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Orion Telescopes
Orion 50" Monster Dobsonian Telescope
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  • Monstrous 50" aperture parabolic primary mirror - forget limiting yourself to the NGC catalog: The Orion 50 opens the door to anonymous galaxies previously unseen by the human eye!
  • Premium, hand-figured optics - each Monster Dobsonian mirror is hand figured by master optician Normand Fullum and will match or beat any commercial mirror on the planet
  • Low-expansion borosilicate glass, molded honeycomb mirror blank, 36-point flotation mirror support and five cooling fans assure you get all the performance the enormous aperture can deliver
  • Fast f/3.75 focal ratio gives bright images, and 187.5" of focal length - great for hunting faint galaxies and small planetary nebulae - or anything else up there!
  • Full tracking and GoTo capability mean you can study objects in detail, even at high power - spend your time observing, not locating objects

Learn more
Item #  09162

Orion is a world leader in Dobsonian telescopes. No one offers a bigger selection of Dobsonian telescopes. At Orion we?ve known that bigger is better and have wanted to take the art of Dobsonian telescope making to new limits. That?s why we?re proud to introduce the new Orion 50" Dobsonian, a Monster Dob in a class by itself. The Orion 50" Dobsonian is larger than even the largest of the telescopes ever used by the Herschel?s (arguably the greatest visual observers of all time) and as of release, is the largest production telescope for amateur astronomers in the known universe.

The Orion 50" Dob is the bigger brother of the Orion 36 and 40 inch Monster Dobsonians and is the biggest amateur telescope in the world. We know of three 48" scopes used by amateurs to explore the night sky. Some larger professional observatory telescopes are occasionally open to the public, but access is limited and viewing is usually restricted to a few "showcase" objects. If your passion is the deep-sky and you want the biggest Dob at the star party, this Monster Dobsonian makes everything else look puny.

Monster Dob Chart

Fifty inches of aperture. Almost 2000 square inches of light-gathering power. That?s almost 33,000 times more light than what your eye can gather (assuming a dark adapted 7mm pupil). That?s almost double the light the Orion 36" Dob will capture; four times what a 25" telescope can collect, or 16 times what a 12.5" gathers! This monstrous light grasp lets you capture some seriously faint objects and bring out the details other observers have only seen in photographs. With a limiting stellar magnitude that is approximately +17.4 and a theoretical resolving power under a tenth of an arc second (seeing conditions limited, of course) you are going to be catching details in the ?faint-fuzzies? up there that no one else can.

The telescope is designed to be light for its size and very stiff ? so that collimation is maintained as you sweep across the sky. The top cage is aluminum with carbon graphite spacers between the top and bottom rings. The main struts are also carbon graphite with Moonlite connectors for easy disassembly, should you want to transport this beast. The side bearings, rocker box and ground board are constructed of an engineered composite of Russian birch with aircraft-grade aluminum epoxy bonded to both sides of the birch core, making exceptionally strong but surprisingly light structural components.

Premium components and exceptional attention to detail are used throughout the construction of this monster, including all stainless steel fasteners, a Moonlite dual-speed, fine adjustment 2" focuser and custom secondary cage light baffle. ServoCAT tracking/slewing system and Argo-Navis digital setting circles, with docking station for the hand control give the telescope complete GoTo capability. The drive and navigation system will interface with most popular planetarium programs on your PC to give you robotic control over your night?s observing. An Orion 12-volt power pack is standard for field operation.

The Orion 50" Dobsonian is the ultimate adventure in astronomy for serious deep-sky observers. You can literally go where no man or woman has gone before. Premium optics, quality construction, complete GoTo functionality and massive light gathering power. Only one element of the optical system ? eyepieces ? are not included, because Orion assumes the owners of these telescopes will have their own collection of favorite eyepieces.

Orion supplies the light. You supply the wonder and awe you?ll feel when you see the universe in a way nobody else can!


This telescope is designed for visual use, but photography would be possible with the addition of a field de-rotator and auto-guiding solutions (not included).

Don?t point a Monster Dob at the sun! Just pointing this at the sun can instantly damage eyepieces and cause irreversible eye damage and burns. Use extreme caution leaving it uncovered during daylight. Concentrated sunlight from this much aperture can damage the telescope or set its surroundings on fire!

Moonlite, Argo-Navis, and StellarCAT are trademarks or their respective companies.

Digital electronics are FCC Class B, CE Class B certified and fully RoHS compliant.

