What should I expect to see of Mars from a 4" reflector?

doctor:
I was looking at Mars using 4 inch reflector. I am very certain that
I could make out a white patch on the top left of the image disk.
Is that what I shoul expect?

That sounds reasonable. That would be the polar ice cap. I'm using a
3-1/2" reflector (Questar) and I can see the polar ice cap and
brownish-gray mottling on the planet's surface. We--you and I--are
limited by small apertures in the magnification that we can use -- the
more you want to magnify, the more photons you need to grab. For me,
the keys to good images of Mars with my small telescope have been a
very sturdy mount, good polar alignment, and careful focus. These
practices help prevent the jumpy images that result from having to
touch the telescope often. The other thing is to sacrifice some sleep
and try to wait until very close to transit time before observing. I'm
observing from a location between Baltimore and Washington DC, and thus
far in this year of unusual weather, have mostly seen Mars through a
bit of haze and intermittent think clouds. I know from having used my
little 'scope in excellent seeing conditions (on unpopulated mountains
in the southern part of the Arabian peninsula, and at the Olgas in your
splendid country, e.g.) that small 'scopes are capable of producing
breathtaking planetary images.

Davoud, a casual observer

--
usenet *at* davidillig dawt com

On Mon, 28 Jul 2003 07:49:29 -0700, "Ron B[ee]"
wrote:

Well, Mars requires practice and with small scope - concentration.
Color filters help too. Use the highest magnification support by your
seeing condition and your optics. Take a look at these sketches
made by a 4-inch APO, which may give you some idea of what can
be seen.
http://members.cox.net/ronby/Solar-System/index.htm

Wonderful reports Ron.

I managed to get some nice digital data with my 4" apo last night.
Going to take a while to process. I'll post a link when ready.

Quite amusing that you lot in the USA are imaging/sketching one side
of the planet, while us Europeans are picking up the other. Almost as
if we're looking at two different objects. Makes comparisons quite
tricky.


--
Pete
Homepage at http://www.pbl33.co.uk
CCD/digicam astronomy

"Pete Lawrence" wrote in message
...
On Mon, 28 Jul 2003 07:49:29 -0700, "Ron B[ee]"
Wonderful reports Ron.

I managed to get some nice digital data with my 4" apo last night.
Going to take a while to process. I'll post a link when ready.

Quite amusing that you lot in the USA are imaging/sketching one side
of the planet, while us Europeans are picking up the other. Almost as
if we're looking at two different objects. Makes comparisons quite
tricky.


--
Pete

Thank you Pete. I look forward to see your picture! There are just
not that many photos of Mars taken through a small telescopes and
thus IMO make them unique and very valuable.

Ron B[ee]

"doctor" wrote in message
...
Hi all,

I was looking at Mars using 4 inch reflector. I am very certain that
I could make out a white patch on the top left of the image disk.
Is that what I shoul expect?

Thank you

I'd say that's not bad. With an 18" reflector, I am able, depending on
seeing conditions, which change minute by minute, to see the white patch
(south polar cap), some surface detail (dark and light areas) and a hint of
the north polar cap.
That would be best case, with reasonably accurate collimation. Worst case,
with bad seeing, my view is probably equivalent to what you describe. And
that's with a very good, large (by amateur standards) mirror.
Oddly enough, I find a moon filter seems to work the best for me. Mars is
so bright, that cutting down the amount of light reaching my eye lets me see
better. Other than that, I find filters more trouble than they're worth.

I have never seen any "canali".

Regards,
Etok



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Pierre Vandevenne wrote in message .84...

Slightly more - you should see differently contrasted areas on the disk.
But that depends a lot on the device your are using, your latitude (how
high Mars is in the sky, etc...)

And also on which side of Mars you happen to be looking at. If Syrtis
Major is facing directly at you, you can hardly miss it. But the
shading on the opposite side of Mars is quite subtle, and requires
good seeing, good optics, and experience to make out.

- Tony Flanders

"Ron B[ee]" wrote:

Well, Mars requires practice and with small scope - concentration.

That's true for large scopes, too, Ron! You just can't get the most
from your scope with a quick glance now and then. You'll see more with
your patient, practiced eye than casual observers will see in much
larger scopes.

Mike Simmons

Mars will be in view for several more weeks -- it is closest to Earth on
August 27 but the days between now and then and following Aug. 27 will
provide plenty opportunities for some good views of Mars with your 4-inch
scope.

If you do not have filters, I recommend you get at least red (#25) and
orange (#21) filters -- you'll be amazed at what difference these make.

The white area you saw was the polar cap.

Mars is so bright that even with the small scope the brightness washes out
some of the details -- filters knock out some of the brightness and make the
detail stand out.

Also, spend as long as you can in an observing session. I have been
spending one hour in the mornings between 0400 and 0500 EDST, 2-3 times a
week. I use 240X and 325X with a 8-inch Dob; red, orange, yellow, and med
blue filters. I see something new each time I look.

--

----
Joe S.

"doctor" wrote in message
...
Hi all,

I was looking at Mars using 4 inch reflector. I am very certain that
I could make out a white patch on the top left of the image disk.
Is that what I shoul expect?

Thank you