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Model: c8xltota-1Part Number: 91020-XLTBrand: Celestron
Celestron products include a two year warranty except binoculars and spotting scopes which have limited lifetime warranties.
Celestron's C8 has been a best-selling optical system for decades with a reputation for optical excellence, lightweight portability and great value.
This OTA is fitted with a CG5 / Vixen / Sky-Watcher style dovetail.
Optical Design : Schmidt-CassegrainAperture : 203.2 mm (8 in)Focal Length : 2032 mm (80 in)Focal Ratio : 10Finderscope : 6x30Optical Tube : AluminumEyepiece 1 : 25 mm (0.98 in)Magnification 1 : 81 xStar Diagonal : 1.25Optical Coatings : StarBright XLTSecondary Mirror Obstruction : 2.5 in (63.5 mm)Secondary Mirror Obstruction by Area : 9.8 %Secondary Mirror Obstruction by Diameter : 31.3 %Optical Tube Length : 17 in (431.8 mm)Optical Tube Weight : 12.5 lb (5.67 kg)
I had C8 for some time (around a year). It weights less than a 150/750 SW Newtonian, and is quite compact. I used it primarily for planetary/lunar imaging with DMK21 and DSI III Pro cameras (lunar and some deep sky). It's the most mobile big aperture scope ever made As you focus the primary mirror moves so for fine focusing in planetary/lunar imaging you need a motorised crayford or a crayford focuser with suitable focus motor. For deep sky imaging a Bahtinov mask will do (for planetary the planet is to big, but on Jupiter one of the moons will be ok). I used JMI motorised crayford and fine-focus with it using the live view from the camera (but you can't look on from a short distance - around 1m or less - more when you have bigger scale). Deep sky imaging - you will probably want the f/6.3 reducer. I use it with Celestron Radial Guider (OAG guider), BS Astro manual filter wheel (like Atik) and DSI III Pro camera. DMK21 was the guider. The scale at bin 1 is still very big, so efficient guiding is required (I used sub-second exposures and low-power corrections - PHD, HEQ5 SynScan).Cooling is rather quick. Can't provide any numbers, but 30-45 minutes were ok at summer, spring. In winter 1-1.5 hour would do I guess. I did not need a cooler.Eyepieces: Erfle based eyepieces work very nicely. They are economical wide-field eyepieces that when used with f/10 SCTs don't have any noticeable issues with field correction. William Optics SWAN eyepieces are similar.
Bob's Knobs Celestron C8 Metric Collimation KnobsFrom: £20.00
Celestron Off Axis Guider (OAG)£249.00
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