William Optics ZenithStar 66mm or 70mm?

On the off-chance that someone out there has experience of both the above, is there a general recommendation please?

I'd all but ordered a 66mm - was waiting for the supplier I want to order from to get back to me - when I noticed there's a 70mm as well. As far as I know they're both Apochromatic ED Doublets. The 66mm is f/5.9 and the 70mm is f/6.1 or 6.2...not sure, I've seen it written as both. My supplier says there's a MkII Field Flattener I could use with the 66mm. Another supplier says there's a MkIII one available for the 70mm. The 70mm is marginally more expensive. They'll both fit straight on my mount.

I'm sure that either would do me fine, but I just can't seem to decide. Have PM'd chris.bailey to ask about his WO ZS 70mm, but would like a few more suggestions about which to go for...things about them I might not have thought of.

Thanks,
Tim.

ADDITIONAL: Can't determine if the 66mm is ED Glass or SD Glass...not even sure if there's a difference. I've *also* just noticed there's a William Optics Megrez 72mm f/6!! AGGGHHH!!!

Chose the 70mm and it's just arrived!! Cue weeks and weeks of bad weather!

I think you made the right decision. With a FFIII it make a very good widefield rig that is also very portable. Though mine generally gets called upon for guider duty I have used it for imaging.

I'd have recommended the megrez 90 - slightly more light gathering power, not a lot bigger. WO make beautiful scopes. I'll probably get one one day

Dave

Well I've got the 70mm now, but it wasn't that much money really, so if I can get it mounted okay, and if I can get the Field Flattener the right distance from my sensor, and if I get some clear nights soon, and if I get some good shots with it and like it, who knows, perhaps the Megrez 90 will be the next purchase...then the FLT 158!

The 70 makes a fantastic guide scope as well as a widefield imager with the 0.8FR. The MZ90 is a bit middle ground for me and I would then be looking at a 110.

The 110 is bigger though, was trying to increase aperture but try and keep size/weight down for the OP. The 110 is a very nice bit of kit. And yes, that 158mm WO is drool material. Very nice. Of course, a tak would probably be nicer

Dave

Had you mentioned the 90 to me three or four weeks ago, when I was also thinking of upgrading my mount, I would've seached and seen the 90 for sale with a "mount of my choice" on a particular site, and I might have clicked on the EQ6 and paid over £1200.

...then you may have looked a bit further and found a FLT110 on a "mount of your choice" and paid even more

chris.bailey wrote in post #7342733
...then you may have looked a bit further and found a FLT110 on a "mount of your choice" and paid even more

That made me chuckle, but it's true!

Dave

Well it's not true, because I wanted something a fair bit smaller than my 102mm Achro. One day though, when I win on the Premium Bonds, I'll add the 110 and 158 to my arsenal!