Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

4" Apochromatic Hyper Shootout

This topic has been archived. This means that you cannot reply to this topic.
422 replies to this topic

#276 moshen

moshen

    Apollo

  • *****
  • Posts: 1,314
  • Joined: 17 May 2006

Posted 05 September 2008 - 01:10 AM

Best review ever, I agree. Was waiting for this one for a long time, thanks Daniel!
 

#277 gjg

gjg

    Explorer 1

  • -----
  • Posts: 81
  • Joined: 22 May 2006

Posted 05 September 2008 - 01:14 AM

Wow, amazing review. It really is a hyper-shootout.

What viewing site do you prefer for planets: Your home near the ocean, Topanga Canyon site, or Charlton flats?

Greg
 

#278 Daniel Mounsey

Daniel Mounsey

    Vendor (Woodland Hills)

  • *****
  • Vendors
  • topic starter
  • Posts: 7,900
  • Joined: 12 Jun 2002

Posted 05 September 2008 - 01:30 AM

Awesome write up Doctor D. Absolutely worth the wait.

I did an A/B comparison over many nights between the TSA102 and FS102; I owned both concurrently.

Like you, I saw no discernable contrast difference between the two. Color correction definitely went to the TSA. Here's my question. With 6 air/glass interfaces compared to 4 for the FS102, I was expecting the FS to be better in contrast. Do you think that the TSA's better color correction and perhaps different/newer coatings were the factors that made up for this equality in contrast???


This is a good question. I actually found the contrast in both scopes equal. I'm not into the science aspects as much as some of the other guys and gals who participate in these forums. I'm mainly a visual observer who can judge differences with trained eyes and I know what to look for visually and learning from veterans like Pons and Grissom. From what I heard, and someone else can probably varify this better than I can, FPL-53 is apparently better than flourite accross the color spectrum, but don't quote me on that until we hear more facts. There's much more to it than this. BTW, here's an excellent essay by Thomas Back
http://geogdata.csun...e/tmb/tmb1.html
Technically, the coatings mainly increase the light transmission, but I believe the coatings in both scopes are phenominal, so it's hard to say that's the difference. I am honestly convinced that as long as a triplet is very well corrected, meaning the star test behaves, I see no reason why any doublet should do any better. I myself admit the obsession with cutting glass out of the equation, buts there's much more to it than that as well. Triplets are fantastic as long as they are made well and I'm convinced of that.

The only two differences we could possibly see between the FS and TSA were color correction on stars going to the TSA and the glass being just completely white without even a trace of warmth in the TSA. To this day, regardless of the TSA coming out on top, I still like the FS102 and FC100 units for the most part because they can get up and start running noticibly quicker than triplets and they behave so well in various climates more easily from what my visual tests reveal. I can't help loving them. I currently use two scopes, the TV101 and FSQ but I actually will one day own an FC or FS again. I have a friend with a really fantastic FC100. It's really hard to say. The TSA, FC and FS are all so good, you could just toss a coin.

I just put this exchange here in case my statements were inaccurate.

Quote:

Quote:

FPL-53 is apparently better than flourite accross the color spectrum,



Totally wrong. CaF2 ALWAYS allow better color correction, with lesser spherochromatism, than FPL53. This is especially true in doublet apos.
Also, CaF2 is transparent in significantly wider spectral range, than FPL53 does.

CaF2 blanks can be grown up even in 24" diameter, while FPL53 is quite limited to about 12".



Thank you for the clarification. I recall a stat list that RC posted on Amart but I probably read it the wrong way around.

--------------------
 

#279 Daniel Mounsey

Daniel Mounsey

    Vendor (Woodland Hills)

  • *****
  • Vendors
  • topic starter
  • Posts: 7,900
  • Joined: 12 Jun 2002

Posted 05 September 2008 - 01:38 AM

Wow, amazing review. It really is a hyper-shootout.

What viewing site do you prefer for planets: Your home near the ocean, Topanga Canyon site, or Charlton flats?

Greg


Charlton Flats is the best, right next to Mt. Wilson. We only recently discovered it being reopened after a 4 year closure and this Saturday will be our last visit there until the planets return. In the meantime, Topanga is a the place because it's closer for now and it's reasonably good enough for nice Lunar viewing. The Moon is really fascinating to view if you pick off specific targets and challenge yourself. Next to the ocean is best because it prevents major ups and downs in temperature, but you sometimes have to contend with marine layer, which is the advantage to Wilson. You get the onshore breeze and the transparency.
 

