Astronomers

David Morton · 03-03-07, 07:19 PM

Just witnessing the eclipse watching through my daughters Meade Scope.
Really quite amazing red and brown tinges as its fully eclipsed and starting to emerge again. Just superb.Getting a running commentary from my daughter about what eclipses meant thoughout the ages.
Dave M.

Keith Hardy · 03-03-07, 09:17 PM

Dave, I thought it was Uranus blocking out the Moon tonight, but I thought nah, it couldn't be that big surely?

Could you tell me what it was that came between us please?

It has been the subject of some discussion around here (what a great view from the Forest, very clear) and I'm ashamed to admit I don't know what it wus....

Doc Watson · 03-03-07, 09:27 PM

It was an eclipse of the moon caused by the earth, I used an apple and two marbles to explain it to my 9 year old daughter. She seemed more excited about staying up late.......

Keith Hardy · 03-03-07, 09:36 PM

C'mon then Doc, get your marbles out and show me. So, it wan't Uranus. Oh well...

David Morton · 03-03-07, 09:48 PM

Uranus - Discovered by William Herschel using a telescope.
some facts:

Discovery date: March 13, 1781
Orbital characteristics
Epoch J2000
Aphelion distance: 3,006,389,405 km
20.096 471 90 AU
1,868,088,249 miles
Perihelion distance: 2,735,555,035 km
18.286 055 96 AU
1,699,799,169 miles
Semi-major axis: 2,870,972,220 km
19.191 263 93 AU
1,783,943,710 miles
Orbital circumference: 18.029 Tm
120.515 AU
Eccentricity: 0.047 167 71
Sidereal period: 30,707.4896 day
(84.07 yr)
Synodic period: 369.65 day
Avg. orbital speed: 6.795 km/s
Max. orbital speed: 7.128 km/s
Min. orbital speed: 6.486 km/s
Inclination: 0.769 86°
(6.48° to Sun's equator)
Longitude of ascending node: 74.229 88°
Argument of perihelion: 96.734 36°
Satellites: 27
Physical characteristics
Equatorial radius: 25,559 km
(4.007 Earths)
Polar radius: 24,973 km
(3.929 Earths)
Oblateness: 0.0229
Surface area: 8.084×109 km2
(15.849 Earths)
Volume: 6.834×1013 km3
(63.086 Earths)
Mass: 8.6832×1025 kg
(14.536 Earths)
Mean density: 1.318 g/cm3
Equatorial surface gravity: 8.69 m/s2
(0.886 g)
Escape velocity: 21.29 km/s
Sidereal rotation period: −0.718 33 day (17 h 14 min 24 s by convention) [1]
Rotation velocity at equator: 2.59 km/s = 9320 km/h
Axial tilt: 97.77°
Right ascension of North pole: 77.31° (5 h 9 min 15 s)
Declination: +15.175°
Albedo: 0.51
Surface temp.:
Surface
Cloudtop min mean max
59 K 68 K N/A
55 K

Adjectives: Uranian
Atmosphere
Surface pressure: 120 kPa (at the cloud level)
Composition: 83% Hydrogen
15% Helium
1.99% Methane
0.01% Ammonia
0.00025% Ethane
0.00001% Acetylene
trace Carbon monoxide
trace Hydrogen sulfide

No - it wasn't Uranus or anybody else's either.

Doc Watson · 03-03-07, 10:25 PM

A lunar eclipse occurs when the moon passes through the shadow of the Earth. When the moon is within the umbra (or darkest) part of the Earth's shadow (see illustration), it is illuminated only by the light refracted through the Earth's atmosphere. This light is usually orange or brick-red. Totality, the length of time the moon is totally within the umbra, may last as long as 1 hour and 40 minutes. Before the moon moves into the umbra, it passes through an area of partial illumination, called the penumbra. In the penumbra, the moon appears nearly the same as when it's in the full light of the sun.

Ohh... and I think I lost my marbles years ago.......

roaldin · 03-03-07, 10:44 PM

Hehe, I thought what we had here was a variation on the old Mars Uranus joke.

I was about to say I would need to see a decent pic' of David before I could comment.

If Uranus (the planet) ever gets between us and either the Moon or the Sun then hide under the bed, things are about to get a lot worse...

Tim.