Where to set focus offset for different filters? #42603
I just have got my first filter wheel. And now I'm beginning to play with it. So I am wondering about focusing - should there not be a place to set a "focus offset" between filters, so I can use the L filter to focus and then capture with, say, Ha? If so, where is this setting?
Where to set focus offset for different filters? #56428
I'm not sure what you mean with setting it in the sequence queue. You can access this offset window from several places, if I am not mistaken, for instance from the Capture module. And they are global settings. When changing filter, these offsets are used, regardless of what is in the Scheduler sequence. So: global. You set them once.
Where to set focus offset for different filters? #56438
But OFFSET value are related to what main value???? The value of the first declared filter??? I have filters in these sequence L-R-G-B-5-6-7, if I want configure offset what i have to enter? Example 0 for L, 20 for R, 15 for G and 25 for B????
Where to set focus offset for different filters? #56447
The offsets are relative to each other, so if you have a bunch of filters that are parfocal, call those 0 and do the other offsets relative to that, that would be easiest. If they are all different, then it’s up to you which one you call zero.
Where to set focus offset for different filters? #56463
Baader filter shuould be parafocal, but I see a little difference from a filter to another. So as you wrote I should set 0 for the first filter and then add +20 for R, -5 for G and +30 for B refered to my example "0 for L, 20 for R, 15 for G and 25 for B".
Obviously automatically Ekos have to change the focus in order to respect the offset values
Where to set focus offset for different filters? #56465
I don't believe you understand what I am saying. The filter offsets are just simply relating how the focus distance of each filter compares to the other, NOT how far to move it when going from one filter to the next in any particular sequence. So your filter offsets could be 0 L, +20 R, +15 G and +25 B, or they could be -20 L, 0 R, -5 G, +5 B and it would have exactly the same effect. Also it doesn't matter what numbers you use, as long as the relative distance between the offsets remains the same. For your example, +1000 L, +1020 R, +1015 G, and +1025 B would work exactly the same as well. Ekos will calculate how far to move it between each filter based upon difference between the offsets. So it doesn't matter how you order them in your imaging sequence or even if you switch filters in a different operation. The offsets are global. If you set the filter offsets relative to each other, then any operation Ekos does, when it changes the filter for any reason, it takes the filter offsets into account and adjusts the focus by the difference between the two offsets of the filters it switches between.
Then these are the values to put in the offset fields for the filters.
After that only use the reference filter for autofocus at the beginning of each session (also only have L filter with the autofocus box ticked?)
Is that a correct understanding of what you've explained?
Where to set focus offset for different filters? #56555
Yes jiberjaber, your offsets should work just fine, or you can also use the "absolute" values you said as well. Since the focus offsets are relative to one another and focus changes are differences between the offsets, then it wouldn't matter to have all the offsets shifted by the same value.
As for which filter you use for focusing, that should not matter as long as the offsets are all entered correctly for each filter and as long as your focuser moves correctly based on the offset when switching filters. I say this because some focusers don't reliably have the same numbers for the same focus positions when focusing in or out and sometimes the focus drifts a little. So really the focus offsets can only be used as long as your focuser can reliably move by the same amount each time.