SVBONY SV503 102mm f/7 ED Doublet Refractor Telescope OTA
- 102mm Aperture ED Doublet Refractor
- 714mm Focal Length (f/7)
- S-FPL51 Extra-Low Dispersion Glass
- 1:10 Dual-Speed Rack & Pinion Focuser
- 101.9mm of Back Focus
The SVBONY SV503 102mm f/7 ED Doublet Refractor combines a 102mm aperture with S-FPL51 extra-low dispersion glass to deliver high-contrast images with minimal chromatic aberration. Its 714mm focal length provides a versatile f/7 focal ratio suitable for a wide range of celestial targets, while the optical system achieves a theoretical resolving capacity of 1.17 arc-seconds. With a light gathering capacity 212 times that of the human eye, this telescope makes faint deep-sky objects accessible for both imaging and visual observation.
At the heart of the SV503 is an air-spaced doublet objective featuring S-FPL51 ED glass, which significantly reduces false color (chromatic aberration) common in standard achromats. This correction results in sharp, high-contrast views of bright objects like Jupiter and the lunar terminator, with Super Multi-Coating (SMC) ensuring maximum light transmission. The 102mm aperture and moderate f/7 focal ratio create a capable deep-sky instrument, resolving stars down to magnitude 12.1 under dark skies.
The SV503 is equipped with a robust Rack and Pinion (RAP) focuser, which eliminates the slippage and flexure associated with Crayford designs when supporting heavy imaging equipment. A 1:10 fine-focus knob allows for the critical adjustments needed to achieve sharp stars in astrophotography. With a generous 101.9mm of back focus, you have ample room to accommodate a full imaging train, including filter wheels, off-axis guiders, and dedicated astronomy cameras.
Constructed from aluminum, the optical tube assembly measures 630mm in length and weighs 5.7kg with the included rings and dovetail, making it a stable and manageable payload for mid-range equatorial mounts. The package includes a 200mm long Vixen-style dovetail bar, providing a secure connection to your mount and allowing for easy balancing adjustments. This combination of moderate weight and rigid construction ensures the stability required for long-exposure astrophotography.
While both the 102mm and 80mm SV503 models share the same f/7 focal ratio and S-FPL51 glass, the choice between them comes down to aperture and portability. The SV503 102mm offers a clear advantage in light-gathering power and resolution, making it the superior choice for imaging smaller galaxies, resolving globular clusters, and capturing fine planetary detail.
With a tube weight of 5.7kg, the SV503 102mm OTA requires a sturdy equatorial mount for astrophotography. A mount with a payload capacity of at least 20-25 lbs (9-11 kg) is recommended to ensure stability for long exposures. Examples include mounts in the Celestron AVX or Sky-Watcher HEQ5 class.
The 102mm aperture and 714mm focal length are well-suited for framing large targets like the Andromeda Galaxy (M31). You will be able to capture the bright galactic core and its surrounding dust lanes. For a full field of view that includes its satellite galaxies M32 and M110, you may need to use a dedicated focal reducer.
Yes. S-FPL51 is an extra-low dispersion glass that provides excellent color correction, especially for a doublet design. While a more expensive triplet apochromat will offer a higher degree of correction, the SV503 102mm delivers sharp, high-contrast images with minimal purple fringing on bright stars, making it a very capable and affordable entry into serious astrophotography.
The 101.9mm of back focus is the distance from the focuser's flange to the focal plane. This generous distance is crucial for astrophotography as it provides enough space to install accessories like filter wheels, off-axis guiders, and astronomy cameras while still being able to reach focus.
Absolutely. While optimized for imaging, the SV503 102mm is an excellent visual instrument. Its 102mm ED objective provides crisp, high-contrast views of the Moon, planets, and bright deep-sky objects. The 1:10 dual-speed focuser makes it easy to snap objects into perfect focus visually.
The S-FPL51 ED glass significantly suppresses chromatic aberration (false color). On extremely bright targets like Sirius or Vega at high magnification, a trace amount of residual color may be visible, which is typical for a doublet design. However, for the vast majority of astronomical targets, the color correction is excellent and will not detract from the view.
| Product Name | SVBONY SV503 102F7 ED Astronomy Telescope |
| Optical Design | Refractor |
| Aperture | 102mm / 4.01-Inch |
| Focal Length | 714mm |
| Focal Ratio | f/7 |
| Objective Lens | S-FPL51 ED Doublet |
| Optical Coating | SMC |
| Focuser | Rack and Pinion (RAP) |
| Gear Reduction | 1:10 Dual-Speed |
| Back Focus | 101.9mm |
| Resolution | 1.17" |
| Limiting Magnitude | 12.1 |
| Light Gathering Power | 212x |
| Max Useful Magnification | 204x |
| Tube Material | Aluminum |
| OTA Weight (with rings) | 5.7kg |
| OTA Length | 630mm |
| Tube Outer Diameter | 121mm |
| Mounting Hardware | Dovetail & Rings Included |
| Dovetail Length | 200mm |
| Product Dimensions | 690mm x 210mm x 250mm |
Download Manual
SV503 102mm f/7 ED Refractor OTA
× 1
Tube Rings
× 1 Pair
200mm Vixen-Style Dovetail Bar
× 1
Lens Cover
× 1
1.25" Dust Cap
× 1