#280 ValeryD

ValeryD

    Vendor (Aries)

  • ****-
  • Vendors
  • Posts: 1,991
  • Joined: 26 Nov 2005

Posted 05 September 2008 - 05:23 AM

FPL-53 is apparently better than flourite accross the color spectrum,


Totally wrong. CaF2 ALWAYS allow better color correction, with lesser spherochromatism, than FPL53. This is especially true in doublet apos.
Also, CaF2 is transparent in significantly wider spectral range, than FPL53 does.

CaF2 blanks can be grown up even in 24" diameter, while FPL53 is quite limited to about 12".
 

#281 Clive Gibbons

Clive Gibbons

    Mostly Harmless

  • *****
  • Posts: 16,724
  • Joined: 26 May 2005

Posted 05 September 2008 - 07:45 AM

That was fun to read and very informative, Daniel! :applause:

You mentioned using a Baader prism diagonal for the comparisons. Did you notice any shift in color correction when using that and if so, which scopes showed a difference
(improvement?).
Much has changed in the ED refractor world since early 2007.
And more developments are close at hand.
If you get a chance to do a shoot-out with some of the newer offerings, and explore the performance possibilities of more readily available 1.25" prism diagonals in those refractors, it would be really great to hear your findings.

:ubetcha: :waytogo:
 

#282 Dave Novoselsky

Dave Novoselsky

    Messenger

  • -----
  • Posts: 462
  • Joined: 16 Jun 2008

Posted 05 September 2008 - 08:21 AM

May I comment on one aspect of your review that may have been passed over as not directly related to its conclusion? The fact that you sold the 'prize' Tak to Tammy is heart warming. I have never met him, but his posts here do show that he is precisely as you described him, a 'gentleman.' That scope went to the best possible home. Dave
 

#283 leexeen

leexeen

    Viking 1

  • -----
  • Posts: 842
  • Joined: 08 Aug 2007

Posted 05 September 2008 - 08:29 AM

Hi Guys, sorry for the off topic but I've been thinking that Tammy is a lady. I saw the photos on the PBase. Sorry if I made a mistake... Can some one correct me if I am wrong?
 

#284 Dave Novoselsky

Dave Novoselsky

    Messenger

  • -----
  • Posts: 462
  • Joined: 16 Jun 2008

Posted 05 September 2008 - 08:40 AM

One aspect of this review is something not often raised, but a fact that exists nonetheless. Despite modern manufacturing techniques, any telescope is an end product of individual parts and final assembly that can effect its ultimate performance. A good company will ensure that both the essential element of the refractor (the optics) is completed within a tight tolerance and then assembled into a lens cell and placed within the OTA and then tests that to again ensure that everything is within that tight spec.

Nonetheless, some end products are just going to be better than others, particularly where some hand finishing or 'final, hand correction' may take place. The prize Takahashi Dan mentioned was one of those, "so good that it is incredible" scopes that are spectacular in comparison not only to other scopes from other companies, but the very peak of the 'pool' of other available and otherwise identical scopes. Dan sold this one to Tammy, a lucky man.

I am aware of one such 'sport' that Roland built and which ended up in the hands of a dedicated astrophotographer. When he wanted to sell it, he sold it to a friend equally dedicated who was well aware that what he was getting, like the Tak Dan described, was the very pinnacle of an already superb scope series.

The late Tom Back would get his optics from a very good optic company, built to his design, and complete the scope with tube assembly, focuser, etc from another source and then test and check each one before shipping them to a customer. (This was when TMB was strictly a one man show, Tom.) We were friends and I acquired many early TMBs. One day Tom called and said that he had just gotten a pair of 100 /f8 optics that were the finest he had ever seen in anything, bar none. He had access to the necessary test equipment and was not going strictly be the papers that came with the optics, and confirmed with his own testing and once the optics were put into a finished product that these two were the very best.

He kept one for himself and sold me the other. I already has a similar, very good, but according to Tom, not quite like this TMB 100 f/8. He was right. Like Dan reports, the best way to find out is to test them side by side. These two TMBs spent a few months on opposite sides of a Giro II going through a workout by myself and some very astute and experienced 'locals' then associated with the original CN crew. The testing then went along with what was then the best of the other 4" scopes available, Tak, AP, etc. When Tom was in the area, he came over and brought the 'brother' of the scope he sold me. We did a few side by sides along with some comparisons with the other brands.

When it was over, I sold the one TMB and kept the other. I still have it and intend to keep it. Like Dan, I agree that from time to time, a 'sport' shows up within a series, some good, and some not so good. When you find yourself with the former, sell the kids off first. Dave
 

#285 Dave Novoselsky

Dave Novoselsky

    Messenger

  • -----
  • Posts: 462
  • Joined: 16 Jun 2008

Posted 05 September 2008 - 08:42 AM

Hi Guys, sorry for the off topic but I've been thinking that Tammy is a lady. I saw the photos on the PBase. Sorry if I made a mistake... Can some one correct me if I am wrong?


