Astro-Physics 110mm f6 StarFire GTX

The new Astro-Physics 110mm f6 StarFire GTX is the ultimate dual-purpose portable refractor.

As the Astro-Physics team notes, “The design goal was three-fold: 1) a compact refractor with as much aperture as possible that would fit into an airline overhead case, 2) a fast, highly-corrected triplet refractor that can cover a full format CMOS chip with pinpoint stars to the corners when coupled to our matching Telecompressor-Corrector, 3) a superb visual refractor with the highest possible polychromatic Strehl in a compact triplet lens.”

Astro-Physics 110mm f6 StarFire GTXThe company has definitely achieved the goal of portability as the Astro-Physics 110mm f6 StarFire GTX fits nicely into the included airline-approved carry-on case with plenty of padding for protection.

The company chose a focal ratio of f/6 for the objective lens and an aperture of 110mm as a sweet spot for portability and deep-sky imaging capability. The lens uses the newest Super-ED glass available from the company’s Japanese optical supplier along with two matched elements to provide diffraction-limited performance from deep red to deep violet.

The telescope is designed for imaging with the Astro-Physics’ F5 TCC (Telecompressor-Corrector), and will cover the full-frame 35mm format of popular CMOS cameras. The /f5 focal ratio produces a 5-degree, 50mm image circle that is matched to the resolution capabilities of the 3.75 micron pixel size. The TCC is designed to extend the color correction range far beyond the visual spectrum to produce high-resolution images from the latest CMOS sensors. The Polychromatic spot size is well within the Airy disc limit, even at the periphery of a full 35mm format.

For the best possible visual performance, the company designed the objective lens to have very high polychromatic Strehl ratio over the visual spectrum for wavelengths of red, yellow, green and blue colors. They chose the wavelength range that was matched specifically to the human eye response for best contrast and resolution at any power – whether it be low-power, wide-field scanning of the Milky Way or high-power observation of the Sun, Moon, planets and double stars.

Furthermore, the lens was designed for best wavefront performance, not for RMS spot radius. The reason for designing the lens this way is to provide the highest contrast over the largest possible wavelength range. In that way, the lens performs extremely well with high power eyepieces, identical to what much longer focal ratio lenses of this aperture would produce. Even so, the polychromatic spot radius stays well below the Airy disc limit for all visual wavelengths and over a field of almost 1 degree or 2 full Moon diameters without adding any extra optics (field flatteners) to the optical train.

To achieve these high corrections, Astro-Physics used carefully-selected optical glass for the outer mating elements that surround the central Super-ED glass. This glass is the perfect material to produce a fast high-Strehl objective. Normally, to get this level of color correction at such a fast focal ratio requires either wide airspaces between the elements, or putting the sensitive ED glass up front where it can be damaged by overzealous cleaning.

As the company notes, “Wide airspaces cause two problems that we want to avoid – one is sensitivity to decentering and the second is long cooldown time.  With close-spaced elements and the expensive ED element safely snuggled between two hard mating-elements, the scope is very rugged and impervious to rough handling. The multi-layer coatings are applied with ion-beam assist techniques, and therefore are almost as hard as the underlying glass.  The entire lens cell can be easily slid out of the scope’s main tube by removing 3 screws. This allows easy cleaning of the rear surface in case of excessive dew or dust settling on this surface.”

Astro-Physics 110mm f6 StarFire GTX features include:

– 3.5″ Astro-Physics focuser that is silky smooth with a greaseless drawtube and the dual-speed mechanism of the 9:1 Micro. The dual-speed feature is particularly advantageous for critically focusing this fast focal ratio. A digital focusing system will be available for imaging.

– Compact, lightweight tube assembly that fits into your carry-on luggage. Fully retractable felt-lined dew shield slides to its fully-extended position with thumbscrew to secure it in place.

– Latest multi-coating technology will provide optimum light transmission.

– The 110mm StarFire GTX will fit into a case for airline transport.

– Optional Telecompressor-Corrector converts the 110mmF6 to a fast 550 mm focal length, f/5 imaging machine with pinpoint stars across the field.

– Optional 3.5″ Prime Focus Field Flattener

The Astro-Physics 110mm f6 StarFire GTX design specifications include:

– Color Correction: Extends from near IR to the violet edge of the visible spectrum

– Clear Aperture: 110mm  (4.33″)

– Focal Length: 660mm  (26″)

– Focal Ratio: f/6.0

– Theoretical Resolution: 1.08 arc seconds

– Coatings: Multi-layer, broadband, overall transmission greater than 97% in peak visual wavelengths

– Magnification Range: 15x to 400x

– Tube Assembly: Cream white, 4.7” diameter, machined aluminum tube, fully baffled, flat black interior, engraved retaining ring.

– Focuser Type 3.5” I.D. Focuser, rack and pinion, 9:1 dual-speed reduction, 4.5” travel, 7.3″ backfocus. Focuser drawtube features millimeter focusing scale. 2.7″, 2” and 1.25” adapters included.

– Telescope Length: ~482mm (19″) with dew shield fully retracted and adapters removed.  Add 1.5″ with visual adapters in focuser drawtube.

– Diameter of Dew Shield: 145 mm (5.720″) O.D, retractable

– Front thread of Dew Shield: 5.600″ x 32  thread, you must remove the trim ring to access

– Weight with Dew Shield: 12 lbs. (5.45 kg)

Astro-Physics 110mm f6 StarFire GTX availability:

As to availability the company says,” Once again, we have decided to offer a brand-new scope design in a random-drawing format. We found that this method was well-received when used for the 92mm Stowaway in recent years. This is a departure from our usual processes, so we know you have questions. We have answers:

What do you mean, random drawing?  After we establish the price and have more details regarding the case, telecompressor-corrector, and other accessories, we will announce the signup for the random drawing. During the week-long signup period, you will have an opportunity to enter and submit your contact information. From this group of interested people, we will randomly choose those who will be notified of the opportunity to purchase a 110mm StarFire GTX.

Why aren’t you just notifying people in order they sign up, like usual?  Traditionally we have collected names of those interested in a particular product and notified folks of the opportunity to purchase the item in chronological order. We’ve occasionally received criticism, most especially if the list is only open for a short time, from people who were unaware of the list, on vacation, on the other side of the world and asleep when the list was open, etc. We only have a limited number of 110GTX scopes in production and want to give everyone an equal chance to purchase one. With advanced notice and a one-week sign-up window, we hope to catch everyone who might be interested in this scope.

How and when can I sign up?  We will announce the random drawing dates on this webpage, the ap-ug and ap-gto forums, our Facebook page and in our newsletter. Additional information will be available at that time. If you would like to receive our newsletter, please sign up in the black banner at the bottom of this webpage.”

You can learn more about the Astro-Physics 110mm f6 StarFire GTX here.

And to make it easier for you to get the most extensive news, articles and reviews that are only available in the magazine pages of Astronomy Technology Today, we are offering a 1 year magazine subscription for only $6! Or, for an even better deal, we are offering 2 years for only $9. Click here to get these deals which only will be available for a very limited time. You can also check out a free sample issue here.

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