Recently, a customer came in to buy a telescope.
He settled on a Meade computerized model, that cost around $1700.
Since he was going to use it in the field, we suggested that he buy an
optional power adaptor, to go along with it, since running it off "D"
sizes batteries would be a costly expenditure.
As a rule, most computerized telescopes do not lend themselves well
to running off rechargeable batteries, due to the power loads required
they will only work for a short period of time.
He said that no it was ok, and that he would use a "universal power supply"
that he already had at home.
Now, this is where we immediately warned him that would not be good idea
due to possible polarity or voltage issues. It could damage the expensive
electronics in his scope, and the manufacturer would not consider it a
warranty issue, should a problem occur.
You can probably guess where this story is going now.
Sure enough, he was back a few days later, with a telescope that did not work,
because the main board had blown.
By the time the fuse kicked in, the damage was already done.
And now a telescope that has to be repaired. :(
Different brands of telescopes, use different amperages and voltages.
It's always a good idea to buy the manufacturer's recommended ac or dc