A 'guy' with a family. Tammy is the shorhand version of his real name. Dave
 

#286 Daniel Mounsey

Daniel Mounsey

    Vendor (Woodland Hills)

  • *****
  • Vendors
  • topic starter
  • Posts: 7,900
  • Joined: 12 Jun 2002

Posted 05 September 2008 - 08:51 AM

FPL-53 is apparently better than flourite accross the color spectrum,


Totally wrong. CaF2 ALWAYS allow better color correction, with lesser spherochromatism, than FPL53. This is especially true in doublet apos.
Also, CaF2 is transparent in significantly wider spectral range, than FPL53 does.

CaF2 blanks can be grown up even in 24" diameter, while FPL53 is quite limited to about 12".


Thank you for the clarification. I recall a stat list that RC posted on Amart but I probably read it the wrong way around. :)
 

#287 Daniel Mounsey

Daniel Mounsey

    Vendor (Woodland Hills)

  • *****
  • Vendors
  • topic starter
  • Posts: 7,900
  • Joined: 12 Jun 2002

Posted 05 September 2008 - 08:55 AM

Hi Guys, sorry for the off topic but I've been thinking that Tammy is a lady. I saw the photos on the PBase. Sorry if I made a mistake... Can some one correct me if I am wrong?


Yes, Tamiji is a guy that started viewing with us and I think he uses Tammy for simplicity.
 

#288 Tamiji Homma

Tamiji Homma

    Skylab

  • *****
  • Posts: 4,364
  • Joined: 24 Feb 2007

Posted 05 September 2008 - 09:01 AM

Hi Guys, sorry for the off topic but I've been thinking that Tammy is a lady. I saw the photos on the PBase. Sorry if I made a mistake... Can some one correct me if I am wrong?


A 'guy' with a family. Tammy is the shorhand version of his real name. Dave


Hi Dave and Kurt.

Yes, I am a guy. Sorry about confusion. My handle is Tammy.
It was started with Tami, Tamy, and then Tammy.
Being ham radio operator since I was a kid, I love
sound of "Tammy" in morse code... That's why I've chosen
Tammy despite Tammy is common girl's name.

Anyway, I didn't know Daniel gave me the best TSA.
Thanks Daniel. I feel honer blessed with chosen one :)

Tammy
 

#289 Daniel Mounsey

Daniel Mounsey

    Vendor (Woodland Hills)

  • *****
  • Vendors
  • topic starter
  • Posts: 7,900
  • Joined: 12 Jun 2002

Posted 05 September 2008 - 09:03 AM

Dave, It's good to read your posts. The story about Back and the TMB's is really interesting and I know you are one of the few people on the planet that's tried just about everything. Back did a good job in the day and I think he cared a good deal. :bow:
 

#290 Daniel Mounsey

Daniel Mounsey

    Vendor (Woodland Hills)

  • *****
  • Vendors
  • topic starter
  • Posts: 7,900
  • Joined: 12 Jun 2002

Posted 05 September 2008 - 09:06 AM

Hi Guys, sorry for the off topic but I've been thinking that Tammy is a lady. I saw the photos on the PBase. Sorry if I made a mistake... Can some one correct me if I am wrong?


A 'guy' with a family. Tammy is the shorhand version of his real name. Dave


Hi Dave and Kurt.

Yes, I am a guy. Sorry about confusion. My handle is Tammy.
It was started with Tami, Tamy, and then Tammy.
Being ham radio operator since I was a kid, I love
sound of "Tammy" in morse code... That's why I've chosen
Tammy despite Tammy is common girl's name.

Anyway, I didn't know Daniel gave me the best TSA.
Thanks Daniel. I feel honer blessed with chosen one :)

Tammy


Tammy works for me. As long as you stay humble, there's no problems here. :lol:
 

#291 Daniel Mounsey

Daniel Mounsey

    Vendor (Woodland Hills)

  • *****
  • Vendors
  • topic starter
  • Posts: 7,900
  • Joined: 12 Jun 2002

Posted 05 September 2008 - 09:32 AM

That was fun to read and very informative, Daniel! :applause:

You mentioned using a Baader prism diagonal for the comparisons. Did you notice any shift in color correction when using that and if so, which scopes showed a difference
(improvement?).
Much has changed in the ED refractor world since early 2007.
And more developments are close at hand.
If you get a chance to do a shoot-out with some of the newer offerings, and explore the performance possibilities of more readily available 1.25" prism diagonals in those refractors, it would be really great to hear your findings.

