[AZ-Observing] Re: Duration of Mars Closest Approach
- From: SaguaroAstro@xxxxxxx
- To: az-observing@xxxxxxxxxxxxx
- Date: Mon, 18 Aug 2003 19:02:15 EDT
Given the fact that it took me me two years of calculus to understand the
concept and that I never did master the actual workings of it (although I
passed
due to the pity of my instructors), Here is a chart I created in Skymap with
the Distance (in AU, I'll let yuo do the math :)) and Size, along with
magnitude & phase (thought I'd throiw that in because I could).
Looks like ours Mars party on the 4th of Oct will still have the planet at
90% of it's maximum size.
Ephemeris of Mars
Date Mag Diam " Distance Phase
19 Aug 2003 -2.8 24.80 0.3773612 0.993
21 Aug 2003 -2.8 24.94 0.3753689 0.995
23 Aug 2003 -2.8 25.03 0.3739249 0.996
25 Aug 2003 -2.9 25.09 0.3730394 0.997
27 Aug 2003 -2.9 25.11 0.3727202 0.998
29 Aug 2003 -2.9 25.10 0.3729725 0.998
31 Aug 2003 -2.9 25.04 0.3737977 0.998
02 Sep 2003 -2.8 24.95 0.3751931 0.997
04 Sep 2003 -2.8 24.82 0.3771529 0.996
06 Sep 2003 -2.8 24.65 0.3796690 0.994
08 Sep 2003 -2.7 24.46 0.3827321 0.992
10 Sep 2003 -2.7 24.23 0.3863328 0.989
12 Sep 2003 -2.6 23.97 0.3904612 0.986
14 Sep 2003 -2.6 23.69 0.3951078 0.983
16 Sep 2003 -2.5 23.38 0.4002623 0.980
18 Sep 2003 -2.5 23.06 0.4059140 0.976
20 Sep 2003 -2.4 22.72 0.4120516 0.972
22 Sep 2003 -2.4 22.36 0.4186629 0.968
24 Sep 2003 -2.3 21.99 0.4257349 0.964
26 Sep 2003 -2.3 21.60 0.4332533 0.960
28 Sep 2003 -2.2 21.21 0.4412023 0.955
30 Sep 2003 -2.1 20.82 0.4495642 0.951
02 Oct 2003 -2.1 20.42 0.4583209 0.947
04 Oct 2003 -2.0 20.02 0.4674549 0.942
06 Oct 2003 -1.9 19.62 0.4769504 0.938
08 Oct 2003 -1.9 19.23 0.4867934 0.934
10 Oct 2003 -1.8 18.83 0.4969715 0.930
12 Oct 2003 -1.8 18.44 0.5074738 0.926
14 Oct 2003 -1.7 18.06 0.5182906 0.922
16 Oct 2003 -1.6 17.68 0.5294128 0.918
18 Oct 2003 -1.6 17.31 0.5408319 0.915
20 Oct 2003 -1.5 16.94 0.5525394 0.911
22 Oct 2003 -1.5 16.58 0.5645271 0.908
24 Oct 2003 -1.4 16.23 0.5767862 0.905
26 Oct 2003 -1.3 15.88 0.5893068 0.902
28 Oct 2003 -1.3 15.55 0.6020776 0.899
30 Oct 2003 -1.2 15.22 0.6150872 0.896
01 Nov 2003 -1.2 14.90 0.6283250 0.894
03 Nov 2003 -1.1 14.58 0.6417821 0.891
05 Nov 2003 -1.1 14.28 0.6554511 0.889
07 Nov 2003 -1.0 13.98 0.6693262 0.887
09 Nov 2003 -1.0 13.70 0.6834026 0.885
11 Nov 2003 -0.9 13.42 0.6976759 0.883
13 Nov 2003 -0.8 13.14 0.7121426 0.881
15 Nov 2003 -0.8 12.88 0.7267991 0.880
17 Nov 2003 -0.7 12.62 0.7416420 0.878
19 Nov 2003 -0.7 12.37 0.7566675 0.877
21 Nov 2003 -0.7 12.13 0.7718711 0.876
23 Nov 2003 -0.6 11.89 0.7872470 0.875
25 Nov 2003 -0.6 11.66 0.8027880 0.874
Rick
In a message dated 8/18/2003 15:41:18 US Mountain Standard Time,
polakis@xxxxxxx writes:
> I just pasted Peter's table into a spreadsheet, and the curve looks a bit
> different than the sine wave that I had in my mind -- more sharply peaked.
>
> http://www.psiaz.com/polakis/diameter.jpg
>
> And for those on the list who enjoy calculus as a hobby, here's the rate
> of change in angular diameter for the rest of the year.
>
> http://www.psiaz.com/polakis/change.jpg
>
> The plot is jagged due to round-off error: there are only two decimal
> points in the table on the EVAC site.
>
> Obviously, the angular size of Mars is not changing when it is at its
> maximum on August 27. Its size is declining most rapidly (0.2" per day)
> in early October, about five weeks past opposition. That's when we're
> pulling away from it the most rapidly, and not coincidentally when
> it's "stationary" at the end of the retrograde loop.
>
> Tom (who really doesn't enjoy calculus as a hobby, honest)
>
>
>
Rick Tejera
Editor SACnews
Saguaro Astronomy Club
Phoenix, Arizona
SaguaroAstro@xxxxxxx
www.saguaroastro.org
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