I am running Kstars 3.6.8 and using my recently added ZWO EAF. I ran a couple of autofocus routines one night over the weekend and they worked fine,. I was wondering if you would take a look at the attached log and tell me if there is something else I should be using in the way of settings. I think I have it set up for Centroid, single pass. I will take a look at your tutorial again to refresh my memory of other options.

Also, I believe in the Indi Control panel there is a tab for setting up to 3 presets, presumably for different scope configurations (f/10, f/6.3 with reducer, etc). I have a 7 filter filter wheel, with standard Baader filters. I am not sure if they are actually all parfocal. I have not run auto focus on each filter, but I will do that one night soon. Is it possible to add, in the software, a focus adjustment, that has been pre-established) for each filter, so that when I change filters the EAF automatically make a small adjustment established for that filter?

thanks

Hi Ronald,

I had a look at the log. Here are a few comments:
1. I would normally suggest using SEP rather than Centroid but some folks have had success with Centroid so its upto you.
2. Worth setting "Use Weights" = on and "Refine Curve Fit" = on.

In the Filter Settings popup you can add your offsets which will do what you ask on filter change.

In order to calculate the offsets you can do it manually or run the Build Filter Offsets tool which will run Autofocus on the filters you want and calculate the offsets for you.

This video should help...

John,
thanks, I knew there was a video somewhere that explained it. If I switch to using centroid then I need to set up some other parameters, as I recall. I will have to dig up my first posts to see what you said about that.

I am using a step size of 50 and an Over scan of 1000 (I have a feather touch focuser on my SCT and it takes 5270 steps for a full turn ) with the backlash set to 0. 1000 steps over scan may be too high but I know when I reverse direction on my focus knob there is a slight offset in the image due to mirror shift. It does not seem to cause a problem with the autofocus routine other than the second point is almost always worse than the first point in the curve. I kept increasing the over scan to see if I can keep that from happening, but it still does. If I am using 'all stars' to focus when does it select the stars? I assume it selects them after doing the over scan and has returned to the first data point. By then the focus should be stable going CCW on the focus knob, so I don't understand why the second data point is almost always larger than the first data point.

With the step size of 50 I seem to take a lot of data points to establish the curve. How much accuracy do you think I will loose if I increase the step size to 100? Is there a way to take a first pass at a larger step size and then take a second pass with small step sizes just right around focus?

I can play with it under the stars, but then I am taking up 'imaging' time. The routine seems to be working for me right now as it is, but I would like to improve where I can and make it more time efficient.

With the filters, if I recall from the video, you can either reference off of a particular filter (like referencing Green off of the position for Lum) or you can reference off of the previous filter in the sequence. So I could have two reference points, say referencing RGB off of L and referencing Sii and Oiii off of Ha, as I would normally autofocus on L to start with for broad band. Then for the NB filters I would start with an autofocus on Ha and reference the other two from it. Does that sound right?

thanks again for all your work on this.

Hi Ronald,

If I switch to using centroid then I need to set up some other parameters, as I recall. I will have to dig up my first posts to see what you said about that.

Centroid doesn't really have tuneable parameters.

I am using a step size of 50 and an Over scan of 1000 (I have a feather touch focuser on my SCT and it takes 5270 steps for a full turn ) with the backlash set to 0. 1000 steps over scan may be too high but I know when I reverse direction on my focus knob there is a slight offset in the image due to mirror shift. It does not seem to cause a problem with the autofocus routine other than the second point is almost always worse than the first point in the curve. I kept increasing the over scan to see if I can keep that from happening, but it still does.

The feather touch is supposed to be low backlash so 1000 sounds too high for Overscan. Sounds like something else is going on. There is a settle parameter that can be set after each movement before the focus frame is taken. It might be worth increasing this and seeing if that improves things.

If I am using 'all stars' to focus when does it select the stars? I assume it selects them after doing the over scan and has returned to the first data point.

Yes, correct.

By then the focus should be stable going CCW on the focus knob, so I don't understand why the second data point is almost always larger than the first data point.

