PHD2 guiding drifts
Kevin Wisdom
Things are fine when it's a perfectly cloud-free night, but where I live, that is a rare occurance.
Bruce Waddington
If you do a search on the PHD2 forum for ‘clouds’, you’ll find all sorts of discussion on this topic. Here’s a starting point:
Bruce Waddington
Aug 18, 2020, 10:55:08 AM
to Open PHD Guiding
This topic has been pounded on several times in the past few months, so you should probably read through these threads so we don't have to type it all again:
To summarize, PHD2 doesn’t move the scope if there’s no guide star visible. If the guide star is lost then regained within the same tracking region, it will move the scope back to the original lock point. If your problem is that PHD2 is locking on to a hot pixel, there are several tools available in the UI to avoid that – basically parameters (e.g. Min-HFD) that define what a reasonable guide star should look like for your setup. All of those tools should be applied, a simple dark library is barely a start. If a guide star is lost for an extended time period, the telescope *will* drift off-target, even as PHD2 keeps taking exposures looking for a guide star within the search region. If something suddenly shows up in the search region, it's a good bet that it's not the guide star you were originally using. If you’re trying to run long unattended imaging sessions, you should be using an automation app of some kind that will handle cloud recovery correctly. That’s really where the recovery process belongs. There are a number of automation solutions available, some better than others with respect to recovery from lost stars and clouds. Without a capable automation app, you'll no doubt have to discard lots of exposures if you have significant periods of cloud cover.
Bruce
Bottom line, if you want to image all night with intermittently cloudy skies while being tucked in bed in your jammies, you only have a couple of choices:
1. Be willing to discard lots of unusable frames and just extend the total time you spend on the target across multiple nights
2. Acquire a capable image automation application that does a professional job of recovering from these events.
Regards,
Bruce
--
You received this message because you are subscribed to the Google Groups "Open PHD Guiding" group.
To unsubscribe from this group and stop receiving emails from it, send an email to open-phd-guidi...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/528e4d94-acb0-4f14-abd8-51c4d3a95d05n%40googlegroups.com.