I tried GSO RC10f8 again after addition of TS Extension for The Baffle Tube. Stray lights disappeared. I could have finished refinement of the OTA twelve years after purchase. I hope to image nebulae and comets with this one.
TS Optics Extension for the Baffle Tube of 10" RC Telescopes:
www.teleskop-express.de/shop/product_info.php/language/en...
Here is a view of the OTA with TS extension:
www.flickr.com/photos/hiroc/52504139488
Here is a frame of the object taken with the OTA with no extension:
www.flickr.com/photos/hiroc/52490891703
equipment: Guan Sheng Optical Ritchey–Chrétien telescope RC 10" f8 with aigrette pattern mask on the vanes, TS 2.5" field flattener and Canon EOS R-SP4II, modified by Seo-san on Vixen AXD Equatorial Mount, auto guided at a star with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 120MM-mini, GPUSB, and PHD2 Guiding
exposure: 15 times x 120 seconds, 18 x 30 sec, 20 x 8 sec, 20 x 4 sec, and 20 x 2 seconds at ISO 1,600 and f/8.0
site: in my backyard at the bottom of almost the center of the world worst light pollution dome over Tokyo
