Some telescopes have not only stood the test of time but have become truly iconic. The Celestron C8 Schmidt-Cassegrain falls into that category. First introduced in 1970, this instrument packed a good-sized aperture into a compact size at an affordable price – and it had a distinctive orange optical tube assembly that made it stand out.
The original C8 came with a fork mount on an equatorial wedge with a basic drive for tracking, all mounted on a tripod.
In 1984, Celestron changed the tube colour to black. Further improvements were made through the 1990s.
In 2006, the distinctive orange colour was reintroduced with the NexStar altaz series.
Today, Celestron offers a choice of optical tube assemblies and mounts, including the NexStar range – a good cross between the old and new designs.
The NexStar 8SE is an 8-inch Schmidt-Cassegrain with a focal length of 2,032mm, giving a focal ratio of f/10. All of this fits into a compact orange tube that weighs 11kg and is just 432mm long.
The mirror surfaces have Celestron StarBright XLT coatings, which now come as standard, but this wasn’t the case with the very first C8s.
A StarPointer red-dot finder, E-Lux 25mm, 1.25-inch fit Plössl eyepiece and a star diagonal complete the optical tube assembly.
The mount is a single-arm, all-in-one unit with the neatly integrated NexStar hand controller, which can be pulled out when in use.
There is a power connector and switch on the outside base of the arm, and a battery compartment for eight AA batteries on the top of the base, along with autoguider and aux ports.
A sturdy, adjustable tripod and a software CD are also included in the price.
Our Go-To and tracking tests gave good results, with our chosen object almost always placed close to the centre of the view regardless of the alignment routine we used.
We were also able to track objects and keep them centred for at least 30 minutes, which was plenty long enough to explore them.
After attaching our iPad using the supplied cable and our own adaptor, we were also able to use a sky app to move the scope to objects in its database.
Optically, we were impressed with the results when using the supplied 25mm eyepiece.
Arcturus in Böotes was pin-sharp across 85% of the field of view, only slightly trailing off towards the edge.
To test the resolution, we added our own 5x Powermate to the 25mm eyepiece, giving 406x magnification, and sought out Porrima in Virgo, easily splitting the 1.6-arcsecond pair.
We were also able to cleanly split 20 Draconis, its two 7th-magnitude stars separated by just 1.2 arcseconds.
Deep-sky views through the NexStar were equally rewarding.
The open star cluster M11 in Scutum appeared as a splash of stars in the 25mm eyepiece and we were able to resolve stars in the core of globular cluster M13 in Hercules.
Turning to nebulae, M17 in Sagittarius showed a wonderful glow shaped like a tick mark, while M27 in Vulpecula displayed a good shape.
We also checked out the Whirlpool Galaxy and its companion, and saw a hint of structure in the main galaxy’s disc.
M82 appeared as a large thin strip of disturbed light, hinting at the turmoil within that galaxy.
The planets were not ideally placed at the time of our review, but we did manage to make out Syrtis Major and a polar cap on Mars, despite the small size of its disc.
Saturn, however, was simply gorgeous. The pale yellow and cream hues of the planet showed up its north belt and north polar haze, while the rings, clearly split by the Cassini Division, were a delight.
We were also able to pick out 5 of the planet’s myriad moons.
We managed to do some limited deep-sky imaging, despite the scope’s altaz mount.
Objects too high would cause a camera attached to the rear end of the tube to catch on the base, but we found we could image objects lower than 60º as long as we used very high ISO values and exposures shorter than 20 seconds.
We took 11 exposures of 15 seconds each at ISO 3200 with our Canon EOS 50D and processed them with DeepSkyStacker.
This produced a respectable image for our efforts.
With its ease of use and the great views we had with it, it’s not hard to see why the C8 continues to thrive. We can see it being a solid performer for many more years to come.
Optics
The 8-inch, f/10 Schmidt-Cassegrain optics have Celestron’s StarBright XLT coatings, improving light transmission, and gave great views with the supplied 25mm E-Lux Plössl eyepiece. Stars were sharp across 85 per cent of the view and even very close faint double stars could be split using high magnification.
Single arm mount
The mount is sturdy in construction and carries the optical tube on a Vixen-style dovetail arrangement. It’s home to the power switch, power connector, battery compartment and, on the arm itself, the integrated hand controller – making for a very compact arrangement indeed.
Go-To controller
The NexStar computerised hand controller has been designed to slot into the single arm and provides a database of 40,000 objects to choose from. It was easy to use and the star alignments worked well every time, placing the desired objects within the inner half of the view.
Tripod
The sturdy tripod easily holds the weight of the mount and the optical tube assembly. It can be extended to give more height for a better viewing position and, once levelled, provides the perfect platform for the rest of the telescope.
Focuser
The focuser is located at the back, below the optical axis, which in an altaz system means it’s always easy to locate and use. The mechanism is smooth in operation and has plenty of focus range to accommodate DSLRs, diagonals and eyepieces.
Vital stats
- Price £1,499
- Otics Schmidt-Cassegrain
- Aperture 203.2mm (8 inches)
- Focal length 2,032mm (f/10)
- Mount Computerised single fork arm altazimuth
- Eyepiece 25mm Plössl, 1.25-inch fit
- Weight 15.6kg
- Supplier David Hinds
- Tel 01525 852696
- www.celestron.co.uk
This review originally appeared in the September 2012 issue of BBC Sky at Night Magazine.
