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Right: An amazing loop Prominence on the Sun as imaged on 21 Oct 2010 though a DayStar 0.4 Angstrom QUANTUM PE Hydrogen Alpha filter. Filter attached to a 110mm refractor telescope with 4x Powermate Lens at f/32. Image courtesy of DayStar (110,780 bytes). The hobby of astronomy is one of the few sciences where amateurs routinely make discoveries and meaningful contributions. Some hobbyists became retailers of astronomical equipment; some names of these retailers which came to "prominence" included the late Ken Hirsch whose regular advertisements in publications including "Sky & Telescope" featured spectacular prominence photos taken by DayStar customers. DayStar filters came to be employed not just on the ground but in space flight too where one sounding rocket crashed upon its return to Earth; among the few recognizable and working components where a DayStar filter. In the mid 1990's Del Woods hired someone whom he trained to replace him at DayStar, but this hoped for transition did not work out. The mid 1990's became a turbulent time in the history of the company, with production numbers plummeting and wait lists for Hydrogen Alpha filters growing to two or more years! Del's absence and later the passing of Ed Hirsh prompted a variety of fictitious rumors about the company. By 1999 Del Woods came back to work at DayStar, bringing his expertise and compassion back to the community until May 2005 when ill health forced Del to retire and sell the assets and knowledge to what became DayStar Filters Limited Liability Corporation. As Del's health declined, Company Seven remained the sole authorized retailer of the DayStar filter line. Even since the days of Del Woods, Company Seven remains the most enduring and longest lived continuously operating representative of the DayStar filter line, and we continue working with Jen Winters and the current team at DayStar. No other retailer than Company Seven has more experience and understanding of these products, or more knowledge of how to implement them with a broad variety of telescopes and other specialized instruments.
Products: The reliable DayStar filter can be found in operation throughout the world's major educational and research institutions, as well as in service of the more demanding amateur. DayStar is best known for providing ultra narrow band optical interference filters primarily for solar observations, these filters transmit a single sub-angstrom bandwidth line from our Sun while rejecting the complete background radiation. However, DayStar has manufactured many custom filters over the years for many applications outside of those original markets targeted by DayStar. DayStar has the technical expertise to design a wide variety of filters and has since branched into other areas of astronomy including the manufacture of a high contrast nebular filter designed to reduce the effects of sky glow pollution from city lights.
With an integrated solar telescope, those that incorporate a Hydrogen Alpha filter, the effective system aperture can only be as large as the that of the telescope in which the filter is incorporated. This arrangement applies to those solar telescopes that Company Seven offers including
The most important revolution since the changeover since 2005 was the development of the QUANTUM series of digitally controlled filter systems:
There are a few points which we wish to emphasize:
2. In addition to being able to study the Sun on any clear day there are special events occurring every year somewhere on Earth including Solar Eclipses, Venus Transit, etc. As we approach another Solar Eclipse the demand for these filters does accelerate. We urge those who need filters for an event to place their orders six months or more in advance for the more complicated models, or a few months in advance for broader bandpass or simpler configurations.
3. Some DayStar solar filters are engineered to function with an energy reduction "pre filter" or an aperture stop attached on to the front of almost any telescope to prevent damage to the telescope or to the filter body, while the filter body is installed onto the focuser of the telescope. So in addition to the cost of the filter body, your may need to budget for the optional Prefilter for your telescope(s). This prefilter is typically a deep red or yellow colored glass, and can be made by DayStar or can be custom made for our clients by Company Seven to a high specification.
The effective system aperture can be as large as the that of the telescope, so we at Company Seven have decided to equip our facility to study the Sun with our Astro-Physics and TeleVue refracting telescopes of up to 206mm aperture! Although for reasons of convenience and limits imposed by our local "seeing" conditions we routinely employ telescopes of only between 90mm to 130mm. Alternatively you can employ the large aperture telescope with a full aperture prefilter, then attach aperture stops over that filter to increase contrast or to compensate for seeing limitations.
4. The DayStar Hydrogen Alpha filter (and some other DayStar filter systems too) are engineered to provide nominal performance when employed with a telescope or lens which is configured to provide an exit cone of light at about f/30. In order to obtain this f/30 beam with most telescopes we employ optional lenses to shape the beam; these include the TeleVue 2X or 4X Powermate 2 inch lens. These lenses resemble a Barlow lens but may incorporate a beam shaping lens to render the light rays more parallel before they enter the DayStar filter.
Right: visitor observing through our DayStar Quantum filter on TeleVue 85 telescope on a Solar Saturday event outside our showroom (126,533 bytes).
Company Seven hosts a solar observing program at our showroom, this convenes nearly every clear Saturday. These events feature our own DayStar QUANTUM PE Series 0.3 Angstrom Hydrogen Alpha, QUANTUM SE Series 0.6 Angstrom Hydrogen Alpha, DayStar T-Scanner 0.5 Angstrom Hydrogen Alpha (a portable model that requires no power to operate), and DayStar 2.0 Angstrom Single Cavity Calcium K-Line filters, among other "white light" filters and purpose built Hydrogen Alpha telescopes which we offer. We invite you to contact Company Seven to learn more about these systems, or visit our showroom to see the DayStar filters in operation.
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Both black and white filtergrams produced through DayStar Hydrogen Alpha filters.
Right: Thumbnail sized image of what is happening on the Sun as seen through a Hydrogen Alpha Filter at the NSA National Solar Observatory (8,997 bytes). Those observers equipped with DayStar Calcium K-Line filtering systems may view and image calcium plage excited by emerging, existing, or decaying sunspot groups. In Calcium K-Line, plage immersed solar active areas will appear across the entire solar disc, not just at the limb. Prominences are commonly seen in the violet light of Calcium during solar active periods. Observing active areas in Hydrogen Alpha and Calcium are each a wondrous experience. With such equipment as these, it becomes easy to expand solar programs toward new and more intense horizons. We are proud to hear that many consider a DayStar filter to be their most powerful observing tool. With a DayStar filtering system, observational programs are limited only by the desires of the observer. As stated by Beck, Hilbrecht, Reinsch, and Volker the authors of one of the finest books on the subject "Solar Astronomy Handbook":
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Contents Copyright 1994-2014 Company Seven and DayStar Filter Co. - All Rights Reserved |
History: DayStar is a familiar name to professional and serious amateur observers of the Sun since February 1975 when Del Woods founded the DayStar Filter Company. Del started learning the optics trade while working at the Spectra Helix company in Sylmar, California. After the 1971 San Fernando earthquake of 9 February caused extensive damage to the facility, Del and others from Spectra Helix came to work for Carson Astronomical Instruments, Inc., a company founded in 1970 by Donald G. Carson at Valencia, California. It was at Carson where the critical concept of a regulated heated filter housing was developed to maintain a nominal bandpass of their 
Company Seven: is the most enduring and experienced distributor of the internationally acclaimed DayStar filter systems in the world. We provides DayStar filters to amateurs, to professional observatories, and to research organizations. It was one of our customers, Michael Olshausen who with a little assistance from us developed the )
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