I have min move set to 0.01, max set to 0.3, aggressiveness (the past few nights) at 7.  But the tiny faint stars aren't always round, and I'm always interested in ways to mitigate that.  I was blown away by the stars in your Pelican image.  As a result I put my name down to be "notified" about the Mach2. 

A min move of .01 is extremely small and can result in lots of unwanted error command being sent to the mount. At 1x sidereal guide rate a setting of .01 means that pulses are sent if the guide star measured centroid is off by only 0.15 arc seconds. This is insane for two reasons: your guide scope cannot resolve this level of accuracy, and the guider software will not be able to measure the star's centroid to that level of accuracy. With that low setting you just end up pushing and pulling the RA axis around without really getting anywhere.

As far as the Mach2, if you are on the list, we will make one for you. It's just a matter of time. These mounts are in full production, but they require a lot of machining and assembly labor time.

Finally, I recently posted an image taken on a Mach1 mount last year:

https://www.astrobin.com/full/jzf18a/0/

Rolando

-----Original Message-----
From: CurtisC via groups.io <calypte=verizon.net@groups.io>
To: main@ap-gto.groups.io
Sent: Thu, Sep 3, 2020 4:43 pm
Subject: Re: [ap-gto] PEMPro vs PHD2 #Guiding

Thank you.  I use 5 seconds for guiding.  I've never experienced much benefit to changing to something significantly different.  For several years I used the Baader Vario-Finder as a guide scope, but I now have the Superstar back in the OAG of the QSI 683.  My main scope is a TEC140ED (1035 mm FL with flattener).  I haven't seen much difference in the shapes of the stars between the two guider methods, but the reported numbers and the graph (MaxIm) are certainly different.  Stars will ride pretty close to the zero line for several cycles, and then they'll wander off to 2.00 or even more, then they get reeled back in over several cycles.  I see more of this in RA than DEC.  I have min move set to 0.01, max set to 0.3, aggressiveness (the past few nights) at 7.  But the tiny faint stars aren't always round, and I'm always interested in ways to mitigate that.  I was blown away by the stars in your Pelican image.  As a result I put my name down to be "notified" about the Mach2.  Maybe I'll live long enough for my name to come up.  I'll get a log for you and/or Ray.  Thanks.

"Heavy air" is rare here.  It occurs mainly when the marine layer is super deep (we're at 4000 ft), but then the humidity is way too high to open the observatory.  Best seeing is when the marine layer is shallow, which means the air is clear but flowing smoothly from the ocean.  It's that weather which made Mt. Wilson and Palomar desirable observatory sites.  If the marine layer is just deep enough to cover L.A. and San Diego with fog or low clouds, then that makes the sky much darker.  Summer and fall bring our best observing weather, with weeks of consecutive cloudless nights.