Re: First light with new Mach1 - and a question

Roland Christen

The pre-defined park positions are only accurate if the mount is actually polar aligned. otherwise they will be off by the amount of polar misalignment.

park positions can be used in the daytime to allow you to pre-align the mount before any stars are visible. The manual describes how to do that.


-----Original Message-----
From: privatekey42@... [ap-gto]
To: ap-gto
Sent: Fri, Aug 3, 2018 10:27 pm
Subject: [ap-gto] First light with new Mach1 - and a question

Apologies if this thread appears twice. I submitted it and it didn't seem to appear - this Yahoo group is very flakey!!


Got my new Mach1 on Monday, and been playing around this week with it indoors. Just got out tonight under the stars - briefly before the clouds came in!

I've put a screenshot of my first guiding session in the Files section (PHD2Screenshot.PNG). I'm happy with that! Especially considering the target (Corona Australis) was only at 45 degrees altitude at the time, and that was out of the box with the same settings I last used with my EQ6 that it's just replaced. Thanks AP! :-)

However, I had one issue I'm looking for ideas on. My sequence of operations was, as far as I can recall,

- Set up mount in Park 3 position and unparked (and switched off tracking)

- Started Sharpcap polar alignment

- Slewed mount west about 90 degrees using the buttons in APCC at a slew speed of 600x

- Completed Sharpcap PA (by the way, those adjustment bolts are super smooth and I can make adjustments in one axis with no effect on the other. Nice!! Got to under 1' PA error in about 2 minutes of adjustment!!)

- Initiated a park to Park 3

- Unparked (now tracking)

- Slewed to target using SGP (connected to APv2 driver to APCC)

- Plate solved (using SGP's "centre target").

At this point it took ages to plate solve, and when it finally did it was about 6 degrees out and the RCAL was rejected as being too far out.

When I parked back to Park3, I noticed the RA axis was way off on the registration marks. Loosening the clutches and putting the marks back in line manually, I was able to do the above SGP slew and solve without a problem.

What could I have done in the above sequence to get the RA out of sync? Was it that manual slew using APCC somehow. I don't think the clutches were loose enough for it to slip (though I could be wrong I guess).

Sorry for the long rambling message. Any ideas appreciated.

Another question would be how do I stop APCC rejecting an RCAL that it thinks is too far out - in this case, that would've been enough to solve my problem without having to manually re-park the mount.

But apart from the query, a nice first night with the mount!



Posted by: privatekey42@...

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