We had a clear night tonight, with no wind or moon.? So out I went again.
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After polar aligning with Polemaster (probably not necessary, since the tripod hadn¡¯t moved, but good practice), I turned off the hand controller, put it in CWD position, then did a cold start.?
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I told it to go to Altair (east side); it wasn¡¯t on the finder scope, but it wasn¡¯t too bad.? I centered, and clicked Menu>Align>Alignment.? I then told it to go to Deneb.? It wasn¡¯t far off center on the illuminated reticle eyepiece; I centered, and clicked Menu>Align>Alignment.? I told it to go to Vega, and repeated the process (it was very close to center).? Finally, I did Alberio (I like Alberio, so I¡¯ll use any excuse to look at it).? It also was close to centered.
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Going to the west side, I told it to go to Mizar.? It was not very close (not on the finder, but it was on the Telrad).? I centered, clicked Menu>Align>Alignment.? And declared victory for the modeling.
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I substituted a 26mm Nagler Type 5 as my eyepiece, and told it to go to M27 (east side).? It was pretty well centered.? Repeated for a number of east side targets, all with good success.? Told it to go to M81 (west side); it wasn¡¯t so well centered, but it was on the eyepiece.? Told it to go to M31 (east side); it was at the very edge of the field of the 26mm Nagler.? Told it to go to M57, and it was reasonably well centered.
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I think that this probably is as good as it gets.? I¡¯ve heard all the people saying that I¡¯m too optimistic expecting everything to be centered, so I¡¯ll accept the imperfections.? It¡¯s good enough for my limited needs.
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I thank everyone for their help, particularly Brian Valente.
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I wish everyone clear skies, and a good night.
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Mark de REgt
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I went through all of the suggestions made, and collected those that seemed might possibly be connected to my problem.? Then I implemented them.
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Last night was a test.
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I carefully determined the CWD position. ?Although, to be honest, there is absolutely no way I know of to know when the counterweight bar really is pointing as down as it can, since a bubble level depends on catching exactly the right part of the curve, and not moving it at all.? But I also understand that that matters only for the first slew.
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I slowed the speed at which the mount slews, to lessen the probability that anything skips with the sudden torque.
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I did a careful polar alignment with PoleMaster.
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I made sure that time, date, and place were all very accurate.
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I deleted any existing model.
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I sent the mount to Altair.? It missed by a fair amount.? I decided that maybe I should only ¡°center¡± using ¡°center¡± or ¡°guide,¡± not ¡°move¡± or ¡°slew,¡± so it took a while to center Altair.? After carefully centering Altair on my illuminated-crosshair eyepiece, I selected ¡°Menu,¡± then ¡°Align,¡± then ¡°synchronize.¡±
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I told it to go to Vega.? It was almost perfectly centered.? I centered, synced, then told it to go to Deneb.
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It was perfectly centered.
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The west side of my sky is pretty much destroyed with Seattle sky glow and trees.? So I decided to play on the east side, to see how it worked,?
It worked very well!? Everything I told it to go to was reasonably well centered.
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Then I told it to go to Mizar, very much on the west side, but easy to see.
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It missed by a lot.? I centered it, and synced.
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I told it to go back to Deneb.? It was on the eyepiece (17mm Nagler Type 4, on a Celestron 11¡± EdgeHD), but quite far off center.? I centered and synced.? Told it to go to M27.? It was centered pretty well,? I told it to go back to Mizar, and it barely was on the eyepiece.
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And so the night went.? I found no way to get it to converge on a model that got everything reasonably close to the center of the eyepiece (I wouldn¡¯t care so much, except that it¡¯s a royal PITA to center anything, to me, on a GEM, since I have no idea which of the four buttons to hit at any time to get it to move in any particular direction).
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It was somewhat promising, in that it always got the target on the (very, very wide) eyepiece, but it is far, far from perfect.
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Mark
Paul Kanevsky