EKOS auto focusing - what parameters do you use ?

[teoria_del_big_bang]

Last night started off so clear (an unexpected according to CO) so managed to drag the rig out onto the patio. 
Nebula targets that are above houses and trees are few and far between at moment for me but ad a go at Horsehead initially then Heart.
But I was not happy with the images I was getting and a close look showed the focus was not precise, in fact far from it.
So using the auto focuser in EKOS I tried tuning it in.

But each time I tried it failed.

I did look on line for suggested parameters and that was not too useful as  there were suggestions to use just about every combination possible.
Now, maybe there is a wide range of parameters being used and which you find best may depend on camera and FL of the scope setup, I think I do not understand the mechanism of auto focusing enough, I sort of assumed it just moved the focusser in and out to get  the star it had chosen as small as it would go.

One thing I did find is that even after trying many different parameters already suggested as the best on-line if the stars had halos due to being a fair way out of focus it never achieved focus at all and basically I ended up manually focusing inwards for a while to see if the image got better, then if not move it outwards, until the stars were pretty much in focus and then an auto focus did pretty well and got the stars pin point.

So is that what other people find ?
Is that pretty normal for most auto focus algorithms ?

Also I thought this might be a good place for people to maybe say what  parameters they use in EKOS and mention the scope and camera if that is relevant ?
If there is somewhere with this info I apologize profusely 🙂 

Steve

 

[Richie092]

Like you I am not 100% convinced by Ekos autofocus yet. I have not had a single session where it just worked. This won't always be Ekos of course. Once I was slightly dewed up, another time the focuser connection had worked its way lose and then I also lost my backlash settings, however...

Have tried all the settings and still don't get a satisfactory focus. Resorted to the Bhat in the end. What did help however were the following.

Keep guiding enabled

longer exposures so seeing evens out

getting as close to focus as possible before starting the auto routine.

I have now fitted a ZWO EAF so I can use the AAP. Will see if that improves things.

I love Ekos and will continue to use on one of my rigs but for the mobile one I have gone with the AAP to keep things "simple"

What focuser are you using?

 

 

[teoria_del_big_bang]

1 hour ago, Richie092 said:

What focuser are you using?

Primulace Sesto Senso V1

[teoria_del_big_bang]

1 hour ago, Richie092 said:

Keep guiding enabled

longer exposures so seeing evens out

getting as close to focus as possible before starting the auto routine.

Yes I agree, pretty much my findings last night

Steve

 

[Richie092]

From what I understand that is a very good focuser so shouldn't have issues there.

 

 

[teoria_del_big_bang]

16 minutes ago, Richie092 said:

From what I understand that is a very good focuser so shouldn't have issues there.

It is and think it is doing exactly what it is told to I assume the software just cant cope with the halos you tend to get when out of focus

Edited March 17, 2021 by teoria_del_big_bang

[ajh499]

EKOS auto focus works fairly well for me, but as you've spotted you do need to be pretty close to in focus before you start. Other than that I just leave things at their default settings. 

Once you've found a good focus position you can save the steps value as a preset so that you can quickly go back to a good position to start from in the next session

[wimvb]

When you use the ekos focus routine, you need to be near focus for it to work. I get there by setting the focus routine to loop exposures and slowly, "manually" change focus in Ekos. It also has more trouble with reflectors due to the donut profile while out of focus. I use the linear focus routine where it measures the v-curve and does two passes. The step size is 40 ticks with focusing 5 steps out (200 ticks). I use full field focusing. This works good enough for me. As the routine starts at the last best focus settings, this almost always finds the best focus. I use the pegasus astro focuscube on my mn190 with stock focuser.

Hope this helps.

[teoria_del_big_bang]

Thanks for the info so far and it does seem as I thought that it struggles with anything that is out of focus by more than a little but if just tuning the focus in then works okay.
So I feel a bit more at ease allowing it to automatically refocus during a session to account for thermal changes.

Steve

[Stuart1971]

4 hours ago, wimvb said:

When you use the ekos focus routine, you need to be near focus for it to work. I get there by setting the focus routine to loop exposures and slowly, "manually" change focus in Ekos. It also has more trouble with reflectors due to the donut profile while out of focus. I use the linear focus routine where it measures the v-curve and does two passes. The step size is 40 ticks with focusing 5 steps out (200 ticks). I use full field focusing. This works good enough for me. As the routine starts at the last best focus settings, this almost always finds the best focus. I use the pegasus astro focuscube on my mn190 with stock focuser.

Hope this helps.

