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Auto focusing


medst22531@msn.com

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Can you tell us when an auto focusing feature might be available?  Moonlite focusers have a simple program for jogging their focusers using a computer.

 

If you mean the ability to control / jog your Moonlite focuser within BackyardEOS then that has been done 4 years ago.  This is a premium feature edition.

 

If you mean the actual process of BYE auto focusing on a star for you I'm expecting to jump back on this algorithm soon now that BackyardNIKON is released.

 

Regards,

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Mert,

 

ASCOM focusers have been supported in the Premium version, for manual focusing, for a couple of years now.  However, there are two types of focusers, absolute and relative.  I would expect that autofocus would require an absolute focuser, but that any ASCOM driver for an absolute focuser should work.

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I was referring to an absolute focuser in the sense that the ASCOM focuser driver reports that it is an absolute focuser and that it can be commanded to move to a specific position.

 

As much as I would like to see autofocus capability be available for DSLR astroimagers who use BYE and BYN, I believe that the best way to get this would be via integration with FocusMax. If FocusMax were able to get images from BYE/BYN, just like AstroTortilla does, it would allow us to leverage the maturity of FocusMax for autofocusing AND the superior camera capture capabilities of BYE and BYN. It would also allow imagers who use both DSLR and CCD cameras to use the same application for autofocusing.

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Naw, it's not really a Big Deal to handle the difference between Relative and Absolute Focuser "Motion" Commands.  It's not difficult to issue a "Move 50 Steps 'In'" Command vs ("Request Current Position" then "Move 'Current-50' Steps").

 

The difficult parts:

1) Auto Star Selection

2) Calculating a Reliable, Repeatable, and Useful Focus Metric

3) Correctly and Efficiently Identifying a Focus "V-Curve"

4) Verifying successful Focus conclusion at Minimum of the V-Curve

 

Then adding Bonus Features:

1) Scheduled "Focus Checks" or "Re-Focus Tasks" based on Timer or Change of Filter or Re-Slew or...

2) Integrating "Re-Focus Tasks" on "Change in Temperature over Threshold"

3) Whatever else makes it a truly Useful Feature...

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It also seems like an Auto-Focus Feature requires significantly greater Integration than the current BYE/BYN API supports.

 

While it would be Serviceable to simply have a FocusMax-like product that itself Manages the Focus Session by posting Requests to BYE/BYN to "Take Image" and then does all the rest of the Work by itself, that would not allow for Integration that allowed Re-Focus Tasks upon Imaging Session Events (Change of Filter, Start of New Exposure Sequence, etc).  Instead, at a minimum, BYE/BYN would need to "Trigger a FocusMax Iteration" and indicate whether it was a Fully "New Focus" or just a "Check-Up" request.

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Rick, s3igell

 

I'm with Rick considering that a version of FocusMax comes with the motorized version of a starlight focuser.

it seems like a no brainer. less work for Guylain and a lot of people already have Focusmax available to them.

 

I have done some reading on how Focusmax works in hat you have to get a star centered and close to focus then Focusmax will do the final tweaking.

since I wear glasses it is difficult to get a good focus looking through a viewer. I currently use the manual focus and the FWHM readout in BYEOS to focus.

 

any way to automate this process would be GREAT.

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S3igell, I'm not sure what competitive product you are talking about.

 

Your are right, or course, if the idea is to automatically re-focus, as needed.  I guess that I am a more hands-on imager.  I don't kick off a plan and then go to bed.  I monitor things pretty closely.  It would be enough for me if BYE did focus tracking and allowed me to suspend a capture plan to use some autofocus application to re-focus.  I do, however, see how your vision would be appealing to many imagers.

 

Jim,

 

That free version of FocusMax is just a teaser.  For a long time FocusMax was a totally free tool.  I suspect that if Steve Brady incorporated BYE integration into FM you would not be able to upgrade the version that you have, just like you could not upgrade the free version to the current FM 4.

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S3igell, Rick

 

I have contacted Steve Brady via privet message on his forum and he seemed at least interested in that he took the time to look at the BYEOS API.

 

Rick

I was not insinuating that the Focusmax upgrade would be free. it would be nice if Focusmax treated BYE/BYN like other CCD software, like it does now.

this way to incorporate autofocus you could take it or leave it, its your choice.

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I was referring to an absolute focuser in the sense that the ASCOM focuser driver reports that it is an absolute focuser and that it can be commanded to move to a specific position.

 

 

 

Yes, so was I. The poor man's stepper motor focus controller solution is http://rigel.datacorner.com/rigelsys/steppermotor.html

 

All of those are physically "relative", but in the ASCOM driver you can pick "Absolute" behavior so it will work with Focusmax, etc.

 

From the manual:

 

Focuser Type
Absolute:
Select Absolute Focuser Type, rack focuser all the way in (to 'Home') and then press Reset Position. The gcusb-nSTEP software will will set the racked-all-the-way-in position to 00000. Absolute Focuser Type limits focuser position to between 00000 and Maximum Position in ASCOM applications.
Relative:
Does not enforce limits on focuser position. Uses Maximum Position value to set the current position to half the max position value, when you press Reset Position.
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Don't know what you mean by "poor man's stepper motor focus controller solution" but I did

it my way.

