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Balance is what lets a small motor move a heavy tube

The best counterweights for 2026

A counterweight balances an equatorial mount so that the tube stays where it is put with the clutches loose, and so that the drive motor turns a load that is nearly weightless instead of dragging one that is not. Balance is not a refinement here — an unbalanced mount tracks badly, backlash shows in one direction and not the other, and the gears wear. The specifications are few and unforgiving. The bore diameter must match the counterweight shaft of the mount exactly; shafts come in several diameters and a weight that does not slide on is not adaptable. The mass has to be considered together with the length of the shaft, because torque is mass multiplied by distance: a heavier weight close to the mount and a lighter one far out can balance the same tube, and the lighter arrangement puts less total load on the bearings while the heavier one keeps the centre of gravity compact. Most owners end up with two weights rather than one, which allows fine adjustment by moving the smaller one. Read the locking method: a knob that bears directly on the shaft marks it over time, while a collar or a brass insert spreads the load. Read whether a safety collar or a retaining bolt is fitted at the end of the shaft, since a weight that slides off is the most predictable accident in the hobby. Coating matters for a part that lives outdoors. We compare mass, bore diameter, locking method, coating and finish, compatible mounts and overall dimensions.

The parts here, column by column

  1. Omegon 2.6 kg steel counterweight with locking screw

    Omegon 2.6 kg counterweight (59253)

    A steel counterweight of 2.6 kg with a 21 mm bore and a locking screw, made for the EQ-500 X and fitting many other shafts.

    Mass
    2.6 kg, as the maker publishes it
    Bore diameter
    21 mm, as the maker publishes it
    Locking method
    A locking screw for a secure seat
    Coating
    Steel
    Finish
    Not published by the maker.
    Compatible mounts
    EQ-500 X · The maker names Skywatcher, Meade and Celestron shafts
    Overall dimensions
    Not published by the maker.
    Amazon reference
    B07JCR2XYG (same reference on 6 Amazon marketplaces)
    EAN
    4049467592532
    • Both figures that matter — mass and bore — are published
    • The maker tells you to measure your own shaft before ordering
    • A 21 mm bore will not fit a 20 mm shaft securely, nor a 14.7 mm one at all

    Best for: Balancing a heavier tube or a camera on a 20–21 mm counterweight shaft

    ≈ £36 / €37
    Check price on Amazon
  2. Bresser 2 kg counterweight for EXOS mounts

    Bresser 2 kg counterweight for EXOS-1 and EXOS-2 (4964400)

    A 2 kg counterweight for a 20 mm shaft, colour-matched to the Bresser Messier EXOS-1 and EXOS-2 mounts.

    Mass
    2.0 kg, as the maker publishes it
    Bore diameter
    20 mm, as the maker publishes it
    Locking method
    Not published by the maker.
    Coating
    Not published by the maker.
    Finish
    Colour-matched to those mounts
    Compatible mounts
    Messier EXOS-1 and EXOS-2
    Overall dimensions
    The listing gives none
    Amazon reference
    B007NIIRFM (same reference on 6 Amazon marketplaces)
    EAN
    4007922194608
    • Mass and shaft diameter both published
    • Made for two named mounts, so compatibility is not in question
    • No overall diameter, so clearance against the tripod is unknown

    Best for: An EXOS-1 or EXOS-2 that has gained a camera or a heavier tube

    ≈ €30
    Check price on Amazon
  3. Explore Scientific 1 kg counterweight for the iEXOS-100

    Explore Scientific 1 kg counterweight for iEXOS-100 (456101)

    A 1 kg counterweight for the iEXOS-100, published with all three of its dimensions as well as its mass.

    Mass
    1.0 kg, as the maker publishes it
    Bore diameter
    14.7 mm, as the maker publishes it
    Locking method
    Not published by the maker.
    Coating
    Not published by the maker.
    Finish
    Not published by the maker.
    Compatible mounts
    iEXOS-100
    Overall dimensions
    80 mm, as the maker publishes it · 30 mm, as the maker publishes it
    Amazon reference
    B07P7WJBVW (same reference on 5 Amazon marketplaces)
    EAN
    4007922060743
    • The only counterweight on this shelf to publish all four figures
    • An 80 mm diameter is small enough to clear most tripods
    • A 14.7 mm bore is specific and will not fit the 20 mm shafts of larger mounts

    Best for: Fine-balancing an iEXOS-100 after adding a camera or a guide scope

    ≈ £31 / €31
    Check price on Amazon
  4. Vixen 1.9 kg white counterweight

    Vixen 1.9 kg counterweight (2577-06)

    A 1.9 kg counterweight for seven named Vixen mounts, for balancing an increased payload.

    Mass
    1.9 kg, as the maker publishes it
    Bore diameter
    The listing gives none
    Locking method
    Not published by the maker.
    Coating
    Not published by the maker.
    Finish
    Not published by the maker.
    Compatible mounts
    SX, SX2, SXD, SXD2, SXP, GP2 and GPD2, all named
    Overall dimensions
    The listing gives none
    Amazon reference
    B002P4KLR6 (same reference on 5 Amazon marketplaces)
    EAN
    4955295257706
    • Seven compatible mounts named individually rather than by family
    • A 1.9 kg increment suits fine balancing on a medium mount
    • The bore diameter is not published, which is the figure that decides fit

    Best for: A Vixen SX or GP mount carrying more than it was balanced for

    ≈ £49 / €52
    Check price on Amazon
  5. Sky-Watcher Star Adventurer counterweight kit in black

    Sky-Watcher Star Adventurer counterweight kit (S20540)

    A counterweight and threaded shaft kit for the Star Adventurer, explicitly excluding the GTi version, with two mutually inconsistent weight figures.

    Mass
    The listing prints 11.3 kg
    Bore diameter
    The listing gives none
    Locking method
    Not published by the maker.
    Coating
    Not published by the maker.
    Finish
    Not published by the maker.
    Compatible mounts
    A counterweight with a threaded counterweight shaft · Star Adventurer · Star Adventurer GTi, stated by the maker
    Overall dimensions
    Not published by the maker.
    Amazon reference
    B00XX646MG (same reference on 6 Amazon marketplaces)
    EAN
    0050234205405
    • The shaft is included, not just the weight
    • The incompatible model is named outright, which prevents a common mistake
    • The two published weights are inconsistent with each other

    Best for: A Star Adventurer carrying a lens heavy enough to need balancing

    ≈ $40 / £44 / €55
    Check price on Amazon
  6. SVRITE 1 kg stainless steel counterweight

    SVRITE 1 kg stainless steel counterweight

    A 1 kg stainless steel counterweight with a 20.5 mm bore, sold for equatorial mounts, with no bullet points in the listing.

    Mass
    1 kg, from the title
    Bore diameter
    20.5 mm, from the title
    Locking method
    The listing gives none
    Coating
    Stainless steel, from the title
    Finish
    Not published by the maker.
    Compatible mounts
    Not published by the maker.
    Overall dimensions
    The listing gives none
    Amazon reference
    B0CQZKVBP7 (same reference on 6 Amazon marketplaces)
    EAN
    4713737267382
    • Both the mass and the bore appear in the title, which is what a counterweight needs
    • Stainless steel resists the corrosion that pits a painted cast weight
    • No description at all beyond the title

    Best for: A 20 mm counterweight shaft that needs a small additional mass

    ≈ €34
    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.