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

BH #SK180MMMCOTA • MFR #S11540
Sky-Watcher
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
  • Anti-Reflection Fully Multi-Coated 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 multi-coated 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.
More on the Way
Expected availability: 2-4 weeks
$1,500.00
$125/mo. suggested payments for 12 Mos.
with the credit card.§ 
or Save the Tax with the credit card. 

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Sky-Watcher S11540 Overview

  • 1Description
  • 2Optical Performance
  • 3Mounting
  • 4Included Accessories

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 multi-coated 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 multi-coated 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

Optical DesignMaksutov-Cassegrain
Aperture180mm
Focal Length2700mm
Focal Ratiof/15
Eyepiece Barrel Diameter2"
Diagonal90° star
2" snout and eyepiece holder
Finderscope8 x 50 straight view
TripodNone
Mount TypeVixen-style dovetail plate
Power SourceN/A
Optical Tube DimensionsNot specified by manufacturer
Weight19.0 lb / 8.6 kg
Packaging Info
Package Weight22.8 lb
Box Dimensions (LxWxH)30 x 13 x 11"

Sky-Watcher S11540 Reviews

Optics Great - Mechanics not so Much

By Peter
Rated 4 out of 5
Date: 2019-12-18

You buy a scope like this to look at planets, double stars, and the moon. The star test is both even (a surprise with this design) and very smooth. A side benefit is the extra light gathering power for looking at deepsky objects. I came to this from a 120mm ED refractor. It does outperform the refractor, and if you insulate with Reflectix, or something similar, this becomes a set-up and go scope that never causes problems. Like a refractor, you may never need to collimate this thing. Weaknesses include fair focusing. There is mirror image shift, just like an SCT, and the focus is a bit coarse above 200x. Overall construction is adequate, but this is a mid level scope so don't expect superb machining. The included extras range from decent (the 28mm LET eyepiece), to adequate (the finder) to pretty bad (the diagonal). Planetary views are superb if you have the skies for it. The field of view is somewhat limited due to the f15 optical system. A 40mm, wide angle eyepiece will yield .9 degrees total field, but you will see vignetting toward the edge of the field. It wide enough for the Double Cluster, but not the Pleiades. Like most hobbyists, I did a bit of tweaking. I had a spare, right angle finder. I use a Takahashi 1.25 prism diagonal for critical work, and a GSO 2 diagonal (sold under the iOptron label here) for deepsky work. Above all I added a two speed, external SCT focuser to ease focusing. Again, GSO makes a very good, fairly cheap one.

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YOUR RECENTLY VIEWED ITEMS

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: 2019-12-18

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: 2020-09-25
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