AURORA SEASON
 

Nice movie.
But how could ISS be recorded
on the very bright and shiny
surface of the sun ?

helmsman wrote:

Space Weather News for August 24, 2003
http://spaceweather.com

AURORA SEASON: In less than one month Northern autumn will begin--and
that
means aurora season is beginning, too. Geomagnetic storms tend to be
most
intense during the weeks around the September equinox because the
interplanetary magnetic field (IMF) near Earth tips farther south than
usual at that time of year. South-pointing IMFs encourage auroras.
September and October are usually best, but already in August sky
watchers
from Canada to Arizona have been enjoying colorful Northern Lights.
Visit
Spaceweather.com for more information and pictures.

SPACE STATION BONUS: A Swiss astronomer has recorded a remarkable
movie of
the International Space Station (ISS) crossing the face of the sun.
See it
on Spaceweather.com.

Probably used a sun filter which blocks a considerable amount of light, and
perhaps reduced the size of the aperture (stopped it down).

On Mon, 25 Aug 2003 11:01:18 +0200, Igor Gros wrote:

Nice movie.
But how could ISS be recorded
on the very bright and shiny
surface of the sun ?

You need to filter out a LOT of sunlight to photograph it. When you do so, even
cooler parts of the sun will look dark. Notice the sunspot picture at the top
of the page under "Daily Sun".

Igor Gros wrote:

Nice movie.
But how could ISS be recorded
on the very bright and shiny
surface of the sun ?

A solar filter is usually (properly) made by coating a clear plastic
film with a very thin layer of aluminum using a process called vapor
depositing. The aluminized film is mounted in a frame which is placed
over the open end of a telescope or camera lense. This kind of filter
blocks out more than 99% of the suns light and is really the only safe
method of looking at the sun directly through a telescope, binoculars or
SLR type camera. You can also view the sun indirectly by projecting the
image through the eyepiece of a telescope (w/o a filter) on to a small
white screen placed near the eyepiece.


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