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Equipment Discussions >> Refractors

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Daniel Mounsey
Vendor (Woodland Hills)
*****

Reged: 06/12/02

TEC140 vs. Ceravolo HD145
      #4774348 - 08/28/11 06:37 PM

OKAY FOLKS!

For pictures go to Tamiji Homma's site here http://www.pbase.com/tammyhomma/oakpark20110827

Let me know of any tech errors as I am exhausted from last night. It's time to share the comparison of the TEC140 vs. Ceravolo HD145 in a VERY constructive way and guess what! We were shooting it out till 3am in the morning last night non-stop! We had some hidden "low key" guest stars, all who participated as follows and what an incredible turnout it was with at least a 100 guests. This shootout was conducted by over a half a dozen observers all trying to be very careful not to stand too near the telescopes while comparing images. I am SUPER critical with people standing around the telescopes. Ask them. I found myself asking everybody to please move behind the scopes. Trust me when I tell you this. Humans give off lots of heat currents which can degrade images and that is a fact! Most of the beginners finally left around 11pm so, we were just about all to ourselves to battle it out to the death for the next 4 hours. I specially wish to thank John Fisanotti for being kind enough to let us scutinize his TEC140 serial #125 to the near max.

For those of you who have never participated in a shootout of this caliber, let me describe the atmosphere. It's intense and intoxicating. It's like watching the greatest boxing match in history. You never know what's going to happen till they meet face to face and the tensions are palpable. You hear things but you never know till they are faced together. It brought me back to the greatest shootouts during the Charlton Flats era with the best telescopes you could possibly look through. The average observer only sees a very small percentage of what is possible with a world class instrument under the best conditions like Charlton.

The guests were as follows and all their opinions are what made up this comparison. This is not a shootout by just me. These are the combined opinions of the most critical eyes and I will share my thoughts as well. Ridwan Angkasa paid me a surprise visit but had top leave early. Ridwan was instrumental in the 4" hypershootout.

THE GUEST OBSERVERS:

Evan Chan:
He was hiding in the back ground. Evan has an amazing collection of the finest optics in the world, but he is very low key on CN. Don't be fooled hehe! Evan had to leave earlier than the rest but had a few peeks in the 140.

Tamiji Homma:
Thank you for providing the incredible array of eyepieces. The all new Takahashi wide fields. The Nikon hypwerwide fields. in 12.5mm and 17mm you loaned me last month. Tamiji has an incredible eye for quality and is incredibly unreserved. I like that. Tammy just calls it like it is without hesitation.

June Trajano:
Through thick and thin June has been the quiet eyes behind the scenes. He has conducted nearly every shoout I have ever posted and without his thoughts, we would not have made an important discovery last night which I will share. June pulled me aside to enlighten me.

Joe Napolitano:
In reality Joe is a movie director, but is hooked on astronomy and mans this fine Ceravolo HD145 for our comparison.

Luigi Manna:
Luigi is bright and new but boy does he ever have an incredible addiction and utter appreciation of fine optics!

John Hawk:
This guy is very critical and loves Dick Suiters star testing book. He has a lot of great experience at the eyepiece.

John Fisanotti:
Owner of the TEC140. A pleasant guy to observe with. John was critical but in a very mellow way. He just seemed pleased to look through both of these fine scopes.

Dennis:
Dennis has the longest, most difficult last name no one can even remember. I had to ask him to repeat it several times but it was broken English and he had some difficulty making magnification calculations on the spot because he was pressing 8 for 3 and 2 for 7 and so on. Dennis is a brand new observer seeing his first shootout ever, but my gosh!!!! Talk about enthusiastic and super critical!! This guy was hooked and no one even knew him, myself included. Great observer and a really nice guy. Joe and I were amazed.

Me:
What compells me is to see light focused to a single point.


THE LOCATION:
Oak Canyon Park California.

THE SEEING CONDITIONS:
7 out of 10

TELESCOPE STATS:

TEC140: F-7 980mm
CERAVOLO HD145: F-6 870mm

THE EYEPIECES:

University Optics 7mm
Televue Dilos 6mm
Nikon 102 deg. 12.5mm
Nikon 102 deg. 17mm
Televue Ethos 13mm
Televue Ethos 17mm
Televue Nagler 16mm T5
Takahashi UW 5.7mm
Televue Nagler 5mm T6
Televue Nagler 3.5mm T6
Pentax XW 5mm
Pentax XW 7mm

THE TARGETS:

a) T-Lyra, an incredible red carbon star to determine color saturation and contrast in each telescope.
b) Epsilon Lyra, better known as the double double in Lyra to determine the cleanest and most beautiful split.
c) Jupiter to determine detail, color contrast, color saturation etc.
d) The Double Cluster in Perseus to determine overall "wide field" pinpoint clarity and sharpness edge to edge.


LETS GET DOWN TO BUSINESS SHALL WE:

T LYRA

We fired both scopes at T Lyra first. The TEC140 was positioned about 12ft away to the north west of the Ceravolo. We used a 6mm Ortho in the TEC140 at 163x while the Ceravolo was using a 5mm Pentax at 174x. Take in mind that it's hard to match the magnifications exactly. This would give an exit pupils almost exactly the same of .83 for the Ceravolo .85 for the TEC140. That's close enough for me. The eyepieces could alter things slightly but it comes with the turf. As everybody went back and forth between the two scopes, it was near to next to impossible to tell which was which. Tammy thought that the reddish color of T Lyra was slightly deeper red in the TEC140. Most of the crowd were undecided and not sure. Some of the observers thought the image in the HD145 may have been a bit cleaner. You could start to see the airy disc of the star in the Ceravolo.

Then after 45 minutes of comparing this object, the images started to look unstable in the TEC140. We were all baffled and perplexed! How could a darn refractor be more unstable looking than a reflector? The HD145 was noticibly nicer and we all agreed. Take in mind that the HD145 was on a Losmandy Gemini mount with smooth servo motors while the G11 an TEC140 used stepper motors. Could it be the steppers we all thought? This actually happened once at Charlton Flats. In this case John asked me to look in the eyepiece of the TEC while he switch the tracking on and off. I could not detect any differences with certainty and said it must be something else.

While all this was going on, Tammy said that there was a colder air blowing right in front of the TEC140 causing eddies with the warmer air, so everybody took turns at standing right where Tammy said the air was blowing. Everyone agreed 100% overwhelming majority vote it was the cause. Incredible just 12ft away from the Ceravolo!!!!! Every time we took turns standing next to the Ceravolo we all agreed it was noticibly warmer air. The second you stepped over to the TEC, it was easily cooler. We believe that the position of a set of big trees to be the root cause while a car also appeared to block colder air from flowing right in front of the Ceravolo's optics. Everyone agreed, so four of us literally lifted the entire G11 mount and TEC140 next to the Ceravolo to stay in the warmer air but not too close to cause harm from our body currents. We re-polar aligned and the problem was immediately solved and we could get back to testing after nearly 30 minutes of torture to the TEC140. This gives you an idea of how important the environment is.

