Stacking Starlight

Choosing an equatorial mount for your payload

The mount matters more than any other purchase in deep-sky imaging — it's what keeps stars round during long exposures. The decision is driven by your **imaging payload** and how/where you'll use it.

1. Start from payload, not price

Rule of thumb: image at roughly 60–70% of the rated payload (mounts are rated for visual, not

imaging). A ~6 kg train wants a mount rated ~10 kg or more. Under-mounting a good scope is the most

common and most expensive mistake.

2. The options

  • Star tracker: tiny, portable, for camera-lens and very short scopes. Outgrows quickly.
  • German equatorial (GEM): the workhorse — counterweights, strong tracking, the most accessories

and support. Heavier to carry; needs balancing.

  • Strain-wave / harmonic: little or no counterweight, high payload-to-weight, very portable —

excellent for travel — but typically relies on guiding and can show more high-frequency error.

GEMStrain-wave
PortabilityLower (counterweights)High
Guiding requiredOften optional at short FLUsually yes
Payload-to-weightLowerHigh
Ecosystem/supportBroadestGrowing

3. For a ~6 kg imaging payload

A solid mid GEM rated ~10–13 kg is the safe, well-supported choice; a strain-wave mount of similar

rating wins if portability is your priority and you'll always guide. Either way, choose

guiding-capable (ST4 or pulse-guide) — you'll want it.

4. Budget tiers (confirm current models)

  • Entry imaging GEM: ~10 kg class with guiding support.
  • Mid: ~13 kg class GEM, or a comparable strain-wave for travel.
  • Pair it with optics it can carry — see choosing a telescope.

A heads-up for later

All geared mounts have some reversal play; if tracking lags/jumps on direction changes, it's usually

tunable — see reducing mechanical play.

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How the mount works: what an equatorial mount does.