Focusing using Bahtinov mask


#1

I find it difficult to perform my initial focus in SGP using a DSLR with a Bahtinov mask. I find myself launching BYEOS for an initial slew to a bright star, grab focus and then open SGP.

Any tricks I’m missing here using SGP frame and focus?

Thanks


#2

I don’t use a bahtinov mask any longer… using FF with the image history tool should be sufficient to get you close enough for AF to work.


#3

Also the same procedure that you’re doing in BYE should also work in sgp.

Thanks
Jares


#4

Also the same procedure that you’re doing in BYE should also work in sgp.

Thanks
Jared


#5

Thanks guys. I am trying the same procedure I use in BYE, using live view but the image isn’t sharp enough to resolve the focus spikes, that’s where I’m thinking I’m missing something. Not sure what the process would be to use image history…just take images while adjusting focus and watch the FWHM?


#6

Do you have auto stretch turned on in SGP?

Yes, that’s it.

Thanks,
Jared


#7

there are some programs that have an assisted focus with the bathinov mask. Maybe it could a new function you can add in your future release! :slight_smile:


#8

We have considered integrating Bahtinov Grabber into SGPro in the past. Of course the original author (the late Niels Noordhoek) created and distributed this software for free. If we ever integrate in this way, it will be part of SGLite so we can continue to propagate the software according to the author’s original intent.

Moving to feature requests.


#9

No auto stretch when I’m using live view, too much noise. Don’t need it for single shots with the mask, those are well resolved.


#10

News about the Bathinov Grabber integration in SGP Pro? :slight_smile:


#11

We have not yet decided if we are going to do this. If we did, it would be in 2.5.


Bahtinov Grabber support
#12

I hope you decide to support. A lot of people use bathinov mask for focus. It would be awesome! good work! :slight_smile:


#13

I’m also looking forward to this feature.
Not all of us uses auto focusing and this makes me much easier to focus than using SGP and he grabber separately.


#14

I agree with donghun. I use several scopes and only 2 have autofocus options.
So a manual aid via a grabber like feature would be of great help.

Thanks
Robert


#15

Another vote here for an integrated Bahtinov Grabber.

Regards
John


#16

Agree, it will be an good focusing option.


#17

I’d also love to see this incorporated into Sgp - would be a great feature


#18

One thing I’ve seen with all these focusing methods is the need to get fairly close to focus before they work. This applies with or without a Bahtinov mask.

What I see in the image when I’m a long way away from focus is a collection of circles or doughnuts. I make a focus change and see what happens. If the circles get bigger I’ve gone the wrong way. If they get smaller I’m going the right way. I continue making focus adjustments until I’m close enough for auto focus to work.

I wonder if this could be automated:

  • Collect an image
  • Detect circles (the Circular Hough Transform maybe)
  • Get the average circle radius.
  • Move the focuser.
  • Collect an image
  • Detect circles and determine their radius
  • Use the change in circle radius and focuser movement to find an
    approximate best focus.
  • Move there.
  • Do fine focus.

I’m not sure how practical this would be and there’s a lot of development and testing needed but it could be very useful, especially if it could be used to avoid the problem of spurious low HFR values with obstructed scopes.

Chris


#19

Another vote here for an integrated Bahtinov Grabber (or similar, of course)
I’ve got two scopes, but not enough money for two autofocus… :blush:
Regards from Spain.


#20

My vote for integrating some sort of Bahitnov Grabber feature !!

-Kai


www.mainsequencesoftware.com