Denk Binoviewer Operation With Solar Filters

"I would STRONGLY urge you to not use a Denk binoviewer with a solar H-a setup! Severe damage is likely to occur when it blows your friggin' socks off! It's almost like getting another 0.2 angstrom closer to solar Nirvana, with detail and contrast increasing significantly!" -Cheers, Paul Hyndman (A very happy DenkII / Power x Switch solar-geek!)
                      
Note: Paul Hyndman is a world-class Solar observer and his photos of the Sun in H-a light have been published in many magazines. This amazing Solar Prominence photo bares witness to Pauls standard of excellence. We are well pleased that he has added a Denk II and a pair of D21 Eyepieces to his Solar observing equipment.

Greg Piepol is another H-a observer with who has constructed a world-class website with fantastic images. He used a Denk II and D21s for his visual observing.Visit his website and see what he says about viewing H-a through a  Denk II Premium Binoviewer and our special matched 65 degree D21s.

H-a Is Great With Two Eyes!
While Denkmeier Optical, Inc. does not produce solar filters, there are certainly a large number of Denk Binoviewer users who view the Sun with two eyes while using a telescope equipped with a Hydrogen Alpha (H-a) filter system or a white-light filter of some kind. In this section, we offer guidelines for using our binoviewers with the most popular H-a systems made by Coronado Technologies. We are not solar filter experts and we urge you to contact the manufacturer of your solar filter for specific questions regarding the general use of that product. We only offer guidelines on obtaining focus when adding our binoviewer to the instrument being used with the solar filter.

Warning!!!  Never view the sun without the proper filter system produced by a reliable manufacturer or eye injury and even blindness can result. Never view The Sun through a telescope that is not equipeed with such a system.

Aknowledging The Work Of David Lunt
The Sun is being viewed around the world in the Hydrogen Alpha (H-a) bandpass and much of the credit is due to Coronado Technologies and David Lunt, the late founder of that company. There are now a variety of instruments being offered by Coronado Technologies that are being used with Denkmeier Binoviewer Systems. The resulting two-eyed views are outstanding. Our Denk II prism coatings are purposely optimized so that peak transmission occurs in the 656.33 bandpass. This provides an extra boost of contrast that is quite noticeable to many observers. Of course, our standard Binoviewer works extremely well also, although the Denk II is our recommendation to all serious H-a observers. We honor the memory of David Lunt, who certainly made H-a observing a reality to thousands by creating user-friendly systems that everyone can enjoy. He will be missed by the astronomical community and will be well remembered.

Coronado Solarmax® Filters
When a typical commecially sold Refractor is outfitted with a Coronado Solarmax Filter, the objective lens of the refractor is covered with the solar filter. Then, a special 1.25 star diagonal made by Coronado is inserted into the telescope focuser. This diagonal contains the blocking filter. There are three diagonals available; the BF5, BF10 or BF15. An additional filter called the BF30 is also available but is best used for photography and it can be problematic when used with a binoviewer because of the additional amount of back focus that it requires. We do have solutions for many refractors when this is used though our typical lower-end magnifications become higher with the BF30 than when the 1.25" BF diagonals are employed.

Denkmeier Parts Needed
If a Denk Binoviewer is to be used, the Coronado 1.25" blocking filter Diagonal must have our #150 1.25" OCS Cell threaded into the diagonal 1.25" filter threads located on the telescope-side. The Binoviewer must also utilize a second optic located within the Power x Switch on the binoviewer for the lowest power setting to function. Using the Power x Switch, it should be set to Logo-Side arm "IN" for this low power 1.4X setting. With the Power x Switch arms in the "OUT" position, 2.5X will occur.

Binoviewers Without Power x Switches
If the Binoviewer itself is not equipped with a Power x Switch (Ex: when Diagonal #R1, #R2 or #S2 are being used), the special 1.25" nosepiece Part O for Coronado usage must be threaded in the binoviewer. This special 1.25" nosepiece contains an optic that works in conjunction with the #150 Cell used in the Coronado BF Diagonal and allows low power to occur with the Binoviewer. For higher Power, the special nosepiece with optic is removed and replaced with the 1.25" hollow nosepiece that is supplied with all Denkmeier Binoviewers.

