Takahashi TOA-150B 150mm f/7.3 Triplet Apochromatic Refractor OTA

Product Overview

The TOA-150B is the largest refractor in Takahashi's TOA line, a 150 mm highly air-spaced ED apochromatic triplet built for a native 1100 mm focal length at f/7.3. Two S-FPL53 ED elements deliver Takahashi's highest published order of color correction, and the published tube weight is 14.5 kg — a figure that puts real demands on the mount underneath it once accessories are attached. The dew shield retracts the tube from 1270 mm down to 1110 mm for storage, and the 4-inch dual-speed rack-and-pinion focuser with camera angle adjuster ships as part of the assembly.

Who It's For

This is a good match if you want the largest aperture Takahashi's TOA refractor line offers and have a mount and pier rated well above the 14.5 kg tube weight — an observatory pier or a large German equatorial mount rather than a portable setup. It suits an observer or imager who has already worked with a smaller apochromat and is stepping up specifically for the resolving power and light grasp a 150 mm aperture provides.

Key Features & Design

• Highly air-spaced ED triplet, 3 elements in 3 groups: two S-FPL53 ED elements deliver Takahashi's highest published order of color correction.
• 1100 mm focal length at f/7.3: the longest native focal length and largest aperture in the TOA refractor line.
• 4-inch dual-speed rack-and-pinion focuser with camera angle adjuster included: built for the load of a full medium-format or heavy imaging train.
• 275 mm back focus at prime focus: published by Takahashi for the native configuration.
• Retractable dew shield: tube length runs from 1110 mm to 1270 mm as it extends.
• Knife-edged internal baffles: reduce internal reflections and improve contrast at this aperture.

Optical / Mechanical Design

The TOA-150B objective is a highly air-spaced triplet using two S-FPL53 ED elements, the same design family as the TOA-130 series scaled up to a 150 mm aperture and a longer 1100 mm focal length. At f/7.3, the design favors resolving power and light grasp — the largest of any TOA refractor — over imaging speed, with hard multicoated optics and knife-edged baffles built for high-contrast planetary and lunar work as much as deep-sky imaging. It accepts the same TOA-series correctors as the smaller TOA-130 models: the TOA-35FL field corrector runs 1080 mm at f/7.2 with a 40 mm image circle and 117.5 mm back focus, the TOA-645FL flattener runs 1085 mm at f/7.2 with a 60 mm image circle and 56.2 mm back focus for medium-format sensors, and the TOA-35RD 0.7x reducer drops the system to 775 mm at f/5.2 with a 44 mm image circle and 62.5 mm back focus.

Recommended Uses

High-resolution visual observation of planets, the Moon and double stars at the largest aperture Takahashi's refractor line offers; tight-framing deep-sky and planetary astrophotography; medium-format imaging with the TOA-645FL flattener; observatory installations on a pier or mount rated well above the 14.5 kg tube weight.

Compatibility and Accessory Notes

At prime focus, back focus runs 275 mm. Adding the TOA-35FL corrector changes that to 117.5 mm at f/7.2; the TOA-645FL flattener changes it to 56.2 mm at f/7.2 with a 60 mm image circle for medium-format cameras; and the TOA-35RD reducer changes it to 62.5 mm at f/5.2. Each accessory resets both the focal ratio and the spacing your imaging train needs to hit, and the Takahashi Back Focus Guide lists all three configurations — send us your camera and filter setup and we will confirm the fit with you. Takahashi's own listing notes the tube ships with a CAA (camera angle adjuster), 31.7 mm and 50.8 mm couplings and adapters, and an extension tube included with the optical tube assembly.

Good to Know Before You Order

Mount, tripod, and finder are sold separately from the pier or GEM you'll need: at 14.5 kg published weight, this tube asks for a mount and pier with real payload margin, not a portable travel setup.

Imaging performance depends on the matched corrector: the bare optical tube favors visual use and longer-focal-length imaging; the TOA-35FL, TOA-645FL, or TOA-35RD is what flattens the field for most deep-sky imaging trains.

Frequently Asked Questions

Is it difficult to set up?

No — it is a fixed-mirror-free refractor with nothing to collimate in normal use, though its size and weight mean handling and mounting it takes more care than a smaller apochromat.

What is it best used for?

High-resolution planetary and lunar visual observation and tight-framing deep-sky astrophotography, both benefiting from the largest aperture in Takahashi's TOA line.

Does it need extra accessories for imaging?

For a flat field, yes — the TOA-35FL, TOA-645FL, or TOA-35RD, matched to the back focus your camera train needs.

What mounts is it suited to?

A large German equatorial mount or observatory pier rated comfortably above the 14.5 kg published tube weight once a full imaging or visual accessory load is added.

How is this different from the TOA-130NS and TOA-130NFB?

It steps up to a 150 mm aperture and a longer 1100 mm focal length, against 130 mm and 1000 mm on the NS and NFB, with a correspondingly heavier 14.5 kg tube.

Bottom Line

In short: a 150 mm f/7.3 ED apochromatic triplet, the largest refractor in Takahashi's TOA line, built for high-resolution visual work and flat-field imaging on a mount rated for its 14.5 kg tube weight.