Hello Fernando,
I would usually start with "technical issues" first. Here is an
example of why this is.
Here is a 2 frame animation of 70 Virginis (one of the first stars
discovered to have an exoplanet and dust disk) taken in the red light
by the Palomar Sky Survey, taken a few decades apart.
http://setisociety.org/70-VIRGINIS-TWO-RED-DSS.GIF
Notice the 3 objects that disappear from beneath the star. As this
star was one of the first ones discovered to haven an exo-planet, I
had to investigate this curious trio of star-like objects in detail.
I gained access to a University of Central Florida's printed copy of
the National Geographic Society sponsored printing of the Palomar
survey plates for the first observing runs (these are thousands of
large printed glossy photo-quality images of the original plates that
were donated years ago by University of Florida to U.C.F. and had
never been digitized and were printed before digital images existed.)
The 3 objects indicated in the image above were not evident in the
printed versions that were created before the computer age. I would
attribute them to some kind of processing artifact (although I cannot
imagine how that could happen in that fashion.) One astronomer said
it could have been from spilled coffee :^)
If one looks at the DSS/Palomar images for awhile, expecially doing a
blink-comparison, one can find that virtually every image has an
artifact of some kind: hair, blotches, scratches etc.
I wish it were otherwise for the trio of objects near 70 Virginis in
the first DSS Red image; I had even expanded the field of view to
several degrees to see if I could re-find/recover the trio (if it were
very fast moving or local) but I couldn't find them in any subsequent
Palomar Survey/DSS plates, and like I said, they didn't appear in
early National Geographic Society prints of the plates showing 70
Virginis, but the trio appears only in the online digital version.
Regards, Jason Higley
___________________________
On Jul 3, 2:47 pm, Fernando_Setibrasilia <walter.dt...@gmail.com>
wrote:
> Very interesting this GIF! We can see variations in the scenario: some
> moving bodies, some fluctuation in brightness here and there, some
> 'traces' can be seen in the plates. Are these technical issues or
> asteroids/artificial satellites that were caught in the action? when
> these plates were taken?
> Regards!
> On 27 jun, 16:22, "Jason H." <exosea...@yahoo.com> wrote:
> > I've created the following animation of images centered on where a
> > major nova burst occured in 1901 from DSS image plates (shot over a
> > time span of decades) to create this 2 frame animation of the
> > expanding shell of hot gas (moving >1200 km per hour)
> >http://setisociety.org/GK-PERSEI-OVER-DECADES.GIF
> > I learned of this variable from the AAVSO website, as nowadays Nova
> > Persei 1901 is known to variable star observers as GK Persei, with
> > very regular outburst or flare-ups in brightness approximately every 3
> > years, you can see a chart of this at
> >http://www.aavso.org/images/LTGKper.gif
> > and here's a Wikipedia article on it
> >http://en.wikipedia.org/wiki/GK_Persei
> > Regards, Jason H.
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