Current Price: $40.86
Buy It Now Price: $40.86
Bids: 0

Bahtinov Mask Focusing Mask for Teleses - F70mm for a Tube Outer Diameter (OD) from 290mm-340mm - can be Mounted with The Brass Screws Inside or Outside The drawtube

The Bahtinov mask has become the preferred method of focusing a telese, either visually or when imaging with a CCD camera, DSLR or webcam.They are an inexpensive tool which will allow you to achieve pin-sharp levels of focus, saving you time and improving your work. Simply place the mask over the front of your 'se, align the se towards a star. 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.Whether you're doing plary visual observing, plary imaging,or deep sky imaging, the Bahtinov Mask is a great accessory to get the best focus for your telese quickly and easily.These high quality Bahtinov masks are adjustable to fit a wide range of optical tubes, unlike masks which are only able to fit one telese.The masks grip the telese tube gently but firmly with three metal posts which have non-scratching silicon sleeves to protect you valued telese surface. This prevents slippage, whilst allowing the mask to remaining perfectly central. Because of this 3-post mounting, the mask remains centered, whilst fitting a wider range of teleses.There is a myth about different Bahtinov grating pattern is required for different focal length teleses. There is no real practical reason for the use of special patterns for different telese types and focal lengths. In fact, the frequency and angle of Bahtinov mask patterns aren't really that important. The diffraction effect is so sensitive to changes in focus, that the results are excellent regardless. Please be assured that these focusing masks will work excellently for both reflectors and refractors with whatever focal length. All you need to do is to measure your telese tube size and choose the right size of the mask.

Product Features

  • Bahtinov masks take the guesswork out of focusing and even get over the seeing conditions as it is a mathematical type approach to the task.The best focus for your telese quickly and easily.
  • Suitable for use on all types of telese - reflectors, rafractors, Dobsonians, Mak-Cas and SCTs. They are made from precision laser cut enforced plexiglass, which is stiff and long lasting. They will never be brittle in the cold, unlike some other masks which are made from normal plastics.
  • The masks grip the telese tube gently but firmly with three metal posts which have non-scratching silicon sleeves to protect you valued telese surface. This prevents slippage, whilst allowing the mask to remaining perfectly central. Because of this 3-post mounting, the mask remains centered, whilst fitting a wider range of teleses.
  • They are made from 2mm thick laser cut plexiglass and the securing screws are capped with soft plastic so that they do not damage your telese.These high quality Bahtinov masks are adjustable to fit a wide range of optical tubes, unlike masks which are only able to fit one telese. They have adjustment latitude of about 290-340mm, depending on model, in aperture making them very versatile.
  • Please be assured that these focusing masks will work excellently for both reflectors and refractors with whatever focal length. All you need to do is to measure your telese tube size and choose the right size of the mask (contact us if you are not sure where to measure).

Shipping:

Shipping is FREE within the lower 48 US States. FREE FOR ALASKA AND HAWAII CUSTOMERS

  • We Do Not Ship to PO/APO Boxes
  • We Do Not Ship Outside of the Continental US
  • All items ship within 24-72 hours of Payment
  • For large items that require Freight shipping a valid phone number is required to call and schedule your delivery

Terms of Sale and Feedback:

  • Feedback is extremely important to us and eBay
  • If you are satisfied with our transaction, please take a moment to leave Positive Feedback. YOUR Satisfaction is our #1 Priority!
  • If there are any issues, PLEASE contact us BEFORE leaving a neutral or negative rating so that we may resolve any concerns.
  • We PROMISE we can make you happy if you give us a fair chance.

Returns / Concerns:

  • All items qualify for returns within 14 - 30 days of receipt. Buyer is responsible for return shipping on any item that is not damaged
  • Please be sure this is an item you want before making your purchase. Customer Satisfaction is our TOP priority!
  • All items are IN STOCK at time of listing.
  • Inventory on eBay changes constantly and it is impossible to maintain a perfectly accurate count of all items.
  • Please do not penalize us if we have to issue you a refund!

Thank You For Your Business!

Filed under: Eyepieces & Accessories