Last night when I attempted to image with the new QHYCCD MiniCAM8, I was unable to achieve focus. Attached is a screenshot from one of the autofocus runs (SGP, ZWO EAF) that shows the issue I ran into. I spent over 3 hours, trying to manually focus and running the autofocus routine in SGP - using different CFW filters, changing the binning and exposure time of the focus image, and changing (radically) the focuser position, all to no avail.
The image captured is very bright (i.e., usually indicating the imaging train is severely out of focus)
The EAF was picking up on “stars” and returning different number of stars, but similar HFR values regardless of where the focuser was located throughout its length of travel (i.e., the same result at “0” and at 7cm
Here are some relevant facts about the set-up:
The only thing that has changed in the imaging train since the last time I successfully imaged with the exact same train, with my ASI2400MC, is the miniCAM8I have the miniCAM8 attached to the back of my Askar FRA600 0.7x reducer using the connection tube that I received with the miniCAM8 {I should have the correct backfocus}.
I installed the filters, per QHYCCD instructions, which had me flip them over from the way that were in the packaging to insert into the filter wheel (to get the pointy end of the mark facing toward the sensor). {Do I have the filters installed backwards?}
I installed the Beta version of the AllinOne driver (25.06.16.16). The only change I made to the camera configuration was to increase the USB speed from “0” to “1”
The documentation doesn’t provide any guidance on focusing, so I used the exposure time (8 seconds) that I use with my ASI2400MC (full frame OSC camera). Although I played around with different binning, exposure length, and focuser positions; after 3 hours, I was never able to achieve focus.
Any ideas to help me understand what is going wrong?
Also, do you have recommended binning, exposure time, and minimum star size (to recognize it’s a star) for the focusing frames based upon camera sensor and pixel size?
It’s hard to tell, but is SGPro actually finding stars in the data? In your message above you put stars in quotes so Im not entirely sure. In other words, just with a visual eyeball inspection does it look like SGPro is finding real stars or finding bright noise?
Once you are certain that you are obtaining measurable data, you can move on to the next step. That graph you posted above means one of 2 things:
Your focuser is not moving enough to change focus in a measurable way (most likely)
Your focus is bound mechanically or gravitationally (camera too heavy etc) (less likely)
Have you been through the auto focus tuning help article?
Your mileage may vary, but because there are a lot of variables here, I always recommend the following when first starting so that you can eliminate data quality as a factor. Then, when you are focusing successfully, dial this in last. For tuning:
Bin 2x2 (a good balance of resolution and sensitivity)
Exposure: 10 sec
NO NARROWBAND FILTERS
Gain: high-ish unless it blows star cores out
Minimum star size: Bump this up until SGPro is ONLY detecting stars. It is essentially a noise filter
Ken - Thanks for your quick reply!!
To answer your “is SGPro seeing real stars or noise” - that’s exactly what I don’t know! The image was so bright and grainy (what I’m accustomed to seeing when the camera is out of focus) throughout the full range of the focuser movement with multiple different filters selected…I don’t know what it is calling a star and using for the number of stars and HFR calculations.
The only variable is the new camera - the rest of the imaging (and focusing) train is the same as I’ve been using since I got the EAF. I went through the autofocus tutorial when I first got the EAF and haven’t depended upon my Bahtinov lens since then! Guess tonight is the night to bring it back out and give it a try!
you can also try slewing to a bright start, moving the focuser to 0, selecting a 5-ish second “Frame and Focus” exposure binned 2x2, then press “Start”. After each exposure move the focuser out 1000 steps until you’ve moved it all the way out (adjust the 1000 steps so that you move the focuser around 10 times).
If your histogram is like it is in your screenshot, decrease the exposure time. The image may be too bright not because it’s out of focus but because the exposure time is too long (or both).
If you never see starts, does the manufacture have a Windows program that you can test the camera with? It’s possible the camera is misconfigured in SGP.
Thanks @Ken and @EricC … I ended up sending the camera back to Agena Astro yesterday. I figured out the focus issue (mostly) but I couldn’t get a stable ASCOM filter wheel driver…QHY’s Beta version worked for 5 days (2 imaging sessions and 1 calibration frame capture session) then reverted to thinking there were only 5 slots (in the 8 slot filter wheel). After struggling with it for 2 weeks…Agena gave me an RMA yesterday.