So there are a few things that come to mind. If the first datapoint is in the "donut zone" then that could be a reason. There is some functionality coming that will substantially improve this situation. Its merged into the code base and will be generally available in the next release. There is a video on my youtube channel about this - its called Donut Buster.

It could be that the first point hasn't "settled" properly although I would have thought that would make the point bigger, not smaller.

Often I see people using too short an exposure in order to make Autofocus run faster. You could try increasing the exposure.

Are you sure you have the "sense" of the focuser correct and that the last movement is CCW (pushing the primary uphill)?

With the step size of 50 I seem to take a lot of data points to establish the curve. How much accuracy do you think I will loose if I increase the step size to 100?

I would start with 11 points and reduce them when you gain confidence. The thing to remember is that with smaller datasets each point makes a bigger contribution to the curve so 1 bad datapoint will have a bigger effect. Set useWeights=on and RefineCurveFit=on and the software will attempt to compensate for this.

Is there a way to take a first pass at a larger step size and then take a second pass with small step sizes just right around focus?

Yes, set walk=CFZ Shuffle.

I can play with it under the stars, but then I am taking up 'imaging' time. The routine seems to be working for me right now as it is, but I would like to improve where I can and make it more time efficient.

What I do is to collect Focus data whilst imaging and then "play" with it in daylight by running it through the simulator. This allows to run "what ifs" where you can change parameters and see what happens in Autofocus. You will need some technical skill but you don't need to be a programmer. This video explains how to do this...

With the filters, if I recall from the video, you can either reference off of a particular filter (like referencing Green off of the position for Lum) or you can reference off of the previous filter in the sequence. So I could have two reference points, say referencing RGB off of L and referencing Sii and Oiii off of Ha, as I would normally autofocus on L to start with for broad band. Then for the NB filters I would start with an autofocus on Ha and reference the other two from it. Does that sound right?

You could do it that way but I'm not sure there's any benefit to it. What I would do if pick a filter that focuses well, e.g. Lum or a light pollution filter. This will be faster than a NB filter as you can use shorter exposures. Set offsets for everything relative to this. When you change filters, Focus moves the focuser from the old filter to the new, so...
Filter Offset
Lum. 0
Red. 100
Ha. 75
Oiii. -50

Moving from Lum to Red: focuser moves 100 - 0 = 100 (out by 100)
Moving from Lum to Ha: focuser moves 75 - 0 = 75 (out by 75)
Moving from Ha to Oiii: focuser moves -50 - 75 = -125 (in by 125)

Hope that makes sense.

John,
Thanks, yes it all makes sense. I am not at the program, so I am asking question from memory of the last time I ran it. I mis-spoke in my last post; if I switch to SEP not Centroid; then I think there are some other parameters that need to be set.

thanks again.

Hi Ronald,

Yes, SEP has quite a few extra parameters. The default values work well for a lot of setups. There is some very recent work to improve things for scopes with central obstructions (like your SCT). If you have the very latest bleeding-edge software you will have this functionality. So if you run Focus Advisor and accept the SEP Parameter recommendations that should work well.

If you don't have the very latest software then SEP still works well with default parameters providing you don't let the focuser travel so far that you get donut shaped stars.

If you have problems post a screenshot of the SEP parameters and I should be able to suggest improvements.

I am having difficulty getting EKOS to recognize the filter focus settings. I ran several Autofocus runs using different filters and it filled in the offests for RGB relative to Lum. Two nights ago I thought it was starting to work correctly, as I could see the filter settings in the imaging window (when I clicked on the funnel looking icon I could see the offsets.) And when I took an image with a filter I could see the position change in the focus module.

However, tonight I cannot access the filter settings in the image window and if I try to change a filter in the focus module it keeps setting it back to LUM. I had to change the focus position manually, which of course worked.

I will attach the log from tonight. I am surprised that the focus settings for filters is contained in the main program as opposed to either in the filter indi control module or the focus indi control module.



