I've finally had time to spend significant hours behind the FC-100DL paired with the Extender QE 1.6X AKA TKA#36595. The results are indeed excellent and the FC-100DL while already sharp and well corrected has even more visual bite and contrast if that is possible than the FS-60Q I used for comparison in the Side-By-Side saddle on the GM8. But I encountered one unexpected change, when using the FC-100DL without the EX QE 1.6X in the city I had always prefered using the Baader Zeiss spec prism vs. the Baader BBHS coated Sitall mirror diagonal. BUT with the EX QE 1.6X there is a definite addition of color with any eyepiece. When swapped with the Baader BBHS mirror the color is gone. Same with the AP and TV mirrors both which had previously been less favored.
Anybody else played with this combination and possibly seen this? Could this be caused by Takahashi's clam for the EX QE 1.6X of higher spherical and CA correction and the once favorable shift from the Baader Zeiss spec prism is now seen as an overcorrection when pushed hard? This is only visible at higher magnification pushing well past 70x per inch but even by 50X per inch I see suggestions of this issue. But the amazing thing is that by using the Baader BBHS mirror the FC-100DL+EX QE 1.6X combination seems to be capable of even higher powers per inch on the one night ot transparency and seeing that supported it. Mars has been spectacular with this combination with surprising surface detail for a 100mm class scope. Saturn and Jupiter are just as spectacular with the right air and you must use caution when observing the moon so as not to cut yourself.
Anyway I am very interested the impressions of others who have spent at east a few observing sessions with FC-100DL or FC-100DZ optics paired with the TKA#36595 EX QE1.6X.
My Q 1.6x is excellent. I use it on more than off, only Tak fixings so all fits & unfits easily.
F14.4 1440mm FL with DL. All my oldie eyepieces; Erfles, Konigs etc work well. With 2" eyepieces I use an AP mirror diagonal, for 1.25", a Tak prism. Neither has bothered me with colour. My Baader Astro Amici may show slight colour but its so excellent in all other respects.
When I viewed Mars with the DL & 1.6 using a Pentax XW 10mm & Morpheus 9mm, no filter, it was spectacular - pole, black bits, red. Manual tracking restricts how high I magnify, but I am sure I could have gone up more.
Main reason for having the Q1.6x is to be able to use longer FL, comfier eyepieces. Viewing/scanning the Moon using my 6.5mm Morpheus with DL & Q, is as far as I've gone, so far. Normally that eyepiece is for the TSA-120 & ED1.5 extender.
Edited by 25585, 20 November 2020 - 04:21 PM.