Sky-Watcher 0.9x Coma Corrector
 Sky-Watcher 0.9x Coma CorrectorSky-Watcher 0.9x Coma Corrector 

Sky-Watcher 0.9x Coma Corrector

  (3 Reviews)
✓ 2 year warranty


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About this product

Model:  sw_coma_corrector
Part Number:  20233

Suitable for use with Newtonian reflector telescopes with f-ratios f4-f6 but is optimised for the new Sky-Watcher Explorer DS f/5 telescopes with 2-inch focuser.

Acts as a 0.9x reducer so a f5 Newtonian becomes f4.5 and f4 becomes f3.6. 

For imaging with a DSLR camera a Sky-Watcher DSLR-M48 Ring Adapter is also required. 

Also includes adaptors for visual astronomy with 2" eyepieces. To use with 1.25" eyepieces you will need a suitable 2" to 1.25" adaptor.

Threaded for 2" filters.

Requires 55mm back focus.

Customer reviews

Average Rating (3 Reviews):  
Write a Review and share your opinions!

Rating (max 5):  
Read this if you Have a 150Pds!
Wednesday, 3 June 2015  | 

Corrects the coma on my Explorer 150Pds almost perfectly across the field of view of my Canon 450D.
I was however disappointed to find that because it also acts as .9x reducer the focuser has to be wound in so there's only 7mm of inward travel left. The problem with this is that the inside edge of the focus tube protrudes in front of the primary mirror causing images of bright stars to have bite marks in them and all stars are slightly D shaped. This would be forgivable if it was made by anyone other than Skywatcher but because the 150Pds is one of the scopes this CC is specifically designed for I find it very poor.
The problem can be fixed by cutting the inside end of the focus tube to make it shorter but this does mean its possible to wind the focuser too far out so that it comes off its mounting wheels.

Rating (max 5):  
Good Round Stars All the Way to the Corners
Monday, 23 February 2015  | 

Using this CC with a Skywatcher 130PDS mounted on an EQ6 AZ GT. My camera is a modded Canon 100D DSLR.

So very good. All sharp pinpoints all the way out to the corners.

Nothing more to add. What it says on the tin.

Rating (max 5):  
Perfect accessory!
Wednesday, 21 August 2013  | 

I bought this coma corrector for use with my Skywatcher Explorer 150PDS. It does exactly what it advertises and does so well above its price. This coma corrector gave me perfectly coma-free images on my large ATIK 383L+'s CCD sensor, with no internal reflections produced. I have zero complaints and would happily buy again.

Please do remember that if using this with a CCD camera like myself, you will need to have 55mm (+/- about 2mm) of spacing between the bottom of the 2" thread and the CCD sensor. This is easily achieved with a combination of spacers. If imaging with a DSLR however, the Skywatcher DSLR adapter will automatically take care of the required 55mm spacing.


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