The Bahtinov mask has become the preferred method of focusing a telescope, either visually or when imaging with a CCD camera, DSLR or webcam. Precise and repeatable focus can be achieved in under a minute, even in poor seeing conditions. The mask displays a unique diffraction profile, one part of the diffraction pattern moves in response to changes in focus and displays error as a displacement from a clearly defined point.
Straight sides ensure the focus mask will not roll away when stored on the shelf, matt-black surface prevents reflections and a reflective high visibility corner makes it easy to locate in the dark.
Credit goes to Russian amateur astronomer Pavel Bahtinov for creating the design and making it available to the astronomy community.
|Average Rating (20 Reviews): |POORLY DESIGNED AND DOESN'T FIT
Thursday, 19 December 2019 | John
Bought this item for my Esprit 150, I expected that it would be designed to fit over the dew cap of my Esprit 150 which has a diameter of 203mm, instead it is a flat piece of rigid plastic with 3 holes drilled in it, and supplied were 2 (not 3) threaded plastic pins, which I assume are designed to hold the mask in place over the dew cap, in any event the holes were drilled in the wrong place.
Not at all what I was expecting,I will be returning the item for a refund.
Used on an SW ED80 DS-Pro
Tuesday, 29 October 2019 | Lee
Performs exactly as expected and is a great help assisting with focusing. Taking stock of other comments about potential structural weakness, I've been careful handling... but it feels solid.
Useful and inexpensive aid for focusing
Wednesday, 25 September 2019 | Clive
I've tried this the last few nights, when it's been blessedly clear. It has definitely helped focusing. I'm using APT as my controlling software, which has a specific Bahtinov Mask focusing aid, but even without that the mask would definitely help to get sharp focus. I did find that for my setup at least I needed a bright star to use to focus on, which means re-focusing in the middle of a series of exposures on a DSO means pointing the scope at a nearby bright star, focusing, then re-pointing at the target DSO, which was somewhat fiddly to get exactly the same framing after the refocusing (using plate solving seemed to work best for me).
I saw other reviews where they had dropped the mask and it broke. I dropped mine a couple of times and it was fine, so perhaps the product quality has improved - it certainly didn't seem brittle. Overall, this is an inexpensive tool, and a definite help.
Thursday, 15 August 2019 | Melvin
Not the quality I thought it would be for the price paid.
Tuesday, 5 March 2019 | Rob
Not a lot to say. Quick delivery, well packed and works well.
Monday, 19 November 2018 | Sheila
I would like to point out to people how fragile these things are. First night out with mine and it broke when it fell off the front of the scope.
I think it will do the job of focusing once you make sure you have secured it to the scope.
StarSharp Bahtinov Focus Mask Celestron C8SCT
Wednesday, 9 May 2018 | John
This item really works, no more chasing focus. Precise focus is achieved in seconds even when using a dew shield. The two plastic screws used to hold the mask in place are simplicityí itself.
Saturday, 28 April 2018 | David
Get perfect focus quickly every time simple to use ,a must have for imaging ,highly recommend
use with Bahtinov grabber for even more accuracy http://www.njnoordhoek.com/?p=325
Wednesday, 14 February 2018 | Roger
Unfortunately I didnít have much of a chance to see how effective this mask is as it blew off my scope and smashed to bits on my patio.
It simply rests on your scope using two nylon threaded bolts so can be dislodged easily.
It may not be so much of a problem if you are using the scope on softer ground.
Saturday, 14 January 2017 | Graeme
Absolutely brilliant - Iíve just tried it out for the first time and it really does take the guesswork out of focusing, especially when viewing via a DLSR tethered to a laptop and using Live View on-screen (which is inherently fuzzy and makes focus hard to judge).
A couple of other things: (1) being the clumsy oaf I am I dropped it twice onto a patio from about 1.5m and it survived unscathed (no shattering like other people have experienced). (2) If you canít find the two plastic screws have a good search through the packaging material, theyíll be in there somewhere in a little plastic bag.
Read all 20 customer reviews...