Smart-1 Saturday

[Jane H Jones]

Hope to see some of you Friday or Saturday night.  As always, our 
schedule is shown at the top right of the Old Town Sidewalk 
Astronomers (OTASTRO) website http://www.otastro.org/

I've been receiving a lot of questions at work today about the 
European Space Agency's Smart-1 lunar orbiter's impact on the moon 
tomorrow night (Saturday, September 2) SO I typed this up for my 
colleagues, and thought I'd share it with you too.

It sort of coincides with our Monrovia Sidewalk Astronomy Saturday 
night, tho' it is highly unlikely that it can be seen from amateur 
telescopes.  But we'll stay out a little later than usual just to 
view the moon at the designated time of 10:41 p.m. I'll bring some 
maps to hand out for those who want them.  Friday night - gosh, 
that's tonight, we'll be in Pasadena 7ish - 10:00 p.m. mostly moon, 
and possibly a low Jupiter view.

The nine-day old waxing (or gibbous) moon will be visible throughout 
the late afternoon, will transit at mid-evening and set after 
midnight.  Refer to the moon map linked below to find the craters I 
describe. One of the moon's most glorious sights, the large (100km/60 
mile) diameter young crater Copernicus (area 31) is located midway 
between north and south on the sunny side of the terminator. Further 
south, the bright ejecta rays of 85km/53mile diameter even younger 
Tycho (area 64) are more and more brilliant as the moon nears full. 
Hitchhikers Guide to the Moon  is my favorite lunar website. 
http://www.shallowsky.com/moon/hitchhiker.html

Meanwhile, over on the night side of the terminator, Smart-1 is 
preparing for its own termination. SMART-1, ESA's "Small Missions for 
Advanced Research in Technology", is about to end its exploration 
adventure after almost sixteen months of lunar science investigations.

Look on this ESA link to see an image of the moon at the nominal 
impact time (10:42 p.m. Pacific September 2. 
http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=39942 
You'll see bright craters Copernicus and Tycho center and south. The 
impact most likely won't be visible through anything but large ground 
or space telescopes, but amateurs everywhere will all be looking 
moonward anyway.

You can share these times with your friends around the world.....The 
expected impact time (07:41 CEST  or 10:41 P.M. PST) will be good for 
big telescopes in South and Northwest Americas and Hawaii and 
possibly Australia. But if SMART-1 hits a hill on its previous pass, 
around 02:37 CEST on 3 September (5:37 p.m. PST Saturday night, 
before sunset) , then it can be observed from the Canary Islands and 
South America. If SMART-1 hits a hill on the pass on 2 September at 
21:33 CEST, then telescopes in Continental Europe and Africa will 
have the advantage.


Smart-1 background info:

It travelled to the Moon using solar-electric propulsion and carried 
a battery of miniaturized instruments. As well as testing new 
technology, SMART-1 made the first comprehensive inventory of key 
chemical elements in the lunar surface.

If left on the course of its lunar orbit, SMART-1 would have 
naturally hit the Moon on 17 August 2006 on the lunar far side, not 
visible from Earth. A 2-week series of manoeuvres started on 19 June 
and concluded on 2 July allowed SMART-1 to adjust its orbit to avoid 
having the spacecraft intersect with the Moon at a disadvantageous 
time from the scientific point of view, and to obtain a useful small 
mission 'extension'.

On 3 September 2006 (Evening of Sept 2 here in California) the 
SMART-1 perilune, coinciding with the point of impact, will be on the 
lunar area called 'Lake of Excellence', located at mid-southern 
latitudes. This area is very interesting from the scientific point of 
view. It is a volcanic plain area surrounded by highlands.

At the time of impact, this area will be in the dark on the near-side 
of the Moon, just near the terminator - the line separating the lunar 
day-side from the night-side. The region will be shadowed from the 
Sun's direct rays, but it will be lit faintly by the light from the 
Earth - by earthshine. The spacecraft's orbit will take it over the 
region every five hours, getting one kilometer lower at each pass. 
 From Earth, a Moon quarter will be visible at that time.

Useful links:

Science at Nasa's Aug 30 Smart-1 feature: 
http://science.nasa.gov/headlines/y2006/30aug_smart1.htm?list117725

Read more from the Aug 4 News release here: 
http://www.esa.int/SPECIALS/SMART-1/SEMKTCBUQPE_0.html

Smart-1 visibility from Earth 
http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=39878


-- 
Jane Houston Jones
Senior Outreach Specialist, Cassini Program
JPL - 4800 Oak Grove Drive, MS 230-205
Pasadena, CA  91109  818-393-6435
jane.h.jones at jpl.nasa.gov
Cassini Saturn Observation Campaign
http://soc.jpl.nasa.gov/index.cfm
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