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Daystar Instruments Quark Magnesium I b2 line filter
Daystar Instruments Quark Magnesium I b2 line filter
Daystar Instruments Quark Magnesium I b2 line filter

Daystar Instruments Quark Magnesium I b2 line filter

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$1,600.00 You save 7%
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Estimated Arrival: Between Oct 05 and Oct 11. *ETA to USA Only

Shipping & Returns: Satisfaction guaranteed 30 day return policy.


Daystar Instruments products currently have a 3 week lead time. Thank you for your patience, it will be worth the wait!

Daystar Instruments QUARK Magnesium I b2 line "Eyepiece"

By popular demand, we are introducing a MgI b2 line version of the Quark, for use in refractors F/4-F/9.  Magnesium, a bright green color is easily visible in the center of the human eye's highest sensitivity.  Studies of the Mg line relate to boundary layers between granulation and spicule.   In addition to heavy surface mottling and high contrast granulation, the Mg line also shows plague in equal or higher detail as the Calcium line.  Magnesium wavelength studies will reveal Zeeman splitting in the absorption of magnetized areas of active regions.

This new, All-In-One design marries high-quality components of a telecentric Barlow, adapters, snouts and Daystar MgI b2 line filter into one simple assembly. Through design efficiency and optimization, now users can enjoy the known high-quality optics of DayStar* at an affordable price.

~ Magnesium I b2 filter Specifications:   CWL:  5172.8 / FWHM: <0.5


Dramatic plasma shapes around AR2335. Large view, false colors.Taken with DayStar Quark H-alpha filter, a monochrome PointGrey USB3 camera and a SW ED 120 telescope. Photo by Gabriel Corban

For use on refractors of F/4 to F/9, the user needn't worry about configurations. Just insert in your diagonal, add an eyepiece and view. The QUARK contains a custom Daystar Instruments 4.2X telecentric barlow lens fully optimized in coatings and optical design. This highly specialized telecentric lens offers superior field flatness. The exact filter bandpass will vary based on the final telescope application.  No specific FWHM bandpass is designated, however, the etalon will be approximately 0.3-0.5 angstroms. Now observers can buy a filter based on their desired observing goals instead of their budget. The fully optimized design eliminates the need for any adapters. It's all combined in one lightweight eyepiece-sized device. The new, compact design configuration eliminates unnecessary components, weight, and associated costs. We even reduced power consumption, so the Quark can now operate all day off a small, palm-sized optional battery pack.

*The QUARK assembly is a product of DayStar Instruments, using DayStar Filters' Fabry Perot etalon technology.

  • 1.25" or 2.0" combo eyepiece snouts with safety indent slot directly into your diagonal
  • Standard 1.25 eyepiece drawtube output with optional 2" and SCT accessories available.
  • Brass compression ring to protect eyepiece. Uses USB power, 5v 1.5amp Includes 90-240VAC wall adapter with international plug adapters.
  • Tuning knob allows wing shifting +/- 0.5 with detents at every 0.1 LED indicator for power, warming, ready, fault 5-year warranty,
  • Optional 8-hour battery pack available. Integrated, fully baffled 2 elements telecentric 4.2X Barlow
  • Integrated 12mm blocking filter 21mm clear filter aperture
  • Best performance with F/4 - F/8 refractors
  • Full disk viewing is possible on refractors up to ~450mm focal length refractors
  • No aperture limitations. It May be used on larger refractors for higher magnification views
  • Ships in convenient Twist-Case for safe, dust-free storage.
  • Not suited for off-axis application.

Daystar Uniformity Standards

Daystar Filters is very proud of our 40+ year history of providing research-grade equipment to the world's top research institutions. Our process can produce the highest grade quality equipment in the world, with unprecedented uniformity and finesse distinction.

Side-by-Side Comparison:

Daystar does NOT warrant, nor shall not replace, restore, exchange, or refund filters based on comparisons to other products or any other non-quantitative analysis or assumption.

While Daystar wishes to assure client satisfaction, we are not hereby obligated to replace, restore, upgrade, exchange, or refund filters based on features outside of our stated specifications.

Daystar uses specially produced test equipment that has been independently verified and tuned for precision and accuracy daily (sometimes hourly). Only 3 known sources worldwide possess equipment capable of quantitative analysis of sub angstrom spectroscopy outside of the Daystar Filters laboratory. Analysis from any of these sources is respected and always welcome. Owners are welcome to contact Daystar at any time with service concerns. Should filters sent for service meet or exceed stated specifications without flaw, filters will be returned to the owner in the same or better condition. 

As each Quark produced may vary from 0.25 - 0.5 FWHM, and each QUARK produced will vary from SE to PE grade, direct side-by-side comparison of one unit vs a different unit does not constitute a standard by which any unit may be qualified or disqualified.

