Exploring Astrophotography with William Optics Telescopes
- 1. Understanding William Optics Telescopes and Imaging Lenses
- 2. Types of William Optics: RedCat 51 Refractor Telescope
- 3. Types of William Optics: ZenithStar 61 Refractor Telescope
- 4. Types of William Optics: GT71 Refractor Telescope
- 5. Types of William Optics: RedCat 71
- 6. Types of William Optics: GT81 Refractor
1. Understanding William Optics Telescopes and Imaging Lenses
Whether a beginner to astrophotography or a seasoned pro, wide-field imaging lenses and telescopes are a hot item for anyone looking to image the night sky. The William Optics line of refractors offers high quality optics and fast focal ratios in a lightweight, portable telescope. The included William Optics soft carry case makes it easy to take these scopes with you wherever your travels might lead you!
The smallest models (such as the RedCat/SpaceCat 51 and ZenithStar Z61II) are easily supported by a small star tracker such as the iOptron SkyGuider Pro, while the RedCat 71/GT71/GT81 may be better handled with a slightly more capable mount if you plan to include auto-guiding equipment, filter wheels, auto-focusers, etc. Smaller go-to equatorial mounts such as the Celestron Advanced VX or iOptron GEM28 will have plenty of payload capacity to meet this need.
Check out the specs on some of the most popular portable William Optics refractors below and follow the links for user reviews, current inventory and more. Click here to see the full William Optics lineup!
2. Types of William Optics: RedCat 51 Refractor Telescope
Released just a few years ago, the RedCat 51 took the astrophotography world by storm and continues to be one of the most frequently recommended widefield imaging telescopes for any level of experience. With a quadruplet Petzval optical design, this scope provides sharp flat images to the corners without the need for additional field flatteners! To top it off, a built-in tilt adjustor allows you to be certain that your camera sensor and optical axis are well aligned. The RedCat 51 offers the widest field of view of all William Optics refractors, meaning perfectly accurate tracking and guiding are much less important than with larger instruments. With a built in bahtinov focusing mask, this scope is ready for you to attach your favorite DSLR or astronomy camera (48mm T ring required not included) and get right into imaging!
Dimensions of RedCat 51
- Focal length: 250mm f/4.9
- Weight: 1.47kg
- Design: Four-element Petzval
3. Types of William Optics: ZenithStar 61 Refractor Telescope
If you’re looking for a budget friendly refractor without compromising on optical quality, look no further than the ZenithStar Z61II apochromatic doublet refractor. With a slightly larger focal length than the RedCat 51, the ZenithStar 61 offers a bit more reach while still allowing for larger objects such as the Andromeda Galaxy and larger nebulae to easily fit into the field of view. Thanks to the superior dispersive qualities and color correction of the FPL-53 glass, this scope is terrific as both a portable terrestrial observing telescope and a high quality imaging telescope when paired with the William Optics 61A Adjustable Field Flattener .
Dimensions of ZenithStar 61
- Focal length: 360mm f/5.9
- Weight: 1.45kg
- Design: Apochromatic Doublet
4. Types of William Optics: GT71 Refractor Telescope
The William Optics GT71 is the smallest of the widely coveted William Optics triplet refractors, featuring a 3-element objective with high-quality FPL-53 extra-low dispersion glass. Each lens is Fully Multi-Coated with a special super-high transmission coating on all surfaces, ensuring sharp views and excellent color correction. Adding the William Optics 6AIII 0.8x Reducer / Adjustable Field Flattener will ensure a completely flat imaging field for most cameras, and a 97% illuminated frame when using full-frame sized sensors. The CNC-machined aluminum tube makes this telescope sturdy yet plenty light for use as a travel telescope!
Dimensions of RedCat GT71
- Focal length: 420mm f/5.9
- Weight: 2.2kg
- Design: Apochromatic Triplet
5. Types of William Optics: RedCat 71
Thanks to the popularity of the RedCat 51, William Optics recently launched the RedCat 71 for those looking for a bit more focal length while keeping some of the features that made the RedCat brand so desirable. The RedCat 71 provides a focal length very similar to the ZenithStar 61, but with the unique “2-1-1” 4 element optical configuration you will see improved image quality across a full frame 45mm imaging circle! This scope comes ready to image out of the box with included mounting rings, vixen style dovetail bar, and upper saddle for connecting your favorite accessories such as the ZWO ASIAIR Plus!
Dimensions of RedCat 71
- Focal length: 348mm f/4.9
- Weight: 3.7kg
- Design: Petzval Quadruplet Astrograph
6. Types of William Optics: GT81 Refractor
With a native 478mm focal length, the William Optics GT81 brings us closer to the medium refractor category, making this the largest of the William Optics refractors we would recommend for use as a dedicated “travel” telescope. When fully retracted, the GT81 measures at only 390mm (15.4”), making it compact enough to qualify as carry-on luggage with most airlines. The new Gen IV version also includes a built-in camera angle rotator within the drawtube for a full 360-degree control of your camera orientation, allowing you to frame your images easily and quickly! A reversible dovetail is included with a Vixen rail on one side and an Arca Swiss mount on the other for mounting the scope to a camera tripod for grab-and-go terrestrial and astronomical observation. The GT81 is available in Space Gray, Gold, or Red, ideal for those who are looking to match the scope with other astronomy equipment.
Dimensions of GT81
- Focal length: 478mm f/5.9
- Weight: 3.9kg
- Design: Apochromatic Triplet
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