Focusing Mask Bahtinov acrylic 140-180mm

Name: ASToptics Focusing Mask Bahtinov acrylic 140-180mm
Brand: ASToptics
Price: 29.9 USD

$ 29.90 incl. VAT plus shipping costs

in stock
ready for shipping in 24 h + lead time

Express shipment possible for delivery tomorrow, 11.04.2026!

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Adjustable pins for adaptation to the telescope
Lightweight yet sturdy

Product questions?

advice for Astronomy

This product is available in the following variants:
	Diameter (mm)	Price
	100-140mm	$ 29.90
	120-160mm	$ 29.90
	140-180mm	$ 29.90
	160-200mm	$ 34.90
	180-220mm	$ 34.90
	200-260mm	$ 40.90
	230-290mm	$ 40.90
	270-330mm	$ 46.90
	60-90mm	$ 17.90
	80-110mm	$ 23.90

Product description

The focusing mask according to Pavel Bahtinov facilitates precise focusing, which is particularly important in astrophotography. The mask is attached to the front of the tube or lens. When looking at a star, it produces a pattern of rays. When the long ray intersects the two slightly shorter rays symmetrically in the middle, the focus is correct. Thanks to its many opening slits, the Bahtinov mask can also be used with relatively dim stars. This is an advantage over the classic Scheiner mask.

A Bahtinov mask should actually be calculated separately for each aperture ratio. However, experience shows that one mask can be used very effectively for an entire aperture range.