Celestron NexStar Evolution 8 Telescope

8" Schmidt-Cassegrain Optics: 0.57 Arc Second Resolution with StarBright XLT

The 2032mm focal length gives f/10, with a limiting stellar magnitude of 14, a Rayleigh resolution of 0.69 arc seconds and a highest useful magnification of 480x. The 432mm (17") aluminum tube is 238mm (9.37") in diameter, weighs 12.5 lbs and attaches by a CG-5 dovetail bar.

Focusing moves the primary mirror, which slides on the primary baffle tube; the focus knob sits on the rear cell just below the star diagonal, and it takes about 30 turns to go from close focus to infinity. Make the final focus turn counterclockwise so the mirror moves against gravity, which minimizes any mirror shift, and start on a bright object such as the Moon or a planet, since out-of-focus stars are very diffuse.

StarBright XLT is Celestron's coating system, built from three parts: enhanced multi-layer mirror coatings of aluminum, SiO2 and TiO2, with reflectivity fairly flat across the spectrum for both imaging and visual use; multi-layer anti-reflective coatings of magnesium fluoride and hafnium dioxide; and water white glass instead of soda lime glass for the corrector. Water white glass transmits about 90.5% of light uncoated, 3.5% more than soda lime glass, and reaches an average transmission of 97.4% with the StarBright XLT anti-reflective coatings.

The secondary obstruction is 64mm (2.5"), 31% by diameter and 9.77% by area.

Integrated WiFi: Wireless GoTo Control with the SkyPortal App

The NexStar Evolution is the first Schmidt-Cassegrain with integrated WiFi. The telescope broadcasts its own "SkyQLink" network: connect your iOS or Android device to it, open the SkyPortal app and slew with a tap, using the planetarium view or a list of objects currently visible. SkyAlign is built into the app: you center and align any three bright stars, with no GPS or site information needed, and SkyPortal's mount modeling accepts up to 10 additional alignment stars for better GoTo accuracy. A WiFi switch selects Direct Connect, to your device, or Access Point mode, through your home router.

In areas with heavy WiFi traffic, such as large star parties, try a site with less traffic, disabling WiFi on nearby devices, "forgetting" telescope networks on devices not in use, or using the included NexStar+ hand control instead.

Internal LiFePO4 Battery: Up to 10 Hours

The built-in 9.6V, 4.5Ah lithium iron phosphate (LiFePO4) battery is a first on a consumer telescope, and runs up to 10 hours on a single charge. It has protection against overcharging, overdischarging and overheating, and it should last thousands of charge cycles with reasonable care. Charge it fully when you receive the telescope, use only the included power supply or a certified 12VDC supply of at least 2 amps, do not leave it discharged or low for long, and charge it every 3 to 6 months. An intelligent power management system goes into power-saving mode when the battery is low.

The power input takes 12VDC, tip positive, up to 5.0A; the included supply gives 12VDC at 2.0A, with USA, EU, UK and AU plugs. The USB charge port supplies 5V at up to 2.0A to top off your phone or tablet; in Automatic mode it switches off when the battery is low, or it can be set to Always On.

25 lb Capacity Mount with Brass Worm Gears

The mount carries a 25 lb (11 kg) instrument load. The single fork arm mount uses brass worm gears with ball bearings driving stainless steel worm wheels of 146mm diameter with 180 teeth, with improved DC servo motors. It slews at 9 speeds up to 4° per second and tracks at sidereal, solar and lunar rates in Alt-Az, EQ North and EQ South modes; the EQ modes need a wedge.

Manual clutches in altitude and azimuth let you point the telescope by hand when it is powered off. Do not unlock the clutches once the telescope is aligned with the app or hand control, or the alignment is lost and you must align again.

The mount head weighs 16 lbs and the tripod 12 lbs, for a kit weight of 40.5 lbs.

Ergonomic Design: NexStar+ Hand Control and a 1.5" Steel Tripod

A NexStar+ hand control is included but not needed with the app. It plugs into any of the 4 AUX ports, 2 on top of the fork and 2 on the bottom, which also accept StarSense AutoAlign and other accessories, and its menus control the logo and tray lighting, battery status, external power and USB charge port settings. Celestron also includes Starry Night Special Edition.

The tripod has 38.1mm (1.5") stainless steel legs; with the mount, the height range is 1193.8mm to 1752.6mm (47" to 69"). Large ergonomic handles make setup quick. The all-metal tripod's metal accessory tray has indentations for storage and can stay attached when the tripod is folded; leg index marks and a built-in bubble level help you set a level, uniform height. Two accessory trays on the mount store up to 7 eyepieces, one with an adjustable red LED illuminator.

Visual & Astrophotography: From 51x and 156x to DSLR Imaging

Out of the box, the NexStar Evolution 8 is ready for serious visual exploration. The included 40mm Plössl eyepiece gives 51x and the 13mm Plössl 156x (2032mm divided by each focal length). A 1.25" star diagonal and the StarPointer red dot finder are included.

The 8-inch Evolution is an excellent way to get started in astroimaging, and its tracking accuracy lets you capture images of deep-sky objects like the Orion Nebula by simply attaching your DSLR camera.

As you progress, the Celestron HD Pro Wedge allows longer exposures; the Evolution works with the wedge when used with the CPC tripod, both sold separately. Polar aligned on the wedge, the EQ North or EQ South alignment makes the telescope track equatorially, moving in one direction so the object stays centered without rotating, which is suitable for astroimaging. There is no autoguide port and no periodic error correction.