Filters shall not be "upgraded" or exchanged because an SE grade filter is not providing PE grade uniformity or a wider etalon exchanged for a narrower etalon unless that etalon is outside of the stated specification for the product purchased.

All certifications of FWHM and CWL uniformity are performed spectroscopically and mathematically on highly specialized and externally certified spectroscopic equipment.

Users should expect a degree of variation from one QUARK to the next.

This is inherent due to both the lower price structure of the QUARK product line and due to the extremely high precision for isolation of the Hydrogen line which requires tolerances measured in >1/100,000 wave. These variations are caused at the molecular level as the chemicals which make up the mica crystal vary in abundance when the crystal is formed in the earth. They are beyond human control. The only control we have is to qualify or disqualify. Quark filters' specification categories allow for a larger number of samples to be qualified and therefore allow for a lower costing structure.

Daystar Bandpass:
Each Quark is warranted to have a FWHM bandpass (when introduced into a focal plane beam of ~F7-F/9) of 0.25 - 0.5.
Combo Quark filters are warranted to have a FWHM bandpass (when introduced into a focal plane beam of >F/25) of 0.25 - 0.5.
A degree of variation from unit to unit will naturally occur, as different FWHM filters are produced and binned into either Chromosphere or prominence specification categories.
A Quark will never be warranted to perform precisely to the standard of a different Quark or Quantum filter, due to the range of acceptable FWHM bandpass within the stated specification standard. More precise certification and smaller FWHM category range greatly increase the production and qualification costs of Quark filters due to the degree of optical precision and associated cost required.

Clients who wish to achieve exacting FWHM performance should consider the Daystar Quantum filter line. Quantum filters have a higher cost structure partly due to the testing required to certify a specific FWHM.


Daystar Uniformity:
Each Quark is warranted to have a spectral CWL uniformity as stated below.
That uniformity may be of Standard grade or on occasion, the PE grade.
All Quark filters are NOT warranted to be PE grade uniformity.


40+ years' standing Daystar Uniformity Standards:
Our Quantum products are offered in SE grade and PE grade uniformity. All Quark filters are warranted to meet or exceed the SE grade uniformity standard.

Due to scarcity and certification requirements, PE grade uniformity is reserved for our top-end Quantum PE product line. 

The uniformity grade of a filter is based on the uniformity in abundances of chemical composition (and subsequent index of refraction) within the natural mica crystal. Prices for the PE grade filters reflect the rarity of the required uniformity in homogeneity.

  • STANDARD SE GRADE filters are specified as: Spectral uniformity: The mean peak wavelength of all 12 mm. dia. areas shall be within 0.5 Angstrom of the full aperture wavelength measurement. (In fractions of a wavelength of light, this accuracy is equal to 1/13,126 wave).

  • PROFESSIONAL PE GRADE filters are fabricated and qualified to very high uniformity tolerances to the specification of Spectral uniformity: The mean peak wavelength of all 12 mm. dia. areas shall be within 0.05 Angstrom of the full aperture wavelength measurement. (In fractions of a wavelength of light, this accuracy is equal to 1/131,260 wave).

  • QUARK Filters share the Standard SE grade filter specifications and are specified as: Spectral uniformity: The mean peak wavelength of all 12 mm. dia. areas shall be within 0.5 Angstrom of the full aperture wavelength measurement

Due to production processes and scarcity considerations, uniformity above the specified SE grade cannot be guaranteed in a production QUARK.  Therefore, hand selection of "honey" or "extra good" QUARKS is also not possible. All filters are tested prior to shipping both spectroscopically and visually to meet or exceed the SE grade qualification standard.

Those who require true PE grade uniformity should consider the original Daystar Quantum PE line of filters for their application. Note that SE grade filters do not qualify as warranty repairs to upgrade to PE grade filters.

Any QUARK may be returned to DayStar for inspection of uniformity standards. If the filter does not pass SE grade uniformity standards, that filter will be replaced under warranty.


Housing No
Wavelength No
Bandwidth N/A
Uniformity SE (Standard Edition)
Price $1,495.00



We know that once you've placed your order, you are anxious to receive it! We make every effort to get your order shipped out to you as quickly as possible.

As soon as you place your order, you will receive an order confirmation e-mail. This means that we have received your order in our system and pre-authorized your credit card for the purchase. We will process the charges to your credit card and your order will ship within five business days from the date of your order. We will send you tracking information within 24 hours of your order leaving the warehouse to the e-mail address you provided when checking out.  If you do not receive tracking information from us within six business days of your order, feel free to follow up with us at

Standard shipping time in the US is between 3-5 business days, though it can vary slightly depending on the destination. We typically For updates on your shipment you can enter your tracking number here.

We distribute nationwide via UPS and Fedex. Unfortunately, at this time we are not able to provide expedited or international shipping.  

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