BAHTINOV MASK TEMPLATE PDF

This is the same method I used to build an aperture solar filter as well. Required tools and materials: Binder made from hard, thin plastic must be non transparent Stanley or a hobby knife and scissors Contact glue Ruler and a marker pen Printer A3 if possible for larger scopes Required materials for a 8" mask First step was to print the mask - you can use the provided templates , or use the original bahtinov mask generator , and then print it any modern browser can open the generated. In my case I had to print the mask on two pages. Then I cut one half of the plastic binder, and attached to it my printed mask. It is important to keep the lines straight and parallel to ensure that diffraction spikes will be bright and thin Then the annoying task - cutting the plastic.

Author:Vusar Targ
Country:Hungary
Language:English (Spanish)
Genre:Career
Published (Last):28 January 2008
Pages:361
PDF File Size:12.61 Mb
ePub File Size:1.20 Mb
ISBN:215-7-80984-984-3
Downloads:80800
Price:Free* [*Free Regsitration Required]
Uploader:Tojat



Although masks have long been used as focusing aids, the distinctive pattern was invented by Russian amateur astrophotographer Pavel Bahtinov Russian : Павел Бахтинов in The mask consists of three separate grids, positioned in such a way that the grids produce three angled diffraction spikes at the focal plane of the instrument for each bright image element.

In reality, all three spikes move, but the central spike moves in the opposite direction to the two spikes forming the "X". Optimal focus is achieved when the middle spike is centered between the other two spikes. Small deviations from optimal focus are easily visible. For astrophotography, a digital image can be analyzed by software to locate the alignment of the spikes to sub-pixel resolution.

The direction of this displacement indicates the direction of the necessary focus correction. The mask must be removed after accurate focus is achieved. The mask works by replacing the aperture stop of the optical system normally the circular shape of the objective itself with a stop which is asymmetric and periodic. Viewing a point source such as a star yields a diffraction pattern at the focal plane representing the Fraunhofer diffraction transform of the aperture shape.

A very bright star and very dark sky are required to produce highly contrasted spikes that are clearly visible. The diffraction effect is similar to producing sunstar patterns in landscape photography with ordinary camera lenses, where the mechanical iris of the lens is adjusted to a small polygonal shape with sharp corners.

In the example below, the central pattern shows good focus. The central spike is noticeably displaced from the central position in the left and right images. Example diffraction patterns produced by a Bahtinov mask middle: in focus, left and right: slightly out of focus Simulation of the Bahtinov mask diffraction pattern, using "Maskulator".

Each frame shows a focus difference of

ELEMENTS OF PHYSICAL HYDROLOGY HORNBERGER PDF

Bahtinov mask

Although masks have long been used as focusing aids, the distinctive pattern was invented by Russian amateur astrophotographer Pavel Bahtinov Russian : Павел Бахтинов in The mask consists of three separate grids, positioned in such a way that the grids produce three angled diffraction spikes at the focal plane of the instrument for each bright image element. In reality, all three spikes move, but the central spike moves in the opposite direction to the two spikes forming the "X". Optimal focus is achieved when the middle spike is centered between the other two spikes. Small deviations from optimal focus are easily visible. For astrophotography, a digital image can be analyzed by software to locate the alignment of the spikes to sub-pixel resolution.

GDQ1-7 QUEEN OF THE SPIDERS PDF

Home Made Bahtinov Focusing Mask & Templates

Better Focus using a Bahtinov Mask February 4, Tutorials 10 Comments A Bahtinov mask can help you achieve a sharp focus for your astrophotography images. This process is an essential step of any deep-sky astrophotography session. With so much time and effort put into your polar alignment and autoguiding accuracy, it would be a shame to spoil a photo due to poor focus. In many cases, I did not realize how bad the focus of my image was until I attempted to process the final image. You can avoid this unfortunate circumstance by using a simple tool that effectively confirms that your focus is as sharp as can be, a Bahtinov mask. Related Post: Practical Focusing Tips for Astrophotography Use a Bahtinov mask for better focus No matter which type of camera you use, a Bahtinov mask can help you achieve a higher level of accuracy when focusing your telescope or a camera lens. The process involves placing the focusing tool on the objective lens of your telescope or camera lens, and observing a bright star.

Related Articles