Daystar Combo Quark Prominence Solar Filter

An All-in-One H-Alpha Filter for F/15-F/30 Telescopes

Daystar's Combo Quark simplifies hydrogen-alpha solar observing by integrating a Fabry-Perot etalon, blocking filter, and adapters into a single, eyepiece-sized device. This self-contained design eliminates the complexity of stacking multiple components, so you can use a compatible nighttime telescope for solar viewing. Just insert the Combo Quark's 1.25" snout into your diagonal, connect the 5V USB power, and add an eyepiece.

The filter is for slow focal ratios: F/15 to F/30 refractors in full aperture. Schmidt-Cassegrains must not be used in full aperture with this unit; an off-axis Energy Rejection Filter (sold separately) reduces the aperture, raising the focal ratio to the preferred ~F/30 beam. Maksutovs usually use a full aperture colored glass ERF.

Prominence Model: Viewing Eruptions at 6562.8 Å

This version of the Combo Quark is the "Prominence" model, intended for features seen at the edge of the Sun. The filter is centered on the 6562.8 Å hydrogen-alpha line with a bandpass generally 0.6Å or above, which favours prominences at the limb: loops, arches and eruptions.

While some surface detail will be visible, the primary strength of this model is limb detail. The trade-off is less surface contrast than the "Chromosphere" model; filaments are only visible in the Chromosphere version.

A 0-Power Design Requiring 67mm of Backfocus

Unlike the original Quark, the Combo Quark contains no internal barlow or focusing elements. It is a true 0-power filter, which means it doesn't alter the telescope's focal length. This design choice is key to its compatibility with naturally long focal ratio instruments. It needs about 67mm of additional backfocus, or 99mm with the included wedge adapter for SCTs, so you will need to dial the focus knob quite significantly.

For faster refractors, Daystar offers optional 2.8x and 4.3x telecentric barlows for the Combo Quark: the 4.3x for F/5 to F/9, showing the full disk at about 480mm focal length or shorter, and the 2.8x for F/5 to F/14, showing the full disk at about 720mm or shorter. You unscrew the silver snout from the Combo Quark and screw on the barlow.

Prominence vs. Chromosphere: A Choice Based on Observing Goals

The Quark FWHM is not specified: Prominence units are generally 0.6Å or above and Chromosphere units generally 0.5Å or below, so you choose by what you want to see.

• Prominence Model (This unit): Features a wider bandpass (typically 0.6Å or greater). This favours prominences at the solar limb.
• Chromosphere Model: Features a narrower bandpass (typically 0.5Å or less). This favours surface contrast; filaments are only visible in the Chromosphere version.

Compatibility: F/15-F/30 Refractors and Off-Axis SCTs

The Combo Quark is designed for a specific optical configuration. If light reaches the filter at an angle it causes wing shift, so the etalon needs slow F/15 to F/30 light.

• Refractors: Compatible at full aperture if the native focal ratio is between F/15 and F/30. For faster refractors, one of the optional Daystar 2.8x or 4.3x telecentric barlows is required.
• SCTs: Must not be used in full aperture with this unit. An off-axis Energy Rejection Filter (ERF) reduces the aperture, raising the focal ratio to the preferred ~F/30 beam, and the included 2° wedge adapter compensates for the off-axis angle; without it the transmission will be off-band.
• Maksutovs: They usually use a full aperture colored glass ERF.
• Full Disk Viewing: It passes the full solar disk for focal lengths under about 1800mm.

Solar Safety: Energy Rejection

Do not disassemble the filter: the blocking element is separated from the etalon and the complete assembly must be used together for safe viewing.

