Jump to content


Photo

Aperture versus experience

  • Please log in to reply
64 replies to this topic

#1 azure1961p

azure1961p

    Voyager 1

  • *****
  • Posts: 10432
  • Joined: 17 Jan 2009
  • Loc: USA

Posted 17 April 2013 - 11:02 PM

Here's the hypothetical. It could pertain to deepsky as well but for the sake of simplicity, lets use Mars...

Say you have a novice observer with a 10" Reflector looking at Mars with all his heart for the first time ever. Along side him we have a high ranking visual observer with seasoned expert skills and experience also with a 10" identical scope.

Obviously the expert will see more. The question however is simply: how large a reflector would the novice need to be able to see the same details as the expert?

I'm going to throw out 12-15" in aperture - my guess.

On deepsky the same scopes, again and a seasoned expert with a novice, but now its M51.

How large a scope might a novice need to see the same nuances? There's real technique here.

We often debate scopes but what about abilities?

Thanks guys.

Pete

#2 Arizona-Ken

Arizona-Ken

    Apollo

  • -----
  • Posts: 1457
  • Joined: 31 Aug 2008
  • Loc: Scottsdale, Arizona

Posted 17 April 2013 - 11:12 PM

Gee, it must be really, really cloudy where you are. :cloudy:

Arizona Ken

#3 Asbytec

Asbytec

    Guy in a furry hat

  • *****
  • Posts: 8335
  • Joined: 08 Aug 2007
  • Loc: La Union, PI

Posted 17 April 2013 - 11:27 PM

It might be cloudy where he is, but someone asked the question in another forum. Gosh, Pete, I just dont know. It might be a complex problem because we dont know what experience means, or how good the novice is at attention to detail or how good his eyes are.

I would think experience is important, however. How much? I dunno, but it does take a while to learn to really observe. I remember, even with the same aperture, it took me a while to recognize (through experience) how small Jupiter's white ovals are. Once I understood what to look for, they became easier. And the more I observed Jupiter and Mars, the more I could see...in the same aperture.

Maybe this is not really an aperture problem at all, just an experience one. There are probably folks who briefly glance at Jupiter in a C14 and only see it's two prominent EQ belts pretty much like the view in a 60mm refractor (APO, of course...LOL. KIDDING!)

Here's my nickle, got $0.03 change?

#4 azure1961p

azure1961p

    Voyager 1

  • *****
  • Posts: 10432
  • Joined: 17 Jan 2009
  • Loc: USA

Posted 17 April 2013 - 11:46 PM

Its probably fairly difficult to nail down because acuity can be so fluid. There's that age old understanding that subsequent observations during an apparition will quicken the eye brain detection to the point previously invisible things will begin to show with clarity. The observer will often think the seeings improved but the eye brain has accommodated the demands of the repeated tasks. That's the edge Im referring to.

I think a lot of beginner success or failure is a perception or expectation thing too so that's factored in.

Pete

Ken, your avatar is perfect.

#5 Tony Flanders

Tony Flanders

    Voyager 1

  • *****
  • Posts: 11208
  • Joined: 18 May 2006
  • Loc: Cambridge, MA, USA

Posted 18 April 2013 - 03:52 AM

Here's the hypothetical. It could pertain to deepsky as well but for the sake of simplicity, lets use Mars...

Say you have a novice observer with a 10" Reflector looking at Mars with all his heart for the first time ever. Along side him we have a high ranking visual observer with seasoned expert skills and experience also with a 10" identical scope.

Obviously the expert will see more. The question however is simply: how large a reflector would the novice need to be able to see the same details as the expert?


Planets are fundamentally different from deep sky in this regard.

Planetary viewing is almost always limited by atmospheric seeing, and in most locations a 10-inch scope is pushing the limits of what the atmosphere will allow even in the best circumstances. So even for an experienced observer, it's a fairly rare night when using a scope bigger than 10 inches will yield significantly improvements.

You would do better to start with a much smaller scope as the base scope -- say, an 80-mm refractor. In that case, on a night of superb seeing, doubling the aperture might, just possibly, compensate for inexperience.

Translating that to your 10-inch scope, that means that on the 1-in-100 night that occurs at the best locations, a newbie with a 20-inch scope might see as much detail on Mars as an experienced observer with a 10-inch scope.

In practice, an experienced observer will almost always see more, regardless of which telescopes the two are using.

On deep sky, it depends greatly on the target. For some large, low-surface-brightness galaxies and nebulae, aperture is almost irrelevant. In those cases, again, an experienced observer will always see more regardless of the instruments the two are using. In fact, the inexperienced observer won't be able to detect the object at all regardless of how big a scope he or she is using.

On objects like globular clusters, the gap is much smaller. For bright spiral galaxies like M51, it's somewhere in between. Here, I think a newbie with a 16-inch scope would have a good chance of seeing as much as an experienced observer with a 4-inch scope -- assuming dark skies, of course. But it would depend greatly on the newbie. I've known people who couldn't see M51's spiral arms through a 30-inch scope under dark skies.

I know for a fact that Sue French has seen things in her 4-inch refractor that I've failed to see in my 12.5-inch Dob. And I'm not exactly inexperienced.

