Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Equipment Discussions >> Classic Telescopes

Pages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | (show all)
starman876
Postmaster
*****

Reged: 04/28/08

Loc: VA
Re: Is bigger better? new [Re: Dan /schechter]
      #6343663 - 01/29/14 04:58 PM

it is nice to hear opinions that are reasonable and not slanted in one direction or another. that is what I was hoping for when I started this post. I am not really interested in how my scope will beat yours. I am interested in the pure fact of how aperture, image scale and overall seeing conditions will guide us to picking the right scope for the right night. I doubt that many of us have looked through every scope that has ever been made. I am sure a good many of us have had plenty of scopes. However, only a precious few have had scopes that just are the best that can pull that last photon out of the night sky and provide that wow factor that many of us seek. This is not a contest of will your reflector outperform the refactor or the inverse. This is the question of how can one obtain the best performance possible from a scope on any given night. What would be the best scope to do that with.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Bomber Bob
Carpal Tunnel
*****

Reged: 07/09/13

Loc: The Deep South, USA
Re: Is bigger better? new [Re: starman876]
      #6343685 - 01/29/14 05:06 PM

Terra had the answer: "All this however is highly subjective and arbitrary."

Post Extras: Print Post   Remind Me!   Notify Moderator  
Petrus351
sage


Reged: 12/17/12

Loc: Spain
Re: Is bigger better? new [Re: starman876]
      #6343697 - 01/29/14 05:11 PM

Quote:

you really do need to look at pictures that smaller aperture scopes have taken. Pictures on Amart of the planets with high end APO's sure are awesome. I would have to argue that with some of them I have never seen anything better with a C14. Having a couple of C14's I know there limitations.




Could you please show some pictures, made with 4" and 5" inch apos, please?


Post Extras: Print Post   Remind Me!   Notify Moderator  
Petrus351
sage


Reged: 12/17/12

Loc: Spain
Re: Is bigger better? new [Re: Bomber Bob]
      #6343717 - 01/29/14 05:21 PM

Quote:

Terra had the answer: "All this however is highly subjective and arbitrary."



I´m not sure. What you can see with a scope is what you can see with a scope, and that´s an objetive subject; not subjetive. If you can see some details with a scope, and the same details, cannot be seen with another one, is not subjetive.

Edited by Petrus351 (01/29/14 05:22 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Petrus351
sage


Reged: 12/17/12

Loc: Spain
Re: Is bigger better? new [Re: Petrus351]
      #6343735 - 01/29/14 05:28 PM

I think, the telescope was invented, in order to be able to see things, beyond the naked eye, so what really matters in a telescope is what you can see. This is not a subjetive matter, and that´s why telescopes have been bigger and bigger as time passes by. When someone asks "is bigger better", I gess he means "what telescope you can see more with"?

Do you see more with a 4" apo than with a C14? In good seen conditions, I don´t think so.

Edited by Petrus351 (01/29/14 05:31 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Bomber Bob
Carpal Tunnel
*****

Reged: 07/09/13

Loc: The Deep South, USA
Re: Is bigger better? new [Re: Petrus351]
      #6343796 - 01/29/14 05:54 PM

"what really matters in a telescope is what you can see"

Yes, and I don't think anyone can argue with objective performance. The differences between us are about individual perception, which can be quite subjective, because what I see at the eyepiece is unique to my own neurophysiology, experience, and - yes! - emotional state.

Which is really a fancy way of saying: Lowell saw canals on Mars, but I only see blobs & smudges.


Post Extras: Print Post   Remind Me!   Notify Moderator  
starman876
Postmaster
*****

Reged: 04/28/08

Loc: VA
Re: Is bigger better? new [Re: Bomber Bob]
      #6343816 - 01/29/14 06:04 PM

Those canals got removed because of urban renewal by NASA.

