Daystar Quark Prominence Solar Filter

The All-in-One H-alpha 'Eyepiece' for F/4 to F/9 Refractors

Daystar's Quark simplifies hydrogen-alpha astronomy by combining a telecentric barlow, adapters, and a Fabry-Perot etalon into a single, compact device. This integrated design eliminates the cost and complexity of assembling separate components, allowing you to simply insert the Quark into your diagonal, add an eyepiece, and begin observing after a 5-6 minute warm-up period. It is one lightweight eyepiece-sized device, with power consumption low enough to operate all day off a small optional battery pack.

Observing the Sun at 6562.8 Å: Prominences and Flares

Each Quark is qualified to show either prominences or surface detail; this model is qualified for prominences. By operating at the hydrogen-alpha wavelength of 6562.8 Å, it reveals the Sun's dynamic chromosphere. No exact FWHM is specified; Prominence units are generally 0.6Å or above, a wider bandwidth that gives a brighter image. This model is recommended for users mostly interested in prominences or who want a brighter image. Filaments are only visible in the Chromosphere version, so this model trades surface contrast for brighter prominences.

Optical Design: A 4.3x Telecentric Barlow for Superior Field Flatness

At the heart of the Quark is a custom 2-element, 4.3x telecentric barlow, fully optimized with coatings and an optical design specifically for the 656.28 nm H-alpha wavelength. The Fabry-Perot etalon requires a highly parallel beam of light (F/15 to F/30) to achieve its narrow bandpass. Unlike a standard barlow, this telecentric lens ensures the light rays are parallel when they pass through the etalon, and it offers superior field flatness. Baffles have been added to increase contrast.

Quark Prominence vs. Chromosphere: Choosing Your Observing Goal

Daystar offers two Quark models tuned for different observing goals. While both operate at the same H-alpha wavelength, their bandpass characteristics are different, leading to a trade-off between surface contrast and prominence brightness.

• Quark Prominence (This Model): With a bandpass generally 0.6Å or wider, this filter passes more light. It is recommended for users mostly interested in prominences or who want a brighter image.
• Quark Chromosphere: This model has a narrower bandpass (generally 0.5Å or below), which increases contrast on the solar disk itself. Filaments are only visible in the Chromosphere version, and it still gives a great view of prominences; most users choose it for its versatility.

Telescope Compatibility: Optimized for Refractors with Focal Lengths Under 450mm

Engineered for versatility, the Quark is designed for use with refractors with a focal ratio between F/4 and F/9, with best performance from F/4 to F/8. Because the integrated 4.3x barlow magnifies the image, the Quark can show the full solar disk only in telescopes with a focal length under approximately 450mm. Longer focal length refractors can be used, but they will provide higher-magnification views of specific regions on the Sun rather than the full disk. The Quark is not suited for off-axis (SCT or Dobsonian) application.

Solar Safety: Energy Rejection Guidelines for Apertures Over 80mm

Concentrated sunlight can create very high temperatures where it falls, so care must be taken to prevent melted components or fire. To prevent damage, use an Energy Rejection Filter on telescopes of 80mm aperture or more, or when tracking the Sun for long periods. The guidance:

• Less than 80mm Aperture: For brief observing sessions when not using a tracking mount, it can be OK to use no energy rejection at all. Be alert for any rise in temperature of your telescope, diagonal or Quark.
• 80mm Aperture or More: Use energy rejection. For telescopes under approximately 120mm of aperture, a screw-in UV/IR cut filter can be employed in front of the diagonal; it reflects UV and IR light back out the front of the telescope.
• Solar Tracking and Best Performance: All dedicated solar tracking applications should employ energy rejection, and for best performance a red or yellow glass front mount ERF should be used, as it prevents almost all heat from entering the telescope.

A Herschel wedge or white light filter cannot be used with the Quark: these pass very little light by design and would give an extremely dark image.

Precision Tuning: ±0.5Å Wing Shift for Doppler Events

The Quark's etalon is heated to a precise temperature to stay "on band" at the 6562.8 Å H-alpha line. A tuning knob allows you to shift this center wavelength by up to ±0.5Å, with detents every 0.1Å. This "wing shift" capability lets you observe Doppler-shifted features. A feature moving towards you will be brighter in blue (counter-clockwise) wing shift, and one moving away will be reddened (clockwise). After every adjustment the filter must settle in temperature for approximately 5-10 minutes before the change becomes effective.

5V/1.5A USB Power: All-Day Operation From a Palm-Sized Pack

The Quark's internal heating system, which heats the etalon to approximately 100-150°F, runs on a common 5V, 1.5A USB power source via a micro-B connector. You can power it from the included 90-240VAC wall adapter, which comes with international plugs, or another USB power source rated for at least 1.5 amps at 5 volts, such as Daystar's optional 8-hour battery pack. An LED indicator shows the filter's status: yellow while the temperature settles, green when on-band and ready, and red to indicate a fault like low voltage. Computer USB ports and cell phone chargers do not normally support this much power.

Visual Use: Achieving Focus from 8mm In-Travel to 10mm Out-Travel

The Quark is designed to be placed directly into your telescope's diagonal. It features combo 1.25" and 2" male snouts with a safety indent. The focus position depends on which snout you use: the 1.25" snout requires approximately 8mm of in-focus travel, while the 2" snout requires about 10mm of out-focus travel from your telescope's normal focal plane. The eyepiece side features a 1.25" female drawtube with a brass compression ring to protect the eyepiece. Plössl eyepieces of 25mm, 32mm and 40mm are recommended; at long focal ratios a high-powered eyepiece can exceed Dawes' limit, so an eyepiece of 32mm or greater gives the best results.

Imaging with the Quark: Adapters and Techniques for Monochrome CCDs

For the highest resolution and sensitivity, image with a monochrome CCD or CMOS camera. On a color sensor only 1 in 4 pixels detect red light, giving 1/4 the sensitivity and 1/2 the resolution of a monochrome chip. Because the Quark outputs a very long effective focal length, imagers with small sensors may require a focal reducer to capture a wider field of view. To combat interference patterns (Newton's rings) common in monochromatic imaging, the sensor must be tilted slightly; Daystar's imaging tilt adapter does this. Optional T-mount and C-mount accessories are available to connect a variety of cameras.

Care and Maintenance: Your 5-Year Quark Warranty

When not in use, the Quark should be stored with its end caps on in the included Twist-Case in a climate-controlled environment ; climate-controlled storage extends optical filter life expectancy up to 2-3 times. The optical surfaces should not be touched; dust can be removed with a gentle squeeze bulb. Cleaning of smudges or fingerprints should ideally be performed by Daystar. Opening the filter assembly will void the warranty. The Quark is covered by a 5-year manufacturer warranty, with blockers and trimmers considered wear items and warranted on a pro-rated basis.

Getting Started: Your First Observing Session with the Quark

Setting up for your first view is straightforward. First, ensure your telescope is pointing away from the Sun. Install your diagonal, then insert the Quark into the diagonal. Connect the USB power supply and wait for the LED indicator to turn green, which takes about 5-6 minutes. Insert a low-power eyepiece (25mm or longer is recommended) into the Quark. Now, with all filters in place, you can safely point your telescope at the Sun using a solar finder. Start with the tuning knob in the central position and slowly adjust your focuser to bring the Sun's limb into sharp view. Once focused, you can begin exploring the chromosphere. With 80mm of aperture or more, fit an Energy Rejection Filter first.