Solarmax Telescopes
Unlike the Solarmax filters that thread onto a refractor in front of the objective lens, The Solarmax Telescopes consist of complete telescopes designed exclusively for H-a observing. Of these, only the Solarmax90 Telescope will focus without the special Denkmeier optical components discussed previously in this section. That is because the focuser drawtube has been designed to cover a very large range of travel. Because of this special Refractor tube design in the Solarmax90 Telescope,, using the Denk II requires no additional optical components to be employed in the BF diagonal. The smaller aperture versions of the Solarmax Telescope (60mm and 40mm) do require the #150 cell and the Power x Switch or the special 1.25" Part O if no Power x Switch is threaded directly on the binoviewer (ex: the 2" Power x Switch Diagonal is being used which means that no Power x Switch is attached directly to the binoviewer).

Multiple Magnifications
Solarmax telescopes feature a sliding drawtube and also a helical fine focuser. If the Power x Switch is used for multiple magnifications, it is very likely that the drawtube will need to be expanded outward from the telescope when the higher power positions of the Power x Switch are used so that focus can be reached. If the combination of the #150 Cell in the BF diagonal and the Special 1.25" Part O Nosepiece is being used for low power, when the hollow 1.25" nosepiece without optic is used instead of Part O, the drawtube will also need to be expanded outward so that focus can be achieved. Using the hollow 1.25" nosepiece instead of the Part O creates high power views. The fine helical focusing mechanism used alone does not have an adequate range to allow focus in both the low and high modes so expect that the drawtube will be used to reach both magnifications. Once a rough focus is achieved, the helical focuser may be emplyed for sharp focus and of course, the binoviewer SCDs (when present) will allow extremely sharp focus for each eye when their focusing mechanisms are finally employed.

Do I Need Additional Parts?
There is a special section under each binoviewer package description entitled Coronado Use that will indicate what additional optical components not included with that package must be purchased. However, many Packages already include all of the optical components needed for Coronado use. We will now review what items are included or what items are needed with each Package.

Standard Packages:
All Standard Binoviewer Packages include either a 1.25" Part S cell, Refractor OCS cell, or a 1.25" 2X Multiplier cell. Any of these cells may be threaded into the 1.25" Coronado Blocking Filter diagonals on the telescope-side so that the Denk Binoviewer will reach focus in a refractor equipped with a Solarmax Filter or in a Solarmax Telescope. The Binoviewer Power x Switch can be used for low and high powers. But remember that the 1.25" Denkmeier Cells mentioned here must always be threaded into the BF diagonal or focus will not be possible.

Denk II Packages:
Because the optical accessories included in Denk II Packages are in a 2" format, additional 1.25" optical components that will allow the Denk Binoviewer to reach focus in a Coronado Scope must be purchased. The Code#150-125OCS
optical cell must be ordered and is priced at $119. This will thread into the 1.25" blocking filter diagonal and allow focus with the Denk II Power x Switch that is included in the denk II Refractor, Newtonian or SCT Power x Switch Packages.

2" Power x Switch Diagonal/Denk Binoviewer Combinations:
Because the optical accessories are in a 2" format, additional 1.25" optical components that will allow the Denk Binoviewer to reach focus in a Coronado Scope must be purchased. The #150 1.25 OCS optical cell must be ordered and is priced at $119. This will thread into the 1.25" blocking filter diagonal and allow focus with the Denk II Binoviewer. However, only a 2.5X magnification will result. For a lower 1.2X magnification option in addition to the 2.5X magnifcation factor, add  Part  1.25" Part O priced at $119.

The Personal Solar Telescope (PST")
Denkmeier Optical, Inc. has produced a special relay corrector that allows the very economical P.S.T. to be used with any Denk Binoviewer at both 1.4X and 2.6X magnifications for onl;y $179 + S/H. We have devoted a special section to this very special Denk corrector. Click on this link for a full description and pricing: The P.S.T. Bino-Corrector Manual

Other Solar Filters
If a white-light Solar Filter is used on a telescope with a single eyepiece, the method of using this filter with a Denk Binoviewer is not any different from using the telescope without the filter. Just follow directions for using that telescope whether it is a Refractor, SCT or Newtonian. When using other H-a systems with a Denk Binoviewer, the same instructions would generally apply though we cannot supply specific guidelines since these systems may vary widely in their mechanical and optical features. We are always willing to answer questions and suggest solutions if focus is not achieved.