Revisiting Jupiter's Moons
 

I went back to Jupiter tonight. Not too hard to do as it's still the brightest "star" in the sky for the northern hemisphere and doesn't set until after midnight. This time I used the H1's stock 20x HD lens at maximum focal length, combined with the Canon 1.6x extender in back and a Century Optics 1.6x teleconverter in front.

So the focal length in 35mm terms is: 5.4mm x 20 x 1.6 x 1.6 x 7.2 = 1990.7mm (roughly).

Here are two shots... IMG 5310 was made without using a custom preset, and IMG 5312 was made with a specific custom preset. I've included crops to better show the differences between the two. And another image, so you can tell which moon is which, if you're into that stuff like I am. Be sure to click on 'em to view at their full size.

Both images were taken at f/5.2 at 1/4 sec. with 0db gain.

The preset settings? BGN -9, BRM -9, BGM -9. What a difference it makes!

P.S. -- charting Jupiter's moons is easy when you have the app:

http://skyandtelescope.com/observing...cle_830_2.asp#

Chris, we've kicked around the idea of getting a good quality telescope to use up at Lake Texoma. There's too much light pollution here. What would be your recommendation?

-gb-

Oh boy, don't get me started. It's kind of like choosing a guitar. Or a camcorder! Heh. I think the important thing for you is, will you leave it at the lake house or take it with you back and forth. If you're going to haul it around, then I'd suggest a medium-sized Schmidt-Cassegrainian, which is kind of a stubby little thing that's fairly transportable. They're a little more expensive but worth it.

If it's something you can leave in Texoma, then the same money will buy you the 3/4-ton extended-cab pickup of all telescopes, an eight-inch f/6 Newtonian reflector with a good German equatorial mount. Bigger, robust, not as delicate.

For real fun, build your own -- I did, twenty years ago. And it still works!

Here's a good place to start before going shopping: http://www.astronomy.com/asy/default.aspx?c=ss&id=9

Mars is coming!!!!!!!!!!!!!
 

Chris,

Does this mean you have an XLH1 now? Shots are cool!

Thought you guys would like the following info, which was sent to me by a friend. I keep it handy so as to remind me.

Mars is coming.


The Red Planet is about to be spectacular!

This month and next, Earth is catching up with Mars in an encounter that will culminate in the closest approach between the two planets in recorded history. The next time Mars may come this close is in 2287. Due to the way Jupiter's gravity tugs on Mars and perturbs its orbit, astronomers can only be
certain that Mars has not come this close to Earth in the Last 5,000 years, but it may be as long as 60,000 years before it happens again.

The encounter will culminate on August 27th when Mars comes to within 34,649,589 miles of Earth and will be (next to the moon) the brightest object in the night sky. It will attain a magnitude of -2.9 and will appear 25.11 arc seconds wide. At a modest 75-power magnification


Mars will look as large as the full moon to the naked eye. Mars will be easy to spot. At the beginning of August it will rise in the east at 10p.m. and reach its azimuth at about 3 a.m.

By the end of August when the two planets are closest, Mars will rise at nightfall and reach its highest point in the sky at 12:30a.m. That's pretty
convenient to see something that no human being has seen in recorded history. So, mark your calendar at the beginning of August to see Mars grow
progressively brighter and brighter throughout the month. Share this with your children and grandchildren.

NO ONE ALIVE TODAY WILL EVER SEE THIS AGAIN

Oh wow, I sure hope not... we're all in serious trouble if it does!

My mom sent me that exact same text a couple weeks ago, which is actually from the 2003 Mars-Earth close opposition. I assume that either out of innocent mistake, or perhaps to carry a trojan horse, someone has started this old info propagating on the 'net as if it applied to 2006. In point of fact, Mars will be on the opposite side of the sun from earth in Aug/Sep, at about 2.5 AU in August.

EDIT: For those interested, a smart guy at JPL has done this Java applet:
http://mars.jpl.nasa.gov/allabout/ni...marsearthorbit

I had the good fortune to be in Yosemite National Park on a night on or around the 2003 Mars opposition, and the Mt. Diablo Observatory skywatcher's club had come down from the Bay area in force with a wide variety of scopes which they shared with the public. It was a wonderful sight to see Mars rising in dazzling red brilliance over Half Dome from a front row seat at Glacier Point; I'll never forget that experience. Here are a couple of shots from before sundown...

Well, now I'm pis*ed! You might remove it so someone doesn't get fooled like I did. I hate it when people do that, I guess they are just trying to cause trouble and get attention for themselves.

Sorry-----Mike

Unfortunately, that kind of thing is just part of the modern electronic landscape. Even within the military, I've seen where some Exec Officer or First Sergeant (and even once or twice a fairly high office within the Pentagon!) got spoofed by an "urban legend" sort of thing and sent out an unnecessary "APB" to hundreds or thousands of people. Then the emails REALLY start flying when the spoof gets challenged.

Ah well, we shrug our shoulders and carry on!