Review – Takahashi FSQ-85ED

FSQ-85ED

The Takahashi FSQ-85ED is a Modified Petzval quadruplet apochromat refractor.

Specifications

Aperture:  3.3 in. [85mm]
Focal Length:  17.7 in. [450mm]
Focal Ratio @ Prime Focus:  f/5.3
Prime Focus Photographic Field:  5.6°
Focal Ratio w/Reducer:  f/3.9
Photographic Field w/Reducer:  7.0°
Limiting Magnitude:  ~ 11.8 urban / ~ 13.1 rural
Resolving Power:  1.5 arc seconds
Tube Diameter:  3.7 in. [95mm]
Tube Length:  14.5 in. [368mm]
Weight:  8.6 lb. [3.9 kg]

FOV and Magnification

TeleVue 31mm Nagler: 5.3° @ 15x
TeleVue 21mm Ethos:  4.6° @ 21x
TeleVue 17mm Ethos:  3.8° @ 27x
TeleVue 13mm Ethos:  2.8° @ 35x
TeleVue 10mm Ethos:  2.3° @ 45x
TeleVue 08mm Ethos:  1.8° @ 56x
TeleVue 06mm Ethos:  1.3° @ 75x

Introduction

In 1998, I purchased what I then believed to be the finest compact 3″ apochromatic refractor available – the Takahashi FCT-76.  It had almost every feature that I desired in a high-quality portable telescope: a beautifully crafted Optical Tube Assembly [OTA] – light in weight and machined with top notch fit and finish, incredibly well-corrected optics, a diverse assortment of observing and photographic configurations, and an affordable price [~ $1650 while available].

Fast forward a decade, and there have been very few telescopes of similar size that have come close to rivaling this excellent refractor – until now.  Meet the finest 3″ apochromatic refractor available today, the Takahashi FSQ-85ED.

Design

The simplest way to explain what makes the Takahashi FSQ-85ED the best 3″ refractor around is this – it is a fundamental redesign and improvement of what was lacking in the FCT-76.

For instance, the FCT-76 was not very easy to use with 2″ eyepieces right out of the box.  This was a function of the telescope’s tube length being longer than what was required to natively bring 2″ eyepieces to focus without additional visual adapters.  By contrast, the FSQ-85ED tube is over 4″ shorter, allowing all 2″ eyepieces and binoviewers to be paired with its generous 200mm of available back focus.

Another FCT-76 drawback that has now been corrected in the FSQ-85ED was the length of its dew shield, which was quite short and allowed in stray light interference from nearby homes and street lights.  With the FSQ-85ED, this is no longer a problem.  The sliding dew shield equals the size of those found on the discontinued FCL-90 and FS-78 models, adequately blocking out light from unwanted sources.  When retracted, the overall length of the telescope is just under 15 inches.

One design similarity between the FCT-76 and the FSQ-85ED that really makes for more enjoyable observing or photographic sessions is that both are equipped with large rack-and-pinion focusers to provide greater stability with heavier loads. The FCT-76 focuser is actually more similar to the FSQ-106ED than the FSQ-85ED, in that the entire focuser rotates.  With the FSQ-85ED, the focuser is fixed but comes with a Camera Angle Adjuster [CAA] to provide for the optimal placement of eyepieces and cameras.  Additionally, the FSQ-85ED utilizes a 1/7 micro focuser knob on the right side that assists in dialing in the focal point with snap-to precision.

FSQ-85ED Focal Plane

Optically, the quadruplet ED Petzval design offers a fast focal ratio with a very corrected flat field of view.  It’s difficult to say which telescope performs better at canceling out chromatic aberrations as both are outstanding at doing so.  And like the FCT-76, the FSQ-85ED offers high-contrast, razor-sharp views of objects assisted by it’s well-baffled OTA.

A Pelican case 1510 will provide the proper protection for road and air trips.

Modifications

One of the changes that I’m making to the focuser’s adapters is foregoing the use of the Takahashi 2″ Ocular Adapter for the Baader Planetarium 2″ Clicklock Eyepiece Clamp.   Designed for Takahashi 72mm threaded couplings, the 2″ Clicklock Eyepiece Clamp has an innovative rotating locking collar that holds eyepieces firmly without marring their barrels from thumbscrews or leaving grease impressions from traditional brass locking rings.

Baader Planetarium 2" Clicklock Eyepiece Clamp

To deal with moisture buildup in the OTA post-observing, I use the Farpoint Astro 2″ Desiccant Cap which contains silica gel pouches of desiccant that are placed within the machined and anodized “electric-blue” cap. The red o-ring acts as a stop when pushed into a rear accessory coupling; in this case, the 2″ Clicklock Eyepiece Clamp.

Farpoint Astro 2" Desiccant Cap

Photography

Prime focus CCD astrophotography produces an image circle of 5.6° at f/5.3; and using the FSQ-85ED’s photographic reducer yields a flat 7.0° at f/3.9 over the entire field.

Photographic accessories for CCD astro-cameras are available through Takahashi and TNR.

Observing

Detailed report from West Texas to follow [May 28 – June 2, 2016]…

Alternatives

Is it unfair to say that there is no real competition for the FSQ-85ED in the market place today?  Well, no it isn’t.  There are several manufacturers that make excellent 3″ apochromatic refractors; however, none come close to producing all of the outstanding features that Takahashi does.

While not quite the bang-for-buck value that the FCT-76 was in 1998 – if you’re used to having the best, this is it.

Priced ~ $3,450 each.

8 responses to “Review – Takahashi FSQ-85ED

    • Unfortunately, I wasn’t able to provide a detailed observing report on my October 2013 trip due to the William Optics 2″ 90° Erecting Prism underperforming on magnifications greater than 20x w/ Ethos eyepieces. For the May 2014 trip, I’ll be bringing along a new Astro-Physics MaxBright 2″ Diagonal.

  1. Hello Steve, Greetings. Keenly awaiting the May report. The weight in the user guide is given as 3.1kg or is it 3.9kg with other items attached? You have gone for the Baader Clicklock. Does the supplied Tak 2″ have the brass clamp? Cheers, Vaidya Sydney, Australia

    • Vaidya, I haven’t had a chance to weigh the telescope w/ accessories but try to do so soon. As for the supplied Tak 2″ Ocular Adapter, it does come w/ a brass locking ring and works well. The Baader is more to my liking for the reason given.

    • Vaidya, I took a look at the Takahashi Extender ED 1.5x and it looks like a fine accessory. The only quibble I have is the price – at $500 USD, you can find effective 2″ Barlows from Astro-Physics and TeleVue at about half the price. But I’d never say never until having a chance to actually use it.

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