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  #21  
Old 01-07-2020, 02:30 PM
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gregbradley
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Originally Posted by loc46south View Post
Hi Greg - I use a 174 in a MMOAG on an AGiDK 12.5 and with PHD2 and its predictive PEC guiding gives excellent results. I am getting sub pixel guiding on 5 or 6 hours exposure runs with a Losmandy Titan 50 mount.
Sounds good. Wha is predictive PEC guiding? Isn't all PEC predictive in that its a file of errors that repeat and used to add or subtract from the current correction?

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Originally Posted by Nikolas View Post
I have the 120 mm mini no issues
Thanks for the feedback.

Greg.
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  #22  
Old 01-07-2020, 02:51 PM
Startrek (Martin)
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Greg
Some detail on PHD2 Predictive PEC guiding -

Advanced Functions for PHD2 - Predictive PEC ( Periodic Error Correction) in PHD2

PPEC is an alternative to the Hysteresis algorithm normally used for your mounts RA guide corrections and can provide improvements to your mounts overall guiding
Go to Brain
Select Algorithms
In ‘Right Ascension’ select “Predictive PEC”
Use all default settings for Predictive Weight, Reactive Weight and Min Move ( Period Length can be adjusted to suit your mounts worm cycle period but always leave “Auto Adjust Period” checked or ticked )
Do your normal Calibration then start guiding
PPEC takes time to train itself and perform
It starts out using the normal RA Hysteresis algorithm then shifts seamlessly to the PPEC algorithm after about 2 worm cycles of the mount when it learns the mounts performance
HEQ5 mount worm cycle period is 638 sec or 10 minutes 38 seconds
EQ6-R mount worm cycle period is about 480 sec or 8 minutes
PPEC will remain whilst guiding , stopping and starting guiding for focusing and dithering on the same target
If you stop and slew to a new target , PPEC must be turned off and then on again , start guiding and then re train itself again on the new target
Once training is complete after 2 worm cycles, the PPEC algorithm uses both reactive and predictive guide corrections which in principle is usually more accurate than just Hysteresis on its own
EQMOD has a feature to store your mounts PEC curve which is created by a third part software like PECprep and allows PHD2 to retain and use this data when running the PPEC algorithm. This saves PHD2 time when setting up and guiding for the next imaging session
The mounts Synscan handcontroller also has a function to record PEC and store it in the mount for PHD2 to use along side the PPEC function

Cheers
Martin
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  #23  
Old 01-07-2020, 05:25 PM
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Thanks Martin.

That sounds very sophisticated. I did use PHD2 for quite a while but my mount was overloaded and also the camera would put a bump on stars that I mistook for guide errors so I stopped using it. It also dropped out too easily when a cloud went over at least in that version of PHD (was about 5 years ago now).

Greg.
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  #24  
Old 02-07-2020, 02:09 PM
loc46south (Geoffrey)
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Hi Greg - I use it for Differential; Photometery where limited pixel shift is desired and it works like a dream - provided you keep an eye on it. But I wouldn't recommend it for unattended photography. The software is still in a beta + stage and there is the odd occasion when it does not perform as expected. The 174 is is best guiding camera I have used - it 's red band capability lets you hang on to guide stars better, especially when there is that pesky high cloud about.

Geof
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  #25  
Old 05-07-2020, 08:24 PM
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Quote:
Originally Posted by loc46south View Post
Hi Greg - I use it for Differential; Photometery where limited pixel shift is desired and it works like a dream - provided you keep an eye on it. But I wouldn't recommend it for unattended photography. The software is still in a beta + stage and there is the odd occasion when it does not perform as expected. The 174 is is best guiding camera I have used - it 's red band capability lets you hang on to guide stars better, especially when there is that pesky high cloud about.

Geof
Thanks Geoff.

Greg.
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