FSQ-85ED "Baby Q" 3.35" F/5.3 dual ED/four element design

by Takahashi Print

What would you like to print?
(Reviews and Documents/Videos will not be printed)

Basic Product Information
Full Description
Tech Details
Supplied Accessories
Recommended Accessories

More product information
The new Takahashi FSQ-85ED (the “Baby Q”) apochromatic ED quadruplet is a clear leader in the ranks of relatively small aperture refractors. Its four-element double ED element modified Petzval optical system has been optimized for imaging as well as visual applications. It is measurably the best no-compromise portable photo-visual refractor under 102mm in aperture that Takahashi has ever built, and they’ve built a lot of very good small scopes over the years.

The FSQ-85ED is a 3.35” aperture f/5.3 (450mm focal length) four-lens photo/visual system using two ED (Extra-low Dispersion) glass elements. Based on the classic two-doublet Petzval design, the FSQ-85ED takes full advantage of the latest exotic glass types to produce levels of correction for coma, astigmatism, field curvature, secondary spectrum, spherical aberration, and spherochromatism that are unsurpassed – even better than their legendary fluorite scopes.

This Telescope’s Optical System . . .

  • Apochromatic modified Petzval refractor optical system: 3.35” aperture f/5.3 (450mm focal length) four-lens fully-multicoated system using two ED (Extra-low Dispersion) glass elements. The modified Petzval design uses a true apochromatic doublet objective lens with an ED element to gather the light. For most telescope manufacturers, this would be enough. But Takahashi goes a step further to perfect your observing and imaging experience. There is a second widely air-spaced ED doublet buried deep within the telescope body. This second doublet optimizes the optical wavefront from the objective lens to eliminate any residual astigmatism. It also acts as a field flattener for wide field astrophotography. The result is a very wide and flat field with high contrast images that are without any hint of lateral color. Color correction has been extended to 1000nm, well into the infrared, to produce non-bloated photographic star images

  • Large Image Circle: At prime focus the 44mm image circle covers a huge area of the sky measuring 5.6° in diameter, over 24 square degrees of sky. The large image circle will fully cover any 35mm negative or 35mm equivalent CCD chip (a 35mm negative and the largest currently available SBIG Research Series chip measure only 44mm across their diagonals). Light fall-off at the edges of the field is minor and easily compensated for in a CCD image by a simple flat field.

  • Long Back Focus: The very generous back focus of 200mm allows the user to attach a variety of imaging packages, binoviewers, 2” star diagonals, and many other visual devices. The 200mm back focus has been designed to handle the ever-larger image trains of CCD imaging experts – electric focusers or temperature compensated focusers, flip mirror systems, filter wheels, adaptive optics systems, etc.

This Telescope’s Mechanical System . . .

  • Compact Optical Tube: The all-aluminum 95mm diameter scope body is finished in ivory, with Takahashi green and black trim, and is very solidly built. The tube length of only 12.7” with the dew shield retracted and no visual accessories attached makes the “Baby Q” highly airline-transportable. The FSQ-85ED uses a special optional #85TH tube holder with offset plate designed specifically to mount this scope on an equatorial mount and balance it properly.

  • Focuser: The focuser is an 80mm (3.15”) rack-and-pinion design whose drawtube terminates in a 2” eyepiece/accessory holder. A 1.25” compression ring eyepiece/star diagonal adapter fits into the extension tube to hold 1.25” accessories and is held in place by the extension tube’s thumbscrews. The scope should reach visual focus with most 2” star diagonals. Straight-through viewing and 1.25” diagonal use will require adding optional eyepiece extension tube #TET0002, at $69.95. The focuser has a silky-smooth motion and oversize knobs that make it easy to achieve sharp focus, even at very high powers. The right focuser knob has a smaller separate concentric knob that controls a 10:1 ratio Micro Edge fine focuser for critical high magnification and photographic focusing.

  • Camera angle adjuster: The focuser includes a built-in camera angle adjuster/rotator that will carry a 5kg (11 lb.) load to handle the weight of the new large chip CCD cameras and their associated accessories. The camera angle rotation is controlled by a large hand-tighten knob on the top of the focuser drawtube.

  • Finderscope: No finderscope is supplied. There is a flat boss on the upper left side of the focuser that will accept an optional Takahashi finder bracket and finderscope. An optional 6 x 30mm Takahashi finderscope is shown in the feature images below.

