Sky-Watcher Quattro 200P Imaging Newtonian with ZWO ASI533MM Pro
0.97″ per pixel across a 0.81° × 0.81° field, at 800 mm and f/3.9. 5 of the catalogue's 29 equatorial mounts carry the 12.16 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 800 mm, with the Sky-Watcher F4 Coma Corrector 2" for Quattro f/4 (US: Quattro Coma Corrector S20204).
Image circle: 28 mm, the corrector's stated figure (Sky-Watcher F4 Coma Corrector 2" for Quattro f/4 (US: Quattro Coma Corrector S20204)). Source
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 2.58 pixels on this sensor. Practical band for typical seeing.
| Seeing | FWHM | Band |
|---|---|---|
| 1.5″ | 1.55px | practical |
| 2.5″ | 2.58px | practical |
| 3.5″ | 3.61px | oversampled |
- Practical band for typical seeing.
- Oversampled: lower per-pixel signal and tighter guiding; binning recovers most of it.
Framing
The 13 catalogue targets against this field, by the fraction of the frame each fills along its tighter axis.
M31 Andromeda Galaxy fills 366 % of the frame and M27 Dumbbell Nebula 14 %. Of the 13, 5 fill the frame, 1 is a tight crop, 6 need a mosaic, 1 is small in the frame.
| Target | Size | Frame filled |
|---|---|---|
| M31 Andromeda Galaxy | 178′ × 70′ | 366%needs a mosaic |
| M45 Pleiades | 150′ × 150′ | 309%needs a mosaic |
| NGC 7000 North America Nebula | 120′ × 30′ | 247%needs a mosaic |
| NGC 1499 California Nebula | 160′ × 40′ | 329%needs a mosaic |
| IC 1805 Heart Nebula | 60′ × 60′ | 123%tight crop |
| M42 Orion Nebula | 90′ × 60′ | 185%needs a mosaic |
| NGC 2237 Rosette Nebula | 80′ × 50′ | 165%needs a mosaic |
| M101 Pinwheel Galaxy | 24′ × 23′ | 49%fills the frame |
| M27 Dumbbell Nebula | 6.7′ × 6.7′ | 14%small in the frame |
| M51 Whirlpool Galaxy | 13.7′ × 11.7′ | 28%fills the frame |
| M81 Bode's Galaxy | 22′ × 11.3′ | 45%fills the frame |
| M13 Hercules Globular Cluster | 16.5′ × 16.5′ | 34%fills the frame |
| NGC 4565 Needle Galaxy | 16.8′ × 2.9′ | 34%fills 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.
This telescope needs a corrector. The maker: “A high quality coma corrector (see next paragraph) is an essential accessory for widefield astrophotograpy.” Source
Sky-Watcher F4 Coma Corrector 2" for Quattro f/4 (US: Quattro Coma Corrector S20204)
- Backfocus
- 55mm
- Measured from
- Not stated: Sky-Watcher says only "Requires 55mm back focus"
- Focal length
- 1.0x, 800 mm
- Image circle
- 28 mm; this sensor is 15.99 mm
Solve the spacer stack with this cameraSourceRow not yet verified
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 12.16 kg, 2.25 kg of it assumed. 5 of the 29 equatorial mounts in the catalogue carry it within the derate; the smallest rated is the Losmandy GM811G (LW tripod), at 54 %. 24 more would run it over 60 %.
| Mount | Rated | Used | Band |
|---|---|---|---|
| Losmandy GM811G (LW tripod) | 22.7kg | 54% | Workable; more sensitive to wind, little room to grow |
| Celestron CGX | 25kg | 49% | Comfortable |
| iOptron CEM70 (iPolar) | 31.8kg | 38% | Headroom for a future upgrade |
| Sky-Watcher CQ350 Pro (with tripod) | 35kg | 35% | Headroom for a future upgrade |
| Sky-Watcher EQ8-R (head with counterweights) | 50kg | 24% | Headroom for a future upgrade |
What the 12.16 kg is made of
| Component | Mass | Basis |
|---|---|---|
| OTA: Sky-Watcher Quattro 200P Imaging Newtonian | 9.50kg | 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 | 12.16kg |
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), 205 mm at 800 mm. Under a Bortle 6 sky it is 3.5 s with no filter and 64 s through a 7 nm dual-band filter.
| Sky | No filter | 7 nm dual-band |
|---|---|---|
| Bortle 421.00 mag/arcsec² | 22 s20 s to 24 sbelow the 30 s floor | 404 s367 s to 443 s |
| Bortle 619.00 mag/arcsec² | 3.5 s3.2 s to 3.9 sbelow the 30 s floor | 64 s58 s to 70 s |
| Bortle 817.90 mag/arcsec² | 1.3 s1.2 s to 1.4 sbelow the 30 s floor | 23 s21 s to 25 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 200P Imaging NewtonianProvisional | $925 | manufacturer, 2026-09-27OTA, rings, V dovetail, 9x50 finder, 1.25/2in adapters; no coma corrector |
| 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 | |
| Corrector: Sky-Watcher F4 Coma Corrector 2" for Quattro f/4 (US: Quattro Coma Corrector S20204)Provisional | $490 | manufacturer, 2026-09-27'Quattro Coma Corrector' S20204 |
| $490 | retailer, 2026-09-27SKU SKY-S20204 | |
| $490 | retailer, 2026-09-27in stock |
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 200P Imaging Newtonian