Celestron Nexstar 8SE Computerized Telescope

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

The 8SE traces back to the classic Celestron 8 and to founder Tom Johnson's method of producing Schmidt corrector plates. The tube is 432mm (17") long and 232mm (9.1") in diameter. 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 limiting stellar magnitude is 14 and the Rayleigh resolution 0.69 arc seconds. The secondary obstruction is 64mm (2.5"), 31% by diameter and 9.77% by area. The 8SE's full 8 inches of aperture shows Cassini's Division in Saturn's rings, the cloud bands on Jupiter and the Great Red Spot; beyond the solar system, hundreds of pinpoint stars in the Hercules Globular Cluster and the spiral arms of the Whirlpool Galaxy; and craters and geographic features on the Moon.

Single Fork Arm Mount: A 32 lb System in Three Pieces

The best telescope is the one you will use most often. Celestron's patented single fork arm mount is designed to be portable and quick to set up, and the NexStar SE breaks down into several lightweight, compact pieces that are easy to transport, even in small vehicles. Fully enclosed motors and optical encoders handle position location, and the NexStar+ hand control sits in the side of the fork arm.

The mount carries 12 lbs (5.44 kg), and the tube attaches with its CG-5 dovetail bar. It slews at up to 5° per second, one of 9 speeds, and tracks at sidereal, solar and lunar rates in Alt-Az mode, or in EQ North and EQ South modes on an optional equatorial wedge. Periodic Error Correction is not offered.

The tripod has 1.5" (38.1mm) stainless steel legs, and with the mount it adjusts from 965.2mm to 1422.4mm (38" to 56"). The tripod comes assembled; the accessory tray slides onto the center support rod and the leg brace locking knob presses its arms against the legs. The telescope base sits over the positioning pin, its 3 feet in the recesses of the tripod mounting plate, and the captive mounting bolts tighten from underneath. The included bubble level, placed on the mounting plate, helps level the tripod.

The NexStar SE runs on eight AA batteries (not included) in the compartment at the center of the base, or on 12V DC at 750 mA from an optional 12V AC adapter or one of Celestron's PowerTank power sources.

NexStar+ Hand Control: 40,000 Objects and SkyAlign

The NexStar+ hand control has a double line, 18 character LCD with 19 fiber optic backlit buttons. Its database holds 40,000 objects, 200 user defined programmable objects and enhanced information on over 200 objects.

SkyAlign makes alignment as easy as 1-2-3: center three bright objects in the eyepiece and press ALIGN. Beginners can take a Sky Tour, which finds the most interesting objects currently visible and slews to each one. Optional accessories include StarSense AutoAlign, which makes the NexStar SE align itself, and SkySync, which provides GPS coordinates. The hand control also offers 1-Star, 2-Star, Auto 2-Star and Solar System alignment, and EQ North and EQ South alignment with an equatorial wedge.

SkyQ Link also lets you control the telescope from an iPhone or iPad. The NexStar+ hand control's mini USB port (cable not included) links to a PC for telescope control and for firmware updates with Celestron Firmware Manager (CFM). Starry Night Special Edition and the SkyPortal app are included.

Imaging: Planetary, Autoguiding and Fastar/HyperStar Compatible

The NexStar SE is Fastar-compatible for ultra-fast, wide field imaging: an optional Fastar/HyperStar lens assembly, sold separately and not included, takes the place of the secondary mirror and turns the f/10 system into an f/2 system, which needs exposures about 25 times shorter. For planetary imaging, the 8SE pairs well with one of Celestron's NexImage cameras.

The 6SE and 8SE have a port labelled AutoGuide next to the AUX port, meant only for long-exposure astrophotography on the optional EQ wedge, with an autoguiding camera on a 6-pin ST-4 cable through an optional off-axis guider or guide scope. It is not wired like an AUX port: never plug anything but an ST-4 autoguider cable into it.