#6 Maverick199

Maverick199

    Voyager 1

  • *****
  • Posts: 12538
  • Joined: 27 Feb 2011
  • Loc: India

Posted 18 April 2013 - 06:00 AM

Gee, it must be really, really cloudy where you are. :cloudy:

Arizona Ken


:lol: I would also like to factor in dark sites. How much would that attribute towards what the novice sees vs the experienced?

#7 jpcannavo

jpcannavo

    Viking 1

  • *****
  • Posts: 924
  • Joined: 21 Feb 2005
  • Loc: Ex NYCer, Now in Denver CO!

Posted 18 April 2013 - 06:06 AM

There is no question that any “as-if aperture gain” function here is multidetermined. But nonetheless the phenomenon is likely quite real, and often reveals itself on a case-by-case basis. (this perhaps at odds with an earlier post of mine suggesting it be conceptualized across a population).

I can clearly recall one night, early in my deep-sky experience, at the Oregon Star Party. I was standing with a handful of experienced observers (one of them, I think, was Steve Swayze) who where commenting on H II regions in M33 with a moderately large dob (16”, 18” ? I’m not sure). I took a long hard look – focusing on the relevant portions of the field - and then quietly slinked away feeling like a dumb-posterior (ahem), I couldn’t see dingy!

Frustrated, I wandered over to some scopes of significantly larger aperture (22” or 25” ?), which began to reveal some of what I could not see earlier. I remember truly thinking I needed an eye exam, as other similar phenomena had occurred that night. It was later that I came to realize that the needed Rx here was experience.

#8 azure1961p

azure1961p

    Voyager 1

  • *****
  • Posts: 10432
  • Joined: 17 Jan 2009
  • Loc: USA

Posted 18 April 2013 - 06:33 AM

Nice account Joseph. I noticed in deepsky things like realizing the most sensitive part of the retina is between eye looking straight ahead and to the bridge of the nose made a difference. The other thing I realized - and this is a CN thing, faint stars and small planetary nebula can stand and benefit from far higher magnification than I was using. Another is becoming familiar with the look and elusiveness of those fringey features. Lastly, time. More experienced deepsky observers can put in a whopping amount of time on objects I wrote off with the same aperture - even the same galaxy. I was amazed Jake Saleronta (spelling) saw details in a face on spiral I gave five minutes and moved on with disappointment . He on the other hand spent well over an hour with the same aperture and began to see clumpy arm shapes. I'm into this for decades - I just recently found out Im too quick to move on. Experience is a progressive thing!

Tony, You make a good point. For the simplicity of it I assumed good seeing. The refractor would've been a more logical choice for the example but most experts use larger aperture. I understand your angle here however.

Thanks.

Pete

#9 Mark Costello

Mark Costello

    Gemini

  • *****
  • Posts: 3110
  • Joined: 08 Mar 2005
  • Loc: Matthews, NC, USA

Posted 18 April 2013 - 07:55 AM

Here's the hypothetical. It could pertain to deepsky as well but for the sake of simplicity, lets use Mars...

Say you have a novice observer with a 10" Reflector looking at Mars with all his heart for the first time ever. Along side him we have a high ranking visual observer with seasoned expert skills and experience also with a 10" identical scope.

Obviously the expert will see more. The question however is simply: how large a reflector would the novice need to be able to see the same details as the expert?

I'm going to throw out 12-15" in aperture - my guess.

On deepsky the same scopes, again and a seasoned expert with a novice, but now its M51.

How large a scope might a novice need to see the same nuances? There's real technique here.

We often debate scopes but what about abilities?

Thanks guys.

Pete




Hi Pete, this is a good thread and I saw it's antecedent "side trail" in the planetary reflector thread.

In another forum (Cats & Casses) someone (Eddgie IIRC) wrote that with patience one can see a lot with any scope. I believe that. Several weeks ago, in the Refractor Forum, I wrote that I wasn't seeing discernibly more planetary detail with my 5" achro then I had with a 4" F6.5 achro I owned before that, attributing that to the extra false color in my current refractor. By the following week, I was ready to eat my words. The interceding weekend, I had a 45 minute session with Jupiter, sketching it. At some point in that session, I hit me that two extra bands and a lot of swirls in some of the major bands had showed up. I was seeing more with Jupiter than I ever saw with any other telescope I owned. A couple of these were 6" and 8" Newtonians. Although I believe I have a nice refractor, IMO it was extra degree of patience and willingness to draw and write about what I was seeing that allowed me to see far more details in Jupiter with a 5" refractor than a 6" and 8" reflector....

Best Regards....

#10 ensign

ensign

    Viking 1

  • -----
  • Posts: 812
  • Joined: 16 Dec 2008
  • Loc: Southwestern Ontario

Posted 18 April 2013 - 11:31 AM

I think that this is one of those issues that has so many variables it's next to impossible to quantify.

A number of years ago I was observing Jupiter with an 80mm achromat from my light-polluted driveway. My son, about 15 years old at the time, asked if he could have a peek. He then started describing in great detail features that I was having trouble seeing.

Ahhh, to have 15-year-old eyes. . . :)

In this case youth and enthusiasm trumped age and experience.

#11 StarStuff1

StarStuff1

    Soyuz

  • *****
  • