Category Archives: Celestron

Celestron COSMOS 90GT WiFi Telescope Specifications

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Celestron Cosmos 90GT WiFi Telescope is a modern telescope designed for ease of use.  This is actually the first telescope equipped with its own WiFi network.

Celestron COSMOS 90GT WiFi Telescope Specifications

Celestron COSMOS 90GT WiFi Telescope
Celestron COSMOS 90GT
ModelsCelestron COSMOS 90GT
Celestron COSMOS 90GT
View the model availability and current price from AmazonCelestron COSMOS 90GT WiFi Telescope
Specifications & Features
Optical DesignRefractor
Aperture (mm)90 mm (3.54 in)
Focal Length910 mm (36 in)
Focal Ratio10.1
Focal Length of Eyepiece 1 (mm)25 mm (0.98 in)
Magnification of Eyepiece 136 x
Focal Length of Eyepiece 2 (mm)10 mm (0.39 in)
Magnification of Eyepiece 291 x
Star Diagonal1.25"
Mount TypeSingle Fork Arm Altazimuth
Accessory TrayIncludes rubberized smartphone or tablet holder
Highest Useful Magnification213 x
Lowest Useful Magnification13 x
Limiting Stellar Magnitude12.3
Resolution (Rayleigh)1.54 arc seconds arc seconds
Resolution (Dawes)1.29 arc seconds arc seconds
Light Gathering Power (Compared to human eye)165 x
Optical CoatingsFully Coated
Optical Tube Length37.2 in/94.5 cm in (945 mm)
Total Telescope Kit Weight14.2 lbs (6.44 kg)
Slew SpeedsUp to 3 deg/second
Tracking RatesSidereal, Solar, and Lunar
Alignment ProceduresSkyAlign, 3-Star Align, Solar System Align
Communication PortsAux port for optional hand control
DatabaseOver 120,000 objects including 220 of the best deep sky and solar system objects
Warranty2-year Telescope Warranty
TechnologyFlash Upgradeable


SkyAlign Technology
Download ManualsCosmos 90GT WiFi Telescope Manual
Official Specs and Features
Learn more from the manufacturer site.Read more about Celestron COSMOS 90GT WiFi Telescope at
Amazon Customer Reviews
Read all the reviews inclusive of the most helpful favorable review and the most helpful critical review (if available)Click here to read the reviews on Celestron COSMOS 90GT WiFi Telescope
Where To Buy
View the model availability and current price from AmazonClick on this link Celestron COSMOS 90GT WiFi Telescope


All telescopes basically work in the same way; they accumulate lights so that you can see and magnify objects being observed. The object can be a star, the moon, another planet, a tree, a leaf, a person, and anything.

The main difference between telescopes lies in the way they work. A beginner telescope commonly does not need difficult maintenance, but it does what it sets out to do.

Celestron Cosmos 90GT WiFi Telescope is designed to work only with a connected smart device including smartphone or tablet running iOS or Android.

Almost all controls are done via a smartphone with the help of Cosmos Navigator App which is available for free from App Store and Play Store.

Because the telescope creates its own WiFi, you don’t need any network connectivity or router to pair your smartphone to the telescope.

You move the telescope directions via the COSMOS Celestron Navigator mobile app. This mobile app replaces the traditional telescope hand control for a 100% wireless experience.

Once you download and open the app, you can connect directly to the telescope’s WiFi. The app provides some onscreen buttons to move the telescope, as if your smartphone or tablet is a remote control.

A simpler way is to use the GoTo option and choose any object listed on the app. Based on your position and time, the app will automatically list all objects available to observe.

A tap on one of the objects will move the telescope so that the object will be in the center of the eyepiece. The app also gives additional information on the object being observed.

There is a search function on the app for you to manually enter an object name; you can type the name of planet, Orion nebula, etc.


Cosmos 90GT WiFi has a refractor optical design with 90mm aperture and 910mm focal length. The package includes two eyepieces; a 25mm to give 36X magnification and another is 10mm for 91X magnification.

It has a single arm fork mount with Vixen-style dovetail. This is the part that contains the integrated WiFi, power connector, and an auxiliary port designed to connect to NexStar handset controller (sold separately). This handset can replace your smartphone to control the telescope if necessary.

Cosmos 90GT features a StarPointer with variable brightness switch, height-adjustable aluminum tripod, and accessory tray to store the additional two eyepieces and your smart device.

This telescope comes with SkyAlign technology for quicker alignment. It does not have GPS so you will need to manually enter time, day, and location. Cosmos Navigator app also takes advantage of the phone’s camera and compass to determine your location. Cosmos GT90 WiFi is powered by using either a Celestron PowerTank, 8X AA batteries, or a 12V DC source.


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