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Thread adapters

ASToptics M54 male to T2 female adapter (57801)

A thread adapter from M54 male to T2 female, whose entire listing consists of generic statements about quality.

ASToptics M54 male to T2 female adapter

ASToptics M54 male to T2 female adapter (57801)

A thread adapter from M54 male to T2 female, whose entire listing consists of generic statements about quality.

Slot count and filter size
M54 male, from the title · T2 female, from the title · Not stated for either thread
Optical path length
The listing gives none
Manual or motorised operation
A thread adapter — no optics, and not a filter wheel
Light sealing
Not stated
Power
Not published by the maker.
Software support
Not published by the maker.
Amazon reference
B0BPXFY2VT (same reference on 5 Amazon marketplaces)
EAN
4049467578017
  • M54 to T2 is a conversion the larger imaging trains genuinely need
  • From a maker whose range is sold through astronomy specialists
  • Five bullets and not one measurement, material or figure among them

Best for: An M54 imaging train that has to meet a T2 camera fitting

≈ £36 / €39
Check price on Amazon

Specifications

Slot count and filter size
M54 male, from the title · T2 female, from the title · Not stated for either thread
Optical path length
The listing gives none
Manual or motorised operation
A thread adapter — no optics, and not a filter wheel
Light sealing
Not stated
Power
Not published by the maker.
Software support
Not published by the maker.
Amazon reference
B0BPXFY2VT (same reference on 5 Amazon marketplaces)
EAN
4049467578017

The title is the specification

M54 male to T2 female. That is the entire technical content of this listing, and it is in the product name rather than in the description.

What the five bullets amount to

High-quality accessory for ambitious stargazers. Complements your existing equipment. Robustly made for outdoor use. Proven in astronomical observation. Easy to integrate into existing setups. Five sentences, no numbers, no materials, no dimensions.

What a buyer still needs

The pitch of the M54 thread, the length of the adapter, and its clear aperture. The first decides whether it engages, the second enters the back focus budget, and the third decides whether it vignettes.

Where it belongs in a train

Between a large-format component threaded M54 and a camera or accessory on T2. That is a real and reasonably common junction — which is what makes the silence of the description more frustrating than it would otherwise be.

Availability

German, French and Italian Amazon stores ran from 39 € to 42 € on the day of the survey.

British Amazon store lists it in local currency, which the euro range above sets aside.

American Amazon catalogue holds a record for it that nobody is selling.

Spanish Amazon store gave no result whatever, so the buy button there opens a search rather than an empty page.

Figures as Keepa reported them on the day this page was last updated. Stock and pricing shift without warning.

Prices quoted in this text were read on 17 September 2026. The live price is at the top of the page.

What this fits

More filter wheels

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    Briny River M42 to M48 step-up ring (390-EG)

    A step-up ring converting the T-2 thread to M48, so that 2 in filters and M48 accessories can be fitted to T-2 components.

    Slot count and filter size
    M42 × 0.75 male — the T-2 thread · M48 × 0.75 female — the 2 in filter thread
    Optical path length
    The listing gives none
    Manual or motorised operation
    A thread adapter — no optics, and not a filter wheel
    Light sealing
    Aluminium alloy, anodised
    Power
    Not published by the maker.
    Software support
    Not published by the maker.
    Amazon reference
    DE B0FM49SGJH · US B0FM48JF46 · GB B0FM48JF46 · FR B0FM48JF46 · IT B0FM48JF46 · ES B0FM48JF46
    EAN
    4895264934644
    • Both threads are named precisely with pitch, which is what an adapter listing must do
    • Anodised aluminium resists the corrosion that ruins a thread left damp
    • No length figure, and every adapter consumes back focus

    Best for: Putting an M48 filter or accessory onto a T-2 threaded component

    ≈ €9
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  • ECSiNG M48 to M42 double-male adapter ring

    ECSiNG M48 male to M42 male adapter

    A male-to-male ring joining M48 × 0.75 to M42 × 0.75 with the shortest possible mechanical length, blackened inside against reflections.

