I give this Product a Rating of 4 Stars
Today is a good day because I now have my new Daystar Calcium H-line Quark and I am excited to give this Calcium Quark a try then share with you my experiences. Let us start with an intro into the Calcium filters. Technically speaking, you are peering into the very edge of the light spectrum that a healthy human eye can see. Named by Joseph von Fraunhofer, Calcium wavelengths occur in the near-ultraviolet at wavelengths of 3969 and 3934, and according to the Daystar literature the Calcium H line quark is suitable for both visual and imaging with a wavelength of 3968.8 but no absolute guarantee, but according to my eye I can see very distinct contrast more so than with any White light & continuum filters I own, to include the top of the line Baader Herschel Wedge and Continuum setup or their Calcium K-filters. That being said, I generally do not spend too much time visually with this spectrum and choose to do most of my activities with a camera for imaging purposes.
There are differing opinions when people discuss Calcium filters for visual use - The general European Literature recommends these wavelengths for imaging only and discourages visuals and according to Baader the spectrum can be harmful over long periods of time when used visually, and is why their Glass Filters are for imaging only. Whatever the real dangers are as debated between the two theories of K and H wavelengths, I can attest the Daystar views are very comfortable to look at and show excellent details with high contrast with my setup visually, but again - I do not spend long periods of time behind an eyepiece viewing, I do so for a few minutes as reference for a quick view or two, then I configure the filter the for my imaging camera sessions.
The obvious questions I receive is there a big difference over the Baader Calcium K line glass filter that costs about $350.00 vs the $1200.00 quark? Truthfully speaking if you no ambitions of viewing in Calcium - get yourself a glass filter, my chart is below. If you want a top-shelf product then the Daystar Quark is worth the price, especially if you already have an HA Quark in your solar toolkit.
In my opinion, if you are trying to save a few dollars - by the time you buy some solar film + the K-line filter + an ND filter you will be in it for about: $ 450.00 and if you only spend a few weekends a year in the white light arena then saving funds for other astronomy gear makes sense. If you want to really experience solar imaging and observing as your passion - I would recommend the Daystar Calcium H line over the glass filter - the quality is superior in all regards. I have used both and have the images taken with both a Glass Kline filter and Daystar Calcium H Line, I do see a difference in the Daystar showing higher contrast and more details throughout.
In the field, it is a very simple filter that goes either at the back of your diagonal or in front of your diagonal depending on your requirement for back-focus. I can get my setup to work either way for imaging but needs to go direct mounted to the telescope for visual in-focus travel to bring the disk to sharp focus. With my 560mm f7 80mm Refactor, I am just shy of achieving a full disk views using my ASI178 camera, and with a 20mm eyepiece I need to carefully position my eye to see around the disk, but with a GSO focal reducer, all is well with a full disk for imaging. Please keep in mind all thread on filters needs to go at the back of the Daystar not at the front due to solar energy load, so if you are using a focal reducer It needs to go on your eyepiece or camera nose piece.
Also according to Daystar, the Calcium H line Quark requires a refactor of f7 or longer - has a 25mm blocking filter with 21mm of clear aperture and this should be plenty of open aperture for amateur CCD cameras.
My visual setup requires me to remove my diagonal and mount the Quark in-line with the telescope in order to achieve in-focus, with the Stellarvue OTA and Baader accessories that are easy to accomplish. For imaging, I can either mount the filter in the diagonal along with my camera or direct mount the Calcium Quark to the telescope and do imaging, either way, it works for me with the correct set of adapters.
Pros: An excellent filter for the Calcium H line, showing high contrast sharp images. Visually, the views are stunning with enough filtering to reduce any eyestrain but enough brightness to ensure fast high-speed exposures. The Daystar is a simple to use drop-in solution for Calcium H visuals and imaging activities. It arrives out of the box ready to go, (you may need a portable battery) can fit a 1.25 or 2" eyepiece holder but does require the optional battery to operate the Quark on the band in the field; I can tell you even without the battery I get good results.
Cons: Expensive, does not come with a battery pack, and the USB cable is too short in my opinion.
Recommendation: For Solar Enthusiasts who wish to have the best in class backyard Solar Setup.