When you say “step size 40 ticks with focusing 5 steps out (200 ticks)” can you explain what or where these settings are and where they are put...as I have the same motor and am just starting with Auto focusing, but been using Ekos for a few years now...thanks 👍🏼
Aslo do you use Backlash setting, as I have measured my backlash to be Approx 70 steps, mostly from the rack and pinion of my TakFSQ85

[wimvb]

12 hours ago, Stuart1971 said:

When you say “step size 40 ticks with focusing 5 steps out (200 ticks)” can you explain what or where these settings are and where they are put...as I have the same motor and am just starting with Auto focusing, but been using Ekos for a few years now...thanks 👍🏼
Aslo do you use Backlash setting, as I have measured my backlash to be Approx 70 steps, mostly from the rack and pinion of my TakFSQ85

Here are my settings (most of the relevant information is under the "Mechanics" tab). As I wrote earlier, the initial step size is 40 for my Pegasus focuser (50 was too coarse), and I just changed the "Out Step Multiple" from 5 to 4. When the routine starts, the focuser will first move  2x4x40 = 320 steps out, then 160 (4x40) steps back in, in order to clear backlash. It will then focus inward 40 clicks until it has detected the V-curve. After that it will move out again (followed by a move inwards to clear backlash again). It will then focus inwards with half the initial step size, to find the best focus position. This position should not deviate more than Tolerance from the prevsiously found minimum HFR value. If you leave the Tolerance at the default (3%?) value, the routine will often fail to get focus, because of variations in hfr due to seeing conditions.

[Stuart1971]

8 hours ago, wimvb said:

Here are my settings (most of the relevant information is under the "Mechanics" tab). As I wrote earlier, the initial step size is 40 for my Pegasus focuser (50 was too coarse), and I just changed the "Out Step Multiple" from 5 to 4. When the routine starts, the focuser will first move  2x4x40 = 320 steps out, then 160 (4x40) steps back in, in order to clear backlash. It will then focus inward 40 clicks until it has detected the V-curve. After that it will move out again (followed by a move inwards to clear backlash again). It will then focus inwards with half the initial step size, to find the best focus position. This position should not deviate more than Tolerance from the prevsiously found minimum HFR value. If you leave the Tolerance at the default (3%?) value, the routine will often fail to get focus, because of variations in hfr due to seeing conditions.

So your backlash is set to 1, this seems very low, mine is on 70 ...i found after a move outward, it needs to move in by 70 to clear all backlash....or does Ekos automatically use its own backlash setting...?

[wimvb]

30 minutes ago, Stuart1971 said:

So your backlash is set to 1, this seems very low, mine is on 70 ...i found after a move outward, it needs to move in by 70 to clear all backlash....or does Ekos automatically use its own backlash setting...?

The double outward move (400 steps initially) and large inward move before the sequence starts is there to clear any backlash. Honestly, I've so far not bothered about this. Next clear night I can try to save a focus sequence and post it here.

Yesterday, before I started imaging, I had to refocus my oag guide cam. When I put a bahtinov mask on the scope to do this, focus of the main camera was still spot on.  The routine works ok for me.

Edited March 19, 2021 by wimvb

[Stuart1971]

1 minute ago, wimvb said:

The double outward move (400 steps initially) and large inward move before the sequence starts is there to clear any backlash. Honestly, I've so far not bothered about this. Next clear night I can try to save a focus sequence and post it here.

So if it clears backlash as part of the sequence, why does it have a separate backlash setting...I don’t get that....??

[wimvb]

Maybe those settings are (also) used in the other algorithms that are implemented. The linear algorithm was added to ekos about a year or so ago. This may be a legacy setting.

[wimvb]

As promised:

Edited March 19, 2021 by wimvb

[Danield06]

If anyone is still in need of help let me know. Ekos AF works great. I use a ZWO EAF and once dialed in, it will work wonderfully. I haven't had an issue in months. just FYI that you need to be close to focus for the routine to work. Thats how it is with most AF programs.

[teoria_del_big_bang]

11 minutes ago, Danield06 said:

If anyone is still in need of help let me know. Ekos AF works great. I use a ZWO EAF and once dialed in, it will work wonderfully. I haven't had an issue in months. just FYI that you need to be close to focus for the routine to work. Thats how it is with most AF programs.

To be honest mine has worded fairly well last few sessions, although the UK weather has meant not too many of these sessions 🙂 

But if you don't mind sharing your settings and parameters on here that owuld be a great help 🙂 

Steve

[Stevekerr]

I'm just waiting to try my ZWO EAF with Ekos for the first time next clear night so it would be helpful to get sight of the settings people are using that work.

 

Steve 

[teoria_del_big_bang]

18 minutes ago, Stevekerr said:

I'm just waiting to try my ZWO EAF with Ekos for the first time next clear night so it would be helpful to get sight of the settings people are using that work.

 

Steve 

I would message @Danield06 and ask for some screen shots of his parameters as he has the same focusser should at least be a great start.

Steve

[wimvb]

1 hour ago, Stevekerr said:

I'm just waiting to try my ZWO EAF with Ekos for the first time next clear night so it would be helpful to get sight of the settings people are using that work.

 

Steve 

This depends very much on your scope’s f-number and focuser. For my f/5.3 scope with Pegasus Astro focus cube, I use a step size of 50. If you use a reflector, the auto focus routine will have difficulties handling donut shaped stars, so keep the maximum travel in the region where this shape isn’t pronounced. Do a coarse focusing with a B-mask or by ”guesstimation”

Edited November 11, 2021 by wimvb

[Stevekerr]

Thanks that’s helpful.