f/2.75.
What used to take a week now takes a night.
The DeltaRho 280 Argus is PlaneWave’s observatory-class wide-field astrograph for serious imagers and sky-survey programmes. Fused silica quartz mirrors, a carbon fibre OTA, and a 55 mm image circle at f/2.75 — 280 mm of aperture that turns nights of integration into a few productive hours.
f/2.75 is not just fast. It is the difference between finishing a target tonight and coming back next month.
13× faster than f/10. Every photon counts more.
At f/2.75, the DeltaRho 280 gathers light 13 times faster than an f/10 instrument of identical aperture. That is not an incremental advantage — it is the difference between a productive one-hour session and a week of cloud-interrupted integration. Research programmes and sky surveys that would otherwise take months become achievable in a single season.
mm image circle — large enough to cover full-frame sensors and beyond, with sharp stars from centre to corner at 4.5 μm RMS or better at 27.5 mm off-axis.
Focus stays locked. All night.
Primary and secondary mirrors are optical-grade fused silica quartz — near-zero thermal expansion, the same material used in premier research observatories. As temperature drops through the night, conventional glass mirrors shift focus. The DR280’s quartz mirrors do not.
Stiff where it matters. Light where it counts.
Carbon fibre delivers exceptional torsional rigidity with minimal mass. At 14.5 kg for a 451 mm OTA, the DR280 is a 280 mm instrument that mounts on observatory-class and high-end portable mounts alike — without needing a counterweight upgrade.
Sensor alignment without shimming or guesswork.
The integrated tip-tilt focal plane adjuster lets you dial in perfect sensor tilt with precision — no shims, no trial-and-error. It is consistent, repeatable, and done in minutes at the start of any session.
The Heart Nebula. In one frame.
The 770.6 mm focal length paired with the 55 mm image circle delivers over 4 degrees of field of view. Large nebula complexes, galaxy groups, and wide-field targets that require mosaics on narrow-field systems fit comfortably into a single frame — or anchor a multi-panel survey.
Dew control built in. Session-ending fog, ruled out.
Integrated dew control heater technology keeps the optical path clear on humid Australian nights. One less cable to run, one less failure point — the DR280 keeps imaging when lesser rigs fog out and call it a night.
Collimation solved. From first session to thousandth.
The DeltaRho 280 ships with PlaneWave’s collimation software that walks you through mirror alignment step by step — no iterative star-testing, no guesswork. Set it once: the rigid carbon fibre structure holds alignment through the night. The low-profile focuser delivers 0.5 inches of travel from a 163 mm back focus distance, giving your imaging train room to breathe.
M51. The Whirlpool Galaxy.
Galaxy arms, tidal bridges, and foreground stars resolved in a single short session. At f/2.75, integration time that would fill a week on a slower system compresses to a few productive hours.
IC 1805. The Heart Nebula.
H-alpha, RGB narrowband composite. The 4-degree–plus field captures the Heart Nebula’s full complex and surrounding star-forming regions in a single pointing — a target that demands a mosaic from slower, narrower systems.
Built for imagers who treat every clear night as a resource. Nothing wasted.
280 mm (11″) aperture with fused silica (quartz) primary and secondary mirrors for temperature-stable performance
f/2.75 focal ratio — 13 times faster than f/10, reducing required integration time dramatically
55 mm image circle at 4.0 μm RMS on-axis and 4.5 μm RMS at the full 27.5 mm off-axis radius
Integrated tip-tilt focal plane adjuster for precise sensor alignment without physical shimming
Carbon fibre optical tube — 451 mm OTA, 14.5 kg total weight for use on observatory-class mounts
Built-in dew control heater and broadband AR coatings (<1% reflection, 400–800 nm) for consistent all-weather performance
4°+ field of view capability with a 55 mm sensor — ideal for large nebula complexes and sky surveys
Compatible with PlaneWave L350 Direct Drive Mount — designed as an integrated professional imaging system
