Ad Astra Observatory

Art Morton wrote:
> Have you gone into the Gemini Set Up?
Yes, the particular settings that I think you’re interested in are:

Mount Type: G11

Guide speed: 0.3
Tracking Rate: Sidereal

… Is there anything else?
> If not just look through that to make sure the mount knows who it is,
> G11. There are some other setting in there, but I do them all from
> ASCOM, because there is interaction I do not like.

I can try to screenshot the ASCOM settings to make sure that they’re all
the same as this.
> I also had cable induced drift that I would have found if I did not
> just sit there and watch it work. I loosened them and that particular
> trouble went away.
This is that you had your cables wrenched on too tight, so the cables
were pulling on the mount?

I have had this problem in the past, and maybe that’s what’s still going
on. I spent some time taking all the cables to the centerline of the
mount before heading off to the computers, etc. It was all set up
perfectly for Veronica. I’ll have to see if there’s binding with the SCT
(which has cables run to different places, obviously).
> The other thing I do in ASCOM and MaxIM is calibrate to that location

> in the sky for tracking. The rate of rotation is different where ever
> you are in the sky.
Do you set the “declination” box on the max guide screen? I had it at 0
for the longest time, and now it’s been at 60 for awhile…
it feels like there are a ton more settings to get the guider working
than there used to be.

> I use software to cancel the effect out. There is a movie on the
> Max page about guiding.
I’ll have to find it.
> I do not start the tracking until I get the “L”. CCD Commander insures
> you get a “L” before the tracking starts. This takes care of how

> long, the direction, and all that gear slop into consideration
Do both legs of the L have to be the same length?
Do you worry about whether the L is along the axes of the guide chip, or
is it OK if it’s tilted (ie camera is rotated relative to the mount axis)?
How far across the guide chip do you like to see the star move? I
usually get ~6 pixels, maybe 8.
> As for the balance. I have my bar marked for which equipment is on

> the G. I also have the weights marked too. I did this with a
> Sharpie. I really did not balance the mount, but instead adjusted the
> weights to as close to zero (EAST/WEST MASS).
I’ve tried this both ways and I can’t decide if I like one better than
the other. Certainly balancing to zero (rather than “slightly heavy to
the east” as everything I’ve read, including the Gemini manual,

suggests) makes meridian flips easier to deal with. I like the idea of
“get it set up and then don’t frigging touch it”, rather than having to
tweak mid-session.

I’ll take a Sharpie to the CW shaft etc. once I get a good balance.

> As you do, I have so much junk on this thing that the rotational
> acceleration of the mass keeps the gears engaged. I also do this all

> over a three demential space. This allows for the camera to swing
> greater than 90 degrees when shooting up, like tonight would be with
> M51. I have no idea what will work for you. It is trial and error
> until it works. Then I tighten down the bolts.
>
> And, my list of bad combinations goes on. My solution was to let the
> Gemini lead the Orchestra, so clocking, position, pointing odel, and

> what ever else comes from the mount. Everything is in the middle of a
> 7mm eye piece. The drifting stopped at that point.
hmm. I need to let the mount do a better job. I’ll see again if I can
get it to guide via ASCOM. I may have to go up to max DL to do that.
> Mike is a good guy and we have had some running discussions in the
> past that have lead to “My Lights” going on.

I sold Mike my filter drawer setup a year ago, and then he almost sold
me his modded Canon camera.

Do you ever leave your mount setup for several nights in a row? I find
that my pointing model deteriorates over time. It pops things to the
center of the chip on the first night, then it’s off-center the next
night, and does that for awhile, and after awhile it starts being off
the chip, at which point I usually re-do the pointing model. Does your
pointing model degrade over time?

Do you know how to calculate PE?

J