Post Extras: Print Post   Remind Me!   Notify Moderator  
SpooPoker
sage
*****

Reged: 06/04/13

Loc: North Bay CA
Re: Is bigger better? new [Re: Bomber Bob]
      #6343819 - 01/29/14 06:05 PM

Eeking details out of a small disc / extended object with lowish contrast is a challenge all in itself. It takes a special eye to resolve special details - and knowing ahead of time what to be looking for gives one a huge advantage.

Actually that is the one thing, the one huge advantage of using small aperture instruments to do observing - training yourself to see better. I learned observing skill far more from a 60mm refractor than I ever did with a DOB.

I regret passing up on a 40mm Unitron frac for a couple of hundred bucks - seeing detail with a 40mm would take some doing, and I have no doubt it could be done and would improve my viewing skills using one for a while. I may plump for the 50mm Unitron listed on eBay, but the price of $360 is plain nuts for that, hopefully the seller drops it to around the 200 mark and I will pounce on it.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Petrus351
sage


Reged: 12/17/12

Loc: Spain
Re: Is bigger better? new [Re: SpooPoker]
      #6343844 - 01/29/14 06:18 PM

What about pictures? Please don´t tell me that what you can see in a jupiter picture, for example, differs from what other people see in the same picture.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Bomber Bob
Carpal Tunnel
*****

Reged: 07/09/13

Loc: The Deep South, USA
Re: Is bigger better? new [Re: Petrus351]
      #6343847 - 01/29/14 06:20 PM

Oh, I can definitely say that people have different perceptions of what they see, hear, smell, & taste -- regardless of the source -- how else to explain Nickelback fans??

Post Extras: Print Post   Remind Me!   Notify Moderator  
jrcrillyAdministrator
Refractor wienie no more
*****

Reged: 04/30/03

Loc: NE Ohio
Re: Is bigger better? new [Re: starman876]
      #6343906 - 01/29/14 06:41 PM

Quote:

Those canals got removed because of urban renewal by NASA.




The same thing happened to the Venus surface details he imagined and wrote about extensively. "Subjective" too frequently means "imaginary". Kind of like the Neptune and Uranus perturbations he imagined and then attributed to a nonexistent outer gas giant.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Datapanic
Post Laureate
*****

Reged: 10/17/09

Loc: Tucson, Arizona
Re: Is bigger better? new [Re: jrcrilly]
      #6344448 - 01/30/14 01:37 AM

What a loaded question.

Post Extras: Print Post   Remind Me!   Notify Moderator  
svdwal
Vendor (mBrain Software)


Reged: 03/10/13

Loc: Leiden, The Netherlands
Re: Is bigger better? new [Re: Datapanic]
      #6344504 - 01/30/14 03:19 AM

There is of course the quote from Suiter: "the best way to get a perfect 12" is to make a good 14".

If you look at the theory, the Modulation Transfer Function (MTF) captures the differences between different telescopes very well. For reasonable optics you can see how optical quality can be traded for aperture. The bigger optics will be better in resolving small high-contrast objects like very close doubles. But at the scale of details on planets there is much leeway, and smaller, better optics can compete with bigger and worse. But not with bigger and as good optics.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Petrus351
sage


Reged: 12/17/12

Loc: Spain
Re: Is bigger better? new [Re: svdwal]
      #6344528 - 01/30/14 04:14 AM

Quote:

There is of course the quote from Suiter: "the best way to get a perfect 12" is to make a good 14".

If you look at the theory, the Modulation Transfer Function (MTF) captures the differences between different telescopes very well. For reasonable optics you can see how optical quality can be traded for aperture. The bigger optics will be better in resolving small high-contrast objects like very close doubles. But at the scale of details on planets there is much leeway, and smaller, better optics can compete with bigger and worse. But not with bigger and as good optics.




Yes, but what are the margins???

I mean, we´re talking about a 4" refractor in comparison to a C14? or are we talking about a 6" vs 8" scope?
What you say, can be true between small differences in aperture, but not between important ones.

