Planet X: Mar 6 Nebula Ghost?
It appears from correspondence with the scope owner that someone took an
image of M42 prior to the Mar 6 single image taken. How convenient for
Arnie said the following to me using Yahoo Messenger.
arnierosner(9:51:21 PM [EST 3/7/2003]: It looks like there was some residual
charge left in the camera previous to your first image. The Orion Nebula is
clearly embedded in the background.
arnierosner: OK. I seem to remember another client taking a 120 second image
of m42. It was probably before your image and it left a latent image on the
chip because it was so saturated.
arnierosner: I just don't remember what days this occured or the sequence of
From: John P. Oliver
Sent: Friday, March 07, 2003 1:01 PM
Subject: Hoax or Mistake?
Arnie: I assume that the image take by Naji posted at
http://www.zetatalk.com/teams/rogue/naji23.htm was taken with
one of your scopes. As presented it is clearly a superposition
of an image of the Orion nebula M42/43 onto a different star
field. Could you look at your logs and see if by chance the same
scope imaged M42 immediately before Naji did his image and it
left a ghost?
What I, Nancy, am not understanding is why the nebula came through as a
ghost, but the intense STARS in the center of the nebula did not! Are
they not more intense than the nebula?
From the technical description of how a ghost works, would not the STARS
transfer more readily than the nebula itself? Yet they are missing.
If the cloud was there, it should have showed up on the
images that I took the next night [Mar 7] as well.
The CCD controller can give a "short circuit" signal or as
they call it a reset signal to erase CCD contents. It's more like a
capacitor discharge. This short circuit is based on transistors,
which have resistance. Its more like a resistor than a short
circuit wire. It takes time to discharge. The default timing is
enough for most applications. It must be a controller malfunction,
and/or the user before me took a really very long bright exposure.
I think its the first, a controller malfunctioned and didnt apply
reset as it should be or didnt apply a long enough rest signal,
or the reset signal was not received correctly by the CCD (most
likely cause). Electric noise can affect controllers signals, and
thus misinterpreted by the CCD electronics.
One way to avoid this is by taking a short dummy image and
through it. This does not happen very often.