William Optics

William Optics ZenithStar 61II

No longer sold

A 61mm f/5.9 ED doublet that has become a favourite first imaging scope, light, affordable and beautifully finished, ideal for wide-field astrophotography on a star tracker.

85/ 100

Polaris Score

#4 of 8 compact imaging refractor

See the breakdown ↓

Aperture

61mm

Focal Length

360mm

Focal Ratio

f/5.9

Mount Type

None (OTA only)

Optical Design

ED Doublet Refractor

Weight

1.6 kg

Try in simulator →

No longer sold

Discontinued by the manufacturer (per Agena Astro). We keep the page for reference — see current alternatives below.

See alternatives ↓

What it's built forOpen these in the simulator →

This telescope was built for sweeping wide.

A short, fast refractor with a generous true field — the whole sword of Orion in one view, star fields that spill past the field stop. It rewards low power and dark skies far more than chasing magnification.

Widest true fieldsTack-sharp to the edge

The view people remember

The Double Cluster, side by side.

Two glittering knots of stars sharing one low-power field — a wide, effortless showpiece that rewards the biggest true field you can throw at it.

See Double Cluster through this telescope →

Where else it shines

Needs patience

Orion Nebula

Bright core visible, outer wisps need patience and dark adaptation

Open view →

Easy first target

The Pleiades

Many cluster members resolved with color contrast between bright stars

Open view →

Rewards a dark sky

Andromeda Galaxy

Faint elongated smudge — averted vision helps

Open view →

Also excellent on

Saturn

Small bright disk — featureless point at low magnification

Open view →

✦

Tight planetary detail belongs to a longer scope. This one trades reach for a breathtaking field.

01What it's good at

What it's best at — and the trade-offs.

Best at

✓The FPL-53 ED doublet controls colour well for its price, keeping stars clean with a flattener

✓360mm at f/5.9 frames large nebulae and the Milky Way, an ideal first imaging focal length

✓At about 1.6kg it rides on the lightest star trackers, keeping the whole rig portable

✓William Optics fit and finish make it feel far more premium than its price

Trade-offs

!A matched flattener is a separate purchase for the flattest stars

!As a doublet it shows slightly more residual colour than a triplet

!61mm and 360mm keep small targets small in the frame

!It is an OTA only and needs a tracker, camera or diagonal to work

02In plain English

What These Numbers Mean

Aperture

61 mm

Under two and a half inches of glass, so faint compact targets require patience. Its purpose is a wide, well corrected field at low cost and low weight, which it delivers.

Focal length

360 mm

Wide field. The Veil complex, the Pleiades, the Heart and Soul and the Andromeda Galaxy all frame comfortably on APS-C, which covers most of the popular starting target list.

Focal ratio

f/5.9

Fast enough to keep exposures short and short enough in focal length that tracking errors rarely show. That forgiveness is the main reason this size is recommended to beginners.

Optical design

ED doublet

Two elements with ED glass remove most visible colour error at a fraction of a triplet's price and weight. The brightest stars can show a trace of halo, which a triplet would eliminate.

Weight

1.6 kg tube

About 3.5 lb, so any star tracker carries it with a camera attached. It packs into a small bag, which is a large part of its appeal.

Mount

OTA only

You supply the mount, and the requirement is minimal. A tracker with reasonable polar alignment is enough for round stars at this focal length.

02The Polaris Score

How it scores, and why.

85/ 100

William Optics ZenithStar 61II

#4 of 8 compact imaging refractor

Performance

Ease of use

Portability

Upgrade potential

Polaris weighs optical capability, how easy the scope is to live with, how portable it is, and how far it takes you before you outgrow it — not list price or brand.

03Who it's for