Re: "A method for optimal image subtraction" on TASS WWW site

[Chris Albertson <chris@topdog.pas1.logicon.com>]

CA:
>  *>One problem is our frames don't line up well at all.  They are cut
>  *>up into short segments of RA and the three cameras are not "in phase".

HJ:
> For testing, we can "hand align" if that makes sense. Presumably an
> automated process could use the same algorithms we use to find RA and
> dec based on reference stars, at least to the nearest pixel. Again, try
> and see what we get: it can't be worse than half a pixel or so...well,
> maybe root 2 over 2 (.707), there is always a root 2 in there.....!

What I meant by "out of phase" was that the frames from different
cameras or the same camera night to night do not have the same
RA boundaries.  Take any two TASS image frames and typically you
get only a half frame in common.  In other words TASS frames don't
stack well.  What would be needed is to re-assemble the frames into
a long strip then cut them on even degrees of RA.  Maybe every
three degrees.  This is not hard to do.  I just wanted to point
out that the current set of images don't stack.


--Chris Albertson

  chris@topdog.logicon.com                Voice:  818-351-0089  X127
  Logicon RDA, Pasadena California          Fax:  818-351-0699