BahtiFocus - Bahtinov Mask Analyzer

BahtiFocus is a precision Bahtinov mask analyzer integrated into N.I.N.A, designed to help astronomers achieve perfect focus for their telescopes effortlessly.

Requirements

• N.I.N.A 3.0
• A connected camera (see N.I.N.A documentation)

Features

• Continuously take photos.
• Analyze each photo to monitor:
  • Focus error (in pixels)
  • Absolute focus error (in microns)
  • Critical focus
  • Mask angle
  • Line angles

Usage

• Install the plugin automatically with the N.I.N.A plugin manager or manually place the DLL file into %localappdata%\NINA\Plugins.
  • A new panel will appear in the Imaging tab called Bahtinov Analyser.

• Create or purchase a Bahtinov mask for your instrument (see Bahtinov section).
• Connect your camera to N.I.N.A.
• Choose, slew, and center a star in your camera's view.
  • If the star isn't bright enough, the lines created by the Bahtinov mask will not be visible.
• Place the Bahtinov mask on your instrument.
• Set the options in the options toolbar of the Bahtinov Analyser for exposure time, filters, etc.
  • Note: Information is taken from N.I.N.A options, such as focal length from Options > Equipment.
• Press the start button to begin the exposure.
• After the first photo is taken and appears on the right, you will see a rectangle on the right side of the screen.
  • The rectangle indicates the area analyzed on the left. You can move or zoom it using the controls at the bottom to center it on the star.

• The analysis will continue automatically, and you can adjust the focus of your instrument to find the critical focus.
• Once the critical focus is achieved, you can stop the process and remove the Bahtinov mask!

Bahtinov Mask

A Bahtinov mask is a device used in astrophotography to achieve precise focus on stars or other celestial objects. It is a piece of material with a specific pattern of slots or lines that creates diffraction spikes when placed in front of the telescope's objective lens or primary mirror.

What Does it Do to the Photo?

When a Bahtinov mask is placed in front of the telescope, it creates a pattern of diffraction spikes on a star image. These spikes form an X shape with a central spike that shifts position based on the focus. By analyzing the position of this central spike relative to the X shape, astrophotographers can determine if the focus is perfect, too close, or too far.

How to Use a Bahtinov Mask

1. Attach the Mask: Place the Bahtinov mask over the front of your telescope or camera lens.
2. Select a Bright Star: Point your telescope at a bright star to ensure the diffraction spikes are clearly visible.
3. Capture an Image: Take a photo of the star using your camera.
4. Analyze the Diffraction Spikes: Look at the image and observe the pattern of the diffraction spikes.
   • If the central spike is perfectly centered between the other spikes, the focus is accurate.
   • If the central spike is offset, adjust the focus accordingly.
5. Adjust Focus: Slowly adjust the focus of your telescope or lens until the central spike is perfectly centered.
6. Remove the Mask: Once the focus is accurate, remove the Bahtinov mask and proceed with your astrophotography session.

How to Create a Bahtinov Mask

You can buy a Bahtinov mask from various retailers, such as Pierro Astro.

You can also 3D print the Bahtinov mask using PLA plastic or create it using cardboard and a cutter. There are many resources available online to guide you through different methods. A useful website: https://skeye.rocks/tools/mask/