What happens if I enable both "Slew to" and "Center on"?


#1

I’ve just set up a sequence for the next few nights that will image two different targets in completely different parts of the night sky. I always start my sequences by manually clicking to slew to the target. I then pick a star and calibrate PHD2 there and once done, I click “Run Sequence”, which centers my target precisely via plate solving, autofocuses and commences autoguiding.

This time however, I won’t be awake to manually slew to the next target and I would like SGP to finish target 1, slew roughly to target 2 and then center on it via plate solving. Does enabling BOTH “Slew to” and “Center on” in target 2’s “Target Settings” do this? If not, what is SGP’s behaviour when both options are enabled?

Thank you in advance! :smile:


#2

Yes, that is exactly what it does. I always check both so that SGP doesn’t waste time hanging around the old target and just goes immediately to the new target, then does the plate solve and center.


#3

I can’t directly answer your question, but I don’t think there’s really any
need to select both “slew to” and “center on” at the same time. If you
have just “center on” selected then SGP will plate solve precisely to your
target. “Slew to” just issues a move command to your mount and can be very
imprecise.


#4

If you don’t also check the slew to, I think SGP does a plate solve at your current location, which is almost always a big waste of time. In a prior post Ken mentioned that this is particularly important at the start of imaging if the mount is pointed at the pole, since the plate solve can cause problems there. He also suggested that a good change would be to check them both by default.


#5

Excellent, thank you both for your input. I do indeed prefer SGP to first slew “inaccurately” and then plate solve where it is to centre precisely. I’ll keep both options enabled then.


#6

That is true it does create an extra step if you just have center on
enabled. I’m not sure it’s a “big” waste of time but a waste of time
nontheless. It’s probably best practice then to enable both options, I
just never have.


#7

Platesolving on the spot might be a problem if your telescope is pointing at a wall or a tree, either because of starting from a park position or letting the telescope track an object until it’s behind trees. Platesolving will then fail. That’s why I always select both options.


#8

FWIW,

I use both. I read the slew is meant to get you at least in the correct neighborhood so that the plate solve doesn’t have to work as hard and take as long.


#9

"plate solve near the pole can cause problems " …that would explain why I was having lots of trouble …I didn’t know that. :confounded:


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