Re: Tracking Rate

Christopher Erickson

Wouldn't stars approaching the meridian be moving faster?

-Christopher Erickson
sent wirelessly from my Android phone and a teeny-tiny keyboard by a guy with big hands!

On Sep 8, 2013 12:00 PM, "topboxman2000" <pnagy@...> wrote:

In case you are not aware of this. The only time stars move at sideral rate is when they are at the Meridian. The further away the stars are from the Meridian, the slower they move. That's due to refraction in the sky.


--- In ap-gto@..., "rickysguy" wrote:
> My Mach 1 is on a concrete pier mounter in an observatory and powered by a 5amp AP Power supply.  All clutch knobs were tight. The mount was initialized using the AP ASCOM V2 driver on my laptop computer.
> Last night I wanted to check my polar alignment since I was getting elongated stars after only two minutes.  I had previously drift aligned this mount and it was working well.
> Upon setting up my first star (on the meridian and celestial equator), I stopped tracking to determine which direction west and east was and then re- started sidereal tracking. I noticed that the mount was tracking very fast and my star was falling behind to the east. North, south star movement was negligible indicating my polar alignment was pretty good. I tried using "custom tracking rate" and did get the mount slowed down that way using a setting of 0.025000 in the RA box. I really don't think this should be needed but, it was.  I checked alignment using a star 20 degrees above my Eastern horizon as well and that showed no north or south movement.
> Then I decided to park the mount, turn off the power and start from scratch before attempting to image. After I did that, the mount reverted back to normal sidereal tracking and showing some star elongation after 1 minute but guiding seemed to clean things up.
> Any ideas on what could cause the mount to track too fast? By the way, it does this anywhere in the sky, not just at the equator.


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