Orion XT12g, Resolux 15x70, Resolux 10x50
TeleVue NP101is, Nagler 31, Ethos 21/13, Delos 10/8/6, Plossl 15x2, Powermate, SIPS
Denkmeier BinoTron-27, D21x2
Baader, Lumicon, DGM Filters
Quote:I have limited experience with the Denk in a Newtonian, but my question is about the 45mm OCA.The last time I used a Denk in my 12" f/4.9 dob, even with the 45mm OCS, it seems like there was a bit of field illumination falloff in low power mode, however at the time, I needed a lot of extension on the OCA because my focuser did not have the necessary in-travel to reach focus otherwise.Since then, I have replaced the factory focuser with a lower profile focuser, and I am confident that I could now reach focus with the OCA screwed fully in.I am looking to buy a either a Denk II or a new Binotron system, but I am torn on the extra cost of the 45mm OCA.I will likely use Explore Scientific 20mm 68 degree eyepecies for now (maybe add D21s later).Has anyone compared the standard OCS and the 45mm OCS when used in this manner, with no extension required?How was the standard 38mm OCS? Did you feel that light falloff was acceptable, or was it noticable? I live under fairly bright skies, so this means that severe illumination falloff is detecatble due to the fact that the sky will appear much brighter at the center of the field than the outside. I can tolerate a little dimming, but not a lot.I know it is subjective, but I would like to hear opinions.
Quote:I have both OCS. Photo. Travel focuser on my 24" f/3.3:1. DenkII+OCS-45. Eyepiece Pan24. Minimum space for diopters on bino. Without extend the OCS by about 3/4th inch. Negative component switch (1.3x) - 0 mm.2. DenkII+OCS-38. Eyepiece Pan24. Minimum space for diopters on bino. Negative component switch (1.5x). Travel + 18 mm.3. For reference. Paracorr-2 + Ethos (21,17,13,8). Travel + 23 mm.In this part of bino with OCS45 placed inside the telescope tube about 30 mm (switch 1.3x)4. For users Mallincam.MFR-6+20 mm spacer (used 2" camera adapter). Travel +13 mm.MFR-3+20 mm spacer (used 2" camera adapter). Travel + 2 mm.I have myopia. For comparison eyepieces and Mallincam add 2..3mm to eyepiece travel for normal vision.