  • Dew shield: The optical tube has a retractable self-storing dew shield. A thumbscrew locks the dew shield in place, either when extended or when retracted. The dew shield serves the dual purpose of retarding the formation of dew during long observing sessions and improving the photo/visual contrast, much as a camera lens shade does.
Highest Useful Magnification:
This is the highest visual power a telescope can achieve before the image becomes too dim for useful observing (generally at about 50x to 60x per inch of telescope aperture). However, this power is very often unreachable due to turbulence in our atmosphere that makes the image too blurry and unstable to see any detail.

On nights of less-than-perfect seeing, medium to low power planetary, binary star, and globular cluster observing (at 25x to 30x per inch of aperture or less) is usually more enjoyable than fruitlessly attempting to push a telescope's magnification to its theoretical limits. Very high powers are generally best reserved for planetary observations and binary star splitting.

Small aperture telescopes can usually use more power per inch of aperture on any given night than larger telescopes, as they look through a smaller column of air and see less of the turbulence in our atmosphere. While some observers use up to 100x per inch of refractor aperture on Mars and Jupiter, the actual number of minutes they spend observing at such powers is small in relation to the number of hours they spend waiting for the atmosphere to stabilize enough for them to use such very high powers.
Visual Limiting Magnitude:
This is the magnitude (or brightness) of the faintest star that can be seen with a telescope. The larger the number, the fainter the star that can be seen. An approximate formula for determining the visual limiting magnitude of a telescope is 7.5 + 5 log aperture (in cm).

This is the formula that we use with all of the telescopes we carry, so that our published specs will be consistent from aperture to aperture, from manufacturer to manufacturer. Some telescope makers may use other unspecified methods to determine the limiting magnitude, so their published figures may differ from ours.

Keep in mind that this formula does not take into account light loss within the scope, seeing conditions, the observer’s age (visual performance decreases as we get older), the telescope’s age (the reflectivity of telescope mirrors decreases as they get older), etc. The limiting magnitudes specified by manufacturers for their telescopes assume very dark skies, trained observers, and excellent atmospheric transparency – and are therefore rarely obtainable under average observing conditions. The photographic limiting magnitude is always greater than the visual (typically by two magnitudes).

Focal Length:
This is the length of the effective optical path of a telescopeor eyepiece (the distance from the main mirror or lens where the lightis gathered to the point where the prime focus image is formed). Focallength is typically expressed in millimeters.

The longer the focallength, the higher the magnification and the narrower the field of viewwith any given eyepiece. The shorter the focal length, the lower themagnification and the wider the field of view with the same eyepiece.

Focal Ratio:
This is the ‘speed’ of a telescope’s optics, found by dividing the focal length by the aperture. The smaller the f/number, the lower the magnification, the wider the field, and the brighter the image with any given eyepiece or camera.

Fast f/4 to f/5 focal ratios are generally best for lower power wide field observing and deep space photography. Slow f/11 to f/15 focal ratios are usually better suited to higher power lunar, planetary, and binary star observing and high power photography. Medium f/6 to f/10 focal ratios work well with either.

An f/5 system can photograph a nebula or other faint extended deep space object in one-fourth the time of an f/10 system, but the image will be only one-half as large. Point sources, such as stars, are recorded based on the aperture, however, rather than the focal ratio – so that the larger the aperture, the fainter the star you can see or photograph, no matter what the focal ratio.

This is the ability of a telescope to separate closely-spaced binary stars into two distinct objects, measured in seconds of arc. One arc second equals 1/3600th of a degree and is about the width of a 25-cent coin at a distance of three miles! In essence, resolution is a measure of how much detail a telescope can reveal. The resolution values on our website are derived using the Dawes’ limit formula.

Dawes’ limit only applies to point sources of light (stars). Smaller separations can be resolved in extended objects, such as the planets. For example, Cassini’s Division in the rings of Saturn (0.5 arc seconds across), was discovered using a 2.5” telescope – which has a Dawes’ limit of 1.8 arc seconds!

The ability of a telescope to resolve to Dawes’ limit is usually much more affected by seeing conditions, by the difference in brightness between the binary star components, and by the observer’s visual acuity, than it is by the optical quality of the telescope.

