Re: [ATM] Tracking Systems for Astrophotography

[Dominic-Luc Webb <dlwebb@canit.se>]

> ADCs after the
> four current to voltage opamps would allow digital processing  and
> conditioning including digital LPF and HPF for us.... SNIP


Easier said than done! Have you actually built a decent I to E
opamp circuit that draws from a PIN? I have been trying and this
has proven to be a very difficult circuit. Most of the circuits
I have seen could just as well skip the opamp because of the
trivial amount of gain. I do not know how the remote sensors for TVs
work, but these are typically orders of magnitudes more sensitive
than other opamp circuits I have seen or built. According to this
reasoning, I propose saving some money by swapping out the image
intensifier for a sensor from an old TV that has a good
sensor. I think these are supposed to operate only around 38 Khz,
but maybe these are filters below whatever is used to get the gain.
However this is done, the TV remote sensors are very sensitive
compared to what most people could build themselves and are
readily available.

Hope this helps....


Dominic-Luc Webb

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