Gatsu87
I'm also using a Quattro 200p and a TS Photon 8" f5 (at f3.8 with the Nexus reducer). Even my broadband imaging with the 2600mc Air on the Photon with no filters has this issue, for some strange reason I have to crank the guide sensor gain above 300 just to get it to select 5+ stars for multi-star guiding and that's at f3.8! I'm imaging in a very similar SQM.
This whole conundrum started for me when I decided to implement Alpaca on my mini-pc and try imaging with NINA and PHD2 for guiding, same cameras, same telescopes, same targets, same guide sensor gain, same guide sensor exposure length and PHD2 had absolutely no problem picking up and maintaining many guide stars all night, whether with filters or not.
The whole 220mm mini grey or black background may or may not be related, I don't know, but I absolutely do not see that same phenomenon when using PHD2 to control the guiding on my mini-pc, either the Air or Duo camera. And like you, this seems to have only been a problem since 5-6 months ago, I don't recall having any guide star issues prior to that with my Air cameras. I too had to switch to bin2 and jacking up my gain to get reasonable guide star selection, luckily I'm imaging with a HAE29c-ec with an encoder on the RA axis so using 3s guide exposures is preferential.
The whole response about having difficulty guiding through narrowband filters is nonsense from ZWO, with my 6nm filters I am having zero issues PHD2 picking up at least 6 guide stars at 3s and gain 350 with my setups. I'm thinking about testing an Antlia EDGE 4.5nm to see if I can go a bit more narrow, as well, given how easy it's been to guide with PHD2 and NINA as my control software.
ZWO needs to figure this out, it's ridiculous this is even an issue.