Edited by Petrus351 (01/30/14 05:19 AM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Petrus351
sage


Reged: 12/17/12

Loc: Spain
Re: Is bigger better? new [Re: Petrus351]
      #6344529 - 01/30/14 04:16 AM

Please show me the best Jupiter pictures made with a 4" apo.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Petrus351
sage


Reged: 12/17/12

Loc: Spain
Re: Is bigger better? new [Re: Bomber Bob]
      #6344532 - 01/30/14 04:18 AM

Quote:

Oh, I can definitely say that people have different perceptions of what they see, hear, smell, & taste -- regardless of the source -- how else to explain Nickelback fans??



At the end, we´ll be talking about the sex of angels.

A good quality picture is the one that shows more detail, period.

I repeat: please show me the best Jupiter picture made with a 4" or 5" refractor.



Edited by Petrus351 (01/30/14 04:20 AM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Petrus351
sage


Reged: 12/17/12

Loc: Spain
Re: Is bigger better? new [Re: Petrus351]
      #6344550 - 01/30/14 05:06 AM

Take a 4" inch refractor, and try and capture jupiter at 60 fps in the blue channel, with a focal lenth of 8000mm, equivalent to a C14+2x barlow, and then you tell me. You will see that´s simply impossible, because even if you increase gain to the top, the image will be too dark with a very poor histogram.
¿Why? Because the larger the aperture, the less you have to increase gain in order to get the same histogram, and a high histogram means noise.
With my C11 EDGE HD, I take captures of Jupiter in the three channels, always at 60 fps with a focal lenth of 5600 with a 2x barlow, with no issues.
Now try and do the same, with the same focal lenth with a 4" refractor. Even with my C8 is just impossible, having double the aperture of a four incher.
So aperture rules, period.

Edited by Petrus351 (01/30/14 05:21 AM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
bremms
Carpal Tunnel
*****

Reged: 08/31/12

Loc: SC
Re: Is bigger better? new [Re: Petrus351]
      #6344710 - 01/30/14 08:57 AM

Yes it does. Beyond 6-8" only rare nights will allow full resolution. The photo of Saturn on the AP site with a 175EDF is exquisite. A nearly perfect 7" scope is going to be hard to beat on all but exceptional nights. One of the reasons I usually take the 6" refactor out vs one of my larger scopes.
Partly cool down too. My C11 shows more detail and contrast than my "6 refractor, but not when cooling or if the seeing is marginal. 4" scopes are just a bit small for most of my observing. Just the way it is, My 4" F15 refractor is easier to set up than the 6" F10, but the little extra effort is worth the gain in performance. The 4" is better for a quick look, and it does excel on the moon due to much less CA.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Chuck Hards
Post Laureate
*****

Reged: 05/03/10

Loc: The Great Basin
Re: Is bigger better? new [Re: bremms]
      #6344748 - 01/30/14 09:23 AM

Hey, after we resolve this question, let's talk about which classic eyepiece is best!

Post Extras: Print Post   Remind Me!   Notify Moderator  
clintwhitman
Caveman
*****

Reged: 01/01/07

Loc: CALI SoEasyACavemanCanSlewIt
Re: Is bigger better? new [Re: Dan /schechter]
      #6344822 - 01/30/14 10:11 AM

Re: Seeing conditions. Are smaller scopes better sometimes? Seem to be, but I am really starting to think it because you can see the bad seeing better at larger mags with more aperture. If you pump up the magnification to match the larger telescope (if possible) the smaller scopes usually looks just as bad or about the same, at least to me.

Dan you post is well said. Many of the nights we spent at Pinos with your 6" AP, Roberts 7" AP, A few dozen other refractors, Kennedy's 32" dob. dozens of C14s, 11s and all the other Newtonians at Pinos is why I,,,
#1 I am a Refractor lover,
#2 Feel that Aperture rules as to what you can see.The Telescopes setup at the Pinos parking lot are the best of the best with some of the best seeing. But nothing on the field ever made me wish I owned or was using any system other than the Pearl. Just mind blowing views.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | (show all)


Extra information
12 registered and 11 anonymous users are browsing this forum.

Moderator:  Rich (RLTYS), Brian Risley 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 2337

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics