Posts Made By: Steve Mathis

There is a stunning photo of a magnetic filament on the sun (taken be NASA's Solar Dynamics Observatory) over at Spaceweather.com. You should take a look!

Is this a quiz?

There are probably a bunch. Beta Caelum, mag 5.1, and Beta Reticuli, mag 3.9, are both listed at 55 LY. Both are in the far southern sky. Caph (Beta Cass) is at 54 LY, and Castor (Alpha Gem) is at 51 LY.

I regularly read Phil Plait's blog "Bad Astronomy". Usually pretty good. Yesterday, he had a blog about the recent total eclipse, and one of his buddies chasing the shadow in a plane. He wrote:

[COLOR="Blue"]They had more than nine minutes of totality to watch — that’s literally more than is ever possible on the ground, because a plane can "chase the shadow", counteracting the rotation of the Earth.
[/COLOR]
I was surprised to find such an inaccurate statement on the blog of a pro...so I made my first (and probably last) comment:

[COLOR="Maroon"]Oh for Pete’s sake. Chasing the shadow in a plane does not “counteract the rotation of the Earth”! It “counteracts” the orbital motion of the Moon, keeping the observer under it and thus in its shadow a bit longer. The rotation of the Earth is in the same direction (eastward) as the motion of the Moon’s shadow during an eclipse. Counteracting the rotation of the Earth would shorten, not lengthen the duration.[/COLOR]

Phil Plait actually responded, saying:

[COLOR="Blue"]Steve M: not sure I agree with you. To be entirely accurate, it would counteract all the motions involved summed together: Moon’s orbit, Earth’s rotation, and Earth’s orbit.
The Moon orbits the Earth at about 1 km/sec, which is roughly the same as the equatorial rotational speed of the Earth. So flying along the path counteracts both motions.[/COLOR]

I guess I should not have let my astronomy teacher instinct (and ego) out of the bag, but I still think he's wrong. The moon's shadow (like the moon itself) moves at about 2000 mph across the surface of the earth, which is moving at about 1000 mph (at the equator). Chasing the shadow in a plane has everything to do with the moon's orbital motion, and nothing to do with earth's rotation. What do you all think?

Maybe lots of good seeing across a big chunk of the country tomorrow morning. I've had some of the best views of Jupiter I can remember this past week, getting out around 5:30 AM. Seeing has been 4/5 on CSC here for 5 of the last 6 mornings.

Maybe lots of good seeing across a big chunk of the country tomorrow morning. I've had some of the best views of Jupiter I can remember this past week, getting out around 5:30 AM. Seeing has been 4/5 on CSC here for 5 of the last 6 mornings.

http://cleardarksky.com/f.php?Mn=photoshop&p=3S2112OklahomaOK

I shot this at 5:52 AM CDT this morning. Nikon D70 at prime focus of a 10" f/5.6 Dob, pushing it by hand to follow the ISS. I used a P-Clix timer to fire the shutter at 1 sec intervals, so all I had to do was keep the ISS in the field. 1/4000 sec @ ISO 800.

Not beer. I don't have a webcam/laptop setup, so I decided to try the old fashioned way of planetary photography. Eyepiece projection, and the hat trick. This Jupiter image is a stack of two frames, made with a 13mm Hyperion eyepiece coupled to the body of my Nikon D70. The exposure was made by quickly moving a piece of black matte board from in front of my C11 and back, an exposure of about 0.5 sec. The camera was set to ISO 200. The resulting images were big and smooth, and a couple were fairly sharp. The seeing was pretty good, or this would not have worked at all.

If you haven't seen it yet, you should check out Spaceweather.com to see Anthony's latest Jupiter image. The consensus is that it is the best amateur image ever. It is the best I've ever seen, for sure!

I tried again this year...sort of an obsession. This is 30 frames in a 3 wide x 10 tall mosaic, taken with a Nikkor 50mm lens @ f/4 on a modified D50. 6 min, ISO 1600. Darks and flats applied in DSS, stitched and beautified with PS CS3. When you span 110° of the sky and 4 hours of time, you get gradients a plenty! The full size version is about 12000 pixels square. Thanks for looking, comments are welcome!

Steve

Here is M27 from last week, 6 x 10 min @ ISO 1600 with a modified Nikon D50 through a C11 @ f/6.3. Thanks for looking, comments welcome!