I went for the Phidgets route and bought a controller card plus stepper motor for aprox. 150€

all together.

Then I wrote a Little control program and done.

Only problem now is the ASCOM part, since I don't know how to make it ASCOM compatible.

I did do some milling to make an adapter to mount it on top of my Moonlight focusser and it

works like a charm.

There is an ASCOM driver on internet for 1063 cards and I think it will work for mine, but then

the rest of the work has to be done by BYE, that is to say for example

 

take 10 images

do focus session

take 10 more images

etc.

 

or whatever the strategy could be, but the "do focus sesión" should be within BYE in my

humble opinión.

 

Regards,

Mert

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Ah, I forgot to mention that the whole thing is relative.

The program accepts "take current position as home" and from there on you

can send an amount of steps in or out.( but is menú driven, no command list )

Only part that is not implemented is the filter offset per cannel.

Would be easy to measure best focus position for each filter and set that

into defaults.

Next time, when filter is changed the offset is automatically applied.

 

As far as I have seen, Automatic Sequence Generator Pro has the capability

to do it all, but that would be another program to buy on the list.

 

Oh well, it's nice to dream :-) :rolleyes:

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"poor man's stepper motor focus controller solution" just meant it's the cheapest commercial and ASCOM solution out there (I've found anyway) and others (moonlite etc.) are MUCH more expensive, but are perhaps, nativity absolute.

 

By the way, I own Sequence Generator Pro, but so far (haven't tried the latest versions) it didn't work will with my canon DSLR and I greatly prefer the UI of BYE. Autofocus in SGP was also problematic with my rig, but again, I haven't revisited since settling on a focal reducer distance setting and re collimatng.

 

Ideally I'd like to see BYE, through the API, be a DSLR capture client for SGP. SGP being less expensive than focusmax (assuming it works as well for autofocus) and doing more.

 

My motivation for SGP was fully automated imaging, but with the latest park mount features in BYE I am fine for now. I can set my rig and forget it and go to bed and can image up to the meridian, or down to the horizon, while I sleep. Can't image across the meridian, or change targets, but what we have now is good enough. 

 

In fact I guess my next priority would be filterwheel control in BYE, vs. even autofocus ;0)

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I am not sure why a stepper motor-based focuser would not be "natively" absolute.  Inherently, the position would be the number of steps from the home, or zero, position.

 

Is the ASCOM driver for your stepper motor-based focuser not absolute (it returns false for the Absolute property)? It seems like it could be, if that were a design requirement for the ASCOM driver.

 

Mert, if you have Visual Studio, the ASCOM Platform, and the ASCOM Developer Components installed, it should not be too difficult to write an ASCOM focuser driver.  The ASCOM templates for Visual Studio give you a good starting point.

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I am not sure why a stepper motor-based focuser would not be "natively" absolute.  Inherently, the position would be the number of steps from the home, or zero, position.

 

Is the ASCOM driver for your stepper motor-based focuser not absolute (it returns false for the Absolute property)? It seems like it could be, if that were a design requirement for the ASCOM driver.

 

 

 

If you read up a couple of posts (#18), you'll see that the ASCOM driver can be set either way.

 

Those rigs must be relative, because you can disengage them from the focuser, manually move the focus point, and re-engage, so the system has no idea of absolute position.

 

You simulate absolute by running it all the way in, set to 0 steps, run all the way out and set that as the max steps, then tell ASCOM you are absolute.

 

These are typically gears installed on the focus knob shaft, behind the knob, and then the servo gear engages that gear with a screw and spring mechanism, allowing you to loosen the screws and release  the gears for manual focus.

 

More tightly integrated (and more expensive) units are probably factory sealed and cannot be disengaged, and thus CAN understand the absolute position of the focuser at all times.

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An ASCOM driver can return either true or false for the Absolute property.  Are you saying that the driver can sometimes return false and sometimes return true?

 

You described how my MoonLite focuser works.  I can disengage it, move it manually, and re-engage it. After I do that, as a matter of practice, I fully retract the draw tube and zero the driver from the settings dialog. This practice allows me to move out to a position that I know to be very near focus for a given optical setup.  However, the MoonLite ASCOM focuser driver always reports that it is an absolute focuser and it always supports moving the focuser to an absolute position. If I try to move the drawtube beyond fully retracted or fully extended it is happy to do this (the knob still turns) but the focuser doesn't move beyond those two extents.

 

You can see now why your description is confusing me.

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Thanks for making such fantastic software!

 

Is there any update on autofocus? Is it still on the roadmap?

I understand it's a lot of work to implement - I'd gladly pay extra for it on top of the premium edition. You could sell it for $20 as a plug-in or something.

 

Respectfully,

Thomas

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