Re: [ap-gto] RE: 1600GTO losing position sense(?)


Dec 25, 2013

 


----------------------------

#42725 Dec 25, 2013

Hi,



I am hoping the issue described below is something I did--loose wire,

bad data entry or some such. I just reassembled my CDK17 to the mount

and reinstalled the CP3 electronics module which had been removed for

safety while working. Wiring was adjusted for thru-mount organization

but not changed. I just powered up to check the system out--everything

appeared to work, although it quickly became obvious the 1600GTO RA axis

was getting lost.......



For example: set up with a level for park 1 as has always worked.....no

problem. Do a goto to polaris, a nearby star in terms of slew--it's off

-- recal to polaris--ok. Go back to park 1 and the mount passes through

park 1 by several degrees in RA but DEC is right on the money. I can do

variations of this simple maneuver with similar results over &

over....each time slightly different. I've also tried a slew from

recalibrated polaris to M42 and the scope ends up about 10 degrees out

of wack......not even close.



My impression is that the RA axis is losing tach pulses or some similar

positional info, but I can't find the problem.



For reference, this happens by keypad and by PC control. The

ever-changing results suggests a positional data issue, but just to be

sure, I have stepped through location, time & date, daylight savings,

upper rs232 port, and all those classic incorrect settings--everything

looks ok. Again, I suspect I've done something inadvertant--just can't

find it.



This is one of those mounts that just hooked up and slewed to the first

target---no fiddling, no issues--any ideas from those more experienced

(or less) than I?



many thanks



John Collins

SW Oregon



----------------------------

#42727 Dec 25, 2013

Hi Joe,



That's a cut & paste problem on my part--yes, I level, power down

waiting 15-ish seconds, power up, select location, then resume from park

1--I think that's right--I've been doing that with great results for

months. If the problem were related to this, I'd expect consistent

results.......wrong, but consistent. I am getting a repeatable type of

error issue but with varying amounts of error.



The procedure I outline is what I've been using--I wonder, though, if

after dismantling everything for several weeks, I need to do the "inform

the mount step".........I'll take a look at the manual again.



thanks for your thoughts



John

---------------

On 12/25/2013 9:42 PM, Joseph Zeglinski wrote:

> John,

>

> After you leveled the mount at Park-1 ... did you then immediately power

> off in that position, then power back on, specifying RESUME from "REFERENCE

> PARK" ?

>

> Unless the AP-1600 is different from the old AP-1200, you can't just

> level, and then slew - the CP3 will not initialize properly.

> Also, you can't Resume from "Last Parked or Park-1", even after leveling and

> powering down. You have to inform the mount, on power-up, that it is to

> assume it is at the "Reference Park", so it can do a proper SYNC to that

> position. Otherwise, it will behave as though no prior re-level had been

> done.

>

> I may be wrong, but I don't think that ASCOM does a SYNC when instructed

> that it is starting from any of the Park positions.

>

> Joe

>

>

>

---------------

>

>



----------------------------

#42728 Dec 26, 2013

Do not sync or recal on Polaris.

Polaris is very close to NCP.NCP has a Dec value of 90 butNCP's RA is all RA's (0-360 or 0-24h)Due to possible orthogonality errors,Polaris is a bad choice to define RA with a recal or sync.Polaris is just too close to NCP.

As always, I could be wrong again.Jimmy



----------------------------

#42729 Dec 26, 2013

Hi Jimmy,



Thanks for your response.. I was not entirely clear in my originalpost, as usual--my understanding is that Polaris is close/but notright on 0/360 --. overall, I agree, but have found that whentweaking or testing, polaris is easy star to find and slew back& forth to/from--that has always worked between polaris andpark 1.......this time it is not working well.. I should be ableto slew back and forth between two defined points, but I'm findingthat after a single slew there is an appreciable error -- forexample, start in park 1 with a resume-from park 1 (after normalstartup), goto polaris, return to park 1.....the mount sails rightby park 1 by 4-8 degrees which creates a counterweights-upsituation.....the exact amount of error varies.. I am alsoconverting syncs to recals as suggested, although I don't know ifthat enters into this particular situation.



I also see similar behavior with larger error on a park 1 - to -M42 slew wherein the mount went right by the target by about 15degrees.....



This being a new day and I haven't been up for 24 hours, I expectI made some dopey mistake......I'll start again fromscratch........I expect my first error was to assume thenonvolatile memory would start right up again after twoweeks........so far I notice that my daylight savings "off"setting mysteriously is "on", although that doesn't account forthe variations from slew to slew--so that's been reset but did notchange the loss of position behavior.



I got shut down last night by flash fog and it's still here--willredo all at next opportunity.



thanks again



John Collins

_______________



On 12/26/2013 9:01 AM, jimmy_an@... wrote:





Do not sync or recal on Polaris.



Polaris is very close to NCP.

NCP has a Dec value of 90 but

NCP's RA is all RA's (0-360 or 0-24h)

Due to possible orthogonality errors,

Polaris is a bad choice to define RA with a recal or sync.

Polaris is just too close to NCP.



As always, I could be wrong again.

Jimmy







----------------------------

#42734 Dec 27, 2013

99% of the time when parks and slews are off it's because of an erroneous time setting. And this can include an improper daylight savings time setting. Rolando

-----Original Message-----

From: john john@...>

To: ap-gto ap-gto@yahoogroups.com>

Sent: Thu, Dec 26, 2013 12:06 pm

Subject: Re: [ap-gto] RE: 1600GTO losing position sense(?)





Hi Jimmy,

Thanks for your response.  I was not entirely clear in my originalpost, as usual--my understanding is that Polaris is close/but notright on 0/360 --  overall, I agree, but have found that whentweaking or testing, polaris is easy star to find and slew back& forth to/from--that has always worked between polaris andpark 1.......this time it is not working well.  I should be ableto slew back and forth between two defined points, but I'm findingthat after a single slew there is an appreciable error -- forexample, start in park 1 with a resume-from park 1 (after normalstartup), goto polaris, return to park 1.....the mount sails rightby park 1 by 4-8 degrees which creates a counterweights-upsituation.....the exact amount of error varies.  I am alsoconverting syncs to recals as suggested, although I don't know ifthat enters into this particular situation.

I also see similar behavior with larger error on a park 1 - to -M42 slew wherein the mount went right by the target by about 15degrees.....

This being a new day and I haven't been up for 24 hours, I expectI made some dopey mistake......I'll start again fromscratch........I expect my first error was to assume thenonvolatile memory would start right up again after twoweeks........so far I notice that my daylight savings "off"setting mysteriously is "on", although that doesn't account forthe variations from slew to slew--so that's been reset but did notchange the loss of position behavior.

I got shut down last night by flash fog and it's still here--willredo all at next opportunity.

thanks again

John Collins_______________

On 12/26/2013 9:01 AM, jimmy_an@... wrote:



Do not sync or recal on Polaris.

Polaris is very close to NCP.NCP has a Dec value of 90 butNCP's RA is all RA's (0-360 or 0-24h)Due to possible orthogonality errors,Polaris is a bad choice to define RA with a recal or sync.Polaris is just too close to NCP.

As always, I could be wrong again.Jimmy


S
e
n
i
o
r
T
u
b
e
.
o
r
g