The Combo Quark sits behind the telescope, so sunlight enters the telescope first. To prevent damage, Daystar strongly recommends using an Energy Rejection Filter, and for apertures over 80mm suggests one. Its guidance:

• SCTs: Must not be used in full aperture with this unit; use a front mounted ERF with an off-axis opening of reduced aperture, plus the included wedge adapter with its set screw on the same side as the ERF hole.
• Maksutovs: Usually use a full aperture colored glass ERF.
• Refractors with less than 80mm of aperture: For brief observing sessions when not using a tracking mount, be alert for any rise in temperature of your telescope, diagonal or Quark.
• Refractors: For telescopes under approximately 150mm of aperture, a screw in UV/IR cut filter can be employed in front of the diagonal. For highest safety, a red or yellow glass front mount ERF should be used.
• Tracking: All dedicated solar tracking applications should employ energy rejection.
• Herschel wedges and white light filters cannot be used with the Quark: they block 99.999% of all light, including the desired H alpha light.

Precision Tuning: ±0.5Å Wing Shift for Doppler Effects

The etalon is heated to approximately 100-150°F to control the wavelength passed. A tuning knob lets you shift the center wavelength by up to ±0.5Å from the central line. The knob has detents at every 0.1Å, giving you fine control over the passband.

Tuning helps if the image lacks contrast, and wing shift also shows Doppler-shifted features. Solar features moving towards you are blue-shifted, while those moving away are red-shifted. By tuning slightly off-band into the "blue wing" (counter-clockwise) or "red wing" (clockwise), you can bring out features moving toward or away from you. After every adjustment the filter must settle in temperature for approximately 5-10 minutes before the change becomes effective.

5V, 1.5A USB Power: Operation and LED Indicators

The filter is powered through a female Micro-B USB port and power is required for proper operation. Other USB sources must be rated for at least 1.5 amps at 5 volts; computer USB ports and cell phone chargers do not normally support this much power. An optional 8-hour battery pack is available. The package includes a 90-240VAC universal wall adapter with plugs for the US, UK, Europe, and Australia.

A multi-color LED indicator on the housing provides status at a glance:

• Yellow: Temperature settling, approximately 5-15 minutes after power up or a change of wing shift.
• Green: The filter has reached its target temperature and is on-band and ready for observing.
• Red: A fault such as low voltage.

Visual Observing: 1.25" Snouts, Diagonals, and Eyepiece Choice

The Combo Quark is designed for visual use with standard 1.25" accessories. The sun-side has a 1.25" male snout with a safety indent, and the eyepiece side a 1.25" female drawtube with a brass compression ring to protect your eyepiece.

Because the filter operates at a slow focal ratio (F/15-F/30), eyepiece selection is important. A high powered eyepiece can exceed Dawes' limit, giving a fuzzy disk without the ability to focus well; Plössl eyepieces of 25mm, 32mm and 40mm are recommended, with best results at 32mm or greater. A viewing hood or cloth over your head is also recommended to limit stray light, so fainter prominences and more surface detail can be seen.

Imaging the Sun: Why a 12-bit Monochrome CCD is Recommended

While designed for visual use, the Combo Quark is also a capable tool for solar imaging. Monochrome imaging is recommended. On a color sensor only 1 in 4 pixels detect red light, so it offers 1/4 the sensitivity and 1/2 the resolution of a monochrome chip. A monochrome sensor uses every pixel, maximizing detail and signal.

Solar features have a wide dynamic range, from bright plages to faint prominences. A camera with a 12-bit or 16-bit analog-to-digital converter (ADC) can capture this full range in a single exposure. An 8-bit camera will often require separate, bracketed exposures for surface and prominence detail that must be combined later in processing. Because seeing cells move quickly, frame rates shorter than 1/10 second work better; try about 1/15 to 1/100 second for prominences with a webcam style camera, and about 1/300 to 1/500 second for surface detail.

Care, Storage, and a 5-Year Warranty

The Combo Quark is a precision optical instrument that requires proper care. When not in use, it should be stored with its end caps on in the included Twist-Case in a climate-controlled environment to maximize the life of the filter elements. A few specks of dust may be blown off with a squeeze bulb (never compressed air), and the preferred cleaning method for fingerprints and smudges is factory cleaning at Daystar's laboratory. Climate-controlled storage extends optical filter life expectancy up to 2-3 times. Do not disassemble the unit, as internal components are pressurized and opening the housing will void the warranty.

Daystar provides a 5-year warranty covering defects in materials and workmanship. Blockers and trimmers are considered wear items and are covered on a pro-rated basis.