Sky-Watcher Quattro 150P Imaging Newtonian with ZWO ASI533MM Pro
1.50″ per pixel across a 1.25° × 1.25° field, at 518 mm and f/3.5. 16 of the catalogue's 29 equatorial mounts carry the 8.38 kg train within the imaging derate.
Every figure is computed from catalogue rows that link their maker's page. Rows marked provisional have not yet had a second, human check.
Optics
At 518 mm, with the included corrector.
Sampling
Seeing divided by image scale: how many pixels a star's core spans. Each band is a tradeoff, and wide-field work is undersampled on purpose.
At 2.5″ seeing a star’s core spans 1.67 pixels on this sensor. Practical band for typical seeing.
| Seeing | FWHM | Band |
|---|---|---|
| 1.5″ | 1.00px | undersampled |
| 2.5″ | 1.67px | practical |
| 3.5″ | 2.34px | practical |
- Undersampled; the standard, deliberate wide-field trade.
- Practical band for typical seeing.
Framing
The 13 catalogue targets against this field, by the fraction of the frame each fills along its tighter axis.
M31 Andromeda Galaxy fills 237 % of the frame and M27 Dumbbell Nebula 9 %. Of the 13, 3 fill the frame, 2 are a tight crop, 4 need a mosaic, 4 are small in the frame.
| Target | Size | Frame filled |
|---|---|---|
| M31 Andromeda Galaxy | 178′ × 70′ | 237%needs a mosaic |
| M45 Pleiades | 150′ × 150′ | 200%needs a mosaic |
| NGC 7000 North America Nebula | 120′ × 30′ | 160%needs a mosaic |
| NGC 1499 California Nebula | 160′ × 40′ | 213%needs a mosaic |
| IC 1805 Heart Nebula | 60′ × 60′ | 80%fills the frame |
| M42 Orion Nebula | 90′ × 60′ | 120%tight crop |
| NGC 2237 Rosette Nebula | 80′ × 50′ | 107%tight crop |
| M101 Pinwheel Galaxy | 24′ × 23′ | 32%fills the frame |
| M27 Dumbbell Nebula | 6.7′ × 6.7′ | 9%small in the frame |
| M51 Whirlpool Galaxy | 13.7′ × 11.7′ | 18%small in the frame |
| M81 Bode's Galaxy | 22′ × 11.3′ | 29%fills the frame |
| M13 Hercules Globular Cluster | 16.5′ × 16.5′ | 22%small in the frame |
| NGC 4565 Needle Galaxy | 16.8′ × 2.9′ | 22%small in the frame |
Target sizes: OpenNGC by Mattia Verga (tag v20260501), CC BY-SA 4.0. This table is shared under the same license. Source and license
Spacing
The corrector rows this telescope links in the Backfocus Solver's catalogue, with the face each figure is measured from.
The corrector ships with the telescope. The maker: “an included coma corrector/reducer for those who want to take their imaging to the next level” Source
The included corrector’s backfocus is not in the catalogue, so the Backfocus Solver cannot check this train yet.
Mounts
The catalogue's equatorial mounts that carry this train within 60 % of their rated payload, the imaging derate. The sum is the Rig Reality Check's.
On the saddle this train weighs 8.38 kg, 2.25 kg of it assumed. 16 of the 29 equatorial mounts in the catalogue carry it within the derate; the smallest rated is the Pegasus Astro NYX-88, at 60 %. 13 more would run it over 60 %.
| Mount | Rated | Used | Band |
|---|---|---|---|
| Pegasus Astro NYX-88 | 14kg | 60% | Workable; more sensitive to wind, little room to grow |
| Sky-Watcher HEQ5-R Pro | 15kg | 56% | Workable; more sensitive to wind, little room to grow |
| Sky-Watcher Wave 150i | 15kg | 56% | Workable; more sensitive to wind, little room to grow |
| ZWO AM5N | 15kg | 56% | Workable; more sensitive to wind, little room to grow |
| Celestron CGEM II | 18kg | 47% | Comfortable |
| iOptron CEM40 (with tripod) | 18kg | 47% | Comfortable |
The other 10 mounts that carry it
| Mount | Rated | Used | Band |
|---|---|---|---|
| iOptron HEM44 | 20kg | 42% | Comfortable |
| Pegasus Astro NYX-101 | 20kg | 42% | Comfortable |
| Sky-Watcher EQ6-R Pro | 20kg | 42% | Comfortable |
| WarpAstron WD-20 | 20kg | 42% | Comfortable |
| ZWO AM7 | 20kg | 42% | Comfortable |
| Losmandy GM811G (LW tripod) | 22.7kg | 37% | Headroom for a future upgrade |
| Celestron CGX | 25kg | 34% | Headroom for a future upgrade |
| iOptron CEM70 (iPolar) | 31.8kg | 26% | Headroom for a future upgrade |
| Sky-Watcher CQ350 Pro (with tripod) | 35kg | 24% | Headroom for a future upgrade |
| Sky-Watcher EQ8-R (head with counterweights) | 50kg | 17% | Headroom for a future upgrade |
What the 8.38 kg is made of
| Component | Mass | Basis |
|---|---|---|
| OTA: Sky-Watcher Quattro 150P Imaging Newtonian | 5.72kg | maker’s figure |
| Rings and dovetail | 0.90kg | assumption |
| Camera: ZWO ASI533MM Pro | 0.41kg | maker’s figure |
| Filter drawer and filter | 0.20kg | assumption |
| Guide scope and guide camera | 0.80kg | assumption |
| Cables, dew strap, focuser motor | 0.35kg | assumption |
| Total | 8.38kg |
Assumptions are the Rig Reality Check’s round placeholders, not measurements; replace them with your own figures there.