Still pounding away at T Lyra, people were still preplexed myself included. We decided to use the all new Takahashi 5.7mm UW at 172x in the TEC to match the Ceravolo. So hard to decide and some felt that the Ceravolo had an edge. After this, June pulled me aside in private. He said Daniel, I think there's something up with the diagonal in the TEC. Look at what diagonal is in the TEC. I will not say the brand name in this forum. I said, how could I forget that DANG, I forgot! I would never expect a TEC owner to use one of these mass produced 2" 99% diagonals but sure enough that's what it was, no hard feelings. I went back and said let's fix this right now. June handed me a 2" mirror diagonal we knew was good. Incredibly we could all descern the difference and everybody was teasing John to get a new diagonal. I said that's like putting regular unleaded into a Mclaren F1 and everyone agreed.

After the change, no one appeared to be able to make a clear conclusion, myself included. It was just too dang hard! As everybody took turns going back and forth, someone would say I like the TEC! then a minute later I like the Ceravolo! I found myself leaning a bit towards the Ceravolo because the airy disc just and the ill-defined faint diffraction ring seemed a tad cleaner. The brightness was identical and the guys kept commenting that the background may have "appeared" to be a bit darker in the Ceravolo. Could it be two decimal points of the exit pupil? the eyepiece? who knows? but both scopes scored even to the group unless any of the guys have something to share I may have overlooked. I'd never seen so many dang confused observers in my life, myself included. It appeared that no one could really decide for sure. Both images were awesome!!!!!

EPSILON LYRA:

Now this gets interesting. We decided on the 6 Delos in the Ceravolo and the 7 Pentax in the TEC. This would give the Ceravolo 145x with an exit pupil of 1.00 and the TEC140 at 140x with an exit pupil of 1.00 as well. It was a pretty split race. Once again it was hard to say which scope was nicer. Luigi commented that he saw very faint but extremely subtle hint of color while the Ceravolo was completely apochromatic. Dennis said he was favoring the TEC a bit while on T Lyra he was favoring the Ceravolo a bit but still remained unsure during both observaions of T Lyra and Epsilon Lyra. I was favoring the Ceravolo a bit. Then John Hawk was favoring the Ceravolo a bit as well as Tammy. Some of us thought the slight fluctuations may have been what caused us to enjoy one scope over the other for that brief moment we were comparing them. Once again we found ourselves all having a really difficult time comparing which scope looked nicer, but I still liked the Ceravolo a tad more because I know when pushing doubles as hard as I have in the past, it's an incredible scope hands down and just doesn't quit impressing me. To me, it just appeared a hair bit tighter on these doubles. Regardless, most thought it was pretty even. I'm not a fanatic about seeing color but I admit that when you really wonna push stars to their absolute limits, a fully apochromatic scope does have the potential to produce a slightly cleaner image around airy discs, but this was by no means what we saw on Epsilon with the TEC at these particular magnifications.

JUPITER:

We then decided to fire both scope at Jupiter. This was really quite an astonishing comparison. There were a couple of moments for whatever the reason where June and I saw scattering in the Ceravolo or bending of light around Jupiter, probably atmospheric. We both attributed it to the seeing or refraction of the light. When we all looked through the TEC, Joe, captain of the Ceravolo thought Jupiter may have had a bit more clarity in surface detail in the TEC. I took a look as well and my conclusion was that it looked a hair bit nicer in the TEC at that particular moment, then I quickly ran over the the HD145 and waited. Sure enough there were moments where it looked equally as beautiful, crisp and contrasty. We made a point to rotate the focuser of the Ceravolo so we were viewing downwind. Luigi said he could not even tell a difference and it was driving him mad. John Hawk thought Jupiter may have looked a bit nicer in the Ceravolo but still seemd unsure as was I. Tammy thought maybe the TEC had an edge. Honestly, I believe most of the differences were attributed to slight fluctuations in seeing because Jupiter was quite low compared to the other targets so far. It was hard to really be sure. I've done many shootouts. I can assure you that when you spend a good amount of time looking through telescopes of this caliber, sooner or later you are going to get some amazing moments! That's the key to success. The more you study and the more you stare, the more susceptible you make yourself to capturing astonishing detail on Jupiter!

THE DOUBLE CLUSTER IN PERSEUS:

It was now time for wide field. In the TEC140 we used the Nagler 16 type 5. This would give 61x with an exit pupil of 2.25. The image in the TEC was absolutely beautiful however on some of the brighter stars it seemed just a wee bit not so flat in the TEC but the faintest stars looks like pin points out to the very edge. All of us were really impressed. At times we used the other eyepieces above but pretty much settle on these eyepieces. We decided to go with the 12.5mm Nikon 102 deg eyepiece in the Ceravolo at 69x with an exit pupil of 2.10. This eyepiece is incredible and is corrected for angular magnification distorsion. This easily gobbled up both clusters in the HD145. It was like a freaking Mural from an Isaac Asimov science fiction tale! Pin pricks right into the field stop regardless of their brightness. At these lower magnifications, the seeing almost seemed non existant and even if we used a Nagler it the Cerevolo, it's pinpoint right to the field stop. I think Tammy liked the Ceravolo here or at least had an easier time deciding. The wide field test seemed pretty easy to conclude unlike the other tests. I think everyone agreed. John the owner of the TEC seemed pleased with both scopes on all targets.

CONCLUSIONS:

Just toss a coin. I think if anyone was in our shoes this night, they would have had the hardest time making a solid and conclusive choice. The TEC140 has almost become the standard of its class, but it just comes to show how awesome the Ceravolo HD145 truly is when properly executed with a cooling fan before observations and what an incredibly versitile, light weight telescope it truly is. We wished we could have had more time to star test each scope on Altair but it took a lot of looking with just these few objects. My prediction is that the TEC140 at really high magnification would not have been completely apochromatic, while the Ceravolo would have been. Does this matter during most observations? Of course not but for me, regardless of price, the Ceravolo HD145 is my favorite telescope in its size class ever! I love that it's different, I love that it's rare, I love that they are so hard to find, yet it is still so sad they are no longer made because there really are observers out there who do appreciate the difference and that to me, is something special. It's just not normal to see a reflector compete with top quality refractor in the same size class, but the Ceravolo will do just that and then some. It doesn't surprise me one bit that Ceravolo does commercial aerospace optics. The man is simply a master. I'm sure some of my friends may pop into the forum and offer more insight with various opinions and maybe we can better discuss it further. In the meantime, Joe, I want my other Ceravolo back, you already have two!


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Scott BeithAdministrator
SRF
*****

Reged: 11/26/03

Loc: Frederick, MD
Re: TEC140 vs. Ceravolo HD145 new [Re: Daniel Mounsey]
      #4774579 - 08/28/11 09:09 PM

Excellent report and I would like to thank everyone who spent their time assisting with the shootout. I really enjoyed reading this one.

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Eddgie
Postmaster
*****

Reged: 02/01/06

Re: TEC140 vs. Ceravolo HD145 new [Re: Daniel Mounsey]
      #4774630 - 08/28/11 09:43 PM

Thanks for the great review.

This review I think serves to re-enforce what many experts have said over the decades, which is that an obstruction of 20% or less does not do enough damage to the contrast that it would be detectable when compared to an unobstructed aperture.

Of course the HD had some extra aperture, to this doesn't provide absolute confirmation, but I think it is rather close enough. A few percentage of differnce in contrast loss is almost impossible to see except under lab conditions.

