Thursday, 4 November 2010

STS-133 Flight Plan (Shuttle & ISS)

Changes and additions:
- July 6: Posting initial release
- July 27: Launch time updated
- Sept. 4: Spacewalk tasks changed
- Sept. 17: Slight tweaks
- Oct. 25: Latest revision
- Oct. 27: Tweaks to docking, undocking and landing
- Oct. 30: New launch date of Nov. 3
- Nov. 4: New launch date of Nov. 5


Flight Day 1

Fri 03:04 PM...00...00...00...00...Launch
Fri 03:41 PM...00...00...37...21...OMS-2 rocket firing
Fri 03:54 PM...00...00...50...00...Post insertion timeline begins
Fri 05:34 PM...00...02...30...00...Laptop computer setup (part 1)
Fri 05:49 PM...00...02...45...00...GIRA install
Fri 06:24 PM...00...03...20...39...NC-1 rendezvous rocket firing
Fri 06:44 PM...00...03...40...00...SRMS powerup
Fri 06:49 PM...00...03...45...00...SEE setup
Fri 06:59 PM...00...03...55...00...Group B computer powerdown
Fri 07:14 PM...00...04...10...00...SRMS checkout
Fri 07:24 PM...00...04...20...00...ET photo
Fri 07:34 PM...00...04...30...00...Wing leading edge sensors activated
Fri 07:34 PM...00...04...30...00...ET video downlink
Fri 07:54 PM...00...04...50...00...ET umbilical downlink
Fri 09:04 PM...00...06...00...00...Crew sleep begins

Animation of the five closest-approach Hartley 2 images ( KFC Chicken leg or cucumber?)

Those of you who follow my blog must have known this was coming: now that I got all five new Deep Impact images of Comet Hartley 2 posted and explained, I had to make an animation. Here they are. I rotated them all counterclockwise by a quarter turn and aligned the frames, but otherwise did no processing.

Animation of Deep Impact close-approach images
About an hour after its closest approach of Hartley 2, Deep Impact downlinked five precious images taken during the nearest part of its flyby. The top two images were taken 82 and 16 seconds before closest approach, and the bottom three 18, 57, and 117 seconds after closest approach (image times are 13:58:07, 13:59:13, 13:59:47, 14:00:26, and 14:01:26 UTC on November 4, 2010). They show a very active comet with numerous jets. Credit: NASA / JPL / UMD / animation by Emily Lakdawalla 


This is how Comet Hartley 2 might appear in the eyepiece of a large amateur telescope. Located about eight degrees (16 full moon diameters) away from the bright star Procyon as it leaves the constellation Gemini, Comet Hartley will be best viewed high in the sky just before dawn. Credit: David A. Aguilar (CfA)

Did Earth encounter pieces of an alien visitor last night? Apparently so! It appears tiny pieces of Comet Hartley 2 may have presented a spectacular and startling sky show across the country yesterday. NASA meteor experts had predicted it was a long shot, but the evenings of November 2nd and 3rd might display a meteor shower from dust which puffed off this visiting comet as it passed within twelve million miles of Earth. And indeed, the Center for Astrophysics has collected several sightings of bright meteors called fireballs, which result when comet dust burns up in Earth's atmosphere.

Helga Cabral in Seascape, California, reported after 9 pm last night, "I saw a bright white ball and tail, arcing towards the ocean. It was quite beautiful and it looked like it was headed out to sea and so picture perfect it could have been a movie!" Three thousand miles away just north of Boston, Teresa Witham witnessed a similar cosmic event. "I was in the Revere area about 7:15 last night, driving north on Route 1, when a brilliant object with a tail passed in front of me -- very similar in appearance to a shooting star but it appeared much lower to the Earth than a typical shooting star would be. If it weren't for the fact that I had my daughter with me, I'd begin to believe I'd imagined it."

Comet Hartley 2 has put on quite a nice show for amateur astronomers over the past few weeks, sporting a vivid green coma or halo around it and a golden auburn tail of dust. NASA's Deep Impact/EPOXI probe will present dramatic close-up images of the comet when it zooms past the nucleus on November 4th.