    Slot count and filter size
    M48 × 0.75 and M42 × 0.75, both male
    Optical path length
    Described as the minimum mechanically possible; no figure is given
    Manual or motorised operation
    A thread adapter — no optics, and not a filter wheel
    Light sealing
    Aluminium, anodised black with a matt internal wall
    Power
    Not published by the maker.
    Software support
    Not published by the maker.
    Amazon reference
    B0C7BYJ588 (same reference on 5 Amazon marketplaces)
    EAN
    4895243557307
    • The matt internal finish addresses internal reflections, which few adapter listings mention
    • Both threads are named with their pitch
    • A double-male ring only helps where both sides are female — which is not every junction

    Best for: Joining two female-threaded components of different sizes in an imaging train

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  • NVZPG M48 to M28.5 filter adapter ring

    NVZPG AP M48 to M28.5 filter adapter

    A threaded ring that holds a 1.25 in filter in a 2 in filter drawer, converting M48 to M28.5.

    Slot count and filter size
    M48 to M28.5 — the 2 in filter thread to the 1.25 in filter thread
    Optical path length
    Not published by the maker.
    Manual or motorised operation
    A filter adapter ring — not a wheel and not a drawer
    Light sealing
    Not published by the maker.
    Power
    Not published by the maker.
    Software support
    Not published by the maker.
    Amazon reference
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    EAN
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    • Both threads are named precisely rather than given as inch sizes alone
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The rest of this rack

  • ECSiNG M48 to M42 adapter ring in black anodised aluminium

    ECSiNG M48 to M42 double-male adapter

    An anodised aluminium ring with M48 × 0.75 and M42 × 0.75 male threads, blackened inside, containing no optical element at all.

    Reduction factor
    Not published by the maker.
    Required back focus
    Not published by the maker.
    Image circle
    Not published by the maker.
    Corrector function
    Not published by the maker.
    Thread standards
    M48 × 0.75 and M42 × 0.75, both male
    Vignetting
    Not published by the maker.
    Housing
    Aluminium, black anodised, matt internal wall
    Amazon reference
    B0C773T289 (same reference on 5 Amazon marketplaces)
    EAN
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    • Both threads named with their pitch
    • A matt bore, which reduces the reflections a shiny adapter introduces
    • It reduces nothing: the category is wrong and this page says so

    Best for: Joining a female M48 component to a female T2 one

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    Reduction factor
    0.5x, per the maker
    Required back focus
    Not published by the maker.
    Image circle
    Not published by the maker.
    Corrector function
    Focal reducer with optics
    Thread standards
    M28.5 × 0.6 — the standard 1.25 in filter thread · Screws onto the nose of a 1.25 in eyepiece
    Vignetting
    Not published by the maker.
    Housing
    Aluminium alloy
    Amazon reference
    B093ZSLSDJ (same reference on 4 Amazon marketplaces)
    EAN
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    • The thread is named correctly, which several neighbours on this shelf fail to do
    • The exclusions are published rather than discovered
    • Shares its entire description with another listing

    Best for: A second reducer, or a first one where price decides

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  • Skyoptikst f/6.3 reducer-corrector with SCT thread

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    A four-element fully multi-coated reducer-corrector that threads onto the rear cell of a Schmidt-Cassegrain and converts f/10 to f/6.3.

    Reduction factor
    f/10 to f/6.3, as the maker states it
    Required back focus
    The listing gives none
    Image circle
    Not published by the maker.
    Corrector function
    Reducer and field corrector with optics — four elements
    Thread standards
    Schmidt-Cassegrain rear thread
    Vignetting
    Not published by the maker.
    Housing
    Fully multi-coated, per the maker · Aluminium alloy; all optical glass elements per the maker
    Amazon reference
    B0CN9CVSBP (same reference on 6 Amazon marketplaces)
    EAN
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    • Four elements correct the field as well as reducing, which a two-element reducer does not
    • The conversion is published as a pair of focal ratios rather than as a bare factor
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