I have owned two Intes Micro MNs and while the quality is not QUITE as perfect as the Ceravolo, I would say that they were among the best I have ever owned. And the first time I looked though a 6" MN, it floored me.

I didn't realize it at the time, but I was looking at a view that was VERY similar to that of a 6" APO.

I know that now.

Congratulations on you Ceravolo. I totally agree that the HD145 is very rare and desirable.

And a heck of a fine telescope, I am totally sure.


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Daniel Mounsey
Vendor (Woodland Hills)
*****

Reged: 06/12/02

Re: TEC140 vs. Ceravolo HD145 new [Re: Eddgie]
      #4774660 - 08/28/11 10:05 PM

Thank you Scott. Eddgie I did the exit pupils just for you sir.

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Tamiji Homma
Post Laureate
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Reged: 02/24/07

Loc: California, USA
Re: TEC140 vs. Ceravolo HD145 new [Re: Daniel Mounsey]
      #4774813 - 08/28/11 11:21 PM

Hi Daniel,

Thank you for a lot of write-up. I enjoyed the shootout very much. I was surprised that everyone stayed focused for the long duration. Adrenaline rush kept us going, I guess.

The micro airflow effect around the scopes was interesting. I think that it resulted in disadvantage for TEC 140 until we figured that out. As you mentioned, two scopes were only 12 feet apart. They showed different images, one steady on HD 145, the other scintillating on TEC 140. It was quite puzzling until we knew why.

I think that the target selection you made for shootout was excellent not only showing beautiful image but also forcing us to think what to look for to see difference between excellent scopes.

One thing, it was very warm day. When I arrived around 18:40, it was 92 degree. When I left around 2:40am, it was 78 degree.

Double Cluster was breathtaking. It was nice way to end observation.

Be safe in driving to OSP next week and enjoy.

Tammy


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edl
professor emeritus


Reged: 06/24/04

Re: TEC140 vs. Ceravolo HD145 new [Re: Daniel Mounsey]
      #4774814 - 08/28/11 11:21 PM

Great review.
It also illustrates how critical external conditions are when doing these types of evaluations.
Thanks for posting.

Best,
Ed L.


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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: TEC140 vs. Ceravolo HD145 new [Re: Daniel Mounsey]
      #4774839 - 08/28/11 11:32 PM

Thanks for the report. Very interesting results.

I'd love to see a follow-up using some doubles closer to the resolution limit of each scope. Perhaps some >4 mag unequal pairs, and some pairs in the 1.x arc second separation range. Some head-to-head in the 80-90x per inch range, too, would be interesting.

Any chance of that happening at some point?

You also said: "My prediction is that the TEC140 at really high magnification would not have been completely apochromatic, while the Ceravolo would have been."

You would be 100% correct. It's not too difficult to tease a little false color out of the TEC 140 at higher magnifications on brighter targets; particularly blue and white first magnitude stars.

Thanks again for matching up these two scopes!

- Jim


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JoeNap
newbie
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Reged: 06/22/10

Loc: CA
Re: TEC140 vs. Ceravolo HD145 new [Re: Daniel Mounsey]
      #4774899 - 08/29/11 12:16 AM

Wow, what a night. Great article Daniel. I think the best part of the night was when I realized that it wasn't really about which scope was better, it became more of an incredible exercise and appreciation for really good optics.
It was really almost impossible to be one sided one way or the other - these are two telescopes that set up right are hard to beat. I packed up the Ceravolo at 3am wanting more and we discussed trying to schedule another shootout under darker skies and with the emphasis on matching eyepieces to bring magnifications closer to each other and utilizing equal quality eyepieces, exit pupils etc. I can honestly tell you one thing that blew me away was the experience of looking through the new Nikon eyepieces. Thanks for bringing them Tammy. Having a wonderful scope like the Ceravolo obviously pinpoint stars edge to edge is something I live to see every time I look through the scope. With the Nikons, not only are they pinpoint but there seems to be plenty more of them across a very flat field -Amazing views - Bravo Nikon! Thanks everyone for a most memorables and enjoyable evening, I hope we do it again soon.
Joe


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jmiele
Patron Saint?
*****

Reged: 12/04/10

Re: TEC140 vs. Ceravolo HD145 new [Re: JoeNap]
      #4774906 - 08/29/11 12:21 AM

Daniel,
Well done sir. As always very complete and an interesting read. Most interesting is the fact that regardless of the type (reflector/refractor), all the good stuff is hard to come by.

Joe


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The Ardent
Pooh-Bah
*****

Reged: 10/24/08

Loc: Virginia
Re: TEC140 vs. Ceravolo HD145 new [Re: jmiele]
      #4774934 - 08/29/11 12:41 AM

Very enjoyable read, thank you.

If I had to choose between the two, Id pick the refractor due to confortable eyepiece position only.


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CounterWeight
Postmaster
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Reged: 10/05/08

Loc: Palo alto, CA.
Re: TEC140 vs. Ceravolo HD145 new [Re: jmiele]
      #4774935 - 08/29/11 12:42 AM

Great report - thank you Daniel and all others that participated, Daniel, a great read.

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Daniel Mounsey
Vendor (Woodland Hills)
*****

Reged: 06/12/02

Re: TEC140 vs. Ceravolo HD145 new [Re: The Ardent]
      #4775009 - 08/29/11 02:03 AM Attachment (90 downloads)

Quote:

Very enjoyable read, thank you.

If I had to choose between the two, Id pick the refractor due to confortable eyepiece position only.




you're welcome guys. Yes, I can understand this. On the other hand, Joe determined that a Televue Air Chair is a perfect arrangement for the Ceravolo. Also, Joe's little home made cooler works perfect. It simply sucks warm air and any dust out of the tube. By sundown, the scope appears to cooperate so far.

Edited by Daniel Mounsey (08/29/11 02:05 AM)


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roadi
Pooh-Bah
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Reged: 08/18/07

Loc: Great Grey Spot "Denmark"
Re: TEC140 vs. Ceravolo HD145 new [Re: Daniel Mounsey]
      #4775027 - 08/29/11 02:16 AM

As one that loves shootout too, and recalling the exciting readings from the 4" hyper shootout! I too want to thank all you guys that made this enjoyable reading possible!

As Jim mensioned, it would also have been interesting to see the difrence, "if any" when both scopes were pushed to the extreme in excellent seeing, maybe then tiny difrences in optics would start to show its self

Anyways thanks for a great report


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mark8888
Carpal Tunnel


Reged: 09/24/10

Re: TEC140 vs. Ceravolo HD145 new [Re: roadi]
      #4775042 - 08/29/11 02:51 AM

Same here... great read, thanks for the report. The writing definitely gives the reader a little bit of the sense of actually being there and looking through the scopes, which is cool.

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CounterWeight
Postmaster
*****

Reged: 10/05/08

Loc: Palo alto, CA.
Re: TEC140 vs. Ceravolo HD145 new [Re: mark8888]
      #4775056 - 08/29/11 03:47 AM

So there is something to comfortble viewing to enjoy the last drop... the right chair, and to help the telescope to do it's best... Joes home made cooler. And then the diagonal and placement of scopes... interesting how the seeming 'little things' aren't so little when you are pushing the envelope.