:ubetcha: :waytogo:


Clive, thanks for the input. My friend Jorge and I tested the prism in a large apo about two years ago. No we didn't notice any difference in color correction but that is by no means meant to imply you wouldn't. I think your recent article, which was very interesting and well needed as prisms have gotten such a bad rap in the past. I like to see things out of the ordinary. :bow:
 

#292 Ziggy943

Ziggy943

    In Memoriam

  • *****
  • In Memoriam
  • Posts: 3,537
  • Joined: 11 Aug 2006

Posted 05 September 2008 - 09:41 AM

Thank you Daniel for a well done informative post. I go between a Baader prism and an AP diagonal with very little difference but I would give a slight edge to the AP diagonal.

But on the planets and the Moon I enjoy the correct view so much that the prism is usually the one I use.

Thanks again and we'll forgive the typos :)
 

#293 Clive Gibbons

Clive Gibbons

    Mostly Harmless

  • *****
  • Posts: 16,724
  • Joined: 26 May 2005

Posted 05 September 2008 - 09:43 AM

Thanks very much, Daniel. :thanx:
Roland C. stated in another forum that his analysis of adding a prism to one of his large ED triplet designs wouldn't make a noticeable difference, so I can see that your trial of the Baader prism in a big APO would have similar results. :ubetcha:
Do you plan on testing any of the latest 4" ED doublets (and triplets, like the AT-111) in the near future?
 

#294 Daniel Mounsey

Daniel Mounsey

    Vendor (Woodland Hills)

  • *****
  • Vendors
  • topic starter
  • Posts: 7,900
  • Joined: 12 Jun 2002

Posted 05 September 2008 - 10:13 AM

Thanks Siegfried!


That's a good question Clive. I think what will happen is that observers will be visiting the new Topanga site and sharing their scopes. I've already gotten a few offers on some of these other doublets. If we can test them while we're there, then I'll add them to this forum so we can convert it into an informative 4" visual forum.
 

#295 Joad

Joad

    Wordsmith

  • *****
  • Posts: 18,433
  • Joined: 22 Mar 2005

Posted 05 September 2008 - 10:47 AM

Congratulations on such a carefully written, detailed and inclusive report, Doctor D. It is encyclopedic and provides an education in general optics as well as in specific telescopes. Much to learn here! Thank you.
 

#296 roadi

roadi

    Surveyor 1

  • *****
  • Posts: 1,504
  • Joined: 18 Aug 2007

Posted 05 September 2008 - 11:50 AM

Great readings and very interesting!!
The last few senteces in the rewiews are just great!! :waytogo:
 

#297 BillP

BillP

    ISS

  • *****
  • Posts: 20,505
  • Joined: 26 Nov 2006

Posted 05 September 2008 - 11:58 AM

Daniel,

WoW....impressive review and a monumental effort to do it. Thanks so much for taking the time and effort to do something so comprehensive involving so many scopes and the consensus of so many observers. Truely unique and a sizable contribution!
:waytogo: :goodjob: :waytogo:
-Bill
 

#298 THESKY

THESKY

    Viking 1

  • *****
  • Posts: 959
  • Joined: 16 Feb 2006

Posted 05 September 2008 - 01:43 PM

DOKTOR . . . awesome review . . . we need to do the 5" next
 

#299 ryderc1

ryderc1

    Viking 1

  • *****
  • Posts: 599
  • Joined: 15 Apr 2006

Posted 05 September 2008 - 03:01 PM

[quote name="Daniel Mounsey"]
About the only potential drawback to the TMB is that it's quite a tank and it uses a composite tube material that could introduce some tube currents in fast dropping temperatures. Dormant materials like this are fine, but in a closed tube like this, it may not be the best way to go in certain climates.[quote]

Dan-
I experienced the tube current issues you mention with a TMB 100/800 "CNC Classic". In winter comparisons to my FS-102 the images in the TMB were consistently inferior. I finally identified tube currents due to the composite tube material as the culrpit. My only choices were to either restrict the scope's use to warmer nights or replace the composite tube with a metal one. Neither was a very practical solution so I ended up selling the scope to someone who lives in FL. The FS-102 (the best sample of four I've owned) has continued to perform superbly and has disposed of several high end apo's, including triplets, in head-to-head visual comparisons. I'll never part with it.

Thanks for your review. It's most insightful and very informative!

Charlie
 

#300 eddie kirkland

eddie kirkland

    Messenger

  • -----
  • Posts: 474
  • Joined: 12 Aug 2004

Posted 05 September 2008 - 03:39 PM

Hi Daniel, great shootout review!! Do you have any idea where in the list a TMB 105/650 (or SV/TMB 105/650) would fit? I have had the SV version for several years and am very impressed. Performance is better than the TV102 I also had.
 


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics