Oh! Man! Thanks for this video! I was about to tear down my focuser to see what was wrong! I have been trying to shoot M74 for weeks to no avail, and I had exactly the same issue. Focusing in NINA worked great (99% on the curve) on other targets, but this one. Now I get it! Thank you!
You know, it's not a feature I've ever used. I never looked to see if it's even a feature. However, unless you're in an area where temperature changes very rapidly, you should be fine just setting NINA to check focus every once in a while. I have NINA automatically check focus every 60 minutes.
Hi, I think you gave me the answer I was looking for. I just bought a autofocuser and for two night all fine. Now last two nights it's imposible to focus. And I think the full moon is the problem. Wish the moon had a switch to turn it of. Thanks for the video.
The moon makes it difficult to focus if you are point close to it because it drowns out the point sources (stars), but if you point away from it you shouldn't have a problem. If you were pointing away from the moon and still having difficulty, the issue is something else. Patriot Astro has an excellent video on initial setup of the AF. Also, are you using Hocus Focus (presuming you're using NINA). Hocus Focus helps a lot, though NINA is gettings its AF feature better and better.
@@SKYST0RY Yes, using Hocus Focus and wached the video op Petriot Astro... many times ;) I did some more thinking and investigating. First night with troubles I hade some very high clouds that lith op the sky by the moon and yasterday I was low on the horison in NNW
Yet another great video, I am in the process of building a tandem rig, and N.I.N.A will be my imaging software on my mini PC, as ASIAIR does not support synchronous dithering. Great tip on the use of Hocus Focus.
I seem to recall that FocusMax could be set to find a star within a user-configurable range of brightness, usually at zenith, then go back to the target and let the imaging software resume its work. I am getting back into the hobby after years away and still learning NINA, but I thought I recalled FM+CCDAP being able to do this. In any case, great video and explanation.
Hmm.. Unless imaging setup is extremely sensitive to telescope and camera attitude (i.e.: bending through or has a lot of flexure), there is no reason (except some extra time spent on slewing) why not focus at low airmass. Focusing can *never* compensate atmospheric seeing, by definition. But at low(er) airmass, the atmosphere turbulence definitely affects focusing accuracy (even when using HFD as indicator and multiple stars and all the modern tools). Focusing results are much more repeatable and less uncertain when focusing at low airmass and then slewing quickly back to imaging location. I found it out as a quite young student quarter of century ago, trying to focus a 60 cm reflector with very good optics. A very good target for visual focusing (there was no autofocuser) is a tight star group of bright enough stars. Someone in our observatory had an idea, that Orion Trapezium is a great location for that, our telescope easily resolved and showed those very tightly packed stars and their appearance is definitely a very good indicator of good focus. When I did it first time, it really was the case. But. Trapezium is at airmass of ca 2.5 during culmination here and that first night to try it out had exceptionally stable and excellent seeing. In coming couple of months myself and my fellow co-students had hard times to focus the telescope, spending sometimes 30 minutes or even more on the task... because seeing is just bad at that altitude, except under rare circumstances ;-) One night there were some low clouds covering Orion region, but most of the sky was completely clear and I decided to be "careless" (=not to follow guidelines for observers) and point the telescope to random place in the sky, that time close to zenith. The difference was insane, focusing in couple of minutes with diffraction peaks around non-saturated stars well visible... And since that it took every time about that much. Because our telescope stayed focused during pointing, there was no need to repeat it more often than it took temperature to change about 1 C..
I like the concept. It sounds like we were in university studying scientific fields around the same time, and the tech we have now is generations beyond what was available then. Just plate solving to a point a few arcminutes off allows for focusing in seconds, and temperature changes do make a difference through the night. However, there are even more advanced methods than the one covered in this video, such as setting the focuser to focus around structures, or changing how it values point sources vs broad masses. I'll cover them somewhere down the line.
Oh! Man! Thanks for this video! I was about to tear down my focuser to see what was wrong! I have been trying to shoot M74 for weeks to no avail, and I had exactly the same issue. Focusing in NINA worked great (99% on the curve) on other targets, but this one. Now I get it! Thank you!