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vahe
scholastic sledgehammer


Reged: 08/27/05

Loc: Houston, Texas
Re: TEC140 vs. Ceravolo HD145 new [Re: Daniel Mounsey]
      #4775203 - 08/29/11 07:55 AM

Quote:

For pictures go to Tamiji Homma's site




Although I know most everyone by name wish I could identify the major players in those excellent photos by Tamiji.
Also did you folks use binoviewers or it was all mono view?

Vahe


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Daniel Mounsey
Vendor (Woodland Hills)
*****

Reged: 06/12/02

Re: TEC140 vs. Ceravolo HD145 new [Re: vahe]
      #4775248 - 08/29/11 08:34 AM

We didn't do Bino mode although you can. The tube is also easily rotates to any desired position without any adjusting. The Telrad base just by chance happens to rotate against the upper tube ring, preventing the OTA from sliding down but still allows smooth action. Joe already has a set of rotating rings but doesn't actually need them. Also, to answer those questions about really high magnification and maybe some double star splitting when the seeing is 8 or better, I think that's where the HD will really shine. We were just out of time with four objects and over half a dozen observers sharing opinions.

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AZStarGuy
Pooh-Bah
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Reged: 05/05/08

Loc: Scottsdale AZ
Re: TEC140 vs. Ceravolo HD145 new [Re: Daniel Mounsey]
      #4775628 - 08/29/11 11:52 AM

Great comparison! I especially applaud attention to not just magnification but exit pupil sizes. That was some spectacular equipment over there! I may need to road trip some day!

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Tamiji Homma
Post Laureate
*****

Reged: 02/24/07

Loc: California, USA
Re: TEC140 vs. Ceravolo HD145 new [Re: AZStarGuy]
      #4775906 - 08/29/11 01:57 PM

Hi Ron,

You're welcome to join the party

I uploaded my eyepiece basket photo that we used for shootout. We tried to match magnification on TEC 140 (focal length 980mm) and HD 145 (870mm) so that some of them didn't get any airtime last Saturday.



I thought TEC 140/XW 7 (140x) was tiny bit better than HD 145/Delos 6 (145x) but it would have been slight seeing changes between switching scopes (5 seconds or so). They were incredibly close, they both were showing what the aperture could show under the condition.

When near perfect scopes are side by side, both would show almost identical image, wouldn't it?

Thank you Joe and John for bringing such excellent scopes to the party. Star party is the only way for us to have such opportunity.

Tammy


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Astrojensen
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Reged: 10/05/08

Loc: Bornholm, Denmark
Re: TEC140 vs. Ceravolo HD145 new [Re: Tamiji Homma]
      #4775973 - 08/29/11 02:33 PM

Tammy, the content of that basket probably presents a value a sizable fraction of my total investment in astronomy gear! Not bad! You are a very lucky man!


Clear skies!
Thomas, Denmark


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BillP
Postmaster
*****

Reged: 11/26/06

Loc: Vienna, VA
Re: TEC140 vs. Ceravolo HD145 new [Re: Daniel Mounsey]
      #4776185 - 08/29/11 04:23 PM

Absolutely love reading your scope comparisons....always!!!


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siriusandthepup
sage
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Reged: 02/14/06

Loc: Central Texas, USA
Re: TEC140 vs. Ceravolo HD145 new [Re: BillP]
      #4776466 - 08/29/11 06:56 PM

Thanks to all involved with this scope comparison. Great read! Enjoyed it immensely.

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dsnope
Carpal Tunnel


Reged: 04/28/06

Loc: OC California
Re: TEC140 vs. Ceravolo HD145 new [Re: siriusandthepup]
      #4776475 - 08/29/11 07:02 PM

Thanks for the great comparison work, guys.

I can bring up a TEC160FL if you have a 7" MakNewt that you want to compare it to.


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Tarzanrock
professor emeritus
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Reged: 12/07/08

Loc: Los Angeles
Re: TEC140 vs. Ceravolo HD145 new [Re: Daniel Mounsey]
      #4776558 - 08/29/11 07:49 PM

Hi Daniel:
Great party! I'm sorry I missed it. It looks like you guys really had some fun.
I'm extremely curious about the homemade "cooler" which "Joe" made as is depicted in the photograph you posted.
Perhaps, Joe could chime in about how he did it.
Bill


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NickG
scholastic sledgehammer
****

Reged: 11/06/06

Re: TEC140 vs. Ceravolo HD145 new [Re: Tarzanrock]
      #4776975 - 08/29/11 11:22 PM

Excellent review!

The Ceravolo must be something to match a similar apertured quality APO!

Clear skies.


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SteveG
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Re: TEC140 vs. Ceravolo HD145 new [Re: NickG]
      #4778118 - 08/30/11 01:19 PM

Tammy - did you find that basket at the bottom of a rainbow?

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Re: TEC140 vs. Ceravolo HD145 new [Re: SteveG]
      #4778183 - 08/30/11 01:47 PM

Quote:

Tammy - did you find that basket at the bottom of a rainbow?




Ha ha ha. I found the basket at Target Store but there was no eyepiece in it

Tammy


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mountain monk
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Re: TEC140 vs. Ceravolo HD145 new [Re: Tamiji Homma]
      #4778785 - 08/30/11 07:09 PM

Daniel and Tammy,

Great project and writeup. The only problem is that the read is so intoxicating that I might give up simple observing for shootouts!

Dark skies.

mm


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Re: TEC140 vs. Ceravolo HD145 new [Re: mountain monk]
      #4779797 - 08/31/11 10:33 AM

Thanks for the report guys. Excellent as always!

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Re: TEC140 vs. Ceravolo HD145 new [Re: ckwastro]
      #4780019 - 08/31/11 12:32 PM

I think if there is one lesson from this test, it is that
quality is essential in optics. The Ceravalo is certainly
at the top as far as quality is concerned. Most of the high
end APO makers produce to high quality standards, and TEC is
certainly one of them. Yes, there are certain advantages to
different telescope designs, but the at the eyepiece
difference becomes very small if they are built to as close
to optimum level as possible.

I've looked through Matthias Wirth's Mak-Newts (an 8" and
a 10" he built), and again, they stood up well against the
large APOs on the field at WSP in Florida. As a result, I
was not really surprised by the outcome of this shootout.

Tom

Edited by Thomas A Davis (08/31/11 03:01 PM)


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Re: TEC140 vs. Ceravolo HD145 new [Re: Thomas A Davis]
      #4780628 - 08/31/11 05:32 PM

That eyepiece at bottom right, the 12.5mm Nikon, was in my eyepiece box all summer. Hundreds of kids looked through it while it was in my paracorr 2 in my 18 inch under dark skies and the views were amazing. Thanks Tammy!

Edited by Darren Drake (09/01/11 08:36 AM)


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Re: TEC140 vs. Ceravolo HD145 new [Re: NickG]
      #4781159 - 08/31/11 10:34 PM

I used an 7" AP and 8" Ceravolo MN side by side for two hours and you would be very hard pressed to tell them apart on planets.

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Re: TEC140 vs. Ceravolo HD145 new [Re: Darren Drake]
      #4781424 - 09/01/11 01:01 AM

Hi Darren,

You're welcome. I am happy to hear that you were able to show DSO to hundreds of kids at dark site. If the eyepiece were here, it did sit in eyepiece basket all summer long, not having any airtime due to marine layers

The eyepiece was back just in time to bring to Aug 27th star party. It impressed people at the party. I was one of them. It was breathtaking Double Cluster on both HD 145 and TEC 140.

Tammy


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Re: TEC140 vs. Ceravolo HD145 new [Re: Scott Beith]
      #4782798 - 09/01/11 05:27 PM

Hi everyone, I have recently joined CN due to the pre-occupation with nasty politics at the other site. Now onto what I want to say: Back in March, 1992, S+T had an article called "Optical Quality in Telescopes", in which four 6" f/8 Newtonians of 1, 1/2, 1/4, and 1/10 wavefront were compared, not just to each other, but to some AP Starfire apos as well. The 1/10 wave Newtonian was superb, as one of the authors concluded: "I was amazed to discover that a well made 6-inch reflector can approach the performance of a 7-inch StarFire refractor. From my observations, the difference between an excellent reflector and an excellent refractor is very subtle". Guess who fabricated the optics for the Newtonians? Peter Ceravolo. I would happily pay $1000 for the 6" f/8 1/10 wave Newtonian he made for that article.

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Thomas A Davis
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Re: TEC140 vs. Ceravolo HD145 new [Re: robert9375]
      #4784060 - 09/02/11 09:54 AM

I had the pleasure of looking through the Ceravalo mirrors
at Stellafane years ago. What made the 1/10th wave scope
that good was that it had a very smooth optical figure,
which brought light scatter to a minimum. This is one
advantage that high-end optics generally have over mass
produced optics. A well executed Newt, with well-figured,
smooth optics, along with good mechanics and small CO, can
perform far better than most would think. What a well
designed and executed Mak-Newt (such as the Ceravalo or
Matthias Wirth Mak-Newts) can provide is a the edge
correction the Newtonian lacks versus a refractor. Optical
smoothness, such as the Ceravalo optics, provides the
contrast factor that many mass-produced scopes lack.

I still wish I never sold the excellent 8" F/5 Telescopics
I owned back in the 1980s (small CO and 1/20th wave, smooth
optics). It was a great planetary scope. Best color
saturation on Jupiter I've had in any scope.

Tom


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Re: TEC140 vs. Ceravolo HD145 new [Re: Thomas A Davis]
      #4784667 - 09/02/11 02:28 PM

Thank you for the great write up on the shootout.

As I stated before, when I was offering to use my TEC140, the only things that bothers me about a shootout is where different eyepieces are used in each scope, each scope is set up on a slightly different spot where conditions can vary. Though high quality eyepieces are just that, they too can vary from piece to piece and focal length. But using different EPs with even different FOV to manage the differences in focal length is just not a good comparison in my opinion.

One other thing I would like to bring up is the use of a diagonal in this kind of testing. Diagonals will magnify defects in the system, plus add some of their own. If you are going to test or compare refractors, they should always be tested with out a diagonal. No extra glass or reflective surfaces should be used so that the optics themselves are as pristine as possible.

I only bring up these points because I believe that any review or comparison should include these explanations. Any one of these could cause one scope to perform at less than perfect and create enough difference to make the other scope seem slightly better

Given all this, I think the comparison was fairly predictable and shows that probably the TEC would have fared slightly better if it were to have been tested without the diagonal, even the better diagonal that was substituted.

Just the same, great fun and I am glad you got the chance to do the test and write it up.
Blueman


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Thomas A Davis
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Re: TEC140 vs. Ceravolo HD145 new [Re: blueman]
      #4784823 - 09/02/11 03:57 PM

What I think what all this shows is how close the two scopes
were to each other in performance. As long as they took
looking at the objects, that little difference shown could
easily be the differences in eyepieces or the effects of
the diagonal. I've done comparisons between several high
end eyepieces (Pentax SMC Orthos, Zeiss Abbe Orthos, and
TMB Supermonos) of the same focal length on the same scope
on the same night. All were at such a level that there
should have been essentially no difference, yet there were
subtle differences to my eye, no less than those shown in
this comparison. I think this was an excellent point to
bring out.

Tom


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Re: TEC140 vs. Ceravolo HD145 new [Re: blueman]
      #4785066 - 09/02/11 06:33 PM

All these issues are reasons that I have been advocating the use of MTF test charts for testing telecopes.

With refractors, you can basically elimiate the diagonal to remove it from the equeation.

And the difference in focal lenght in totally unimportant because you can move the test target closer or further as necessary to get to the maximum spacial frequence to make the comparison.

This eliminates all of the variables. There is no turbulance to deal with , no diagonal, no worry about magnification diffrences, and so on.

It is to me the only way to get a reliable result.

This page presents a nice overview of the process:
http://www.normankoren.com/Tutorials/MTF.html

Here is a link to charts that can be printed:

http://www.normankoren.com/Tutorials/MTF5.html

These charts off a superb way to compare optical quality. You can basically use the chart to measure the lowest spacial frequency that the scope is capable of resolving vs the theoretical limit.

It will also show mid-frequency falloff that will occur when there are abberations like spherical abberation or chromatic abberation, or a central obstruction.

I have mentioned this many many times, but for some reason, people seem to trust under the stars shootouts. It would seem to me to be much easier to simply set up a controlled test using MTF charts.

The MTF tests don't lie. That is why it is the standard for camera lens testing.

Also useful for comparing eyepieces. Again, it doesn't matter that the focal lenght is different. You simply move the target further or closer to get the same number of lines per millimeter at the focal plane into the field of each eyepeice. Using this, you can compare a 10mm to a 20mm using the same telescope if you desire.

Again, I don't know why people resist this kind of testing. It has far fewer variables and is easily repeatable.


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Re: TEC140 vs. Ceravolo HD145 new [Re: Eddgie]
      #4785633 - 09/03/11 12:46 AM

Eddy, excellent post and very true.
Blueman
Quote:

All these issues are reasons that I have been advocating the use of MTF test charts for testing telecopes.

With refractors, you can basically elimiate the diagonal to remove it from the equeation.

And the difference in focal lenght in totally unimportant because you can move the test target closer or further as necessary to get to the maximum spacial frequence to make the comparison.

This eliminates all of the variables. There is no turbulance to deal with , no diagonal, no worry about magnification diffrences, and so on.

It is to me the only way to get a reliable result.

This page presents a nice overview of the process:
http://www.normankoren.com/Tutorials/MTF.html

Here is a link to charts that can be printed:

http://www.normankoren.com/Tutorials/MTF5.html

These charts off a superb way to compare optical quality. You can basically use the chart to measure the lowest spacial frequency that the scope is capable of resolving vs the theoretical limit.

It will also show mid-frequency falloff that will occur when there are abberations like spherical abberation or chromatic abberation, or a central obstruction.

I have mentioned this many many times, but for some reason, people seem to trust under the stars shootouts. It would seem to me to be much easier to simply set up a controlled test using MTF charts.

The MTF tests don't lie. That is why it is the standard for camera lens testing.

