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Old July 31st 03, 02:59 PM
Reece Watkins
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Default Processing VHS Images

(Jb2269) wrote in message ...
This morning Rick and I imaged Mars for ~2 hours using a Mintron XE on a
Meade 12.5" RG Newtonian at f = 24. During periods of a few seconds of steady
seeing rich detail could be seen on the monitor. How can I process the string
of images on VHS tape into individual pictures for stacking? This camera also
has a s-video output and I have heard that this can be used to download
pictures directly to my HD, bypassing intermediate storage on tape. Has anyone
done this?
Bill Bambrick
41 N, 73 W, 95 ASL


What you need is an analog video-capture device, either a PCI card or
an external USB device. Dazzle and Pinnacle are two companies off the
top of my head that make this sort of thing. (I can't recommend a
specific model, because I do all my videotape capturing digitally via
FireWire off a MiniDV camcorder.) Hook up a VCR to the vid-cap
device, cue up the tape to the point where you thought you saw a good
image or two, and start the vid-cap program.

Keep your captures short, and do NOT use any form of compression on
the incoming stream. You always want to use the AVI - Uncompressed
format to avoid any loss of picture data. Since each frame will be
stored fully, the file will be very large, multi-megabytes at least.
Several programs, like the freeware RegiStax can open the video AVI
file directly as frames for stacking. Choose the best few and start
from there. Some programs will let you de-interlace the video frames
to clarify the individual images.

To be honest, though, VHS isn't a very high-resolution format. The
s-video will help, but VHS typically has about 240 horizontal lines of
resolution, and that's split between the two interlaced frames. If
your computer is portable, you can use the S-video feed from the
camera to capture directly. S-video has over 400 lines of resolution,
and you don't have the generational loss of going to tape and back.

Good luck!
Reece Watkins