Kendrick Kwik Focus Mask for OD's 289mm-299mm
Kendrick manufactures two different types of Kwik Focus Mask. The rigid masks will not bend whereas the plastic film masks are rollable and extremely lightweight.
This innovative concept was invented by a Russian amatuer astronomer, Paul Bahtinov, and Kendrick is producing these masks with his permission.
The Bahtinov mask allows digital astrophotographers and visual observers to get razor sharp focus in seconds!
The difference in focuser position between the four pictures shown below is very small, a few tenths of a mm. The method is very fast and incredibly sensitive. There is no guessing when you are focused during times of poor to moderate seeing. Simply put the mask and the status of your focus will become immediately apparent.
The masks have a series of slots that create a unique diffraction pattern that can be used to quickly bring your telescope to focus with an absolute minimum of fuss.
How to use a Bahtinov Mask?
First of all, the rigid masks come with three adjustable rubber bumpers. This allows them to fit to a wide variety of tube diameters. Simply push the bumper to the desired location on the slot to ensure that the mask is properly centered over your optic. The plastic masks will require the user to devise a method of attachment. We suggest masking tape.
Then focus. The graphic below describes visually what you will see on either side of being focused. This graphic represents movement of the focuser in very small amounts (fractions of a mm). It is extremely sensitive.
The Bahtinov Mask is probably the easiest product on the market to achieve tight focus for visual use and for digital astrophotographers, regardless of whether you use a DSLR or CCD camera.
The Kendrick Kwik Focus is a multi purpose tool that is indispensable for anyone wanting to get optimum performance from their telescope and the best possible focus they can achieve.
The Kwik Focus can also be used to determine if your telescope's optics are properly aligned and collimated. By observing the out of focus star images through the Kwik focus you can bring your telescopes optics into accurate alignment.
It can be used to easily and quickly achieve critical focus for astrophotographers, CCD imagers and observers. We believe it is the easiest product to use on the market to achieve accurate focus.
By purchasing our solar filter inserts the Kwik Focus can now be used as an off axis solar filter. Full aperture solar filters will often give a poorer image than a smaller filter because of the secondary obstruction and poor seeing conditions caused by the suns heating of the atmosphere. An off axis filter removes the image degrading influence of the secondary and minimizes the effects of atmospherics turbulence to give a better solar image.
Constructed of aluminum and powder coated black, it is elegant in both concept and design. It can also be used a lens cap when your telescope is not in use. When using it as a lens cap the three plastic plugs that come with the Kwik Focus are placed into the three holes on the front of the device.
We have 52mm and 82mm solar filter inserts available for our popular Kwik Focus. Now your Kwik Focus can be quickly and easily converted to a solar filter. Unscrew the filter from the Kwik Focus and it is back to being a focusing aid. Available in visual and photographic versions.
The Kwik Focus works by projecting three images onto the focusing screen of your camera, imaging chip of your CCD camera or your eyepiece. As you come closer into focus the three images tighten up and eventually merge. When the images have merged you are now at the optimum focus your system can accomplish. As this is a mechanical focus, your eye can no longer compensate for slightly out of focus images. Remove the Kwik Focus and shoot, image or observe. It is that easy.
Unlike other focusing systems on the market, you can use the moon, planet or any other object that is at least 6th magnitude to focus on and focusing is achieved with considerably more ease.
With the "Kwik Focus" on the end of your telescope all point source objects will form THREE round images. Turn the focus adjustment in the direction that brings the images closer together. When the images overlap each other and become one, you are focused at the best your lens system is capable of. You will find this is easier as power is increased. You can focus right on a planet or the moon and not have to move back and forth between a bright star and the planets. (As other products on the market require). No doubt, you have seen articles that recommend, under certain conditions, stopping down your telescope for better viewing and to help increase contrast and reduce glare. The cap can be left on to do just this while viewing a bright object like the Moon, which has the added benefit of helping to save your dark adapted eyes. It may also eliminate the need for a neutral density filter.
Other benefits of this device include:
* Making the splitting of double stars easier.
* Eliminates difraction from the secondary mirror (in SCT's and Newtonians)
* Can cancel out most of the problems associated with mirrors that have turned edges or zonal errors.
* Can be used as an off axis aperture mask to diminish the effects of poor to medium seeing.
