×

INDI Library v2.0.6 is Released (02 Feb 2024)

Bi-monthly release with minor bug fixes and improvements

New Bahtinov Mask Assistant Tool

  • Posts: 14
  • Thank you received: 15
Dear all,

I have started to make a prototype for a Bahtinov aid, which eventually I would like to put into the EKOS Fokus module.
The idea is the same as with the tools available in APT or the Bahtinov grabber. Since I wanted to understand the problem (and Bahtinov grabber is not very well documented) I developed my own solution in the form of a likelihood fitter.

I attach a few examples what the Bahtinov fitter can do at the moment. For the examples on the Wikipage (en.wikipedia.org/wiki/Bahtinov_mask) it can correctly identify the two out of focus pictures, by measuring the displacement of the center line (shown in green) with respect to the two crossing lines.
So I am quite happy and think I understand the problem well enough to start thinking about how to put this into EKOS.

If you guys can send me example shots taken with your Bahtinov mask I would be able to see how robust the fitter is. That'd be super helpful!
Also, the framework can easily be adapted to fit non-standard mask shapes. If you have one of those, please send me the specs and pictures.

If there are suggestions what you would like to see in such a feature I can try to accommodate this.

Thanks!
Sebastian
The following user(s) said Thank You: Jasem Mutlaq, Radek Kaczorek, Stephen Wong, Wouter van Reeven, AstroNerd, David Tate
5 years 1 month ago #34550
Attachments:

Please Log in or Create an account to join the conversation.

Sebastian,

This is awesome! Many users have requested this feature before. Though I am quite spoiled with the autofocusing and my bahtinov mask is collecting dust now :P
5 years 1 month ago #34561

Please Log in or Create an account to join the conversation.

  • Posts: 1957
  • Thank you received: 420
Sebastian,

Many thanks for this effort!!! Let me know if you need testers for the module. I'll try to collect some images and will share them with you. When I image with my Canon DSLR I always take RAW images (i.e. CR2). I hope that's not a problem?


Cheers, Wouter
The following user(s) said Thank You: Sebastian Neubert
5 years 1 month ago #34568

Please Log in or Create an account to join the conversation.

  • Posts: 14
  • Thank you received: 15
Hi Wouter,

Canon raw files should be fine. I'll need to learn to work with FITSIO anyhow, which can handle them. For initial testing I can just convert them myself.

Cheers, Sebastian
5 years 1 month ago #34571

Please Log in or Create an account to join the conversation.

The focus module switches the mode to FITS when it captures images from DSLRs so you don't need to worry about converting them.
5 years 1 month ago #34572

Please Log in or Create an account to join the conversation.

  • Posts: 90
  • Thank you received: 12
Awesome!! most wanted feature!!!
5 years 1 month ago #34573

Please Log in or Create an account to join the conversation.

  • Posts: 14
  • Thank you received: 15
Hi Jasem,

I'll need to make an option to import pictures into EKOS for testing purposes, I guess I can copy how that is done in the alignment module, right?
Also if you can point me to a piece of code where a FITS picture is read into a 2D array, that'd be helpful.

Thanks, Sebastian
5 years 1 month ago #34574

Please Log in or Create an account to join the conversation.

  • Posts: 1309
  • Thank you received: 226
Fantastic! I have been hoping to see this one day. I have a number of bahtinov examples to share since I've been producing masks made from acrylic for people. I will also point you to this tool Maskulator To simulate bahtinov masks.

Here are a bunch of assorted bahtinov mask samples.
Dropbox Samples

Hope these help.

Andrew.
The following user(s) said Thank You: Sebastian Neubert
5 years 1 month ago #34600

Please Log in or Create an account to join the conversation.

  • Posts: 14
  • Thank you received: 15
Dear Andrew,

This is exactly what I was looking for. Many thanks!!

Sebastian
5 years 1 month ago #34605

Please Log in or Create an account to join the conversation.

  • Posts: 15
  • Thank you received: 3
note that APT has already built in this module: ideiki.com/astro/usersguide/bahtinov_aid.htm maybe this iswhere the idea iscoming from
5 years 1 month ago #34630

Please Log in or Create an account to join the conversation.

  • Posts: 14
  • Thank you received: 15
Indeed as I wrote above APT is one of the inspirations for this.
I'd be curious for suggestions how we can be better than APT. E.g. the two circles that indicate the Focus error in APT.. are they really useful? Why use circles here? What is measured is just a single number.
Instead what I want to provide is an uncertainty of the measurement, so that the user sees when they have reached the sensitivity of the method and further tuning becomes pointless.
This can be expressed visually through a "Focus achieved" message.

BTW: is color vision deficiency (CVD) a design consideration in KStars? Might be an issue when we use differently colored indicators.

Cheers, Sebastian
5 years 1 month ago #34633

Please Log in or Create an account to join the conversation.

  • Posts: 1309
  • Thank you received: 226
I believe the circles in Bahtinov Grabber / APT implementation show a scaled up magnitude of error and whether it is inside or outside focus. It's intuitive enough to get the circles to overlap as much as possible. The software is also capable of averaging over a number of frames to combat seeing conditions.
5 years 1 month ago #34651

Please Log in or Create an account to join the conversation.

Time to create page: 2.897 seconds