Askar Metal Bahtinov for FMA230

Codice articolo: FMA230-BA

• The Bahtinov mask allows accurate focusing and fits directly the FMA 230 APO telephoto lens and camera objectives with M62x0,75 filterthread
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• Thread on the telescope side: fits FMA 230 - M62x0,75 photothread
• Material: black anodized aluminum
• Fits to many camera lenses with transition adapter

Free aperture: 53 mm

This is how focusing with your camera on the telescope or objective works

Put the mask on the telescope and point it at a bright star.
Turn on the camera and observe the constellation on Live View or on the computer.
If the image is not exactly in focus, the central line has been shifted. Adjust the focuser until the central line passes exactly through the center of the star.
Now you have achieved the optimum sharpness. Remove the mask from the telescope and you can start exposing the image.

Practical tips from Teleskop-Service
Focusing with a Bahtinov mask is suitable for deep-sky photography in the focus of the telescope or with a camera lens. Correctors and Barlow lenses can be used.
Use a star of medium brightness for focusing, it should not be too bright, but also not too dark. The reflex lines must be easily visible.
The star should not be exactly in the center, because the field of view of the corrected telescope or objective is often not 100% flat. Take a star in the outer third of the field. This will give you better averaged sharpness for the entire image.