From: [email protected] [mailto:[email protected]] On Behalf Of astroitalian@...
Sent: 27 April 2020 16:40
To: [email protected]
Subject: Re: [Losmandy_users_io] Pointing Issues

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Hi Brian,

I do appreciate your responses, but may I ask if you work for Losmandy?? Not getting defensive here, it's just that you seem to be on the defense for them!? Not all issues are user-caused, as I'm sure you know, and I'm trying to eliminate as much of that possibility as I can.? My polar alignment is perfect.? I use a Polemaster, and it's dead-on.? As I've always understood it, "close enough" should be good enough because the computer model should compensate for it.? But I'm not happy with "close enough."? The mount is also level.

Could you suggest please what it is that I might be "adding" to the pointing model?? And is it not true that adding alignment stars is supposed to refine pointing ability?? That is not happening.? I choose Menu > Align > Bright Star > Align > Alignment.? Isn't that supposed to refine the pointing capability?? As far as flexure, I have a Tele Vue NP127is.? The 2.4" focuser in that is rock solid.? I'm using a few short threaded couplings between that and my Nikon D5300, then I use the D5300 live screen to point and center.? It has a handy small red square in the center, with a red dot in the center of that.? I in-focus so stars are slightly out of focus and fit nicely into that square and I can see they're properly centered.? Has worked well for me for years now.? So, to give an example, let's say I get my model configured and I then focus on Arcturus using a Bahtinov mask, and it's right in the center of that red dot.? Then I'll slew to Spica, and Spica is completely outside of the red box, not even near the red center dot.? I realize no mount is going to have perfect pointing, but to me that's unacceptable.

The amount it's off varies, as does the direction.? I've had cases where I refine the alignment on one star, and the next isn't even in the field (example, say, Spica, then on to Dubhe, or Mizar).? And it's not the refining that's the cause, because I've had pointing issues whether or not I use additional alignment stars.? I'm going to keep playing with ideas.? Maybe do three alignment stars on each side of the meridian, instead of three on one and one on the other.? I have tried that and it didn't work, but I'll try it again now that I've checked other variables.

Thanks,
John