Celestron CPC 1100 GPS (XLT) Computerized Telescope

11" Schmidt-Cassegrain Optics: 0.42 Arc Second Resolution

The 11" optics use a zero power corrector plate, a spherical primary mirror and a secondary mirror in a 610mm (24") tube 312.42mm (12.3") in diameter. Light gathering power is 1593x the human eye, the limiting stellar magnitude is 14.7, and the resolution is 0.42 arc seconds (Dawes) and 0.5 arc seconds (Rayleigh). The highest useful magnification is 660x and the lowest 40x.

• StarBright XLT Coatings: 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.
• Primary Mirror Focusing: The focus knob moves the primary mirror along the primary baffle tube; it takes about 30 turns to go from close focus to infinity. For critical astronomical focusing, turning the knob counter-clockwise moves the mirror against gravity, minimizing mirror shift.
• Secondary Obstruction: The secondary mirror obstructs 34% of the aperture by diameter and 12% by area.

Dual Fork Arm Mount: 5°/Second Slews with DC Servo Motors

The fully computerized dual fork arm altazimuth mount and the tube weigh 65 lbs together. DC servo motors drive both axes, and the manual lists fully enclosed optical encoders for position location among the CPC's standard features.

The dual-axis clutch system lets you move the telescope by hand even when it is not powered on, but both clutches must be tightened for GoTo use, and any manual movement invalidates the alignment. Leave both clutches somewhat loose when transporting, to reduce the load on the worm gear assemblies.

Nine slew speeds run from 0.5x sidereal, for accurate centering and photographic guiding, up to 5° per second, and the mount tracks at sidereal, solar and lunar rates in altazimuth, EQ North and EQ South modes.

Internal 16-Channel GPS and SkyAlign

The CPC's internal 16-channel GPS links with the orbiting satellites, works out the telescope's location to within a few meters and the time to the second, and enters them for you, so there is no need to enter the date, time, longitude and latitude or even know the name of a single star. SkyAlign, used with the telescope in altazimuth, then asks you to center any three bright celestial objects, including a planet or the Moon; the hand control has over 80 bright alignment stars down to magnitude 2.5. Auto Two-Star, Two-Star, Solar System, EQ North and EQ South alignments are also available.

GPS alignment only works outdoors with an unobstructed view of the sky. The first time, the CPC may take 3 to 5 minutes to link with its satellites; leave it powered on for at least 20 minutes so it downloads the satellites' orbital almanac, which it stores for future alignments. After moving a long distance, linking can take up to an hour.

NexStar+ Hand Control: A 40,000+ Object Database

The CPC 1100 is commanded by the NexStar+ hand control, which has a two-line backlit display and a database of 40,000+ objects; the database includes customized lists of the best deep-sky objects, planets and bright double stars. Beginners can start with the built-in Sky Tour, which finds the most interesting objects in the sky for the current date and time and slews to each one.

The drive base has a hand control port, AUX ports, a PC interface port, an autoguider port, the on/off switch and a 12V input jack. The NexStar+ hand control's USB 2.0 port connects a PC, and Celestron includes Starry Night Special Edition and the SkyPortal app.

Weights and the 2" Steel Tripod

The kit weighs 84 lbs and breaks down into the 65 lb tube and fork mount and the 19 lb tripod. An ergonomic design lets you comfortably lift and move the telescope; carry it by the lower part of the fork arm on the hand control side and by the handle on the opposite side.

Celestron's newly designed heavy-duty tripod has sturdy 2" (50.8mm) stainless steel legs and makes attaching the telescope so easy you can do it in the dark.

The tripod's leg support bracket doubles as the accessory tray and is tightened against the legs with a tension knob, which increases stability and reduces vibration and flexure. The telescope base drops over the positioning pin on the tripod head, its three feet sit in the recesses on the head, and the three attached mounting bolts thread up from underneath. The tripod is less stable the higher it is extended; set it low for photography.

Visual Observing with the Included 40mm Plössl Eyepiece

The CPC 1100 kit includes a 40mm Plössl eyepiece, a 1.25" star diagonal, and a 9x50 finderscope to get you observing right out of the box. The 40mm eyepiece gives 70x (2800mm / 40mm).

The star diagonal gives a more comfortable viewing position for objects high in the sky, and the 9x50 finderscope in its quick release bracket helps you find objects accurately and center the SkyAlign objects.

Astrophotography: Alt-Az Tracking and the Optional Wedge

The CPC suits short-exposure prime focus photography of the Moon and planets. The CPC tracks precisely in altazimuth, but long-exposure astrophotography needs the fork arm aligned with the Earth's axis, which requires an optional equatorial wedge between the telescope and the tripod. Without it, stars slowly rotate around the center of the field; this goes unnoticed in the eyepiece but is very noticeable when imaging. On the wedge, EQ North and EQ South alignments and the Align Wedge routine help you polar align with the wedge's latitude and azimuth adjustments.

Periodic Error Correction reduces the amplitude of the worm gear errors to improve photographic quality, and is meant for advanced astrophotography with the telescope polar aligned on the optional wedge. Even with PEC, off-axis guiding is still mandatory for long-exposure deep-sky astrophotography; for filtered solar, lunar and piggyback photography up to 200mm, PEC can make unguided photography possible. The drive base has an autoguider port. Celestron's optional Reducer/Corrector reduces the focal length by 37%, making the 11" a 1764mm f/6.3 instrument.