Also useful for comparing eyepieces. Again, it doesn't matter that the focal lenght is different. You simply move the target further or closer to get the same number of lines per millimeter at the focal plane into the field of each eyepeice. Using this, you can compare a 10mm to a 20mm using the same telescope if you desire.

Again, I don't know why people resist this kind of testing. It has far fewer variables and is easily repeatable.




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Re: TEC140 vs. Ceravolo HD145 new [Re: Thomas A Davis]
      #4785636 - 09/03/11 12:47 AM

Hi Tom, your post exactly agrees with my own observations. I have even seen differences between two examples of the same EP.
Blueman
Quote:

What I think what all this shows is how close the two scopes
were to each other in performance. As long as they took
looking at the objects, that little difference shown could
easily be the differences in eyepieces or the effects of
the diagonal. I've done comparisons between several high
end eyepieces (Pentax SMC Orthos, Zeiss Abbe Orthos, and
TMB Supermonos) of the same focal length on the same scope
on the same night. All were at such a level that there
should have been essentially no difference, yet there were
subtle differences to my eye, no less than those shown in
this comparison. I think this was an excellent point to
bring out.

Tom




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Re: TEC140 vs. Ceravolo HD145 new [Re: blueman]
      #4785715 - 09/03/11 01:56 AM

Eddgie,
As you know, a test chart must lie at some minumum distance from the instrument, that distance depending on aperture and f/ratio. Inside that minimum and the non-optimal cojugate results in spherical aberration. Therefore the tester had better know at what minimum distance to place the target, lest an additionally-aberrated image result.


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Re: TEC140 vs. Ceravolo HD145 new [Re: GlennLeDrew]
      #4786535 - 09/03/11 01:54 PM

So much being said in this forum. I am at OSP right now and unable to respond properly because I'm writing from a cell phone with hardly any reception here. Many good points raised. I will later explain why "field" tests like this are important and why I do tests this way. I also want to share some issues Evan Chan raised in a private email. Evan has great insight I will explain later. John if you are up for another comparison I'm game. I would like you to come to my site where the air stands still. The temps also behave. I can setup both Ceravolos. We can push the limits. Floyd Blue says he to would enjoy comparing his TEC140 to the Ceravolos. The skies on the coast can easily achieve sub arc second. Also when I explain what Evan shared, the Jupiter comparison can be solved and concluded finally.

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Re: TEC140 vs. Ceravolo HD145 new [Re: Daniel Mounsey]
      #4786803 - 09/03/11 04:19 PM

Looking forward to your next shoot-out Daniel. Are you including your FS152 as well?

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Re: TEC140 vs. Ceravolo HD145 new [Re: GlennLeDrew]
      #4786961 - 09/03/11 05:38 PM

Yes, of course you are correct. The charts should be placed no closer than 10 to 20 times the focal length, but again, if the telescopes are of different focal lenghs and focal ratios, the targets will have to be move in and out as needed to get the max spacial frequency at the focal plane.

But that is not usually difficult to do because in order to get to the max spacial frequency, the charts usually have to be at a fair distance.

But the link I sent earlier has the formulas needed to determine much of what is needed to be successful using charts to test contrast transfer.

And I am not saying that testing this way (using MTF charts) is EASIER than just plopping down to telescopes and pointing them at an ever changing target like Jupiter.

Is all I am saying is that when done properly, it eliminates many of the variables have potential to color the results of testing done in the field.

The result if also more "Quantifiable." One can see very specifically where contrast is being affected and can actually evaluate somewhat more scientifically how MUCH contrast is being affected. Is it being affected 5%? 10%?

And this is important because in the FIELD, contrast has to be down about 20% before it will be readibly detectable.

The whole point of MTF charts is to allow the tester to ascertain how BADLY the contrast is being affected.

I personally don't care if people choose not to believe that MTF test charts are a better way of testing, but people that have started doing testing this way have often told me that it is hard to go back once you start.


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Re: TEC140 vs. Ceravolo HD145 new [Re: blueman]
      #4804773 - 09/13/11 12:24 AM

Hi Floyd,

Okay back on track after OSP. Let me explain a few things regarding this test so there's no misunderstandings. First, I already know both the TEC140 and HD145 are excellent telescopes optically and Iíve seen enough to verify this already, so no need to be concerned about confirmation of that. The diagonals we use are time tested with tons of experience and are unquestionably excellent. June, the observer I barrowed it from is very particular about diagonals. My issue is that I have concern with the publics general perception of comparing optics which is why I do tests this way.

I still think there are many readers who spend too much time anylizing over data with telescopes they have little or no experience using under the stars whether it be glass type, color correction, F ratios, designs, triplet, doublet whatever it is. Of course I can understand if they donít have a speciman to test, so they have little choice but to rely on the best data they can get their hands on.

The point of this exercise however was to express what "really" goes on in the field and that's what matters to me. Let's look at this practically. Who views without diagonals others than the Japanese? Okay maybe there's a couple of observers who don't use diagonals but for the most part, everybody uses them. Let's not forget too that the HD145 has an inherent diagonal. I think it only fair and practical that the TEC140 have a diagonal as well.

Doing these special procedures like the MTF or removal of the diagonal certainly have importances and donít get me wrong, I respect that. My concern though is to help give others a realistic understanding that hey! This is what itís really like comparing scopes sometimes, and it helps us remember that when we are haggling over percentages, it isnít always a walk in the park like others often think. ďThermal GremlinsĒ are one of the most distructive forces to optics hands down. Itís like an invisible force. I myself find myself challenged to convince observers of its existance.

Even after lectures at public star parties and outreach programs Iíll have people walk up to me saying, that was an interesting topic you covored, I wasnít even aware of that. Neil English of ďAstronomy NowĒ http://www.astronomynow.com/books/Choosing%20and%20Using%20a%20Refracting%20Telescope.html is one of only several individuals to approach me on the seriousness of the problem regarding thermal gremlins, yet many of the incredible points Neil has covered have gone unnoticed.

You can take the most exquisite large aperture reflective optics money can by, only to watch their dimise unless acted upon by a greater force. Have you ever watched planets in a Newtonian reflector and youíre sitting there just waiting for that moment where everything comes together? Their it is! the moment of truth! And it stuns our imagination! Detail beyond belief on other planetary worlds. Then, the next day you go out and things just donít come together or have that same spark.

The moral of the story is that we have to be at the right place at the right time. We ourselves, have to be there to experience it first hand with an open mind.

The purpose of a telescope is to collect light but most of all, to enjoy using them in the field where they belong and that includes testing. If I can not take the time to see or appreciate the differences myself, then it becomes an almost fruitless endeavor in my opinion. Sure, in this case it was harder to judge because like most observers, the location wasnít the most ideal. I rated seeing a 6 to averaging a 7, but trust me, I've seen planetary feature at the best observing locations that most humans will never see in a life time. I'm planning on better seeing conditions very soon for the next rally if we do it the way I suggest.

Shortly after this review was posted, Evan Chan sent me a private email explaining that during the observations, the Ceravolo having been about 2 ft closer to the warm pavement caused some currents to hurt the images in the HD145 and most likely granted the TEC140 more consistant images on Jupiter. At the time of observations, Jupiter was still considerably low compared to the other targets like the Double Cluster which were tested at lower, less critical magnifications. Evan stated that when he placed his hands to the gound at one point, the pavement was still warm.

