, a 6- to 8-inch instrument, say,
will reveal broad details on the planet's surface such as dark
volcanic terrains and the bright south polar cap. Larger 12- to
16-inch telescopes equipped with CCD cameras can record spectacular
images of individual volcanoes, wispy clouds and frosty mountains
emerging near the south pole.

Or if you're like my mom, not ready to deal with telescopes, just
use your naked eye. The planet that won't go away is a lovely
sight no matter how you look at it.

So with my Meade ETX-70AT, I was under the impression that I would be able
to see surface features on Mars. But so far I have only been able to focus
in on a very small orange dot, about twice or three times larger than a
typical bright star in my view finder. I only have the two eyepieces that
came with the scope, a 25mm and a 9mm. Do I need a Barrow lens, or different
eyepiece? Any tips appreciated.

Thanks
paul

Hi there. You posted:

Even a modest backyard telescope, a 6- to 8-inch instrument, say,
will reveal broad details on the planet's surface such as dark
volcanic terrains and the bright south polar cap. Larger 12- to
16-inch telescopes equipped with CCD cameras can record spectacular
images of individual volcanoes, wispy clouds and frosty mountains
emerging near the south pole.

Err, Ron, who wrote this? The dark markings are not necessarily volcanic.
The Tharsis region is mostly light in color, as is the region of the Elysium
volcanic complex. These are the major volcanic provinces of the planet. As
for "frosty mountains", there are none "emerging near the south pole". The
brighter patches sometimes referred by some to as "the Mountains of Mitchel"
are *not* mountains but are merely outliers of the seasonal polar cap as it
receeds. In fact, the "mountains" feature is just about gone now. It might
be nice, for accuracy sake, to not stretch the description beyond reality in
such a public release. Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 10th Annual NEBRASKA STAR PARTY *
* July 27-Aug. 1st, 2003, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
**********************************************

Hi there. You posted:

So with my Meade ETX-70AT, I was under the impression that I would be able
to see surface features on Mars. But so far I have only been able to focus
in on a very small orange dot, about twice or three times larger than a
typical bright star in my view finder. I only have the two eyepieces that
came with the scope, a 25mm and a 9mm. Do I need a Barrow lens, or different
eyepiece? Any tips appreciated.

I'm afraid that your scope probably won't perform all that well for viewing
the details on Mars. The ETX-70AT is designed for wide-field viewing and not
for quality close-up views of the planets, so it does not perform particularly
well at high power. You need a *lot* more power (and probably a somewhat
larger telescope) if you are to see much on the planet Mars. The powers
needed to resolve much detail are often in the 120x to 200x range at the low
side. Even with the 9mm eyepiece, you will only have about 39x, which is far
too low to see much other than the disk of Mars itself. Even with a 3x Barlow
and the 9mm, you would still have only about 117x, which is still a little on
the low side if you want to see very much on the disk of Mars. The quality of
the image at that high power in the ETX-70 is also somewhat poorer than in a
longer focal length refractor or a larger Newtonian. If you want to see more,
I might suggest a larger scope from Orion, like their SkyView Pro line, or
Meade's ETX-125 Maksutov. Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 10th Annual NEBRASKA STAR PARTY *
* July 27-Aug. 1st, 2003, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
**********************************************

With only 70mm of objective, you can see some of the larger and more
prominant surface features like Syrtis Major, but you need to use every
trick in the book to increase your chances. Using filters, and waiting
until
Mars gets close to the meridian (the imaginary line running directly North
to
South in the sky) so that it's at its highest to minimize atmospheric
effects. That's for starters. And don't get discouraged if you don't see
anything right away. You need to learn to be patient and gaze slowly
at Mars and take in the details.

This is also good training when viewing all the planets where some
surface features can be seen; Mars, Jupiter, and Saturn. The features
on these worlds are shades of the same colors, often just barely different
from one another. So just stay with it.
--
----------------------------------------------------------------------
Never be afraid of trying something new for the love of it.
Remember... amateurs built the Ark.
Professionals built the Titanic!


----------------------------------------------------------------------

"Paul F. Aubin" wrote in message
...
So with my Meade ETX-70AT, I was under the impression that I would be able
to see surface features on Mars. But so far I have only been able to focus
in on a very small orange dot, about twice or three times larger than a
typical bright star in my view finder. I only have the two eyepieces that
came with the scope, a 25mm and a 9mm. Do I need a Barrow lens, or
different
eyepiece? Any tips appreciated.

Thanks
paul

"David Nakamoto" wrote in message ...
With only 70mm of objective, you can see some of the larger and more
prominant surface features like Syrtis Major, but you need to use every
trick in the book to increase your chances.

With an F/5 ratio , 350mm FL it's he's not likely to
see any detail. As mentioned in another post a 9mm
ocular will only give him 39X. He might as well be
looking at mars through high power binoculars.

--
Hilton Evans
---------------------------------------------------------------
Lon -71° 04' 35.3"
Lat +42° 11' 06.7"
---------------------------------------------------------------
CCD Astroimaging
http://home.earthlink.net/~hiltoneva...troimaging.htm
---------------------------------------------------------------
ChemPen Chemical Structure Software
http://www.chempensoftware.com

Thanks for the replies!