Sky-Watcher 180mm f/15 Maksutov-Cassegrain Telescope (OTA Only)

BH #SK180MMMCOTA • MFR #S11540
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Sky-Watcher 180mm f/15 Maksutov-Cassegrain Telescope (OTA Only)
Key Features
  • 180mm Aperture Maksutov-Cassegrain OTA
  • 2700mm Focal Length, f/15 Focal Ratio
  • Limited-Diffraction Optical System
  • Antireflection Fully Multicoated Glass
With the largest aperture in the series, the Sky-Watcher 180mm f/15 Maksutov-Cassegrain Telescope is a powerful astronomical tool that remains manageable and portable. The Maksutov design exchanges the conventional front corrector plate of a Schmidt with a convex meniscus lens, resulting in a smaller secondary mirror that limits obstruction and increases contrast, while eliminating the need for periodic collimation. This modified optical path results in a slower focal ratio and narrower field of view versus a similar Schmidt, but the optical benefits, when coupled with the larger aperture and fully multicoated optics, make this an ideal scope for making detailed solar, lunar, and planetary observations, while being able to resolve deep-sky objects like stars, clusters, galaxies, and nebulae.
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Sky-Watcher S11540 Overview

With the largest aperture in the series, the Sky-Watcher 180mm f/15 Maksutov-Cassegrain Telescope is a powerful astronomical tool that remains manageable and portable. The Maksutov design exchanges the conventional front corrector plate of a Schmidt with a convex meniscus lens, resulting in a smaller secondary mirror that limits obstruction and increases contrast, while eliminating the need for periodic collimation. This modified optical path results in a slower focal ratio and narrower field of view versus a similar Schmidt, but the optical benefits, when coupled with the larger aperture and fully multicoated optics, make this an ideal scope for making detailed solar, lunar, and planetary observations, while being able to resolve deep-sky objects like stars, clusters, galaxies, and nebulae.

The scope is outfitted with a large 2" visual back. To get users started, Sky-Watcher includes a 28mm long eye relief eyepiece that produces 96x magnification and a 90° star diagonal for viewing with the optical tube assembly (OTA) pointed at or near the celestial zenith. The OTA is offered here without a mount or tripod for users who have a reliable support system or want to use it as part of a dual-OTA setup for star parties or observation/imaging rigs. It is outfitted with a Vixen-style dovetail plate for use with compatible mounts. This OTA's compact form factor belies its observation power and resolution and is ideally suited as a grab-and-go option for quick observation sessions or heading out to remote locations.

Optical Performance
  • 180mm aperture
  • f/15 focal ratio
  • 2700mm focal length
  • Front convex meniscus lens corrects spherical and chromatic aberrations as well as comas (off-axis aberrations) across the entire field of view
  • Smaller secondary mirror versus Schmidt-Cassegrains reduces obstructions and increases contrast
  • Fully multicoated optics maximize light transmission to improve brightness, color rendition, sharpness, and contrast
  • Resolution: 0.64 arcsec
  • Internal primary mirror focus
  • 2" diameter visual back accepts larger eyepieces and accessories
Mounting
  • Requires mount and tripod for proper use
  • Vixen-style dovetail plate
  • Weight: 19 pounds including OTA, dovetail plate, finder, diagonal, and eyepiece
Included Accessories
Eyepiece:

  • 2" barrel diameter
  • Accepts most 2" astronomical filters
  • 28mm eyepiece yields 96x power
  • Comfortable long eye relief

Diagonal:

  • 2" snout and eyepiece holder
  • 90° angle places head in a comfortable viewing position
  • Star configuration corrects image horizontally for terrestrial use

Finderscope:

  • Relatively low 8x magnification provides a wide field of view for easier alignment and faster star-hopping navigation
  • 50mm aperture helps resolve dimmer objects that dot finders cannot
UPC: 050234115407

Sky-Watcher S11540 Specs

Key Specs
Aperture
7" / 180 mm
Focal Length
2700 mm
Focal Ratio
f/15
Eyepiece
Yes, Removeable: 2" Diameter with 90° Star Diagonal
Optical Design
Maksutov Cassegrain
Aperture
7" / 180 mm
Focal Length
2700 mm
Focal Ratio
f/15
Eyepiece
Yes, Removeable: 2" Diameter with 90° Star Diagonal
Finderscope
Yes (8 x 50)
Mounting
Vixen Style, Dovetail
General
Weight
19 lb / 8.6 kg
Packaging Info
Package Weight
22.8 lb
Box Dimensions (LxWxH)
30 x 13 x 11"

Sky-Watcher S11540 Reviews

Best online astronomy company

By Mary
Rated 5 out of 5
Date: 2025-10-16

B&H sells many things, but for astronomy I find them to be the best overall. It starts with their prices- I purchased the 180 Mak for $250 less than any other store. It shipped immediately and their online and phone Customer Service was so prompt as to be almost immediate. Granted, the CS team does not have the technical knowledge astronomy retailers have, but they were otherwise very helpful..

Excellent Maksutov

By Jeremy
Rated 5 out of 5
Date: 2024-02-03

I’ve wanted one of these for quite some time, and am glad I finally pushed the purchase button. The scope is well made. The optics are sharp and contrasty; what one would expect from a good MCT. The collimation seems to be very good, if not just slightly off. I added a third-party dual-speed focuser for imaging, and the focus accuracy was much improved. I’m not fond of the mounting plate being attached to the optical tube. It’s not a light scope, so rings and a handle would make handling way easier. Overall, I’m happy with it. The attached moon image was taken at prime focus with an APS-C sensor to give a reference to the magnification at a roughly 4300mm focal length with the cropped sensor. MCT’s aren’t usually used for deep sky objects, but I wanted to see what it was capable of. So, I imaged the Orion Nebula with a narrowband filter for approximately two hours at 30 sec. subs. I didn’t want to blow out the core, so I pushed the levels and curves just a little to get this image of Orion’s stellar nursery.

See any errors on this page?

question

what is the actual size of the central obstruction INCLUDING the baffle?
Asked by: itzchak m.
With secondary baffle, the obstruction is about 30% by diameter.
Answered by: Peter
Date published: 2025-01-13

What are some good goto mounts / tripods for this ...

What are some good goto mounts / tripods for this telescope?
Asked by: Jeff
That Celestron 93607 is not nearly sturdy enough for this telescope. The rated capacity is only half the weight of the scope.
Answered by: David
Date published: 2022-12-31

question

Do you sell a focal reducer that would be suitable for this telescope, the 7 inch Maksutov f/15, or do you know of one?
Asked by: William K.
The Celestron f/6.3 Reducer/Corrector will be compatible with this scope. Website link: http://bhpho.to/1JT4a4N
Answered by: Alex S.
Date published: 2025-07-15
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