Varrow Forge 203 Schmidt-Cassegrain, tube only

Specifications

Description

The Forge 203 Schmidt-Cassegrain is an 8 in catadioptric telescope with a 203 mm corrector plate and primary mirror. Light enters through a thin corrector plate, reflects from a spherical primary mirror, and returns through a central hole to a secondary mirror mounted on the plate. This folded light path gives a focal length of 2030 mm in a tube roughly half a meter long, which is how the telescope reaches f/10 in a compact body.

At f/10 the Forge 203 suits lunar, planetary, and double-star work. With a 10 mm eyepiece it reaches about 203 times magnification, and with a 25 mm eyepiece about 81 times. Its theoretical resolution is about 0.6 arcseconds, so on nights with steady air you can see fine detail in the Cassini Division of Saturn's rings and along the crater walls near the lunar terminator. The sealed tube and central obstruction also reduce the contrast of faint extended objects compared with a refractor of the same aperture, so you should expect galaxies and nebulae to look smaller and dimmer than they do in long-exposure photographs.

The tube weighs 9.8 kg, so you need a mount rated for at least 12 kg of payload, such as a sturdy equatorial head or a heavy alt-az mount. The corrector plate and mirror take 45 to 60 minutes to reach outdoor temperature, so carry the tube out well before the session starts. A dew heater for the corrector plate is not included, and dew can form on the plate on humid nights. The 2 in dual-speed focuser carries a star diagonal and a heavy eyepiece, and the 8x50 finder helps you locate targets at low power before you switch to the main eyepiece.

About this configuration

This listing covers one specific configuration of the Varrow Forge 203 Schmidt-Cassegrain, defined by its bundle, finish, accessory kit, and edition year. This is the optical tube on its own, so you need to supply a mount that can carry its weight steadily. Buying the tube alone makes sense if you already own a suitable mount or plan to choose one separately. The gloss white tube reflects sunlight, which helps it stay closer to air temperature while you set up before dusk.

With the imaging kit, a camera attaches at prime focus, so the telescope works as a long telephoto lens. This is the 2023 edition of the Forge line, the earliest version that is still listed in the catalog. Check the specifications table for the optical figures, since they stay the same across every configuration of the Forge line.

What's in the box

• Optical tube with corrector plate and dust cap
• Dovetail bar for mounts
• 2 in dual-speed focuser with 1.25 in adapter
• 8x50 finder scope with bracket
• 1.25 in star diagonal
• T-ring and T-adapter
• Bahtinov focusing mask

Compatibility notes

• Accepts 2 in eyepieces through the focuser and 1.25 in eyepieces through the supplied adapter.
• The dovetail bar fits standard dovetail saddles on equatorial and alt-az mounts.
• The tube weight requires a mount with a payload capacity of at least 12 kg.