Run the Rig Reality Check with the ZWO ASI533MM Pro as yours, then give it your budget, sky and targets.
Sub length
The shortest sub at which read noise adds no more than 5 % to the stack's noise, from the Exposure Planner. Each figure opens the planner with the same inputs.
At gain 100 (high conversion gain on, 1.5 e⁻ read noise), 150 mm at 518 mm. Under a Bortle 6 sky it is 2.8 s with no filter and 50 s through a 7 nm dual-band filter.
| Sky | No filter | 7 nm dual-band |
|---|---|---|
| Bortle 421.00 mag/arcsec² | 17 s16 s to 19 sbelow the 30 s floor | 316 s288 s to 347 s |
| Bortle 619.00 mag/arcsec² | 2.8 s2.5 s to 3.0 sbelow the 30 s floor | 50 s46 s to 55 s |
| Bortle 817.90 mag/arcsec² | 1.0 s0.9 s to 1.1 sbelow the 30 s floor | 18 s17 s to 20 sbelow the 30 s floor |
- This design has a central obstruction, which the catalogue holds only in prose. The figures are computed unobstructed, so each is a floor: the obstruction lowers the sky signal and lengthens the shortest sub. The planner takes the obstruction as an input.
- The read noise is read off the maker’s chart; the small figures give the range its reading uncertainty allows.
- Under 30 s, download and dither time dominate, so the planner raises shorter results to 30 s. The dual-band column uses the reference’s approximation: Dual narrowband 7 nm (Ha + OIII).
Prices
Dated readings from the maker's store or a major US retailer, with the page each came from. A first-year total needs a mount and the essentials, which the Rig Reality Check adds.
| Part | Price | Read |
|---|---|---|
| Telescope: Sky-Watcher Quattro 150P Imaging NewtonianProvisional | $665 | manufacturer, 2026-09-27OTA, rings, V dovetail, 6x30 finder, 22mm 70-degree eyepiece, 1.25/2in adapters, coma corrector/reducer |
| Camera: ZWO ASI533MM ProProvisional | $999 | manufacturer, 2026-09-27camera only (variant ASI533MM-P); the page's 'Sold out' applies to the filter-kit bundles |
| $999 | retailer, 2026-09-27 |
Provisional rows have not yet had a second, human check against their source. The Rig Reality Check prices whole builds, essentials included.
How this is computed
scale["/px] = 206.265 × pixel[µm] / focal length[mm]
field[°] = 2 × atan(sensor side[mm] / (2 × focal length[mm])) × 180/π
sampling = seeing FWHM["] / scale["/px]
frame filled = max(major axis / field width, minor axis / field height)
utilization = Σ imaging mass[kg] / rated payload[kg]
shortest sub = R² / (e_sky × ((1 + p)² − 1)), p = 5 %Focal length is the telescope’s, times a corrector’s factor only where its maker states one. The image scale and field use the exact forms; the worked example shows the arithmetic. The sampling bands are the physics reference’s presentation choice, and every band is printed so the tradeoff can be read in full.
The payload sums every part on the saddle, the way the Rig Reality Check does, and the bands encode the 50 to 60 % imaging derate, which is forum practice rather than a maker’s figure. Spacing figures are the Backfocus Solver’s rows; sub lengths are the Exposure Planner’s.
Source: docs/03-physics-reference.md §§ 1, 3 and 4. Implemented in packages/physics (optics.ts, payload.ts, exposure.ts, scoring.ts), each with the reference's worked examples as unit tests.
Last updated Computed from the catalogue when the site is builtEvery camera on the Sky-Watcher Quattro 150P Imaging Newtonian