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  • SkyWatcher coma corrector for Newton telescopes up to f/4 SkyWatcher coma corrector for Newton telescopes up to f/4

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SkyWatcher coma corrector for Newton telescopes up to f/4


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Quick Overview

Coma is an effect that create a deformation of the image (the stars are stretched) to the edges of the imaged area and occurs in Newtonian telescopes especially in models with short focal length (the ones most used for astrophotography). This effect is most visible when the focal ratio of the instrument is short (eg f/4) and when using large sensors (such as those of DSLR cameras).

This coma corrector, inserted into the focuser in front of the camera, corrects the image and doesn't reduce the focal length of the telescope. This accessory is perfect for our NEWTON telescopes with shorter focal lenght (focal ratio between f/4 and f/5) but is also suitable for other manufacturers' equipment.

Availability: In stock in Italy headquarters

Excl. Tax
if you pay by bank transfer €280.66


This coma corrector is the perfect photographic accessory for all NEWTON reflectors with focal ratio lower than f/5 and it flatten the field with the cameras also with large sensors (up to Full Frame size 24x36mm). It fits in the 50.8mm focuser like a normal diagonal and it has, on the camera side, a M48 thread (male 48x0,75) for connection to the CCD cameras or DSLRs (with special M48 ring). On the telescope side it also provides a M48 thread for 50,8mm filters connection: thus you can add for example a filter for light pollution reduction.

This coma corrector, to work best, requires you to place the camera sensor at a precise distance from the back of the flattener thread.

- focal lenght up to 800mm: working distance 53,5mm
- focal lenght higher than 1000mm: working distance 55mm

For DSLR cameras, this distance is normally achieved by positioning (between the flattener and the camera body) a normal M48 ring. The CCD cameras instead have the sensor placed forward so if you want to connect them directly to this flattener will require an extension. In addition, most of the CCD cameras has a front thread T2 (42x0,75) then, to connect to this flattener, you will also need our "Adapter M48 female - T2 male" (which adds 8mm thickness). For example, since the CCD ATIK 428EX or 460EX have a back focus (distance between the sensor and T2 frontthread) of 13mm, if we have to achieve 55mm:

55mm - 13mm (CCD camera) - 8mm (M48-T2 adapter) = 34mm

So you'll need a 34mm extension to bring the sensor to the proper working distance from the coma corrector.

Technical specifications:
- does not decrease the focal length of the instrument
- 4 elementi optical design, one with FPL-51 glass
- 50.8mm external diameter
- M48 front thread to connect 50,8mm filters

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