1.36 arc seconds
This is the diameter of the light-gathering main mirror or objective lens of a telescope. In general, the larger the aperture, the better the resolution and the fainter the objects you can see.
The weight of this product.
8.8 lbs.
Telescope Type:
The optical design of a telescope.  Telescope type is classified by three primary optical designs (refractor, reflector, or catadioptric), by sub-designs of these types, or by the task they perform.
Based on Astronomy magazine’s telescope "report cards", scopes of this size and type generally perform as follows . . .
Terrestrial Observation:
Observing terrestrial objects (nature studies, birding, etc.) is usually possible only with refractor and catadioptric telescopes, and convenient only when the scope is on an altazimuth mount or photo tripod. Most reflectors cannot be used for terrestrial observing. Scopes with apertures under 5" to 6" are generally most useful for terrestrial observing due to atmospheric conditions (heat waves and mirage, dust, haze, etc.) that degrade the image quality in larger scopes. 
Lunar Observation:
Visual observation of the Moon is possible with any telescope. Larger aperture scopes will provide more detail than smaller scopes, thereby getting a higher score in this category, but may require an eyepiece filter to cut down the greater glare from the Moon's sunlit surface so small details can be seen more easily. Lunar observing is more rewarding when the Moon is waxing or waning as the changing sun angle casts constantly varying shadows to reveal craters and surface features by the hundreds.  
Planetary Observation:
Very Good
Binary and Star Cluster Observation:
Very Good
Galaxy and Nebula Observation:
Terrestrial Photography:
Photographing terrestrial objects (wildlife, scenery, etc.) is usually possible only with refractor and catadioptric telescopes, and convenient only when the scope is on an altazimuth mount or photo tripod. Most reflectors cannot be used for terrestrial photography. Scopes with focal ratios of f/10 and faster and apertures under 5" to 6" are generally the most useful for terrestrial photography due to atmospheric conditions (heat waves and mirage, dust, haze, etc.) that degrade the image quality in larger scopes.
Lunar Photography:
Photography of the Moon is possible with virtually any telescope, using a 35mm camera, DSLR, or CCD-based webcam (planetary imager). While an equatorial mount with a motor drive is not strictly essential, as the exposure times will be very short, such a mount would be helpful to improve image sharpness, particularly with webcam-type cameras that take a series of exposures over time and stack them together. Reflectors may require a Barlow lens to let the camera reach focus. 
Planetary Photography:
Star Cluster / Nebula / Galaxy Photography:
5 years
There are currently no Cloudy Nights reviews associated with this product

User Ratings/Reviews from our Customers (www.astronomics.com)
Overall Product Rating: AstronomicsAstronomicsAstronomicsAstronomicsAstronomics(0.00)   # of Ratings: 0   (Only registered customers can rate)

General Accessories
Tube Rings (1)
Tube holder with offset plate for FSQ-85ED ("Baby Q") refractor
by Takahashi
This product does not have supplied accessories... or supplied accessories have not been assigned.
No documents have been associated with this product.
No videos have been associated with this product.
There are currently no formulas associated with this product
Takahashi - FSQ-85ED "Baby Q" 3.35" F/5.3 dual ED/four element design

Click icon(s) below & hover image above for zoom

Takahashi - FSQ-85ED "Baby Q" 3.35" F/5.3 dual ED/four element designThe Close-up of the
   · No ratings/reviews   Only registered users can submit ratings - Register Here
Our Product #: FSQ85
Manufacturer Product #: FQK0085
Price: $3,450.00  FREE ground shipping - Click for more info
Congratulations. Your order qualifies for free ground shipping within the 48 contiguous United States.

 E-mail this product to a friend E-mail this product to a friend

Your Email:  
Your Friend's Email:  
Confirm Friend's Email:  

  200 characters or less

An email containing a link to this product has been sent to the email address you provided.

Clear Skies!

 Have a question? Do you have a question about this product?
 Found a better price? Found a lower price? Click to let us know... or call 800-422-7876 before you buy.

If you’ve found a lower delivered price on this product, let us know about it below. We’ll do our best to meet or beat that price and will get back to you within one business day with our best offer. Thanks for giving us the opportunity to give you a better deal.

Your Name:  
From Who:  
Context:  Magazine AdOnline
Website Address:  
Cut and paste the web address into the box above
Your Email:  
Confirm Email:  

We’ll do our best to meet or beat that price and will get back to you within one business day with our best offer. Thanks for giving us the opportunity to give you a better deal.

Clear skies,

This new Takahashi FSQ-85ED apochromatic quadruplet (the “Baby Q”) is the ultimate portable no-compromise photo/visual refractor under 102mm in aperture . . .

. . . our 38th year