Before I bother Leonardo further, am wondering if anyone is running an Optec Gemini Focuser / Rotator with RoboFire. The Gemini has a very short travel distance of 12.7mm (115200 steps). I am struggling with the parameters (HFD Near, Start, Max and others). Cannot get RoboFire to create first lightcurve.
Appreciate if anyone is successfully using the Gemini if you could share your settings. OTA is EdgeHD @ F11. Camera is 16803. @F3 has worked fine. And LocalField usually works. Just not RoboFire VCurve.
Thanks for any help .
Bob
Hi Bob, so many users have Optec Gemini Focuser and use it without problem in Voyager, usually is not needed to change anything. I’m sure you will find solution. Be sure to have focus at mid travel. Without VCurve caratherization single star focus cannot work.
All the best
Leonardo
Thanks Leonardo. Yes I am sure I will eventually get it working. I did have everything centered and actually ran an instance of @F3 so that it started out in focus. But it never did complete. Unlike the session we had together I could never get it to get past producing the right side of the curve. Various errors but when it finished the right side and commanded to essentially go back to starting point that typically was where it would fail. I tried lower resolution (per the error message recommendation) But nothing seemed to work. Am just hoping someone can send a sceenshot of their working settings so that at least I can sort of start from what should be a working state for this configuration.
One thing I noticed is that my HFD values when at focus are around mid 3’s. This is at around 60000 step point. The HFD barely gets up to 8-9 by 90000 steps and only after that does it start to rise rapidly. Not sure if that is a factor.
Perhaps it is possible that it is the combination of Gemini with long FL (3910mm) and .97 pixel at 2x2 that is the issue.
I’ll keep you informed.
Bob
Hi Bob,
long focal lenght , fast telescope and resolution is not the problem … the problem is that is not possible to shrink too much the interval for vcurve because algorithm enter in the non linear parts of the vcurve … and this is exactly what is to avoid in all ways (this cause exactly the behavior you report). Solution for your sistem is to use the LocalField … that like all the focus on more stars use the non linear parts of vcurve near the focus.
Another possible cause can be collimation problem or optic problem, but I dont know if this is your case.
All the best
Leonardo
Thanks Leonardo. I will plan to use Local Field or @F3 moving forward. Don’t believe it is optics or collimation problem.
Bob
Hi Bob,
These are the settings for a 3500 mm. FL scope using a Gemini
Thanks Mike. I’ll try one more time with those settings. Curious what camera you are using and possibly what FR. If it still doesn’t work would be interested in what our differences are. As I think Imentioned earlier I am F11 at FL 3900 using a 16803 @ .97"/pixel
Bob
Hi Bob,
These were the settings for an F/7 500 mm scope (FL 3500mm), the camera is a PL 16803. Image scale is .53"
Regards
Mike
Thanks Mike. Very similar. Weather here is poor next few days but should be able to check it out later this week. Really appreciate it. Will let you know ho it goes.
Bob
Just to close the loop on this thread. Mike’s settings essentially worked for me. I was able to get a good Vcurve. Only mod I had to make was to change the Vcurve limit HFD from 30-25. This was necessary due to high ambient temperatures resulting in CFZ being around 39000 steps as opposed to Gemini focuser midpoint of ~57600 steps. Once I made that change the Vcurve completed.
Thanks mike and Leonardo.
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