92 mm f/6.65 Stowaway

with 2.5" FeatherTouch Focuser

92 mm f/6.65 Stowaway on Mach1GTO Mount


Astro-Physics introduced the redesigned Stowaway at the Northeast Astro-Imaging Conference on April 18, 2018. Long-time astronomers will recall that we offered f5 and f7 Stowaway refractors from 1999-2002 that are cherished today for their portability and performance. Indeed, our own Stowaway has traveled with us to star-gaze in far off places as well as to watch whales, boats, birds and other wildlife. While observing the solar eclipse in August 2017 from Wyoming, we had so much fun with our original 92 mm Stowaways that we decided to make another production run.

This triplet lens scope has the same extraordinary quality that you have come to expect from Astro-Physics with a few new exciting features:

The Mach1GTO German Equatorial mount is recommended for visual observation or astro-imaging. The unique quick-and-easy daytime polar-alignment routine makes it ideal when setting up for star parties and public outreach. The intuitive GoTo Keypad serves as a full-featured mini-computer or use a planetarium program on your PC or Mac computer. You can even control the basic functions of the mount with your mobile smart device.

Optical Design

The air-spaced 3-element lens has broad band multi-coatings on all surfaces. The design was made using the latest version of the ATMOS lens design program. Optimization was chosen for the polychromatic Strehl ratio to be above 90% for the entire visual spectrum with a peak value of 99.8% at the visual peak. The result is unprecedented color correction. Visually the scope shows sharp contrasty images without color fringing with well-corrected high-power oculars.

The custom field flattener design achieves wide band color correction that extends into the violet regions with diffraction-limited performance designed for the most demanding modern astronomical cameras. This is especially important for the latest CMOS chips which have their highest sensitivities in the violet part of the spectrum and will show large blue halos with lesser optical designs. The 92 mm with dedicated field flattener produces sharp images at all wavelengths without blue halos or bloated stars.

Color correction Less than +/- 0.003% focus variation from 656 nm to 436 nm (c to g wavelengths).
Clear aperture 92 mm (3.62”)
Focal length 612 mm (24.1”); Backfocus of 160 mm (6.3”)
Focal ratio f/6.65
Theoretical Resolution 1.1 arc seconds
Coatings Multi-layer, broadband, overall transmission greater than 97% in peak visual wavelengths
Magnification range 18x to 360x
Tube assembly Cream white, 3.62” diameter, machined aluminum tube, fully baffled, flat black interior, engraved retaining ring.
Focuser type 2.5” I.D. Starlight Instruments FeatherTouch Focuser with rotating collar, rack and pinion, Feather Touch Micro 9:1 dual-speed reduction, 3.5” travel. Focuser drawtube features millimeter focusing scale. 2” and 1.25” adapters included.
Telescope length 19.5” (495 mm) with dew shield fully retracted; 21.75” (553 mm) with dew shield fully extended.
Diameter of dew shield 4.4” (112 mm) OD, retractable
Weight with dust cap 7.1 lb. (3.2 kg)
Carrying case Pelican Air 1525 with TrekPak Dividers

Photographic Field
Photographic field with dedicated Field Flattener

Image circle: 50 mm diameter
35 mm format: 3.2 x 2.2 degrees
Focal ratio: f/7
Focal length: 644 mm
Backfocus Spacing: 2.52" (64.1 mm)

Photographic field with 0.8x Telecompressor Corrector Image circle: 40 mm diameter
35 mm format: 4.2 x 2.9 degrees
Focal ratio: f/5.3
Focal length: 488 mm
Backfocus Spacing: 2.52" (64.1 mm)
Photographic field with 2x Barlow

Image circle: 32 mm diameter, 1.2 degrees
Covers APS format
Focal ratio: f/13 @ 90 mm backfocus


92mm F6.65 Stowaway (92F665): $ 3,490

Field Flattener for 92mm F6.65 Stowaway, Machined Covers (For use with 2.5" Focuser) (92FF): $ 450
0.8x CCD Telecompressor for 92mm Stowaway, Machined Covers (For use with 2.5" Focuser) (92TCC): $ 550

Delivery: Unfortunately, the 92mm Stowaway is not available off the shelf for immediate purchase. We typically maintain notification lists so that we can contact prospective customers when a particular scope or mount is available to order. The notification list for the 92mm Stowaway is now closed due to the very high demand for this scope. We are not accepting additional names at this time. If you are already on the list, check the Notification Update page to see if we have a production run underway. Please refer to our Availability page for more information regarding our notification lists.

Stowaway - What's Included? Items That You Will Need For Your Scope Accessories to Consider

There are many other accessories to consider. Please refer to these sections for additional recommendations:
Visual Accessories
Photographic and CCD Imaging Accessories
Baader Planetarium Filters

Specifications subject to change without notice.

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Copyright © 2018 Astro-Physics Inc. All rights reserved.
Last modified: March 11, 2019

Astro-Physics, Inc.
11250 Forest Hills Road, Machesney Park, IL  61115, U.S.A.
Phone: 815-282-1513   Fax: 815-282-9847