I haven’t encountered this issue yet. Can’t wait! 😛
Great explanation, thanks for sharing your knowledge
Excellent solution and well explained 😉 Got yourself a new subscriber 👍✅
Maybe a stupid question, but what if you've set to do a focus based on a change of temperature during the sequence?
g.
You know, it's not a feature I've ever used. I never looked to see if it's even a feature. However, unless you're in an area where temperature changes very rapidly, you should be fine just setting NINA to check focus every once in a while. I have NINA automatically check focus every 60 minutes.
Hi, I think you gave me the answer I was looking for. I just bought a autofocuser and for two night all fine. Now last two nights it's imposible to focus. And I think the full moon is the problem. Wish the moon had a switch to turn it of. Thanks for the video.
The moon makes it difficult to focus if you are point close to it because it drowns out the point sources (stars), but if you point away from it you shouldn't have a problem. If you were pointing away from the moon and still having difficulty, the issue is something else. Patriot Astro has an excellent video on initial setup of the AF. Also, are you using Hocus Focus (presuming you're using NINA). Hocus Focus helps a lot, though NINA is gettings its AF feature better and better.
@@SKYST0RY Yes, using Hocus Focus and wached the video op Petriot Astro... many times ;) I did some more thinking and investigating. First night with troubles I hade some very high clouds that lith op the sky by the moon and yasterday I was low on the horison in NNW
Yet another great video, I am in the process of building a tandem rig, and N.I.N.A will be my imaging software on my mini PC, as ASIAIR does not support synchronous dithering. Great tip on the use of Hocus Focus.
You'll love NINA. I haven't used ASIAir though I hear it works great. I find NINA to work very well and it is very versatile.
I seem to recall that FocusMax could be set to find a star within a user-configurable range of brightness, usually at zenith, then go back to the target and let the imaging software resume its work. I am getting back into the hobby after years away and still learning NINA, but I thought I recalled FM+CCDAP being able to do this.
In any case, great video and explanation.
I haven't used FocusMax. But there are some other strategies you can implement to improve focus that I'll cover soon.
Make sure simulator focuser ISNT set as your af
Hmm.. Unless imaging setup is extremely sensitive to telescope and camera attitude (i.e.: bending through or has a lot of flexure), there is no reason (except some extra time spent on slewing) why not focus at low airmass. Focusing can *never* compensate atmospheric seeing, by definition. But at low(er) airmass, the atmosphere turbulence definitely affects focusing accuracy (even when using HFD as indicator and multiple stars and all the modern tools). Focusing results are much more repeatable and less uncertain when focusing at low airmass and then slewing quickly back to imaging location.
I found it out as a quite young student quarter of century ago, trying to focus a 60 cm reflector with very good optics. A very good target for visual focusing (there was no autofocuser) is a tight star group of bright enough stars. Someone in our observatory had an idea, that Orion Trapezium is a great location for that, our telescope easily resolved and showed those very tightly packed stars and their appearance is definitely a very good indicator of good focus. When I did it first time, it really was the case. But. Trapezium is at airmass of ca 2.5 during culmination here and that first night to try it out had exceptionally stable and excellent seeing. In coming couple of months myself and my fellow co-students had hard times to focus the telescope, spending sometimes 30 minutes or even more on the task... because seeing is just bad at that altitude, except under rare circumstances ;-) One night there were some low clouds covering Orion region, but most of the sky was completely clear and I decided to be "careless" (=not to follow guidelines for observers) and point the telescope to random place in the sky, that time close to zenith. The difference was insane, focusing in couple of minutes with diffraction peaks around non-saturated stars well visible... And since that it took every time about that much. Because our telescope stayed focused during pointing, there was no need to repeat it more often than it took temperature to change about 1 C..
I like the concept. It sounds like we were in university studying scientific fields around the same time, and the tech we have now is generations beyond what was available then. Just plate solving to a point a few arcminutes off allows for focusing in seconds, and temperature changes do make a difference through the night. However, there are even more advanced methods than the one covered in this video, such as setting the focuser to focus around structures, or changing how it values point sources vs broad masses. I'll cover them somewhere down the line.