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Posts Made By: Alan French

June 30, 2007 06:33 PM Forum: Astro-Physics

Made in America Reruns

Posted By Alan French
I happened upon Made in America while channel surfing, and got to wondering if their visit to AP would be on again in the reasonably near future.

I found the visit to AP is scheduled for three dates in July on the Travel Channel...

July 24 at 10:30 PM
July 25 at 1:30 AM
July 28 at 2:30 PM

Just in case anyone hasn't caught the segment yet, or wants another look. Check your local listings to be sure.

Clear skies, Alan

July 2, 2007 08:48 PM Forum: Insects - Flowers and Other Small Stuff - Photos

Chicken Mushroom

Posted By Alan French
In my wanderings yesterday I encountered a log covered with lovely mushrooms. They seem to be called Chicken Mushrooms.

Clear skies, Alan

July 7, 2007 01:59 AM Forum: Equipment Talk

Re: Dawes' limit and the human eye

Posted By Alan French
As your eye's pupil opens, aberrations of the eye increase. It doesn't work as well wide open. Try some binoculars with a 6 or 7mm exit pupil after your next eye exam when your pupil is "wide open."

Also, the dark adapted eye has poorer resolution than our day eye. The cones are responsible for the best resolution. Rods are more sensitive to motion (and to light).

Clear skies, Alan

July 8, 2007 01:22 PM Forum: Refractors

Minimum Aperture for Planetary Viewing?

Posted By Alan French
I'm curious. What is the minimum aperture apochromat or achromat you'd consider for your serious planetary viewing?

Thanks!

Clear skies, Alan

July 9, 2007 02:08 PM Forum: Equipment Talk

Re: how come we never see these on the 'mart

Posted By Alan French
I'll wager sales are sparse to non-existant. For a relatively modest $27K you can get a nice 200mm f/8 fluorite from TEC, and it would probably be every bit as good as the Tak, and perhaps a bit better.

Clear skies, Alan

August 1, 2007 09:55 PM Forum: Solar System Observing

Ganymede Passing through Jupiter's Shadow Tonight

Posted By Alan French
For folks on the east coast, the timing is wonderful for a passage of Ganymede through Jupiter's shadow tonight. You can watch it fade from view as it enters the shadow, and reappear as it leaves the shadow.

9:42 PM EDT III EcD - Ganymede will move into Jupiter's shadow and fade from view.

The portion of the Jupiter's shadow that Ganymede will pass through is entirely to the east of Jupiter. Ganymede will be just east of the planet, and will be moving farther away from Jupiter as it moves into the shadow.

12:06 AM EDT III EcR - Ganymede will move out of Jupiter's shadow and again become visible.

Ganymede will appear from darkness when about 1 Jupiter diameter east of Jupiter.

Callisto will be east of Jupiter, and Io and Europa will be to the west.

Jupiter will set at 1:25 AM on August 2.

Clear skies, Alan

August 4, 2007 01:29 PM Forum: Solar System Observing

Transit of Io Tonight (8/4)

Posted By Alan French
The Red Spot transits at 9:43 PM EDT tonight (Sat, 8/4).

Io begins a transit across the face of Jupiter at 7:27 PM EDT, during daylight. The Sun sets at 8:13 PM EDT.

8:35 PM EDT I ShI - The shadow of Io moves in front of Jupiter (from the east)

9:37 PM EDT I TrE - Io moves off the planet (to the west)

10:46 PM EDT I ShE - The shadow of Io moves off the planet (to the west)

Ganymede will be east of Jupiter, and Europe and Callisto will be to the west.

A magnitude 9.4 star will be east and somewhat north of Jupiter, and a 4.4 magnitude star will be west and somewhat south. There is another magnitude 9.9 star southwest of the 4.4 magnitude star.

Jupiter sets tonight at 1:14 AM EDT (Aug 5).

Clear skies, Alan

August 5, 2007 01:09 PM Forum: Insects - Flowers and Other Small Stuff - Photos

Promethea Moth

Posted By Alan French
Here is a shot of a Promethea Moth that posed nicely on out back deck one year.

Clear skies, Alan

August 7, 2007 01:59 PM Forum: Solar System Observing

Europa Transit Tonight (8/7)

Posted By Alan French
9:49 PM EDT II TrII - Europa moves in front of Jupiter (from the east).

Seeing a satellite itself in front of Jupiter can be difficult. It depends a great deal on the coloration of the moon and the coloration of the region of Jupiter it passes in front of, and on the seeing.

The easiest way to see one of the moons in front of Jupiter is to watch it as it begins the transit, and see how far across the planet's face you can follow it. For east coast, this transit of Europa provides a fine chance to do this.

For folks farther west, here are the times for the shadow ingress, transit egress, and shadow egress.

4:11 UT II ShI
4:24 UT II TrE
6:46 UT II ShE

Clear skies, Alan


December 23, 2007 04:38 PM Forum: Equipment Talk

Fifty Years of Progress

Posted By Alan French
Comet Arend-Roland was one of my first experiences with enjoying the night sky. It is a bit frightening to realize that was fifty years ago, but it also got me thinking how much the world of amateur astronomy has changed since then. There are so many things we have today that were not available back in 1957.

1. Large, relatively portable Newtonians with quality optics.
2. High quality apochromats.
3. High quality, portable mounts.
4. Tracking altazimuth mounts with GoTo.
5. Digital imaging (amazing deep sky and solar system abilities).
6. A choice of conventions near virtually every new Moon.
7. Well corrected, wide field eyepieces.
8. Short focal length eyepieces with good eye relief.
9. Internet "astronomy communities" (help is close at hand).
10. A wealth of information right at hand via the web.

I am sure there are many more, but those are the ones that come to mind easily and quickly.

Clear skies, Alan

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