AncientBrit wrote:Hi Harry,
re the star in the centre of the lens the zoom lens that formed part of the colour camera I took apart to make my NBTV saticon had a form of auto-iris.
Sorry Graham should of checked for some reason my reply didn't post !
So Its not the iris Graham..in the photos it looks like it is just the photo angle off the black part of the iris the Star is a transparent .
With power off the iris was pulled closed by means of a small spring.
Yes i worked that out now have it just wired open fully .
The iris was mechanically connected to a solenoid and when power was appled to this solenoid the iris fully opened.
I didn't try to power it open there were a few wires reminded me of a stepper motor so i just took the easy way out .
Looking in the handbook I bought it appeared that the solenoid was fed with some form of PWM signal so its effective power could be modulated thereby opening or closing the iris a measured amount.
Yes looked a little to much work to bother with when just wireng it open so it doesn't spring back any more i just wanted all the light and not bother with that part .
The Star is a transparent sticker i think i took the 3rd lens i had apart and its between the first 2 lens thats closest to the target apart of the image tube .
I would need to cut it open to see for sure ..i can only think its used when the camera is fully in sun light and the iris is shut a fair amount do that part is used perhaps as a filter of some sort ..i still don't understand why its not seen in the image if the iris is fully open unless the size of light to the target is always around under the size of that transparent star.
Its used in 3 different brands of camera i scrapped..
In my camera I applied the full voltage so on power up it fully opens the iris, so I have to drive the camera on Target volts alone.
Thats what i was thinking its no use for what we want so just open it fully.
Could the star be an iris which is fully closed so it cuts off most light??
Are you getting light through the lens??
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Yes i am getting light past the lens i made sure before i put it back on the image tube and with a light test seems to work also i can tell with focus the light level changes so i again hope this is a good sign .
Sorry the muck up in replying !
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.