Tuesday 14 April 2015

Iridium Flare on Thur Apr 16 - Orillia

Several of you have asked me for written accounts of what the Philae landing was like, and whether I would/could write a regular "colum" for some purpose. I do not know. I filled in for a friend 50 years ago to write a monthly article on something astronomical and topical and I found that very difficult.

I wanted to do something for Earth Day on Wed Apr 22 but that required more time than available so I thought I would try just for myself to prepare for this Thursday's very bright Iridium Flare and see what I need to learn about myself and the interested public. There will probably not be any feedback since the time afterwards is very "knapp".

This is the situation: a satellite, Iridium 10, in a nearly polar orbit will reflect an image of the sun along that red line. The sun spotlight will pass over that red balloon at 20:37:23 causing a flare nearly 70-80 times brighter than Venus. The flare will last only 1-2 seconds, believe me, and ought to be bright enough to cast a shadow even though we are still in twilight. Thursday's weather may be OK.

For more info on the Iridium Constellation of satellites click on this link. If you write to me I will give you instructions to where I hope to be observing this. Iridium flares are not rare but it is unusual to be so close to the track. The path is approx 50-60km wide; the satellite is above the horizon but nearly invisible for nearly 15 minutes and the flare turns on and off with very little warning to the uninitiated.. It is definitely a "WOW" event. In 7 days there are 22 flares from 20 different Iridium satellites. This is the brightest for me and I do not have to move/drive to see it.

Oh yes, about an hour later the ISS will cross the northern sky but that will be visible for everyone without too much effort. An interesting comparison.

The link to Heavens Above is here. Simply drag the orange balloon to where you are going to observe and raise the scale/magnifing bar as you zoom in. I change to satellite to locat my position to a meter or so.

Please write me to share your opinion of this - was it useful, interesting, a waste of time. Thanks. wob

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