Daystar Quark Chromosphere Solar Filter

An All-in-One Hydrogen-Alpha Filter 'Eyepiece'

Daystar's Quark design condenses a complete, multi-component Hydrogen-Alpha filter system into a single, compact device that inserts into your diagonal just like an eyepiece. This approach eliminates the need to source and assemble separate barlow lenses, etalons, and blocking filters, turning a refractor into a solar telescope.

It is one lightweight eyepiece-sized device whose compact design eliminates unnecessary components and weight, with reduced power consumption so it can operate all day off a small optional battery pack. For F/4 to F/9 refractors, the user needn't worry about configurations: insert it in the diagonal, add an eyepiece and view.

Viewing the 6562.8 Å Chromosphere

This Quark is tuned to the Hydrogen-Alpha wavelength at 6562.8 Å, allowing you to see the Sun's dynamic chromosphere, a layer of plasma just above the visible photosphere. Unlike a white-light filter, an H-alpha filter reveals a constantly changing landscape of magnetic activity.

The Chromosphere model is specifically qualified to maximize contrast on surface features. With it, you can observe:

• Filaments: Dark, snake-like structures that are actually prominences seen against the bright solar disk.
• Plage: Bright, active regions that often surround sunspot groups, indicating concentrated magnetic fields.
• Active Regions: Complex areas of magnetic activity around sunspot groups, where solar flares occur.
• Prominences: While optimized for surface detail, the Chromosphere model still shows prominences at the Sun's limb; both versions show prominences.

The Integrated 4.3x Telecentric Barlow System

The performance of a Fabry-Perot etalon is critically dependent on the angle of light passing through it; the filters need slow light, with best performance at F/27-F/32. The Quark achieves this by incorporating a custom-designed, 2-element 4.3x telecentric barlow lens directly into the optical train. This highly specialized telecentric lens offers superior field flatness; on F/4 to F/9 refractors it gives an F/17 to F/38 final image.

This telecentric system is fully optimized for the 656nm H-alpha wavelength, with specialized coatings and internal baffles to maximize transmission and increase contrast by minimizing internal reflections. This works because the Quark is matched to F/4 to F/9 refractors; F/9 and higher gives a dimmer visual view, and below F/4 a brighter view but a wider effective bandpass.

Quark Chromosphere vs. Prominence Models

Daystar offers the Quark in two variations, allowing observers to select a filter based on their primary observing goals. While both models show prominences, they are tuned differently to emphasize specific solar features. The Chromosphere model generally operates at a bandpass of 0.5Å or below.

• Chromosphere Model (This Product): Provides higher contrast on the bright solar disk itself. Filaments are only visible in the Chromosphere version, so it is the choice for monitoring active regions and filaments on the Sun's face.
• Prominence Model: With a wider bandpass (generally 0.6Å or above), this model gives a brighter image for users mostly interested in prominences.

Most users choose the Chromosphere version for its versatility, while users mostly interested in prominences or wanting a brighter image should choose the Prominence model.

F/4-F/9 Refractors and 450mm Full-Disk Views

The Daystar Quark Chromosphere is designed for use with refractor telescopes with native focal ratios from F/4 to F/9, with best performance in the F/4 to F/8 range. It is not suitable for use with off-axis systems like Schmidt-Cassegrains or Dobsonians. The integrated 4.3x barlow multiplies your telescope's focal length, giving an F/17 to F/38 final image on F/4 to F/9 refractors.

Because of this magnification, the ability to see the entire solar disk in a single field of view depends on your telescope's focal length. The Quark can deliver a full-disk view in telescopes with a focal length of about 450mm or less. In longer focal length instruments, you will get higher-magnification views of specific regions on the Sun, for studying the intricate details of a sunspot group or active region.

Energy Rejection 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 (ERF) on telescopes of 80mm aperture or more, or when tracking the Sun for long periods; all dedicated solar tracking applications should employ energy rejection.

This can be accomplished in two ways:

• UV/IR Cut Filter: For telescopes under approximately 120mm of aperture, a screw-in UV/IR cut filter can be employed in front of the telescope diagonal. It reflects unwanted ultraviolet and infrared radiation back out the front of the telescope.
• Front-Mounted ERF: For best performance, use a red or yellow glass front mount Energy Rejection Filter; it prevents almost all heat from entering the telescope.

For brief observing sessions with less than 80mm of aperture 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. A white-light solar filter or Herschel wedge cannot be used with the Quark.

±0.5Å Wing Shift for Doppler Effects

The Quark features a tuning knob that allows you to shift the filter's center wavelength by ±0.5Å from the central H-alpha line, with detents at every 0.1Å. This "wing shift" capability lets you observe Doppler-shifted features on the Sun, moving toward or away from you.

After every adjustment of the knob, the filter must settle in temperature for approximately 5-10 minutes before the change becomes effective.

• Blue Shift (Counter-Clockwise): Turning the knob counter-clockwise shifts the center wavelength toward the blue wing, where features moving toward you will be brighter.
• Red Shift (Clockwise): Turning the knob clockwise shifts toward the red wing; features moving away from you will be reddened.

5V, 1.5A USB Power for Precision Heating

The Fabry-Perot etalon at the core of the Quark is highly sensitive to temperature. To maintain its precise bandpass on the H-alpha line, the etalon is heated to approximately 100-150°F to control the wavelength passed. The heater and its electronics are all powered by a standard micro-B USB port.

The filter requires a power source capable of delivering 5V at 1.5A. The included 90-240VAC wall adapter with international plugs ensures you can power it from any standard outlet. For field use, an optional 8-hour battery pack is available, or you can use any portable USB power bank that meets the 1.5A requirement. A computer USB port or standard cell phone charger will not provide sufficient current.

Adapters, Focus, and Eyepiece Selection

The Quark is designed for maximum compatibility and ease of use. It features a combination 1.25" and 2" snout on the telescope side, allowing it to be inserted directly into any standard diagonal. The eyepiece side has a 1.25" female drawtube with a brass compression ring to protect the eyepiece.

Due to the integrated barlow, the focal point shifts. Using the 1.25" snout requires about 8mm of in-focus travel, while the 2" snout requires about 10mm of out-focus travel. For visual use, Plössl eyepieces in the 25mm to 40mm range 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.

Capturing the Sun with Monochrome CCDs

The Quark can also be used for solar imaging. For best results, use a monochrome astronomy camera, as color sensors only use 1 in 4 pixels to detect red light, reducing both resolution and sensitivity. Hydrogen-Alpha imaging is done in monochrome light, so a color camera provides no advantage.

When imaging in monochromatic H-alpha light you may encounter interference patterns known as Newton's Rings, which are caused by the sensor and its cover slip acting as a small interferometer. Tilting the sensor slightly prevents the pattern. Optional T-thread and C-mount adapters are available, as well as specialized tilt adapters designed to correct for this phenomenon. Because the Quark creates a long effective focal length, imagers with smaller sensors can use optional focal reducers to capture a wider field of view or the full solar disk.