"Kwik Focus" may also be used for prime focus on your scope if you want to photograph any nebula. Simply point your camera and scope at the closest sixth magnitude star or brighter near the object of your choice and adjust your focus so all double image star points become single points of light. Take a little extra time here because your star images are very small compared to planet images. When you have finished focusing, do not forget to remove the "Kwik Focus Cap" for maximum light for the camera.
Double star watchers will find "Kwik Focus" helpful in that you will get better resolution of close stars and better colors. The Kwik Focus can also be used as a step down mask to cut down glare when observing the moon. It also acts as an off axis aperture mask. As an aperutre mask the cap can be rotated until the best surfaces of the mirror are beneath the holes in the Kwik Focus cap. Planetary observation is enhanced by the reduction of the effects of nominal seeing, lengthening the focal ratio of your telescope and eliminating the light scattering effect of the secondary mirror.
The Kwik Focus is presently only available for the Meade ETX, Celestron C5, Astro Physics Traveler, 130mm and 155mm refractors, Televue 101,the Meade 7" Maksutov-Cassegrain and 8", 9.25", 10", 11", 12" , 14" and 16" Schmidt Cassegrain Telescopes.
Below are pictures of a portion of the moon taken through a 16" F4.5 Newtonian by an individual who had never done astrophotography before. He was asked to focus as best he could without using the Kwik Focus. In the second photograph he took the same shot, this time using the Kwik Focus. The results were dramatic. Both of these photos are details taken from a photograph with a slightly wider field.
HOW TO FOCUS A CCD CAMERA
For CCD imaging use the following process for quick and easy focus.
Place the Kwik Focus over the front of your telescope. Set your CCD camera to its coarsest binning, which would be 3 x 3. If you are using the ST7 or ST8 use the 27 micron pixel size. Using a 2nd magnitude or brighter star, start to focus on the star using the softwares focusing mode. An exposure of 0.11 to 0.5 seconds should suffice. Continue adjusting focus until the duplicate star images converge on your monitor.
Set your CCD to its finest binning, which would be 1 x 1 or the 9 micron pixel size for the ST7 or ST8. Using a 4th or 5th magnitude star and the same exposure times as described above, adjust your focus until the images converge again on your monitor.
If you have a digital focus counter, record the focus position for future reference. A digital focus counter is highly recommended for users of Schmidt Cassegrain Telescopes or any other tlescope with an internal focusing mechanism. If your focuser is external then measure the distance from the back-plate of the OTA to an easily accessible spot on the CCD and record this measurement.
Skip step 1. Using your previously recorded focusing measurements, set your CCD camera in position. Repeat step 2.
The first time procedure should only take 30 to 60 minutes. All subsequent setups should only take 10 minutes at the most.
HOW TO FOCUS A 35mm CAMERA
Procedure for 35mm or larger cameras
Place the Kwik Focus over the front of your telescope. With your camera in the focuser look through the view finder and begin to bring the images into focus. You will see multiple (3) images of all objects in the field of view. As you focus the images will tighten up and converge. The point where the images converge is the point of precise focus. Remove the Kwik Focus and begin to shoot. Very easy, very quick and very effective!
The Kwik Focus can now be used as a collimation diagnostic tool and for collimating. To determine if your telescope needs collimating, put a reasonably bright star (5th magnitude or brighter) in your telescopes' field of view with the Kwik Focus on the front of your telescope. With a fairly high power eyepiece (150x to 250x) in your focuser, move your focuser from "inside focus" to "focus" to "outside focus". All three images should converge perfectly on top of one another. If they do not, your optics are out of collimation and are contributing to your focusing problems. Seeing conditions will determine just how much magnification you can use when collimating so work within the limits of your sky conditions.
The Kwik Focus works very well in collimating if you have a fast telescope (F5 or faster). It still works well on longer focal lenghts but we recommend after collimating with the Kwik Focus that the single star collimation method be used to bring your telescope into fine collimation.
If you have determined that your telescope is out of collimation and you want to use the Kwik Focus to bring it into collimation you need to do the following procedure:
Place the Kwik Focus on the front of yor telescope, following the steps described above. Remove the Kwik Focus each time you need to tweak the collimation screws. Replace the Kwik Focus and go through the focusing procedure again to recheck collimation. Do this until you have a perfect image.
These two drawings indicate how an uncollimated and a collimated image may appear in your telescope as seen through the Kwik Focus. The center star is at focus and the two either side of it are inside and outside focus. The top drawing depicts an uncollimated telescope and the bottom drawing is a collimated scope.