Dynamic Duo Delivers:
Both fracs used TV eyepieces for high-power, and RKEs for low-power & sweeping. Dak had the Excellent GSO 2" dielectric, and the Tak had the very good older AT 2" dielectric. While I waited on the Planets to approach the meridian, I did some sweeping at about 25x, using my vintage 2" Erfles. Both fracs are close to RFT Fun with the summer Milky Way! But, low-level wet air put a damper on all but the very brightest nebulae...
In 6.5 / 10 seeing last night... Saturn: 3 Belts & 3 Moons in both; disk & (especially) the Rings are snow white in the Tak, off-white tinged with pale yellow in the Dak; Tak Belts have hints of salmon, olive, & tan mixed with the grays, Dak shows shades of gray; Cassini is easier to see in the Tak, but both displayed excellent contrast -- lots of faint stars made Moon identification tough! Seeing limited both to about 160x -- dang it! Because... Jupiter! Almost too bright at a "medium" power for both fracs. I tried 225x, and had to back off -- got tired of chasing best focus. Both fracs presented a sketchable Giant with a prominent GRS -- salmon in the Tak, and redder in the Dak. GRS Notch was bolder in the Tak, but both resolved it very well. So many belts, and so many textures & features within the belts & zones. However... look slightly eschew, and you get the blue-violet corona around the disk in the Dak -- a cool reminder that it's an F10 achromatic refractor...
- In less than 7/10 seeing, the F8 Tak fluorite has a noticeable advantage over the F10 Dak achro. Saturn was in & out of roiling air, yet the Tak didn't lose belt colors, Cassini, or the ring shadow on the disk; Dak lost the colors to grays, had slight smearing, and Cassini would flash in & out. Jupiter was higher & in better air, so the differences were minimal, except as already noted.
- The Dak's contrast is as good as the Tak's. I actually counted the number of faint stars between the Delphinus Double-Double, and the Dak was higher with both averted & straight-on viewing with both fracs using RKEs at about 35x. Mitigating Factor: Much newer GSO 2" mirror in the Dak, older but visually very good AT 2" mirror in the Tak.
- The Dak was built for 2" accessories, and has ZERO vignetting of the field; whereas, I adapted a 2" Baader ClickLock to the Tak. With 2" eyepieces, the field is larger, and is visually more appealing in the Dak, even though it's slower than the Tak. Honestly, I'm more likely to tote the less expensive Dak to the country for deep-sky -- but my Triple Nickle 5" F5 Triplet will go before either of these two slower fracs.
- Mizar EQ Comparisons: Overall, excellent motions & tracking with AR-1 & SP EQs. However... the SP's wood tripod has about 1//3 the damping time of the AR's aluminum tripod at high-power, which made fine-focusing the Tak tougher than the Dak. Much as I like having 2 all-original Mizars, I may get another wood surveyor tripod with a compatible hub if I continue using the Tak with the AR-1. SP has no damping issues carrying the heavier Tak 4" OTA.
This Duo reinforced my opinion that a quality 4" Refractor is a must for us city-dwellers. I got sketchable views of both planets in both fracs in sub-par seeing. Views of doubles, star fields, and open clusters were quite nice, too. The Dakin is a hand-crafted instrument, but Clammy (my 1980s Celestron / Vixen C102 F10 achro with a circlet of tiny clams in the flint) isn't that far behind my Dakin, and I got it for $100. It's much lighter than either Duo member, so any SP-equivalent EQ can carry it well, even a high-power. Food for Thought if you're considering a Classic 4" Refractor. IME, they are worth more than they cost.
Edited by Bomber Bob, 03 September 2021 - 12:45 PM.