Re: ISS Solar Transit

From: Debasis Sarkar via Seesat-l <seesat-l_at_satobs.org>
Date: Thu, 29 May 2014 01:34:27 +0530
Hi Ted,
Thanks for your interest. Pl see the image here
https://www.flickr.com/photos/sky-watchers-association-of-north-bengal-india/14103590419/

The movement was in the direction from 5:00 O clock position to 9:00 O
Clock position. Means, the position of ISS at right lower position came
first and then the left middle position. Please note, I took this with a
SCT loaded on a EQ mount. Hope this can give you the direction of ISS
movement.
Regards-
Debasis Sarkar


On Wed, May 28, 2014 at 9:56 PM, Ted Molczan <tedmolczan_at_rogers.com> wrote:

> Hello Debasis,
>
> I am interested to attempt to explain the discrepancy between the
> predicted and observed track. Could you provide me
> with the other image that shows ISS against the solar disc? Please
> indicate which image was the earliest in the
> sequence.
>
> Thank you,
> Ted Molczan
>
>
> > -----Original Message-----
> > From: Seesat-l [mailto:seesat-l-bounces+ssl3molcz=rogers.com_at_satobs.org]
> On Behalf Of Debasis
> > Sarkar via Seesat-l
> > Sent: May-28-14 8:31 AM
> > To: seesat-l_at_satobs.org
> > Subject: Re: ISS Solar Transit
> >
> > 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:
> >
> https://www.flickr.com/photos/sky-watchers-association-of-north-bengal-india/14103590419/
> >
> >
> > On Wed, May 28, 2014 at 3:07 PM, Kevin Fetter via Seesat-l <
> > seesat-l_at_satobs.org> 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 <seesat-l_at_satobs.org>
> wrote:
> > >
> > >  Subject: ISS Solar Transit
> > >  To: seesat-l_at_satobs.org
> > >  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.
> > >
> > >
> > >
> https://www.flickr.com/photos/sky-watchers-association-of-north-bengal-india/14024037178/
> > >
> > >  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 - 15:35:22 UTC

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