William Optics AP 81/478 81 - Compact power for razor-sharp astrophotos
The William Optics AP 81/478 81 is made for those who want to photograph bright and crisp without effort. Thanks to its apochromatic design, you get images that are immediately striking: sharp stars, high color purity and a flat image across the entire frame. You'll work faster, more consistently and with more confidence-even if this is your first time shooting with a premium apo.
Sharp, clear and immediately usable
The 81 mm aperture captures enough light to make faint nebulae and star fields visible. The 478 mm focal length gives you wide, beautiful shots full of detail. So you get deep, bright photos without the need for long sessions.The lens is made of FPL53 glass, so your colors remain natural and pure. No distracting color errors, no blurry edges-just a clear image that feels right the first time.
Stable focusing, even with large cameras
The WIFD system keeps the focuser completely inside the tube. Everything stays straight, solid and perfectly aligned. Your camera doesn't sag, the framing stays neat and your stars stay round.Because the focuser moves internally, the whole thing stays protected from dust and weather changes. The position indicator helps you see exactly where your focus is handy when you often need to go back to the same setting.
Created with photographers in mind
The built-in rotator lets you rotate the camera smoothly without shifting the entire setup. So you always choose the perfect composition easily.The tube is light, rigid and designed for accessories such as a guidescope or heavy full-frame camera. The handle makes lifting, mounting and alignment easier.
Always ready for the next session
The Gran Turismo series is known for its reliability. The tube is sturdy, the workmanship high quality, and you immediately notice that everything is balanced. For travel, mobile astrophotography or a quick session in the garden, this refractor feels instantly familiar.
Specifications
Optics
| Feature | Description |
|---|---|
| Type | Refractor |
| Design | Apochromat |
| Aperture (mm) | 81 |
| Focal length (mm) | 478 |
| Aperture ratio (f/) | 5,9 |
| Resolution | 1,70″ |
| Limit value (mag) | 11,3 |
| Light output | 130 |
| Max. useful magnification | 162× |
| Tube weight (kg) | 3,9 |
| Transport length (mm) | 390 |
| Tube length (mm) | 460 |
| Coating | SMC multilayer coating |
| Stray light baffles | Yes |
| Lens Design | Triplet |
Focuser
| Feature | Description |
|---|---|
| Design | Helical |
| Ocular connection | 2″ (RotoLock) |
| Free opening (mm) | 64 |
| Motorized | No |
| Ring clamp | Yes |
| Reduction | 1:10 finesse |
| Telescope side connection | M92 / M63 |
Mount
| Feature | Description |
|---|---|
| Design | OTA |
| Type of mount | Without mount |
Included accessories
| Section | Description |
|---|---|
| Seeker | No |
| Dew cap | Yes |
| Divergent optics | No |
| Dovetail | Vixen-Style |
| Miscellaneous | Bahtinov mask |
| Handle | Yes |
| Transport bag | Yes |
General
| Feature | Description |
|---|---|
| Series | Gran Turismo |
| Color | Red |
| Observation goals | Astrophotography (very good), Moon & Planets, Nebulae & galaxies |
| Sun | No (only with suitable filter) |
| Recommended for | Advanced |
| Observatory use | No |
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