Hi Roland,
The timer idea certainly works well for manual imaging where the
operator is available to set the timer once a target is dialed in.
That is basically what I used to do before I started automated
imaging with automated meridian flips and multiple targets. This
solution will not work at all for automated imaging. In automated
imaging, the mount can be sent at any time to a target that may be
very near or 6 hours away from a required flip. In order to set the
timer, there would need to be a program that determines how far away
from the flip that the target is when the mount is sent to this
target. The target call could be a a given time, or after some
preprogrammed sequence, therefore, it is not simple to calculate the
time before the required flip. This is possible by programming some
software to read the automated imaging program, then determine the
proper timeout, and then setting a programmable timer. There are
some of us pursuing this type of trap; however, since this requires
much of the software to be operational, we would use the trap to
send a signal to the mount to park rather than simply turn off power.

The type of error that one is protecting is when the computer or
software gets stuck and the mount keeps on tracking. That is why a
physical limit is preferred although having both is even better.

I haven't seen such a mounting (that allows all mount positions and
tracks through meridian without interference) unless you are
referring to a fork mount (and even these usually have stay out
zones). A standard straight "pipe like" pier runs around $700 and up
for the AP 1200 and I expect this unique pier would be quite a bit
more, but that is simply my speculation.

I am continuing to pursue both a mechanical and a software solution
and am very open to suggestions.
Thanks, Rick


--- In ap-gto@..., chris1011@... wrote:

One of our local astrophotographers uses a simple alarm clock

which has a

built-in 110 volt outlet. he plugs the power supply into the alarm

clock, sets

the time for the alarm to go off and goes to bed. When the preset

alarm goes

off, the scope simply turns off and cannot hit the pier.

Of course, then there's the time honored astrographic mounting,

where the

pier is made in a bent configuration, allowing the scope to clear

underneath at

all declination settings. It would not be that difficult to make

such a pier

for a permanent observatory.

Rolando

In a message dated 7/9/2007 3:29:03 PM Central Daylight Time,
rickwiggins@... writes:

Hi Roland,
I have a few items to post here:
1. I would love to see an option to add a microswitch shutoff
capability to the AP mounts (see below).

2. A software version would also be nice, but of course these

rely

on computers for remote applications. A version for the
handcontroller would be nice for single session portable imaging.

3. My current design: I designed and built a relay box to shut

off

power to my mount (or anything) when it receives an input from a
microswitch. It requires a microswitch and a trip block to be
installed on the mount. One of the devices can be attached to

any

stationary section of the mount and one must be attached to the
moving portion of the mount (most likely, I will mount the block

to

the moving section). When the block hits the switch, it triggers

the

relay to shut down power. I designed the system such that I can

turn

off the switch to allow resetting of the system or simply defeat

the

system. I have not determined a best method of mounting the

switch

and would love to get ideas from you or the group. So far, I

have

considered using strong double sided tape, epoxy, or silicone to
attach the devices to the mount. Obviously, this design does not
easily accomodate adjustment, but works fine for a permanent,
automated observatory. I can make a section of the trip block to

be

removable to accomodate tracking past the meridian when desired.

If

you were to build in this type of feature (adding adjustability

of

the position is even better) into the AP mounts, I believe it

would

be very useful. The reason that I like a hardware stop is that

it is

not dependent on the computer or any software.

Thanks, Rick

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