Losing guide star(s) at nights with bright moon

[Reinhold Friedrich Auer]

Hello colleagues, 

I am doing off axis guiding with a Starlight Lodstar X2 on a ASA 12" f/3.86 Newtonian.

Today we had full moon, but also the days before when the moon was around 80% PHD2 had big problems to keep the guidestars (normally I am doing multistar guiding).
As soon as the moon is on low altitude it still works, but asfter the moon rises the problems inceases until I have to stop the observation. The higher the rel. humidity the worse is the situation. 

With my second 8" Newtion with 60mm guiding refractor I do not have this problems.

I use binning 1x1 with both. Does binning 2x2 better the situation?
Does anybody have similar experiences? 

Solutions?

Thanks for your advices and experiences.

rfa

[Clayton Yendrey]

Did someone replay offline?

With an OAG, the sky is more limited as are the number of available guide stars vs. your other OTA with a separate guide scope.  Moonlight will drastically impact the contrast between sky and stars; this is exacerbated by humidity, airborne dust, etc.  I'm not familiar with that OAG but some have the option of rotating around the image circle to a point that 'might' have more/brighter stars.  The only other option may be to increase the exposure time which should improve guide star visibility.  The downside is your mount performance (tracking) and polar alignment have to be pretty good to be able to take advantage of the longer exposure times in PHD2.

I've seen in my area, times when due to humidity/high level dust that there only a handful of stars visible to the naked eye except at the furthest reaches away from the moon (and metro sky glow to the west) during a full moon.  I gotten the habit of avoiding imaging when the moon is more than 3/4 full (and dependent on other factors that affect seeing).  YMMV