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Change the filter without touching the focus

The best filter wheels for 2026

A filter wheel holds several filters in a carousel between the telescope and the camera so that one can be swapped for another without opening anything, without touching the focuser, and — the point of the exercise — without shifting the alignment of the frame. In imaging that takes separate exposures through separate filters, everything depends on the frames landing on the same pixels, and a wheel is what makes that possible. Two figures govern compatibility before anything else. The filter size the wheel accepts — threaded cells or unmounted discs, in one of a few standard diameters — has to match the filters, and a wheel bought for the wrong size is not adaptable. The optical path length the wheel adds is subtracted from the back focus the camera and the telescope allow between them, and that budget is unforgiving: a millimetre out shows as elongated stars at the corners. Beyond fit, the choice is manual or motorised. A manual wheel is cheaper, thinner and needs someone at the telescope; a motorised one is controlled by the capture software and is what makes an unattended sequence possible. Read whether the wheel seals against stray light between the slots, because a bright star in an adjacent position can leak. Read which capture software the maker supports, and read whether the wheel can be powered from the camera or needs its own supply. We compare slot count and filter size, optical path length, manual or motorised operation, light sealing, power and software support.

The parts here, column by column

  1. Astromania five-position 2 inch filter wheel

    Astromania 2 in five-position filter wheel (FW2M5)

    A manual filter wheel holding five 2 in filters in an aluminium body, with a 2 in adapter on the telescope side and T-2 and M48 threads on the camera side.

    Slot count and filter size
    Five, numbered 1 to 5 · 2 in (5.1 cm) standard filters · T-2 and M48, as the maker states them
    Optical path length
    The focuser must travel about 20 mm further inward than normal, as the maker states it
    Manual or motorised operation
    A filter wheel — the only one in this group · Supplied with a 2 in adapter for the focuser
    Light sealing
    Aluminium, described by the maker as suitable for heavy cameras
    Power
    Not published by the maker.
    Software support
    Not published by the maker.
    Amazon reference
    B0140UA9F6 (same reference on 6 Amazon marketplaces)
    EAN
    6970019290355
    • Publishes the 20 mm of inward focus it consumes, which is the figure that decides whether it works at all
    • Two accessory threads — T-2 and M48 — cover most imaging trains
    • Twenty millimetres of inward focus is more than some refractors have to give

    Best for: A Newtonian or Dobsonian imaging train where back focus is short and filters change often

    ≈ $91 / £95 / €105
    Check price on Amazon
  2. ZGYDNM M54 filter drawer with two filter slides

    ZGYDNM M54 filter drawer with two slides

    A filter drawer rather than a wheel: two slides carry the filters, and the body threads M54 × 0.75 at both ends.

    Slot count and filter size
    M54 × 0.75 at the telescope end and M54 × 0.75 at the output · Two
    Optical path length
    4 mm is given for the interface and 16 mm as the extended length; both are reproduced as published
    Manual or motorised operation
    A filter drawer — the filters slide in and out, they do not rotate
    Light sealing
    Not published by the maker.
    Power
    Not published by the maker.
    Software support
    Not published by the maker.
    Amazon reference
    B0DK5TJY4G (same reference on 5 Amazon marketplaces)
    EAN
    9106666473491
    • A drawer consumes far less optical path than a wheel
    • Two slides mean a filter can be swapped in seconds without unthreading anything
    • The listing gives two different thickness figures without saying which is which

    Best for: A short back-focus imaging train where a wheel would not fit

    ≈ £61 / €72
    Check price on Amazon
  3. 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
    B0FBL5WGD6 (same reference on 5 Amazon marketplaces)
    EAN
    9106667044416
    • Solves a real and common problem for a few euros
    • Both threads are named precisely rather than given as inch sizes alone
    • A 1.25 in filter in a 2 in path can vignette a large sensor

    Best for: An imaging train with a 2 in drawer and a collection of 1.25 in filters

    ≈ £35 / €42
    Check price on Amazon
  4. Briny River M42 to M48 anodised aluminium step-up ring

    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
    Check price on Amazon
  5. Omegon low-profile M48 to T2 adapter ring

    Omegon M48 to T2 adapter, low profile (49749)

    A short adapter converting an M48 internal thread to a T2 external thread, with the maker emphasising that its low profile avoids focus problems.

    Slot count and filter size
    M48 female · T2 male — that is M42 × 0.75
    Optical path length
    Very low, as the maker states it; no figure is given
    Manual or motorised operation
    A thread adapter — no optics, and not a filter wheel
    Light sealing
    Not published by the maker.
    Power
    Not published by the maker.
    Software support
    Not published by the maker.
    Amazon reference
    B01KPR3X1K (same reference on 6 Amazon marketplaces)
    EAN
    4049467497493
    • The maker addresses back focus directly rather than leaving it to be discovered
    • A named list of what it is meant to connect, which most adapter listings omit
    • “Very low” is not a millimetre figure

    Best for: Bringing a 2 in filter thread onto a T2 camera fitting with minimal focus loss

    ≈ £19 / €19
    Check price on Amazon
  6. 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
  7. 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

    ≈ €10
    Check price on Amazon

Any figure written into the body of this page was true on the day it was written. The amount shown next to each instrument is requested from the retailer as the page loads, and it is that amount, not the text, that stands.