Rambling travelogs from a world traveler

Wednesday, February 16, 2011

Lunar Venus Eclipse

"It has been conclusively demonstrated by hundreds of experiments that
the beating of drums will restore the sun following an eclipse." ~ James Gregory

Gentle Readers and Loved Ones,

As most of you know, I'm an astronomy geek. I've made one or two astronomical posts here on this blog. Tonight I saw this picture and it set my inner geek free. Please remember you can click on all of these pictures to blow them up larger.

What you see is Venus and the moon just minutes after the moon has eclipsed Venus in the daylight. Both Venus and the moon are relatively close to the sun so that they show as early crescents. I stole the picture from this NASA website. A Hungarian Photographer / Astrophotographer named Ivan Eder took this picture just after noon on May 21st, 2004.

I have a great astronomical mapping and planetarium program written by Chris Marriot called Skymap. This next picture is setup for Budapest on that date and will give you a rough idea of how the sky might have looked if you could see the planets and the stars in the bright blue sky. In fact, you probably would have needed a pair of binoculars at a minimum to have seen the moon and Venus. Mr. Eder used the very nice TMB 130 refractor at the bottom of this page.

This map faces due south, west is to the right east to left. The straight up zenith is at the top center. Therefore, the moon and Venus would have hung up high in the southeast.

Skymap will let you set the heavenly bodies in motion exactly as they would have in reality. As I set about doing that I discovered some new things. (Not the least being how to make an animated gif file.)

The astronomy of this eclipse is such that it could only happen in the day. But if it had been a deep dark night, this eclipse would have occurred over the top of some interesting deep sky objects. This image will show you that. When you click on it, it will move and show you the eclipse. Please do not click on it yet.

The green arcs in this picture represent the very faint supernova remnant Simeis 147 (Sh2-240). If you click that link you see a picture of it using a 25" telescope that dwarves the little scope that Mr Eder used. The link says that Sh2-240 is one of the faintest objects in the sky and requires hours of exposure using a camera just to 'see' it. At the bottom right of the picture are two green circles. These represent the open star clusters DoDz 3 and 4.

Back to the eclipse. If you click the picture, the moon and Venus will move and give you a taste of the geometry of the eclipse. The first frame starts a 11 am Budapest time and runs at one hour intervals until 3 in the after noon.

I filtered the star brightness to declutter these pictures. The dimmest (and therefore smallest star in the picture is about Magnitude 8 or about the dimmest you can see with a pair of binoculars. The brightest is about Mag 5 and would just barely be visible with your naked Mark I eyeball.

I hope you found this as cool as I did. On that note, I remain,

Dad / Geoff

Sunday, February 13, 2011

Zoom and Boom

It's better to be down here wishing you were up there, than to be up there wishing you were down here.

Gentle Readers and Loved Ones,

A friend just sent me this wonderful video. Please watch it now.

Like some others that read this blog, I have a little experience in zooming and booming. I found that video fascinating.

In general, one is not supposed to make a boom close to the ground unless one is operating in "Special Use Airspace" specifically set aside for such activity - these areas mostly exist in the western desert and off-shore. Booming San Francisco Bay is most definitely not such airspace - but the Blue Angels are special too so I guess they get a pass......

The perspicacious reader will have noted that the movies on the ships are way out at sea where such rules no longer apply.

As I have mentioned in other posts, I instructed in the T-38. The student syllabus contained one supersonic flight. It was regulatory to perform this boom ride over 30,000' above mean sea level so that your shock cone did not reach the ground and upset civilians and harm the environment. At that altitude, the only way you could tell that the T-38 was supersonic was by looking at the mach number on the airspeed gauge. If you started around 40,000' in a slight descent, you could get up to Mach 1.2 or so. It was in fact pretty underwhelming.....and you had to complete paperwork when you landed. Most guys didn't like doing it.

High speed, low altitude flight on the other hand is about as exciting as it gets.

When I was a cadet at the Air Force Academy it was accepted as gospel that a flight of F-105s had boomed the zoo in the 60's. As the story goes, they had broken a LOT of windows out of the glass filled architecture that is the Academy. We all retold the story not really knowing what we were talking about but loving a good story. This is the way of many urban legends.

In this modern day of google, I decided to see what the internet contained. I found this fascinating link and this picture:

So, it's not such a legend after all....

I remain,

Dad / Geoff