My EAF is mounted to my Astrotech 70MM.
I had great success with it when I got it a handful of months ago.
My image train includes said Astrotech 70mm, Astrotech 0.8x FF reducer, Svbony 2" filter drawer, and my QHY183c.
All the grub screws attaching the EAF are tight.
Here is a link to a screenshot of my latest NINA settings. Ive been tinkering with all these settings, so I am now quite lost.
https://ibb.co/JFj0Zq4q
And here is a link to the 4 most recent JSON NINNA EAF results
https://drive.google.com/drive/folders/1kspTTmvvr-Ivp01lwso02InIoGe7iY4C?usp=sharing
Eaf can mess itself out of reasonable range and start acting up, it get sometimes this kinda error, when i'm way too of when starting af. I did measure backlash back in the day, but been using it without backlash compensation enabled for the past few years.
As someone said backlash only one way and that way is the one that goes against gravity.
You need backlash only in IN or OUT. Typically, it is the IN. 75 for step size is rather a large value. Usually, 40 or 50 is sufficient.
Are you having issues with focusing even the first time on a bright star? Or is it during a session?
I have had issues during a session (not zwo) when clouds move in. Usually the HFR will be all over the place and the autofocus will fail and return to previous known good point.
Really? Because my SVBONY 70ED has a step size 80 with blacklash OUT 200. ;)
Most refractors/reflectors are OUT backlash where scopes like SCTs are IN.
Autofocuser backlash is nothing esoteric.
It is the effort of the focuser to work against gravity. In refractors, IN direction takes a little more effort, as the focus is always pointing up, along the telescope axis. That little effort can be felt even by hand if one is sensitive enough to feel the difference.
In reflectors, the backlash can be in any direction as it depends on how the focuser is situated. But, it will be in the direction that works against the gravity.
In SCT type of focuser, it is about the mechanical ability of the focuser and how the mirror moves.
I have a SVBONY SV48P. The first thing I did was to tune the focuser and lube it. Always had only IN backlash.
Same with my Askar. Didn't have to tune it though.
Thanks for that! I will def change those settings next time and try it out.
Yes, the past two sessions, I’ve had to bail on AF and manually focus using the arrow keys.
When the autofocus fails, look at the PHD2 window.
I got into settings on the left of the graph and select to display guide star SNR as a trace in the graph. If there are clouds, that trace will dip.
Helps me to keep my monkey paws away from messing up the settings.
Sorry, forgot to reply to the Clouds comment.
It was 100% clear that night. my PHDViewer log shows no low SNR throughout that entire night. I actually had of the best guiding nights too haha figures!!
Must be gremlins then.
I have had an instance of the autofocuser getting disconnected during the run. About 2 am.
The next session had no issues at all.
Damn. Well I will give the backlash settings a change and go from there.. Thanks!