Mars/Earth ???

This question was posed to me last night, and I didn't have an answer, but
later did some rough (real rough) calculations to come up with an answer.

How much closer is Mars this time around as opposed to a few years ago?

I think this year it will be about 44 million miles. About 8 years ago Mars
& Earth caught up to each other on the other side of the sun, they were
about 63 million miles apart. And when Mars and Earth are on opposite sides
of the sun they are about 235 million miles apart.

I know the numbers aren't correct, but am I close?


--

Don Baker
Go 18, 5 & 14....(also 8, 40, & 30)
www.geocities.com/thebugbomber

Don Baker posted:

How much closer is Mars this time around as opposed to a few years ago?

Depends on what you mean by "a few years ago". This year's closest
approach will be a distance of about 55,758,006 kilometers or about
34,646,408 miles. In 1924, the approach distance was only about 1900 km
farther away from us than Mars will be in August, so it isn't much of a
significant difference when you are talking about millions of
kilometers. Two years ago at the last apparition, it was somewhat
farther away at its closest point to Earth (about 17 percent more
distant), and you have to go back to 1988 to find another fairly close
distance. While oppositions of Mars occur roughly every two years,
these fairly close oppositions occur roughly every 15 to 17 years or
so. It is more important to consider the maximum angular size at
closest approach. This year, Mars will appear 25.1 arc seconds in
diameter on August 27th, which is about as big as it can appear at any
approach (in 2001, it got to 20.8 arc seconds and in 1988, it was 23.8
arc seconds across). Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

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"David Knisely" wrote in message
...
Don Baker posted:

How much closer is Mars this time around as opposed to a few years ago?

Depends on what you mean by "a few years ago". This year's closest
approach will be a distance of about 55,758,006 kilometers or about
34,646,408 miles. In 1924, the approach distance was only about 1900 km
farther away from us than Mars will be in August, so it isn't much of a
significant difference when you are talking about millions of
kilometers. Two years ago at the last apparition, it was somewhat
farther away at its closest point to Earth (about 17 percent more
distant), and you have to go back to 1988 to find another fairly close
distance. While oppositions of Mars occur roughly every two years,
these fairly close oppositions occur roughly every 15 to 17 years or
so. It is more important to consider the maximum angular size at
closest approach. This year, Mars will appear 25.1 arc seconds in
diameter on August 27th, which is about as big as it can appear at any
approach (in 2001, it got to 20.8 arc seconds and in 1988, it was 23.8
arc seconds across). Clear skies to you.
--


In others words..on Aug 27, Mars will be 72 X's smaller than a full
moon..correct?

60/25 X 30 = 1800 arc sec = 1/2 degree

this implies that a modest 100 x's magnification will give you a good sized
image!!

Mr. Mick,

You wrote:

snip
this implies that a modest 100 x's magnification will give you a good sized
image!!
unsnip

Indeed it will. What I've been seeing at 123x is quite satisfying.
Additionally, at lower powers like this, "seeing" conditions are not as
critical as they would be at 200x and beyond.


Martin