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Old 09-09-2020, 08:16 AM
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The_bluester (Paul)
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Join Date: Feb 2011
Location: Kilmore, Australia
Posts: 2,722
I had an Evostar 72, I bought it as a toe in the water exercise in imaging at this sort of scale and did not expect miracles out of it. For the price I was happy with it.

They need a filter to cut the UV and IR ends of the spectrum as they really are not an apochromatic scope. There is detectable bloating at the blue end of the spectrum which was helped by the ZWO IR cut filter used with mine as it is really a luminnance type filter with sharp cuts at both near IR and UV. The blue issue was still there but vastly reduced (Along with a reflection issue) Some new one shot colour cameras have that type of filter incorporated into the sensor chamber window so for those a separate filter would presumably not be required. When I bought mine they did not have a dedicated adapter to fit the reducer/corrector (Which at least at that time was the one designed for the 80mm) so I had one made and then had it modified to accept the 2" filter internally when I worked out it was required.

As a toe in the water it was a good thing and I used it for the best part of a year before deciding to buy a much higher class short refractor, I sold it to someone else who was looking to do the same sort of toe in the water exercise. They definitely require the flattener/reducer though, field curvature was very obvious without it, even with a 4/3 sensor.
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