Re: ISS Solar Transit

From: Debasis Sarkar via Seesat-l <>
Date: Wed, 28 May 2014 18:01:08 +0530
Thanks for your response. I have interpolated two images of ISS to show the
path I have got.

Kevin, you are correct. That was the reason I had my camera firing at 5fps.
It helped me in getting two frames with ISS on Solar disc although I did
not have 100% of the disc in frame as I was using a APS-C format cam with
F2000mm. The shift of ISS from center of Sun is not along its path but in
perpendicular to that. And that happens only due to parallax. Moreover, as
mine was a  4928 x 3264 pixel panel. I did not want it to have a drift of
more than 1 pixel during the exposure. So used 1/3000 sec exposure.

Leo, thanks for your response. you have mentioned a very important issue. I
have suffered twice earlier due to last minute orbital correction. But
here, in this case, I checked the predicted center line  around 65 minutes
before the T Time. Interestingly, even after 4 hours of the exposure, I
found my location being shown as on center line by Calsky. By then, they
must have incorporated the actual TLE that remained applicable at the T
Time of my shooting.

Could there be a reason - that the altitude of the place played a role?
Calsky, the altitude of the place considered by Calsky was incorrect as it
happens with many places in mapping softwares ?

Thanks and regards-
Debasis Sarkar

The frame with two ISS images on solar disc is here:

On Wed, May 28, 2014 at 3:07 PM, Kevin Fetter via Seesat-l <> wrote:

> Looking up the info on the pass, it happened around 5:50:43 utc.
> At the time, the sun was very high in the sky, so when the iss passed
> across the sun, it was travelling at a good speed across the solar disc. So
> when you when to take the exposure, the iss had moved a good distance away
> from the centre of the solar disk. You would need to capture at very short
> exposure times, and get a few images during the transit,  to hope to catch
> the iss at the centre of the solar disc.
> They say the camera you have, can capture up to 6 frames per second, so
> set the camera to do that.
> Kevin
> --------------------------------------------
> On Wed, 5/28/14, Debasis Sarkar via Seesat-l <> wrote:
>  Subject: ISS Solar Transit
>  To:
>  Received: Wednesday, May 28, 2014, 2:34 AM
>  Hi Friends,
>  I am new in this list and thanks for allowing me to be
>  here.
>  I am sharing a picture of ISS transit that I have taken on
>  17th May 2014
>  from a location lat=26.101400 & lon=87.984298.
>  The optics was Celestron SCT 8" with Nikon D7000 at Prime
>  Focus.
>  I have taken a Video too with Sky Watchers 120mm f/8
>  reflector fitted with
>  a HD Video cam.
>  Interestingly, despite being on centerline (Plus Minus 200
>  meters), I did
>  not get ISS to run through the center of solar disc.
>  Instead, I had it pass
>  through a distance of at least 1/4 solar radii from the
>  center of Sun.
>  Width of visibility path was 6km. I was following Calsky fro
>  the
>  prediction. Could you please enlighten me on what might have
>  gone wrong?
>  Thanks and regards-
>  Debasis Sarkar
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Received on Wed May 28 2014 - 07:32:27 UTC

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