APQ News

Engineering refinements to APQ Polychromats
The thermally compensated lens cell has been further optimized, reducing weight by an additional 0.15 kg without compromising mechanical stability or thermal compensation.
An advanced collimation concept supports even more precise, reproducible and long-term stable alignment of the optical system. Further design details will be published at a later date.
The APQ quick-change system now incorporates an additional clamping ring. This allows the system to be aligned precisely to the required position angle and securely locked while also increasing the mechanical stiffness of the connection.
APQ Technology
APQ Compensation

Statement on "Christen Superachromat"
Astro-Physics uses the terms "Christen Superachromat" and "diffraction-limited polychromat telescope", which in technical optics denote a higher class of chromatic correction insofar as these terms are used as technical performance descriptors. According to Herzberger/McClure, "The Design of Superachromatic Lenses", Applied Optics, 1963, a superachromat is corrected for four colors and thereby, in practice, for all colors; the reference wavelengths stated there range from 0.365 µm to 1.014 µm, i.e., from 365 nm to 1014 nm.
Haferkorn, in "Optik", 1981, describes the corresponding extension from dichromat and trichromat to polychromat as a system in which additional dichromatism conditions make the paraxial focal position coincide for a greater number of colors.
However, the data published by Astro-Physics for the 155CS and 190CS do not document such UV–VIS–IR correction. Astro-Physics describes both instruments as "Christen Superachromat" and as a "diffraction-limited polychromat telescope", while the published performance data refer to the visual or photo-visual spectrum; for the 155CS, the theoretical ray trace is expressly stated only for 435–656 nm. For both models, the 155CS and 190CS, Astro-Physics states that the color correction extends from the near IR to the violet edge of the visible spectrum, but not from 365 nm to 1014 nm.
The addition "Christen" does not in itself change the established technical meaning of the term superachromat. By contrast, APQ JENA uses the term Polychromat specifically and verifiably for diffraction-limited correction over 365–1014 nm and thus across the full UBVRI range of modern CCD and CMOS sensors. For the APQ 150/1200, APQ additionally specifies a polychromatic Strehl ratio of ≥ 0.95 over the range 365–1014 nm.
The Astro-Physics designation is therefore not technically substantiated by the published data and may suggest an equivalence with UV–VIS–IR- or UBVRI-corrected polychromats that is not documented by those data, as defined and documented by APQ JENA.
Astro-Physics 155 mm f/6 StarFire CS (155CS)
Astro-Physics 190 mm f/6 StarFire CS (190CS)
APQ Optical Design

APQ Eyepieces for Planetary and Wide-Angle Observation – Advance Announcement
APQ is developing a new generation of high-quality eyepieces for visual astronomical observation.
Development focuses on contrast transfer, natural color rendition, and consistently high image quality across the wavelength range and field of view.
Different versions are planned, ranging from orthoscopic eyepieces uncompromisingly optimized for image purity to modern wide-angle and ultra-wide-angle concepts.
Further technical details will be announced at a later date.

Comparison of Published Manufacturer Spot Diagrams with APQ
This comparison uses theoretical spot diagrams published by the respective manufacturers. The diagrams have only been rescaled to a common 100 µm graphical scale.
Wavelengths, field positions, focus definitions, weightings and calculation methods are not fully identical. The presentation is not an independent laboratory test or a measurement of production instruments and, by itself, does not permit a definitive ranking of overall optical performance.
Comparison of Published Manufacturer Spot Diagrams with APQ

New Generation of Polychromatic Flatteners and Reducers – Advance Announcement
APQ is developing a new generation of polychromatic field correctors and focal reducer correctors for maximum imaging performance and focus stability under changing operating conditions.
Further technical details will be published after completion of the development and intellectual-property work.

Responsive Web Design for apq.de
Our website now features responsive web design. The pages automatically adapt to different screen sizes.
Whether viewed on a smartphone, tablet or large computer monitor, text, images and menus rearrange themselves so that the site remains easy to read and use without horizontal scrolling.
APQ JENA

Astronomical exhibition 2027
We are planning to present the APQ 150/1200 Fluorite Quadruplet Polychromat at an astronomical exhibition next spring.
Further details will follow soon.
APQ 150/1200 Fluorite Quadruplet Polychromat

Current APQ JENA delivery status
APQ JENA has been working on the design and development of the world's only polychromatic refractors for several years now. During this time, we have invested substantial personnel and financial resources.
We do not attribute the delivery delays to familiar factors such as material shortages or higher energy and labor costs resulting from global crises. The decisive factor is that our products are innovative new developments that have presented unexpected technical challenges.
Please be assured that we have mobilized all available resources to complete production as quickly as possible so that we can deliver high-quality, flawless products to you. However, this will require additional time.
Based on our current schedule, we anticipate a further delay of approximately 12 months. Your deposit is, of course, fully protected.
We sincerely regret any inconvenience and ask for your understanding in these exceptional circumstances. We are always available to answer any questions or address any further concerns you may have. Thank you for your trust and patience.

Claims about APQ JENA
Inaccurate and unfounded claims about APQ JENA's delivery situation have been circulating in some astronomy forums. We unequivocally reject these claims.

