From: "KirkusMcGurkus" <kirk@stenvall.net>

Date: June 22, 2008 1:22:59 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: Quick question about alignment

--- In Astro_IIDC@yahoogroups.com, Milton Aupperle <milton@...> wrote:

Hi Kirkus;

On 21-Jun-08, at 3:28 PM, KirkusMcGurkus wrote:

-----------SNIPPED for brevity

I did the same thing to my HEQ5 mount.

It had lots of black "gunk" they call "grease" (I think it's just

spit, soot and old newspapers ground into a paste). At -38°C it would

turn into concrete and the mount would basically not move or just

binds, regardless of how much I fiddled with the gear / motor tension.

I removed it all (toothbrush, lots of paper towels, toothpicks and

several cans of WD40 and degreasers) and re-greased my HEQ5 with a

yellow lithium based grease. I also cleaned out the bearings too and

then re-oiled them with good quality machine oil.

Also make sure you have no play in the RA or Dec motion when

"locked". That will causes all sorts of erratic issues.

Just this spring I finally tracked down and eliminated the cause of

my 4 second Dec reversal time and it's now at 1 second maximum to

reverse directions. The Dec gearing had some play (from the factory)

and they also had no lubricant on the Ra or Dec gears at all. So I

greased them up and they now run and it tracks a lot smoother.

I did notice a little amount of "play" in the DEC last night. I'll

readjust the wormgear today to get rid of that. I'll also check and

double check the axis alignment on my mount.

-----------SNIPPED for brevity

I don't think the 2x2 binning will make a difference, unless you also

had hot pixels (i.e. a pixel that is stuck white or brighter than

normal and stays that way). I normally have Astro IIDC do a Dark

frame with the guide camera just before I start tracking, especially

if I use high Gains / Brightness or longer exposures to remove them.

Also the camera temperature can make "hot pixels" appear after a

period of time too, so I let the camera run for a while to achieve

steady state before guiding with it. With the old Unibrain / iBot /

Pyro cameras, I do a dark Dark and a Flat frame to remove the

inherent "Isoch Step" noise, which is that vertical band that appears

on the left side of the view too.

Poor polar alignment will be the main issue. Pretty much all guiding

software assumes that the corrections it has to make are for periodic

error, not poor off axis alignment. And the biggest issue will be

Dec, because Dec Lag makes it far more difficult to correct.

Also, Astro IIDC 4 can also optionally send 2 move command per

correction cycle now so it can correct RA and Dec at the same time,

which improves latency.

I'll be looking at upgrading to version 4 next month!

I'm feeling fairly confident that if I can figure out and fix the

cause of my lousy polar alignment, it will fix my tracking problem.

This exchange with you has been a big help, Milton. Thank you so much

for taking the time.

HTH..

Milton J. Aupperle

President

ASC - Aupperle Services and Contracting

Mac Software (Drivers, Components and Application) Specialist

#1005 - 815 14th Avenue. S.W.

Calgary Alberta T2R0N5

1-(403)-229-9456

milton@...