Slew & return

[muletopia (Chris)]

Last night my imaging run was wrecked by temperature change 18 down to 7 over a couple of hours,steel tube Mewlon210 with 4 X secondary mirror.
The scope is on a good mount controlled by Sidereal Servo controller 11..


The obvious thermal solution is to re-focus every half hour or so.
My question: how do you save the current pointing direction in Sitech and return to it after slewing to focus?
I can't find the answer in the Sitech manual, not that that means that it is not there.
Chris

[RyanJones]

Originally Posted by muletopia

Last night my imaging run was wrecked by temperature change 18 down to 7 over a couple of hours,steel tube Mewlon210 with 4 X secondary mirror.
The scope is on a good mount controlled by Sidereal Servo controller 11..


The obvious thermal solution is to re-focus every half hour or so.
My question: how do you save the current pointing direction in Sitech and return to it after slewing to focus?
I can't find the answer in the Sitech manual, not that that means that it is not there.
Chris

I don't know about your exact hand controller but mine use " user object ". Set it once the subject is centred then slew back and forth as you please.

[muletopia (Chris)]

Ryan,
What you say is absolutely true, my problem is that once I slew to my target I use Nebulosity 3 to preview the object an move the telescope around to get my desired framing. Thus return from slew will not be in the same position as it left from.
Reframing is a time consuming operation, especially as the position is critical for off axis guiding.



Chris

[RyanJones]

I know what you mean Chris. I’m not sure if you have the option in a utilities section on your had controller that has a user objects in it. What I do is the same as you. I slew to the object then adjust it to get the framing right. It’s after this that I set the custom user object then rather than slewing to and from the object as listed in your hand controller, you slew to the user object which is where it was after you did you frame adjustments. As I said though, I don’t know your hand controller and if it has this option.

[muletopia (Chris)]

An answer was staring me in the face.
Sidereal technology servo controller 11 displays the scopes RA and Dec down to the second.
So:- Go to the target
use the hand pad to frame the target
make a note of the position where you are working

when refocus is required slew to star & focus
go to target
use the hand pad to point the scope to the noted position
continue capture.
This worked well last night.

I use Cartes du ceil to find and slew to target and Nebulosity 3 for camera control. The Nebulosity preview was good on return to target and the two nigh't images stacked with no problem.
Now a camera tilt problem to address.


Chris