ISS solar transit over Bangalore - 9th February, 2014

From: Sankaranarayanan K V <>
Date: Mon, 10 Feb 2014 13:21:08 +0530
This is what I could capture of yesterday's ISS solar transit event over

I am very thankful to this group who helped with the preparation -
specifically, Thierry Legault, Jon Mikel, John Locker, and Marco Langbroek.

Photography was done in two ways: 1. Using a Canon EF 100-400 lens at 400
mm focal length together with a 1.4X tele-converter (effective focal length
of 560 mm) on a Canon EOS 60D for still photography and 2. Using an Explore
Scientific ED 80 mm f/6 refractor on a Canon EOS 1000D for 1920x1080p 30
fps video.  Baader AstroSolar filter of visual density was used in both.
Tracking was done using a SkyWatcher NEQ6 Pro mount. The stacked image at
the link above is from the first setup.

The transit lasted about 2 seconds. The image is a stack of 10 frames
during those 2 seconds. Since this was my first attempt, I didn't want to
capture RAW images and stop the high speed shooting early - within 1.5
seconds of starting - which my camera body allowed. So I went for JPEG
still capture which allowed a longer duration of continuous high speed

The seeing conditions were not very good as the sun was low on the horizon
(19 degrees altitude) and the ISS was at a distance of about 1033 km
subtending an angle of about 26 arc seconds (0.43 arc minutes) compared
against Sun's angular diameter at the transit time of about 1945 arc
seconds (32.42 arc minutes).

I should aim to capture some structure of the ISS next time with better
sharpness and contrast. For now, I think, I am only imagining a thick H
seeing the image.

The following prediction sites and/or applications were used in locating
the place to shoot from and determining the timing:

   1. CalSky (
   2. Havensat (
   3. ISS Transit Prediction Android application (

Though there were variations between these tools some days prior to the
event, they all converged eventually closer to the event.

During the shoot, timing was obtained from a smart phone with GPS. The
Android app Smart GPS Time (
was used to time the event. This app shows both GPS derived local time and
the local clock time on the phone.

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