TMB 40mm Paragon

Well, I finally got a chance to do some real observing with my new TMB Paragon.

WoW. Performs wonderfully! Easily equals the light throughput of the Siebert 36mm Observatory and beats it hands down in edge performance in my 10" f4.7 Dob. There is a very minute amount of pincushion, but you really have to look for it in daytime observing, and only at the extreme edge. Central 75-80% afov is sharp, then at 20-25% from edge some barely detectable CA happens but only on Mag 1 to 1.5 stars. Also at 20-25% from edge start getting some field curvature that becomes noticable or moderate at last 10% (but on a re-focus even the last 10% to the edge the star stayed sharp).

Absolutely no blackout/kidney beaning and zero secondary shadow and no ghosts of any kind on Mag 1 stars.

Field stop tac sharp and very good contrast. Advertized as 69deg AFOV and looks every bit of it. AFOV of Nagler looked larger or course but only by 10-15 deg max. Interestingly, the Siebert AFOV did not look as big and advertised as 70deg afov but appeared smaller, perhaps perhaps 8-10 deg less in comparison to Paragon. Could easily get 4 widths of the Perseus Double Cluster in my TFOV, so that should be 2+ degrees as predicted.

Fit and finish excellent, light but still heavy enough to feel solid and well built.

This is a real keeper and quite a bargain price at $250 new. Based on the performance of this, will definitely want to get the 16mm and 24mm when they come out.

-Bill

Bill:

Thanks for the report. I wonder is there may be some differences in design between the 34mm Siebert Observatory Series and the 36mm unit.

I have a 34mm Siebert that I use occassionally in a 12" f/4.9 Dobsonian and it is one of the flatest field and best corrected eyepieces in my collection for edge performance in fast scopes and is the best edge corrected hands down among my "wide field" designs. It is considerably sharper at the very edge than my 27mm Panoptic for example.

The 34mm Siebert has other weaknesses (so-so coatings, some internal reflections, etc.), but poor edge performance isn't one of them. Now I am itching to do a head to head between the 36mm and 34mm Sieberts.

Based on your report on the 40mm I'll have to give those 16mm and 24mm TMBs a look when they are available.

Regards,

Jim

Thanks Bill,
Appreciate the report. It definitely sounds like the Paragon is worth a try. Anybody you know have a 41mm Pan you can do a comparison with?
I'm a little like James B. regarding the 36mm OG Seibert. Mine is pretty flat in my 12.5" f/5 Starmaster. Certainly not as bad as yours sounds. Did you buy yours new from Harry?
Either way it definitely sounds like I should give the TMB a try.
Thanks again!
Clear Skies, Bill

William Paolini said:

Well, I finally got a chance to do some real observing with my new TMB Paragon.

WoW. Performs wonderfully! Easily equals the light throughput of the Siebert 36mm Observatory and beats it hands down in edge performance in my 10" f4.7 Dob. There is a very minute amount of pincushion, but you really have to look for it in daytime observing, and only at the extreme edge. Central 75-80% afov is sharp, then at 20-25% from edge some barely detectable CA happens but only on Mag 1 to 1.5 stars. Also at 20-25% from edge start getting some field curvature that becomes noticable or moderate at last 10% (but on a re-focus even the last 10% to the edge the star stayed sharp).

Absolutely no blackout/kidney beaning and zero secondary shadow and no ghosts of any kind on Mag 1 stars.

Field stop tac sharp and very good contrast. Advertized as 69deg AFOV and looks every bit of it. AFOV of Nagler looked larger or course but only by 10-15 deg max. Interestingly, the Siebert AFOV did not look as big and advertised as 70deg afov but appeared smaller, perhaps perhaps 8-10 deg less in comparison to Paragon. Could easily get 4 widths of the Perseus Double Cluster in my TFOV, so that should be 2+ degrees as predicted.

Fit and finish excellent, light but still heavy enough to feel solid and well built.

This is a real keeper and quite a bargain price at $250 new. Based on the performance of this, will definitely want to get the 16mm and 24mm when they come out.

-Bill

You're the first person I've seen report results with a scope faster than F6.

Bill,

Glad you are happy. It's your money and gear. However, $250 for an EP still isn't cheap to me and I can get a 40mm Axiom on the used market for quite a bit less. I gave $150 for a NEW 2" 34mm Axiom on eBay recently from a telescope dealer. Nobody bid against me. People are CRAZY for the big fat EP's these days. Would be nice to compare that 40mm Paragon to a 40mm Axiom on about an f/8 scope.

