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Guiding Nirvana


griz11
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Wow using PHD2 to make sure the polar align is right sure does a number on the guiding accuracy. I did a run the other night just using the polar scope for alignment and it was something like 2.5 arc sec off. The guiding was pretty good 5 arc sec or so but tonight it was sub 1 arcsec.

PhdLog-2.jpg

Needless to say I'm a very happy camper with these results. Just have one little glitch to fix with the Argo and I'll be ready to concentrate on some imaging.

Griz

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I must read up on doing this.... I use AlignMaster in my set up, which seems to work pretty well, but I've heard good reports about the PHD2 process.

That graph suggests I should make the time investment!!

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Its pretty decent and doesn't take much time once you figure out which way to move. There is a little note box in the panel so when you figure out which way to move depending on if its positive or neg then you can put that into the note box and its there every time you do it from then on. On my mount negative needs to go east and positive needs to go west. So first time takes longer but after that its pretty quick. In fact last night I ran a quick run right before I started a sequence just to check then recalibrated the guider and I had a trouble free night. Ran until the batteries died :)  Its amazing how the graph just settles right down when you are right on the alignment. I've done drift alignment the old way and I hated it. Took forever. This starts showing a trend line after about 4 shots. It usually settles down after 4-5 more so each drift run doesn't take that long. On that run I didn't even do the Alt :) Didn't see that button until the next night. My wedge has a decent scale on it so I figured that would be pretty close since I level very carefully.

3-D balancing your mount is something else I was clued in on and seems to work as well. Loosen both axis and balance them both at the same time not one at a time. Takes a little getting used to so you know what to move where. In my case I have a dual saddle so you have that and the two instruments mounted on top to deal with. Once I had it all done I used a scribe to mark the dovetails. I thought I had my mount balanced until I loosened up both axis and then I found it wasn't very well balanced at all. 

Didn't even use the polar scope last night. Eyeballed it and then used the guider to center Polaris then started the PHD2 routine. I had it in 4 iterations.

Another trick I discovered last night if you are guiding and turn off the dec guiding after a couple of iterations it will put up the trend lines and tell you if you are off. So if your guiding goes whacko all of a sudden just flip that switch and see if something has happened. I forgot to tighten up the az locks after doing the align and bumped the scope or something changing batteries in the camera. Once I restarted it was all over the place. So I'm thinking turn off the dec and let it settle then turn it back on. Thats when I discovered that it would give you the alignment there as well. I haven't tried the drift align in BYE or APT yet. I'm sure they are similar. The Argo Navis will also show you how far out you are. Similar to the goto routine but you move the scope. After seeing what effect it has on pretty much everything mount and guider related Its silly not to spend the time to get it spot on. Takes all the strain off the mount and guider. On that run there were no guiding moves at all. And I took a little of the overbalance off and now the group is all around the center with no tendency to one side or the other. Graphs will tell you a lot about your mount PHDLab puts out the most information although there is one that is on the Open PHD/PHD2 site as well. http://openphdguiding.org/  There is an excellent tutorial there on polar align tool use.

Griz

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Griz, 

When you need to slew to the appropriate bit of sky for each of the two phases of the PHD alignment, do you get the PHD tool to issue the slew command, or do you do it through your planetarium software?

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