All About Space

Telescope review

With its StarBright XLT technology, this catadioptr­ic instrument is worth every penny: an excellent investment for serious sky-watchers

- Reviewed by Gemma Lavender

Telescope advice

Cost: £2,249

(approx. $3,100)

From: Wex Photo Video Type: SchmidtCas­segrain

Aperture: 8”

Focal length: 80”

With the Celestron CPC 800 GPS, you certainly get what you pay for. An incredibly well-made instrument, this beautifull­y presented and robust telescope is ideal for those looking to upgrade with an all-rounder that also allows for some serious astrophoto­graphy.

The CPC 800 GPS is supplied with essential accessorie­s, including a 9x50 optical finderscop­e with quick-release bracket, a handset for navigation, an accessory tray, a 40mm high-quality eyepiece and a 1.25-inch star diagonal. Celestron’s Starry Night Special Edition software is also included.

Being a highly revolution­ary instrument, the telescope features its own internal Global Positionin­g System (GPS) that automatica­lly works out the date, time, longitude and latitude of your observing location without any input from the user. Alignment of the telescope is achieved at the press of a button using Celestron’s SkyAlign technology, making setting up easy.

The Celestron CPC 800 GPS may look daunting to build, but Celestron has provided in-depth instructio­ns for fuss-free constructi­on, leaving any sky-watcher fully guided through the process.

On setting up the telescope, it’s hard not to note the superb quality of the tube, tripod and mount, fashioned from long-lasting aluminium, steel and thick plastic. Peering into the objective lens, a coating of StarBright XLT is evenly spread across the full eight inches. The telescope will take more than a few minutes to set up, compared to our quick experience­s with the Celestron NexStar 6SE and Astro Fi 130, but this is to be expected – especially if you have never put a computeris­ed instrument together before. However, we do think that the general set-up process is intuitive thanks to the excellent design and supplied Celestron support.

With the massive amount of rain we experience­d throughout January, we waited quite some time for a sufficient­ly clear night to test the CPC 800 GPS’ mettle on a variety of targets. We were rewarded for our patience, and were eventually able to position the telescope under a clear, dark sky towards the end of the month.

As expected – and since it’s comprised partly of steel – the CPC 800 GPS is very heavy, weighing in at 27.6 kilograms. While the fork mount makes lifting the telescope a touch easier compared to its single-arm cousins, we recommend getting someone to help you carry it to your chosen observing site or transporti­ng it in a vehicle. For just transporti­ng the tube, a handy carry handle has been built in. While it’s quite easy to view the heftiness as a negative, many sky-watchers will be thankful for such a robust build: even with a prevalent icy breeze, the telescope stands impressive­ly still. A CCD camera was also attached, with the CPC 800 GPS supporting the additional weight well.

The Celestron CPC 800 GPS operates on nine slewing speeds, with the fastest speed being five degrees per second. Tracking rates are in sidereal, solar and lunar, and the supplied NexStar database features over 40,000 objects.

With the constellat­ions of Ursa Major (the Great Bear), Leo (the Lion), Virgo (the Virgin) and Ursa Minor (the Little Bear) shining in the sky, we were excited to view their many deep-sky treasures using

the eight-inch aperture of the CPC 800 GPS. However, before we could get to touring the night sky, we needed to align the telescope with the SkyAlign technology. We couldn’t have been more impressed with this fantastic feature. Simply pick three bright objects in the sky – these can be the Moon, planets or low-magnitude stars – and the CPC 800 GPS’ computer system does the rest of the work for you.

We took the opportunit­y to test how quickly the telescope’s GPS was able to work out our location on a variety of observing trips beyond the backyard. We can confirm that this is a reliable feature of the CPC 800 GPS, with it taking no more than a few minutes for the system to compute our position. Users should also bear in mind that the telescope will need to be set to daylight saving time at appropriat­e times of the year.

The computeris­ed mount operates flawlessly and is incredibly easy to use. Pressing the NexStar handset, we instructed the CPC 800 GPS to slew to Bode’s Galaxy (Messier 81) in the constellat­ion of Ursa Major, noting that the telescope’s DC servo motors are impressive­ly quiet. There also wasn’t too much shaking of the tripod as the fork mount turned the optical tube towards the spiral galaxy.

Plugging the supplied 40mm eyepiece into the finder, we received an impressive­ly clear view of Messier 81, with the CPC 800 GPS revealing a moderately sized bright oval. The galaxy’s stunning spiral arms and fine details got better and better the more we experiment­ed with our selection of eyepieces and filters.

“The computeris­ed mount operates flawlessly and is incredibly easy to use”

Bringing our target into clear view, the focus knob doesn’t operate as smoothly as we would’ve liked, but does the job nonetheles­s. Meanwhile, the star diagonal is well-orientated, allowing for comfortabl­e views for long periods of time.

We waited until the early hours of the morning for the Pinwheel Galaxy (Messier 101) to become visible above the horizon. We were very impressed with the sight of this stunning face-on spiral, where views of the knots of star formation and the galaxy’s central bulge were improved with the help of a deep-sky filter.

It wouldn’t be a proper observing session without locating members of our Solar System, and Jupiter was a stunning sight at magnitude -1.7 through the

Celestron CPC 800 GPS during the small hours of the morning. Using the 40mm eyepiece, the gas giant appeared as a small but crystal-clear disc, with its Galilean moons – Io, Europa, Ganymede and Callisto – showing up as points of light either side of its limbs. Allowing our eyes to adjust to the view of the planetary king, we could make out its atmospheri­c belts and bands clearly, while some of the gas planet’s cream-coloured zones shone a bright white. No colour fringing could be seen through the telescope’s optical system.

We waited until the following evening to catch Mars, which at the time could be found low in the southeast and in the constellat­ion of Ophiuchus

(the Serpent Bearer). The Red Planet was glowing at magnitude +1.6.

Locating the planet with the CPC 800 GPS’ database was nothing short of a breeze, and within seconds it appeared at the centre of our field of view as an orange disc. Valles Marineris, the canyon system that stretches across Mars’ equator, could be seen as a dark ‘shadow’. This is an impressive sight for all levels of sky-watcher, whether you’re a beginner or more seasoned observer.

While the CPC 800 GPS is considered to be an expensive piece of kit, we have to say that given the instrument’s build, operation and the revolution­ary technology offered, it is worth every penny.

It’s built to last, offers a reliable computeris­ed mount and is a great investment for those hunting for an upgrade. The CPC 800 GPS is an all-rounder for visual observing and astrophoto­graphy. The only minor downsides are the telescope’s weight and a slightly stiff focuser.

Views of both the Solar System and deep-sky objects are exceedingl­y sharp and clear, with the optical system displaying no signs of distortion. As with all telescopes, we recommend furnishing the CPC 800 GPS with further accessorie­s to get the very best out of it – views become even more pleasing the more sky-watchers experiment with magnificat­ions and filters.

 ??  ?? Left: Both aligning the telescope and finding objects to observe are made so simple
Left: Both aligning the telescope and finding objects to observe are made so simple
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Although the set-up looks complex, it’s very easy to use, and detailed instructio­ns are included
Right: Although the set-up looks complex, it’s very easy to use, and detailed instructio­ns are included
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Controls are simple, with a variety of connection­s for external devices
Below: Controls are simple, with a variety of connection­s for external devices

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