You use a fast Dob. The Paragon might work better on a Dob, but what will it be like on an f/10 to f/16 scope I would noirmally (normal is for daytime, noirmal is for nightime) use for visual observing? My Axiom gives no blackout and no kidney beaning. It is sharp all the way to the edge on my Mak-Cass. My 38mm Siebert Observatory is sharp all the way to the edge in my Mak-Cass and causes no kidney beaning or blackouts. Even a 2" 26mm fully multicoated Kellner is sharp to the edge in my Mak-Cass, and contrasty as can be. The Kellner cost $55 new. If I ever forget to bring EP's one night, I can just put my magnifying lens up to the diagonal and expect it to be sharp to the edge at f/14.2.

Yep, fast scopes have changed EP design. EP's have gotten big, fat and expensive. Light transmission and contrast have dropped. They work almost as well on edge in fast scopes as the cheaper classic EP's do in a long focal ratio scopes. Short tube achromat refractors, f/6.5 APO refractor, f/4.5 Dobs, f/5.5 Mak-Newt. People want faster scopes and bigger, fatter EP's. Now the EP case is starting to weigh as much as the scope case, and probably contains more dollars worth of goods. Once the scope was big and expensive and the EP's were small and relatively cheap.

Since my Mak-Cass can use cheaper EP's and still perform like a million, I took the money I saved by NOT buying Naglers, Pans and Radians and bought a TEC eyepiece turret that allows me to hang 5 Ultimas and Axioms on my scope at once. Deducting the $150 average price difference that I saved by NOT buying a Pan or Radian, never mind the Naglers, and multiplying by 5 for the number of holders in the TEC turret, that gives $750 savings, then deducting the $500 for the TEC turret, I still saved $250 over what I would have spent if I had bought similar FL Radians and Pans and stuck them in my diagonal one at a time and fumbled around in the dark and occasionally dropped one. That's the beauty of a longer focal ratio scope. You can save money and still get at least as good a view. The dropped Pan doesn't need to go back to Uncle Al for repair, either.

BUT WAIT, it gets better. The TEC turret contains a very high grade 1/10 wave mirror diagonal of enhanced aluminum on astrosital or quartz substrate. Easily worth $100 on todays market. That saves another $100 if anybody was needing a better diagonal for their scope, so the savings comes to $350 and mostly pays for my OTA as well. Yes, getting a really great long focal ratio scope and saving on EP's and getting more convenience in the bargain is the way I went. In other words,I got a 6" Russian Mak-Cass (used), A TEC turret, and 5 of the best new EP's for about $150 more than I would have paid for 2 Pans and 3 Radians alone....AND, they probably work better in the f/14.2 Mak-Cass than Pans and Radians work in f/4.5 Dobs. The TEC turret with 5 EP's weighs about as much as a 31mm Nagler and costs not a whole lot more (and you get a nice diagonal in the deal).

Let's see, a 10" f/4.7 Dob is 47" focal length. That's about 1200mm focal length. A fat little 4" f/6 refractor is about 600mm focal length. I can hang a 20mm EP on the refractor and see the same slice of sky as the Dob sees with a 40mm EP. I get 30X mag either way. The refractor and 20mm EP cost a lot less and are easier to transport. Cheaper EP's start to perform at f/6, and while the Dob has an exit pupil that is already too big, I can hang a 30mm EP in the refractor and get even lower 20X mag and have a 5mm exit pupil that wastes no light. It looks like downsizing the OTA works better than upsizing the EP to me, if low mag is the issue, and it costs a lot less to boot. Or am I missing something?

Certainly , the Dob would be better for deep sky at high power vs. the refractor, but for $250 I can get a good used fast 4" refractor and use an EP I already have to do low power deep sky work. Heck, I'll just slam in the turret with 5 EP's and get several low and mid power views. The Paragon might not be a bargain for me, but for allowing a bigger scope than you really needed for low power viewing to work anyway, the Paragon might be the hot ticket. I would think it would be better for those with a big f/12 to f/16 achromat refractor to get a decent sized exit pupil for high contrast deep sky work. Eye defects rapidly increase when the exit pupil gets beyond 3mm, especially in older observers. I am waiting for a review from one of those f/15 guys on the Paragon. A 6" f/6 Dob with a 30mm wideangle gets you 30X mag as well and produces a 5mm exit pupil that wastes no light. Going beyond a 5mm exit pupil has NEVER helped me detect the faintest fuzzies one tiny bit better. Others may see things differently and have eyes that dilate to 8mm. 8O

I need to start selling eye pupil dilation fluid so that people can use long FL EP's on their Dobs to their fullest extent.

Phil

Wouldn't most of the edge performance and field curvature issues you are seeing come from the normal issues with fast Newtonians?