I am running kstars 3.6.8 stable. Let me know if you want a previous log.

thanks,
Ron

Hi Ronald,

I'm not sure what you mean by:
However, tonight I cannot access the filter settings in the image window

Are you saying that the Filter Settings popup isn't working?

and if I try to change a filter in the focus module it keeps setting it back to LUM.

Are you running from the scheduler or are you manually trying to focus and capture?

John,
Thank you again for your work and help with this tool

Yes, I am saying that the filter settings popup in the imaging window is not working. It can not be accessed, I click on it and nothing happens. the same icon in the focus window works, however, last night, in the focus window if is tried to set a filter (red) it would go back to LUM when started looping on focus. NOTE: I do not hve the Autofocus on LUM set in the filter settings, I just have offsets for RGB and they reference the LUM position.

In my session three nights ago I set up the filter offsets and tested them in the focus module. They were working as expected then, but I was not using that camera for imaging so I did not test them in the imaging module. Two nights ago, I did try them in the imaging module and at first the filter settings popup was not working, but later on in the evening it started to show up as highlighted so I could click on it and see the settings. Also, when I ran a filter in the imaging module I could see what was taking place in the comment lines of the focus module and it was working as expected.

Last night, I did an autofocus (using LUM) and then went to the imaging module. Again, the filter settings popup would not open and when I changed a filter and started imaging, nothing happened in the focus module to indicate that the focus was being adjusted. Further, last night, I could not even change the filter in the focus module and just test focus (I did not try to autofocus in something other then LUM). I would change the filter (in the focus module), start looping to see if it would adjust the focus and it would just change the filter back to LUM. I could change the filter in the imaging module and it would image with the proper filter, but nothing changed in the focus module.

I attached last nights log, I have the other nights as well. I don't know if this is a bug or if I inadvertently changed something. I did not change the filter offsets, just was trying to use the filters and test the offsets.

Everthing else about the focus module seemed to be working. If I changed the focus position manually it would add the overshoot amount in one direction and not the other, as expected. And the lum autofocus ran well, I tried it was some different settings (not yet tried SEP), just changed step sizes.

thanks again.
Ron

John,
A little more about my equipment. I have two imaging trains, one uses the EAF and a filter wheel the other does not (a second camera on another scope for plate solving). Last night I was only imaging with the optical train that uses the EAF and the Filterwheel. I did plate solve with the second system, but I never ran a focus routine with it. I did run a focus routine on that system in my last outing, but it does not use the EAF, so I only loop with it while I adjust focus manually using a Bahtinov mask. I don't know if somehow the system could get confused about what was bing used to image, however the imaging last night worked with the filters, I was just not getting automatic focus adjustments.

Hi Ronald,

It looks to me like the Filter Settings button on Capture is a bug. I think it's just greyed out which is why it's "not working". I'll try and progress this tomorrow. In the meantime the button on Focus launches the same popup (as you know).

On the "framing" behaviour I can reproduce what you describe. To be honest I've never actually tried what you're describing so I don't know what "should" happen. I guess, because you have a lock filter set (Luminance) its flipping back to that. As to whether that is correct or incorrect behaviour I'm not sure. The Filter Offsets are usually used when focusing automatically from the scheduler so I haven't thought about how they "should" work when driving manually from the Focus screen. I'll think about this more tomorrow.

John,
OK, Glad that you understand the issue I was having. I have never used the scheduler, I roll my scope out of the garage down the driveway to use it. So I only use the capture module to take images, one night at a time. I would expect the capture module to adjust focus when I change a filter to take an image. It seemed like that worked during my previous night, I will attach that log. I don't really need to see or use the filter settings popup from the capture module. Once it is set up in the focus module I would expect it to use those values whenever I use any filter.

I have my filter offsets registered from LUM, but I don't want it to do a LUM Autofocus when ever I change a filter. I want to be able to set up the offsets, then in am evening I will perform a lum autofocus to establish its best focus for that night (at that time and temperature - I may update that later in the evening) Then I would expect the imaging module to adjust the focus (using the pre set offsets) whenever I go to use a filter for imaging.

At least that is what I was expecting the program to do. I will work with whatever you decide. I think this is the correct log.



thanks again,
Ron