john,

under well defined conditions the direction of guiding-correction in declination is reversed.

Material involved:
Mount AP900GTO
Autopilot 4.15.7
CCDSoft 5.00.188
Sky6 6.0.0.60

Setup conditions autopilot:
--initialized east of real meridian
--Self guiding active (ST2000XM)
--"enable meridian flip" disabled

Setup conditions mount AP900GTO:
--meridian set 6 hours east of real meridian.
--all visible objects appear now to be west of this pseudo meridian.

Remark 1:
the position of the meridian in autopilot and mountsoftware are out of sync.

Remark 2:
using this setup, no meridian flip occurs, which is a must, as my balcony wall does not allow it.

Remark 3:
CCDSoft alone: picturestart in the east or the west of real meridian: no guiding correction problems in declination.

Remark 4:
Autopilot: picturestart in the east of real meridian: no guiding correction problems in declination.

Problem:
Autopilot: picturestart west of real meridian, the declination correction is 180 degrees out of phase.

Conclusion:
in my opinion Autopilots "enable meridian flip" in disabled state should not reverse the direction of the declination motor.

Discussion:
What do you think about the above stated conclusion? Is there a must to leave it as is?
If yes:
I could enable the meridian flip in autopilot und put some timer values in the provided fields, but I fear inadvertent flips.
So I prefer to leave the meridian flip in autopilot, for security reasons, in the disabled state.

What about a feature in autopilot to move the meridian in one-hour-steps (up to six) either east or west?
As this is possible with the AP900GTO mount, I think that the idea is not completely off the road.

Regards Beat

Need to see a log as usual, Beat.

Sorry John,
I thought that this is only a question of design. So I did not attach a log.
The log is definitaly deleted.
As the weather is not good for the next day's it will take some time to continue.

Beat

John,
please find attached autopilotlog, CCDSoft autoguiderlog and picture.

Beat

CCDSoft Tracking Report
Start Date Time = 2009-10-31T19:22:17.432
Camera = Imager's built-in autoguider
X Axis = Enabled
Y Axis = Enabled
ExposureTime = 3.00
Aggressiveness Factor = 5
Calibration Time X = 25.00
Calibration Time Y = 25.00
Calibration declination = 0.00
Declination now = 31.46
Minimum Move = 0.01
Maximum Move = 0.50
Backlash X = 0.00
Backlash Y = 0.00
Delay After Move = 0.00
Autoguide using Relays

Calibration Determined Velocity Vectors (pixels/sec)
XPlus Speed= 3.82143 (XPlus X= 3.81878, XPlus Y= -0.14238) Angle= 357.86000
XMinus Speed= 3.82143 (XMinus X= -3.81878, XMinus Y= 0.14238) Angle= 177.86000
YPlus Speed= 4.03403 (YPlus X= 0.18548, YPlus Y= 4.02976) Angle= 87.36000
YMinus Speed= 4.03403 (YMinus X= -0.18548, YMinus Y= -4.02976) Angle= 267.36000

|Elapsed Secs|RefCentroidX|RefCentroidY|CurCentroidX|CurCentroidY|GuideErrX |GuideErrY |TotGuideErr |XPlusRelay |XMinusRelay |YPlusRelay |YMinusRelay |PECIndex RA |PECIndex Dec|
| 0.0000| 16.0000| 16.0000| 16.4113| 16.7924| 0.4113| 0.7924| 0.8928| 0| 6| 0| 10| 0| 0|
| 12.9080| 16.0000| 16.0000| 16.6333| 16.9335| 0.6333| 0.9335| 1.1281| 0| 9| 0| 12| 0| 0|
| 16.9540| 16.0000| 16.0000| 16.4577| 17.3079| 0.4577| 1.3079| 1.3857| 0| 6| 0| 16| 0| 0|
| 20.8600| 16.0000| 16.0000| 16.2776| 17.8860| 0.2776| 1.8860| 1.9064| 0| 3| 0| 23| 0| 0|
| 25.1260| 16.0000| 16.0000| 16.0468| 18.5816| 0.0468| 2.5816| 2.5821| 1| 0| 0| 32| 0| 0|
| 29.3820| 16.0000| 16.0000| 15.7285| 19.9048| -0.2715| 3.9048| 3.9142| 6| 0| 0| 48| 0| 0|
| 33.7780| 16.0000| 16.0000| 16.0501| 21.9911| 0.0501| 5.9911| 5.9913| 2| 0| 0| 50| 0| 0|
| 39.4160| 16.0000| 16.0000| 16.0071| 23.8602| 0.0071| 7.8602| 7.8602| 4| 0| 0| 50| 0| 0|
| 43.7330| 16.0000| 16.0000| 16.2925| 26.0176| 0.2925| 10.0176| 10.0219| 1| 0| 0| 50| 0| 0|
| 47.9990| 16.0000| 16.0000| 16.2319| 28.1675| 0.2319| 12.1675| 12.1697| 3| 0| 0| 50| 0| 0|
| 52.3950| 16.0000| 16.0000| 16.3633| 30.0220| 0.3633| 14.0220| 14.0267| 2| 0| 0| 50| 0| 0|
| 56.8010| 16.0000| 16.0000| 16.2147| 31.0448| 0.2147| 15.0448| 15.0463| 5| 0| 0| 50| 0| 0|
| 101.9360| 16.0000| 16.0000| 15.6999| 31.3131| -0.3001| 15.3131| 15.3161| 13| 0| 0| 50| 0| 0|

ccdap20091031_192035.log (7 KB, 6 downloads) Log Autopilot

here the test image

Test_Dec_correction.jpg (187 KB, 7 downloads) Testimage

here once more the CCDSoft autoguider log in monospace

Autoguider.log (3 KB, 5 downloads) Autoguiderlog

Hi Beat,

I am a conference until tonight and will get back to you when I get back home tomorrow.

Beat,

Regardless of any "artificial meridian", CCDAP determines the meridian crossing point via an ephemerides calculation. If you want to take advantage of the AP mount's ability to image through the meridian, I suggest you initialize in the east and declare your mount type as fork. This should resolve the problem.

John,

thank you very much.
I am convinced that it will work with this definition.
The next days will be rainy. I'll try it as soon as possible.

eat

John,

the definition "Fork" does the job.
The guiding in declination is now in phase.
Thank you very much.
The loop can be closed.

Beat