When a comet approaches the Sun, it heats up unevenly, throwing off dust, ice and bits of rock. When the Earth encounters some of this space debris, it is seen as a beautiful meteor shower.

"Many people don't realize that the famous periodic meteor shower in August, the Perseids, is the remains of Comet Swift-Tuttle and the Orionids, appearing in late October, are leftovers from Comet Halley," said Tim Spahr, Director of the Minor Planet Center at the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA.

So for the next two evenings, we may see more of Comet Hartley 2. And if you have dark skies and a small telescope or binoculars, try to find Comet Hartley 2 itself. It will be near the bright star Procyon in the constellation Canis Minor near Orion the Hunter, which will be high overhead in the early hours before dawn.


A map of water in Comet Hartley 2, observed by Odin on 29 October
2010. Copyright 2010 Swedish Space Corporation/Centre National
d’Etudes Spatiales/Observatoire de Paris.

The Odin satellite observed Comet Hartley 2 almost continuously from 29 October to 1 November. The water signature (line) was easily detected. Its extension and space distribution is shown on a map (Fig. 1). The production of water derived from the observations ranges from 180 to 300 kg (400 to 660 lb) per second.

This production of water (Fig. 2) is rapidly varying with time. This is in line with variations reported from other means of observation. It may be related to the rotation of the comet's nucleus, for which periods around 17h have been reported.

Comet 103P/Hartley 2 is a Jupiter-family comet orbiting the Sun close to the ecliptic plane, with a period of 6.5 years. Its return this year is exceptional. It passed perihelion on 28 October at 1.059 AU from the Sun (158 million km; 98 million miles) and on 20 October, it came close to the Earth, at only 0.121 AU (18 million km; 11 million miles). Furthermore, it is the target of NASA's mission EPOXI, which is to fly by the comet on 4 November.

At this occasion, this comet is the object of an intense, international campaign of observation which mobilizes all major astronomical resources, including the Herschel Space Observatory. The Odin satellite is participating to this campaign.

The Odin satellite is a small spacecraft, orbiting the Earth, designed and built by Sweden, in collaboration with Canada, Finland and France. It was launched in February 2001. Aimed for studying both the Universe (astronomy) and the terrestrial atmosphere (aeronomy), it allows for the observation of a number of molecular lines, at radio (submillimeter range) wavelengths, otherwise not accessible from the ground: in particular the fundamental water line at 556.9 GHz.

Odin is thus well suited for the study of water, the main constituent of cometary ices, released as water vapor following heating of cometary nuclei by the Sun.

Since its launch, Odin has observed about 15 comets. Now closed for astronomical observations, the Odin satellite concentrates on aeronomical studies, except for special occasions such as the passage of Comet Hartley 2.

Figure 2:

The evolution of the production of water in Comet Hartley 2, as observed with Odin. Copyright 2010 Swedish Space Corporation/Centre National d'Etudes Spatiales/Observatoire de Paris.

Reference:International Astronomical Union electronic telegram No. 2524.

Tuesday, 2 November 2010

Solar ring sigbaar in Gauteng: Pretoria en Secunda

Foto:  Roland Friend, Secunda.
So 10:30 (Maandag 1 November) bel my broer Ben uit Johannesburg. "Daar's `n sirkel om die son! Gaan kyk! Ek besef dadelik wat dit is, want die vorige een was `n sirkel om die maan (Sien blog). Tog loer ek by die venster uit en sien niks. Dit het toe die vorige dag by hulle gereën en hoë cirrus wolke was nog in die lug. 

Skaars `n halfuur later storm  kollega Nellie Friend  van die Universiteit by my in en vertel van die kring om die son, maar die son is te skerp en sy  kan dit nie sien nie. Haar seun, Roland Friend van Secunda het gebel en gesê sy moet kyk. Hy het ook die foto hier bo geneem en vir ons aangestuur. 

Ek kan nie die foto dadelik op die blog laai nie en stuur dit vir Auke Slotegraaf in die Kaap. Hy is toe in dieselfde bootjie - besig om van internet versakaffers te verander. Hy kon toe darem die foto gistermiddag op sy blog gaan laai.

Besoek dit gerus: en lees meer oor die verskynsel.

Solar ring visible in Gauteng Pretoria and also Secunda.