Samyang 135mm F2.0 Lens (EOS mount)

Now recently I was looking for a fast focal ratio lens for astrophotography, as it would be great to be able to image at F/2.0-2.8. As the ZWO ASI178MM-cooled has a crop factor of 4.8x, it would mean a 135mm focal length lens would be ~650mm, and a 200mm focal length lens would function at ~960mm. Hence I had bought the Samyang 135mm F/2.0 lens in Canon EOS mount for this purpose. Continue reading Samyang 135mm F2.0 Lens (EOS mount)

iOptron ZEQ25 Polar Scope LED Illuminator replacement

There have been a few issues with my iOptron ZEQ25 which have required some attention to. The good thing is that it is a mount which is rather easy to tune up – I must have taken it apart and reassembled it at least 10 times now. But one of the things which I had not had the time to sort out until now was the polar scope light – this was no longer functional following the upgrade to the ADM Losmandy/Vixen Dual Mount clamp. Continue reading iOptron ZEQ25 Polar Scope LED Illuminator replacement

ZWO ASI178MM-cooled UV-imaging

One of the areas of photography that I have an interest in, and wanted to test out of the ASI178MM-cooled for a while, is UV-imaging. That is imaging below 400nm wavelength, which is  invisible to normal human vision. Now it is unclear the response of the IMX178 Sony Starvis sensor to the light below 400nm, but I felt I needed to test this out, particularly as it does not have a Bayer Matrix to affect UV-transmission. But the big question I had was whether the AR window protecting the sensor would block deeper UV? Continue reading ZWO ASI178MM-cooled UV-imaging