Hi Al, everyone.
This thread caught my attention a day ago.
I'm not sure if this project is really suitable but it does do time
overlays with a bit of programming and a PC.
I built this years ago for doing Jupiter occult stuff with mini PCB
video cameras.
It's based on the STV5730A video overlay chip which can be
programmed easily via the I^2R bus serially.
Here's a link to a quick google of STV5730A.
http://www.alternatezone.com/electronics/vtg.htm
I mounted it in a box along side a video splitter module which was also
very handy ...needing to record signal and view on a monitor
at the same time.
This was an EA project Aug 99 and a follow up project with easy
AT keyboard interface Oct 99.
Quite out of date technology nowadays anyway.
Another alternative is using a webcam with time date stamp function
software.
There are literally dozens of freeware apps that can do this and also
upload to FTP for webcasting or checking on your remote
observatory etc.
I use ATComedy32 webcam software (free) and it FTPs my site at
whatever interval I choose. Here's a shot:
http://mywebsite.bigpond.com/astrosteve/livewebcam.jpg
It obviously can be used to webcast or send live feed (minus processing
and HD delays) to the HD.
Steve