APQ 110/550 Fluorite Wide Field Polychromat
The first APQ Wide Field Polychromat has the following specifications:
110 mm aperture
550 mm focal length
f/5 focal ratio
Ten-lens aspherical design
3 CaF₂ lenses
Integrated special focal reducer corrector
Retractable and lockable dew cap
Feather Touch Focuser FTF3545
The previously announced design variant with a 10 ° (Ø96.7 mm) image field requires a focuser with a larger clear aperture.
Ø67.4 mm unvignetted image field
UBVRI Fluorite Wide Field Polychromat
Polychromatic RMS spot radius vs. field ≤ 1.0 µm in the spectral range from 365 nm to 1014 nm over the entire field diameter of Ø67.4 mm (7 °)
Polychromatic Strehl ratio ≥ 0.95 (365 nm – 1014 nm)
Compact travel-ready dimensions (427 mm transport length)
High imaging performance for astronomy and nature observation
APQ 110/550 Fluorite Wide Field Polychromat

APQ 100/640 Fluorite Quadruplet Polychromat
The APQ 100/640 completes the current series of Fluorite Quadruplet Polychromats:
100 mm aperture
640 mm focal length
f/6.4 focal ratio
Polychromatic Strehl ratio ≥ 0.95 (365 nm – 1014 nm)
APQ Field Corrector (system focal length 640 mm): ≤ 4.2 µm (365 nm – 1014 nm) / unvignetted flattened image-field diameter Ø45.5 mm (4 °) polychromatic RMS spot radius vs. field
APQ 0.78× Focal Reducer Corrector (system focal length 500 mm): ≤ 3.25 µm (365 nm – 1014 nm) / unvignetted flattened image-field diameter Ø44.8 mm (5 °) polychromatic RMS spot radius vs. field
Airline carry-on compatible (487 mm transport length)
APQ 100/640 Fluorite Quadruplet Polychromat

APQ website: expanded product section
The product section of the website has been expanded with detailed descriptions of features and technical specifications:
APQ Fluorite Quadruplet Polychromats (including recommended accessories, applications and downloads)
APQ Polychromatic Focal Systems
APQ Accessories
A separate flyer with the most important information is available as a PDF for each APQ Fluorite Quadruplet Polychromat.
APQ Products

APQ 110/550 Wide Field Polychromat – Advance notice
The APQ 110/550, the first Wide Field Polychromat, is designed for astronomical and nature photography with modern small-pixel CMOS cameras while offering a very large corrected image field. Visual observers benefit from the high polychromatic Strehl ratio and its compact, travel-ready dimensions. The APQ 110/550 has the following (preliminary) features:
110 mm aperture
550 mm focal length
f/5 focal ratio
10 ° (Ø96.7 mm) image field diameter
Polychromatic UBVRI correction from 365 nm to 1014 nm throughout the field of 10 °
Polychromatic Strehl ratio ≥ 0.95 (365 nm – 1014 nm)
RMS spot radius ≤ 2 µm for all wavelengths from 365 nm to 1014 nm in the entire field of 10 °
Airline carry-on compatible
APQ 110/550 Fluorite Wide Field Polychromat

APQ Accessories
Mechanical design has been completed for our own range of telescope accessories:
Dovetail Plates
Tube Rings
Carrying Handles
Steering Wheels
Dew Caps
Changer
Change Rings
Extension Tubes
Adapters
Dustcaps
APQ Accessories

APQ Polychromatic Focal Systems
Specially designed polychromatic field correctors (flattener) and polychromatic focal reducer correctors (reducer) for each individual APQ Polychromat:
APQ 130/1000 Fluorite Quadruplet Polychromat
APQ 150/1200 Fluorite Quadruplet Polychromat (previously announced)
APQ 180/1440 Fluorite Quadruplet Polychromat
APQ 200/1600 Fluorite Quadruplet Polychromat
APQ Polychromatic Focal Systems

APQ Fluorite Quadruplet Polychromats – The APQ Polychromat family with apertures from 100 mm to 300 mm is nearing completion
Optical and mechanical design has been completed for the following Polychromats:
APQ 130/1000 Fluorite Quadruplet Polychromat
APQ 150/1200 Fluorite Quadruplet Polychromat (previously announced)
APQ 180/1440 Fluorite Quadruplet Polychromat
APQ 200/1600 Fluorite Quadruplet Polychromat
APQ Fluorite Quadruplet Polychromats

APQ 150/1200 Fluorite Quadruplet Polychromat
An APQ 150/1200 Polychromat was interferometrically tested at 546.1 nm and achieved a Strehl ratio of 0.976. According to the optical design, the theoretical maximum Strehl at this wavelength is 0.986. A design revision enabled us to reduce the weight by approximately 3 kg. The OTA 150/1200 will therefore not weigh 15.8 kg as originally stated, but less than 13 kg!
APQ 150/1200 Fluorite Quadruplet Polychromat

APQ Astronomical optics from Jena
APQ JENA is reviving astronomical optics and instrument technology in Jena after a 25-year interruption and announces a new line of Fluorite Quadruplet Polychromat refractors. The APQ concept is designed to use the full UBVRI spectral range (365 nm – 1014 nm) of modern electronic sensors (CCD, CMOS).
APQ JENA