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.
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.
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
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
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.
Science@Nasa's Aug 30 Smart-1 feature:
Read more from the Aug 4 News release here:
Smart-1 visibility from Earth
Jane Houston Jones
Senior Outreach Specialist, Cassini Program
JPL - 4800 Oak Grove Drive, MS 230-205
Pasadena, CA 91109 818-393-6435
Cassini Saturn Observation Campaign