Re: Some odd RA issues?


Mike Shade
 

Guiding through the guide chip on the STL6303E.



Mike J. Shade: mshade@q.com

Mike J. Shade Photography:

mshadephotography.com



In War: Resolution

In Defeat: Defiance

In Victory: Magnanimity

In Peace: Goodwill

Sir Winston Churchill

Already, in the gathering dusk, a few of the stars are turning on their
lights.

Vega, the brightest one, is now dropping towards the west. Can it be half

a year since I watched her April rising in the east? Low in the southwest

Antares blinks a sad farwell to fall...

Leslie Peltier, Starlight Nights



International Dark Sky Association: <http://www.darksky.org/>
www.darksky.org



From: ap-gto@... [mailto:ap-gto@...]
Sent: Sunday, October 01, 2017 11:35 AM
To: ap-gto@...
Subject: RE: [ap-gto] Some odd RA issues?





Off-axis or piggyback guiding?





-Christopher Erickson
Observatory engineer
Summit Kinetics

Waikoloa, HI 96738
<http://www.summitkinetics.com/> www.summitkinetics.com





_____

From: ap-gto@... [mailto:ap-gto@...]
Sent: Sunday, October 1, 2017 6:58 AM
To: ap-gto@...
Subject: [ap-gto] Some odd RA issues?

Here is the scenario: AP1600GTO permanent in observatory with CP4
controller, Planewave CDK17, Optec Gemini focuser-rotator/SBIG STL6303E
camera, unbinned resolution .64"/pixel. Running Maxim 5.18 and ACP. So far
so good. Now here is where it gets curious. As I am in SE AZ, had to shut
down for monsoon from early July to middle of September. All electronics
were unplugged, I do not suspect lightning damage. Prior to shutdown in
July this system returned round stars across the frame in 10-minute subs,
guided.



After starting up again in September, noticed that the stars were ever so
slightly off in RA, maybe a pixel or two, just enough to be not quite round,
again in RA only. However, images in RA last night showed several frames
where there were actually double stars. Looking at the guider log showed
some pretty good jumps in RA. The guider calibrates just fine with a 40+/
pixel move, and I have been able to do a 5-minute unguided with round stars
after startup in September. Of course checked primary mirror spacing,
collimation, if everything is snug, cable drag and so on. I have remeshed
the gears and redone PEC, issues persists. This is a random issue. The
Maxim guider log shows some hefty jumps in RA but NOT in DEC.



It is curious that prior to shutdown it worked like a champ...now...some
issues with a number of images that are just out of round enough as to be
useless, in RA. It is always in RA. I have looked for rodent damage, none.



I am suspecting something with guiding, easiest is weird guider cable, maybe
the guider plug on the camera. Anyone else seen this or have thoughts? I
know this is about as broad as "gee doc, I have a headache"...could be
anything.



AP driver number is 5.09.07.









Mike J. Shade: mshade@q.com

Mike J. Shade Photography:

mshadephotography.com



In War: Resolution

In Defeat: Defiance

In Victory: Magnanimity

In Peace: Goodwill

Sir Winston Churchill

Already, in the gathering dusk, a few of the stars are turning on their
lights.

Vega, the brightest one, is now dropping towards the west. Can it be half

a year since I watched her April rising in the east? Low in the southwest

Antares blinks a sad farwell to fall...

Leslie Peltier, Starlight Nights



International Dark Sky Association: www.darksky.org
<http://www.darksky.org/>







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