Shape of the Earth's shadow

Hi all,

Fantastic pictures from everyone. Well done!

The sky misted up during the partial phase and by totality it was very hard to see the Moon with the unaided eye. The overall impression was of an enlarged Mars complete with Polar Cap.

The 10x50 binoculars showed up the colour well enough but probably not as good as under a clear sky.

What struck me though was the asymmetrical shape of the Earth's shadow during the partial phase. In the 10x50s the shadow sloped gently up from the right limb (with a slight notch in the shadow at the limb itself) and beyond the centre part it sloped back towards the left limb at a slightly steeper angle. It'd probably be better to do up a diagram of what I saw so will try and scan something later in the week.

Anyone else spot anything unusual about the shadow????

John

John --

Sorry to hear about your weather. Up in Louth the high clouds and water vapor didn't roll in until about 20min after midnight (when the moon was coming out from the shadow).

I didn't note any odd shape to the shadow, but I did find it interesting that the Earth's shadow entered at a position angle of about 7 o'clock, yet after totality the moon brightened first at a position angle of about 10 o'clock. I would have expected the shadow to traverse more linerally, but I guess the movement between the 3 bodies is more complicated even over an hour or so than one would expect.

(Oh, and even under clear skies the Mars impression -- complete with polar cap -- was quite striking.)

-- Jeff.

Jeff,
the reason for the positions for entering and leaving the shadow at those positions is because the moon did not pass through the center of the umbra, it passed through the left hand side of it.
The Mars effect was amazing especially then leaving the umbra.

Dave --

Ah... makes sense. How wide is the shadow? Would I have needed to go to Galway or somewhere like the Canary islands to get the full effect?
Or was it that the Earth/Sun/Moon positioning wasn't completely lined up?

-- Jeff.

How wide is the shadow? Would I have needed to go to Galway or somewhere like the Canary islands to get the full effect?
Or was it that the Earth/Sun/Moon positioning wasn't completely lined up?

-- Jeff.

Hi Jeff,
I found on the net that the widest part of the Earth's shadow at the point that the Moon crosses it is 16,782km. To have seen a conentric (right word?) lunar eclipse, you would have had to be about midway into the Atlantic from our latitude. People much further east of us would have seen a partial phase - the upper right of the Moon from their perspective would have been in 'daylight'. Likewise, people west of America would have seen the lower left of the Moon in 'daylight' as a pertial eclipse.

Seanie.

This one here, taken at 2223 GMT shows that the cone of the Earth's umbra had a bluish outer section and a copper inner section. I don't think the NW part of the Moon ever completely cleared the bluish section.



Clear skies,

Paul.