Letís think about the fact that no matter how great an optic may be, it could be altered by a greater force such as thermals from the ground. Itís hard for most observers to believe or grasp it, but it can in fact have a dramatic impact on the images. Iím absolutely confident the HD145 will deliver breathtaking images on Jupiter compared to any TEC140. During the last Mars approach, June and I both saw some of the most detailed and amazing images of Mars with the HD145. Truly memorable. Due to the Mak Newts inherent design, we have to factor in the thermal gremlins from the pavement below.

If that means setting up on grass, then fine, we can do that. Honestly, I didnít go into this expecting the most ideal conditions during this comparison and too often, observers walk away with premature conclusions without consideration and I rarely ever do that. Iíve been around and seen enough at Charlton Flats for many years against some of the best planetary telescopes in the world.

Cheers!

Edited by Daniel Mounsey (09/13/11 12:28 AM)


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Re: TEC140 vs. Ceravolo HD145 new [Re: Daniel Mounsey]
      #4804811 - 09/13/11 01:04 AM

Hi Daniel,
I respect your opinions and am not trying to say your test have no merit.

But I will still stand behind my comment though, you stated that the original diagonal used had problems and so it was replaced with a known good one. Well, I think that if you are comparing optics you must compare them in their native condition. For the refractor, that means no diagonal.

The reflector on the other hand has a secondary mirror, but that is part of the design, so that is its native condition. Therefor it is being tested without any extra glass or reflective surfaces. This is an advantage to me.

Now honestly, I think the C-145 is a great instrument and probably does a great job of producing images. I have never actually used one, they are a bit rare.

Myself, if I want to see planets with the most detail, I use my Starmaster 14.5" DOB. It produces fantastic views of Jupiter or Saturn or even Mars. Aperture rules if the optics are excellent.
Floyd
Quote:

Hi Floyd,

Okay back on track after OSP. Let me explain a few things regarding this test so there's no misunderstandings. First, I already know both the TEC140 and HD145 are excellent telescopes optically and Iíve seen enough to verify this already, so no need to be concerned about confirmation of that. The diagonals we use are time tested with tons of experience and are unquestionably excellent. June, the observer I barrowed it from is very particular about diagonals. My issue is that I have concern with the publics general perception of comparing optics which is why I do tests this way.

I still think there are many readers who spend too much time anylizing over data with telescopes they have little or no experience using under the stars whether it be glass type, color correction, F ratios, designs, triplet, doublet whatever it is. Of course I can understand if they donít have a speciman to test, so they have little choice but to rely on the best data they can get their hands on.

The point of this exercise however was to express what "really" goes on in the field and that's what matters to me. Let's look at this practically. Who views without diagonals others than the Japanese? Okay maybe there's a couple of observers who don't use diagonals but for the most part, everybody uses them. Let's not forget too that the HD145 has an inherent diagonal. I think it only fair and practical that the TEC140 have a diagonal as well.

Doing these special procedures like the MTF or removal of the diagonal certainly have importances and donít get me wrong, I respect that. My concern though is to help give others a realistic understanding that hey! This is what itís really like comparing scopes sometimes, and it helps us remember that when we are haggling over percentages, it isnít always a walk in the park like others often think. ďThermal GremlinsĒ are one of the most distructive forces to optics hands down. Itís like an invisible force. I myself find myself challenged to convince observers of its existance.

Even after lectures at public star parties and outreach programs Iíll have people walk up to me saying, that was an interesting topic you covored, I wasnít even aware of that. Neil English of ďAstronomy NowĒ http://www.astronomynow.com/books/Choosing%20and%20Using%20a%20Refracting%20Telescope.html is one of only several individuals to approach me on the seriousness of the problem regarding thermal gremlins, yet many of the incredible points Neil has covered have gone unnoticed.

You can take the most exquisite large aperture reflective optics money can by, only to watch their dimise unless acted upon by a greater force. Have you ever watched planets in a Newtonian reflector and youíre sitting there just waiting for that moment where everything comes together? Their it is! the moment of truth! And it stuns our imagination! Detail beyond belief on other planetary worlds. Then, the next day you go out and things just donít come together or have that same spark.

The moral of the story is that we have to be at the right place at the right time. We ourselves, have to be there to experience it first hand with an open mind.

The purpose of a telescope is to collect light but most of all, to enjoy using them in the field where they belong and that includes testing. If I can not take the time to see or appreciate the differences myself, then it becomes an almost fruitless endeavor in my opinion. Sure, in this case it was harder to judge because like most observers, the location wasnít the most ideal. I rated seeing a 6 to averaging a 7, but trust me, I've seen planetary feature at the best observing locations that most humans will never see in a life time. I'm planning on better seeing conditions very soon for the next rally if we do it the way I suggest.

Shortly after this review was posted, Evan Chan sent me a private email explaining that during the observations, the Ceravolo having been about 2 ft closer to the warm pavement caused some currents to hurt the images in the HD145 and most likely granted the TEC140 more consistant images on Jupiter. At the time of observations, Jupiter was still considerably low compared to the other targets like the Double Cluster which were tested at lower, less critical magnifications. Evan stated that when he placed his hands to the gound at one point, the pavement was still warm.

Letís think about the fact that no matter how great an optic may be, it could be altered by a greater force such as thermals from the ground. Itís hard for most observers to believe or grasp it, but it can in fact have a dramatic impact on the images. Iím absolutely confident the HD145 will deliver breathtaking images on Jupiter compared to any TEC140. During the last Mars approach, June and I both saw some of the most detailed and amazing images of Mars with the HD145. Truly memorable. Due to the Mak Newts inherent design, we have to factor in the thermal gremlins from the pavement below.

If that means setting up on grass, then fine, we can do that. Honestly, I didnít go into this expecting the most ideal conditions during this comparison and too often, observers walk away with premature conclusions without consideration and I rarely ever do that. Iíve been around and seen enough at Charlton Flats for many years against some of the best planetary telescopes in the world.

Cheers!




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Re: TEC140 vs. Ceravolo HD145 new [Re: blueman]
      #4804823 - 09/13/11 01:17 AM

Okay Floyd. Let's try it your way and see what happens. I'll bring a couple of really good diagonals for you including a supurb prism diagonal. We can compare the images with an without a diagonal on Jupiter using your TEC140.


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Re: TEC140 vs. Ceravolo HD145 new [Re: Daniel Mounsey]
      #4804887 - 09/13/11 02:34 AM

Hi Daniel,
That sounds reasonable.
Really, I have never even looked through my TEC140, though I have looked through others. I have only imaged with it.
Floyd


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Re: TEC140 vs. Ceravolo HD145 new [Re: blueman]
      #4804936 - 09/13/11 04:32 AM

Quote:

Really, I have never even looked through my TEC140, though I have looked through others. I have only imaged with it.








