Field flattener Starizona EvoFF v2 for SW EvoGuide 50ED

• Telescope side connection: 1.25" barrel with filter thread - suitable for 1.25" nebula filters.
• Camera side connection: T2 male thread - M42x0,75
• Working distance from T2 thread: 55 mm
• No extension factor, focal length of finder is fully maintained
• Illuminated and corrected field of view: 28 mm diameter, sufficient for APS-C
• Also well suited for other compact ED refractors and finder scopes, such as the TSSU1060ED 60 mm ED Finder
• New: The corrector is also suitable for use with DSLR cameras!

The field flattener is optimized for astrophotography with astrocameras and system cameras (both mirrorless and DSLR) through the Evoguide 50ED, other compact refractors and finder scopes also benefit. These compact telescopes have a highly curved field of view. As a result, off-center stars are distorted into streaks and the image becomes blurred. The EvoFF corrects this error and allows wide-field astrophotography with very good results. With a ZWO-ASI camera with APS-C sensor, the field of view is about 5.5°x3.7°!

Comparison with/without EVOFF (predecessor)

The two test images were taken with an astro ZWO ASI294 camera with 23.2 mm diagonal sensor. The imaging telescope was a Skywatcher EvoGuide 50ED refractor.

♦ On the left is the result without the EvoFF corrector. The stars are distorted to distinct lines.

♦ On the right is the result with EvoFF. The stars are sharp over the entire image field.

For which cameras is EvoFF v2 suitable?
The working distance of the field flattener on the Evoguide 50ED is 55 mm from the T2 thread, so the corrector of this new version is also suitable for DSLR cameras. For use on refractors with longer focal lengths, the distance would have to be reduced.

for which telescopes is the EvoFF v2 suitable?
The corrector has been developed for the Evoguide 50ED, but can also be used on other small and fast refractors with focal lengths between 240 mm and 450 mm. The corrector is attached through the 1.25" barrel.

The refractor must have sufficient backfocus, which is given with the Skywatcher EvoGuide 50ED after unscrewing the 40 mm extension tube.

The T2 rings, T2 extension tubes and tuning rings needed for the camera are linked in the accessories section.

Astrophotography with the Skywatcher EvoGuide 50ED:
The Skywatcher EvoGuide 50ED has a double ED lens with a 50 mm aperture and a fast f/4.8. The viewfinder offers a good helical focuser and a 1.25" receptacle. Thus you can attach the corrector directly to the telescope.

The working distance from the T2 thread of the EvoFF is 55 mm, so you can attach a DSLR or mirrorless system camera directly through a T2 ring and have the correct distance.

For a cooled ZWO camera with 17.5mm flange focal length, you will need the 21mm T2 spacer ring, T2-M48 adapter and 16.5mm M48 T2 adapter ring, all included with the camera.

Technical details:

• Optics: 2-element design
• Coating: Multi-coating on all glass-air surfaces
• Telescope side connection: 1.25" tube with filter thread
• Camera side connection: T2 male thread (M42x0.75)
• Field of view: 28 mm illuminated and corrected
• Weight: less than 100 grams