Ordering Information:
Due to the exclusive nature of these telescopes, a purchase contract is required and will be supplied by an Orion Sales Representative that will be your personal contact throughout the sales, building, delivery, installation and use of your custom-built telescope. Once your order is received you will be contacted by your Orion representative.

A 75% down payment will be required to place your order. Although a credit card number is taken at the time you enter your order information online, your credit card is not charged. A wire transfer of the deposit will be required prior to beginning to build your telescope. Final payment by wire transfer will be required prior to shipping.

The estimated expected shipping date is displayed, but this is only an estimate. As this is a custom built product the actual shipping date may vary.

This product will ship directly from the North American factory. Shipping is arranged by Orion, usually by air freight and in consultation with the customer. The Customer is responsible for all shipping, insurance, brokerage fees, duties and taxes.

The customer is also responsible for arranging for needed material handling equipment at the delivery site (for example, the crated 50" mirror will weigh about 500 lbs ? you?ll want a forklift or a whole bunch of friends!).

Some customization options and installation services are available at an additional expense. Your personal Orion Sales Representative can provide additional information.


Limited Warranty against defects in materials or workmanship for one year from date of purchase. This warranty is for the benefit of the original retail purchaser only. For complete warranty details contact us at 800-676-1343.


Please note this product was not designed or intended by the manufacturer for use by a child 12 years of age or younger.

  • Best for viewing
    Fainter deep sky
  • Best for imaging
    Lunar & planetary
  • User level
  • Optical design
  • Optical diameter
  • Focal length
  • Focal ratio
  • Optics type
  • Glass material
    Low thermal expansion borosilicate glass
  • Resolving power
  • Lowest useful magnification
  • Highest useful magnification
  • Highest theoretical magnification
  • Limiting stellar magnitude
  • Optical quality
    Diffraction limited
  • Finder scope
    Reflex sight
  • Focuser
    2" dual-speed Crayford
  • Secondary mirror obstruction
  • Secondary mirror obstruction by diameter
  • Secondary mirror obstruction by area
  • Mirror coatings/over-coatings
    Enhanced Aluminum & Silicon Dioxide
  • Mount type
  • Astro-imaging capability
    Simple moon shots
  • Motor drive compatibility
    Clock drive included
  • Computerized compatibility
    Go-To included
  • Alignment procedure
    2-star alignment
  • Number of objects in database
  • Tracking rates
  • Bearing material
    Ebony Star/PTFE
  • Power requirement
    12-volt DC (tip positive)
  • Setting circles
    Electronic, via the hand controller
  • Available ports
  • Tube material
    Carbon graphite
  • Tripod material
    17-layer Russian Birch & aluminum bonded composite
  • Length of optical tube
    172.0 in.
  • Weight, fully assembled
    900.0 lbs.
  • Additional included accessories
    5 cooling accelerator fans, Argo-Navis digital setting circles
  • Other features
    36 point floatation mirror cell, Carbon fiber struts, Engineered honeycomb primary mirror
  • Warranty
    One year

Orion 50 f/3.75 Truss-Tube GoTo Dobsonian Telescope w/parabolic primary mirror made of low-expansion borosilicate glass
Premium hand-figured optics by Normand Fullum
36-point flotation primary mirror cell with collimation adjustments
Secondary mirror features spring loaded collimation adjustments
6 carbon graphite collapsible truss tubes with Moonlite(TM)* truss-tube connections
Dual-Speed 2" Moonlite(TM)* Crayford focuser w/1.25" telescope eyepiece adapter and adjustable focusing tension
Orion EZ Finder Deluxe Telescope Reflex Sight
Unique low-mass/high rigidity compact Dobsonian mount fabricated from CNC machined, 17-layer Russian Birch & aluminum plate epoxy bonded composite material
Ebony Star and UHMW bearings
Argo-Navis(TM)* electronic setting circles with over 29,000 astronomical objects in the on-board database
ServoCAT(TM)* tracking and GoTo system; can be controlled from most popular planetarium programs for robotic telescope control
5 cooling accelerator fans located in mirror box
Collapsible secondary cage light shield
Lens/dust cap
Orion Dynamo Pro 12V Rechargable Power Station
Starry Night Special Edition software

When an item is not in-stock we will ship it as soon as it becomes available. Typically in-stock items will ship first and backordered items will follow as soon as they are available.


This product is available to ship Standard delivery within the 50 US states, APO/DPO/FPO addresses and US territories/protectorates. Delivery is not available to Canada.

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