Clear skies!
Thomas, Denmark


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Daniel Mounsey
Vendor (Woodland Hills)
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Reged: 06/12/02

Re: TEC140 vs. Ceravolo HD145 new [Re: blueman]
      #4806513 - 09/13/11 11:20 PM

Quote:

Hi Daniel,
That sounds reasonable.
Really, I have never even looked through my TEC140, though I have looked through others. I have only imaged with it.
Floyd






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blueman
Photon Catcher
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Reged: 07/20/07

Loc: California
Re: TEC140 vs. Ceravolo HD145 new [Re: Daniel Mounsey]
      #4806644 - 09/14/11 01:36 AM

Sorry guys, but I bought the TEC140 for imaging and that is how I use it.
Blueman


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skybsd
Post Laureate
*****

Reged: 02/01/08

Re: TEC140 vs. Ceravolo HD145 new [Re: blueman]
      #4806689 - 09/14/11 02:46 AM

Quote:

Sorry guys, but I bought the TEC140 for imaging and that is how I use it.
Blueman




No need to apologize, Floyd There's someone further along on the street where I live who only drives his (rather expensive) italian GTO to and from his office - less than 2 miles away each day, Hahahaaaa!!!

Regards,

skybsd


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Astrojensen
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Re: TEC140 vs. Ceravolo HD145 new [Re: blueman]
      #4806725 - 09/14/11 04:58 AM

Quote:

Sorry guys, but I bought the TEC140 for imaging and that is how I use it.




No need to be sorry, Floyd. Each to his own, and I'm sure it's a wonderful astrograph. I was just teasing you.

I'd like to have a TEC 140 one day, but that day seems to be quite a way into the future right now in this economy.


Clear skies!
Thomas, Denmark


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Vondragonnoggin
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Reged: 02/21/10

Loc: Southern CA, USA
Re: TEC140 vs. Ceravolo HD145 new [Re: Astrojensen]
      #4806950 - 09/14/11 09:08 AM

Personally, I would rather see results from two telescopes setup in real observing conditions. Seeing what the telescope can do to it's optimum potential is great, but I view with a diagonal in. I view where conditions can have thermal gremlins.

I often wondered about collimation itself with my doublet. If I collimate the scope and it is perfect with no diagonal, then put my diagonal in to where it always sits and I use the same diagonal all the time, and find collimation out again, wouldn't it be better to conditionally align the scope with the diagonal in? That is how I'll be viewing all the time. I understand that if I change diagonals, then I would have to conditionally align it again.

I also understand it should probably be aligned under load to give accurate real world conditions.

I would think this would result in a better view when you are taking the scope to the same viewing areas all the time and have it setup the same way.

Just a thought Daniel sparked whe mentioned testing with diagonal in.


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arkeoastro
newbie


Reged: 01/26/09

Loc: Laval (Quebec)-Canada
Re: TEC140 vs. Ceravolo HD145 new [Re: Daniel Mounsey]
      #5032014 - 01/22/12 11:24 AM Attachment (51 downloads)

Hi,

Thanks for this great review, very professionnal! I own a Ceravolo HD-145 and wish to have more details on the fan you used for cooling the optics.

Pierre


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arkeoastro
newbie


Reged: 01/26/09

Loc: Laval (Quebec)-Canada
Re: TEC140 vs. Ceravolo HD145 new [Re: Daniel Mounsey]
      #5032024 - 01/22/12 11:28 AM Attachment (66 downloads)

Great review, very professionnal, thanks! I own a Ceravolo HD-145 (see picture) and wish to have more details on the fan you used for cooling the tube ans mirrors.

Pierre


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jrbarnett
Eyepiece Hooligan
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Reged: 02/28/06

Loc: Petaluma, CA
Re: TEC140 vs. Ceravolo HD145 new [Re: Vondragonnoggin]
      #5032108 - 01/22/12 12:16 PM

One nice thing about most refractors is that they have to be WAY out of collimation to make much of a difference in image quality. Not so most other designs.

Regards,

Jim


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maknewtnut
Member
*****

Reged: 10/08/06

Re: TEC140 vs. Ceravolo HD145 new [Re: Daniel Mounsey]
      #5033619 - 01/23/12 09:22 AM

Contributions such as Dainiel's shootout do a great service to the community as a whole. IMHO, it provides a blueprint of sorts when it comes to strive for objectivity in comparisons. Perhaps more important is that it might tend to affect the advice we might offer in forums such as this as a result.

Blanket statements about aperture, telescope design type, or even make alone become suspect to those who ask themselves questions about what they see in the eyepiece. The human eye can be a wonderful detector, surpassed only by the human brain as an image processor.

I recall countless numbers in the past several years who have been delighted by "the best view of Jupiter I've ever seen", provided by a budget priced sub-4" refractor they just bought. One can't help but think, "I wonder if they've ever looked through a 6-10" reflector with great optics?" The same thought comes to mind after reading posts claiming aperture rules..period, for high mag observation.

There are a bunch of variables to consider when assessing ANY telescope. The very best placed on black and white will always address those variables.


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pbsastro
professor emeritus
*****

Reged: 03/21/07

Re: TEC140 vs. Ceravolo HD145 new [Re: maknewtnut]
      #5034484 - 01/23/12 07:36 PM

Such a small secondary results in a tiny tiny 100% illumination field. 1mm? Outside that minuscle spot it is all sub-aperture.
No thanks. Apo all the way for apertures up to 7". Reflectors are amazing, but start at 8", and shine starting at 12". The larger the reflector aperture the smaller secondary (relative) size is required for 2" field illumination. That is until we start making them f/4 and f/3...


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Reef58
super member


Reged: 08/06/06

Re: TEC140 vs. Ceravolo HD145 new [Re: pbsastro]
      #5353008 - 08/05/12 11:56 AM

I think the bottom line is optical quality is of the utmost importance, and design, reflector, refractor, ect is based on needs for the scope. That is why I have a love hate with SCT's. They have so much potential, but they are made in a hurry for max profit. I would pay a nice ransom for a Spooner, Zambuto, Cerevalo 10 to 12 inch f10 SCT. That would be one nice scope.

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jmiele
Patron Saint?
*****

Reged: 12/04/10

Re: TEC140 vs. Ceravolo HD145 new [Re: maknewtnut]
      #5353056 - 08/05/12 12:24 PM

Mark, Agreed. Not sure if it's only a US phenomenon that we continually keep comparing instruments best on only subjective opinion. TBH, I'd say 50% of our threads are focused on just that, and based only on opinion - very subjective opinion. I know I'm guilty. When folks take the time to do extensive in depth and well thought out analysis (like Daniel), it's very much appreciated.

Best,
Joe


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jm510227
member


Reged: 12/02/06

Loc: Tulsa, OK
Re: TEC140 vs. Ceravolo HD145 new [Re: arkeoastro]
      #5581071 - 12/20/12 05:05 PM

Pierre:

Your telescope is beautiful, but the wooden tripod is a work of art. Not to hijack the thread, but did you make it or puchase it? If you purchased it, who is the manufacturer?

Regards,
Jim Miller/Tulsa, OK


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Astrojensen
Post Laureate
*****

Reged: 10/05/08

Loc: Bornholm, Denmark
Re: TEC140 vs. Ceravolo HD145 new [Re: jm510227]
      #5581170 - 12/20/12 05:48 PM

The tripod is a Berlebach. http://www.berlebach.de/


Clear skies!
Thomas, Denmark


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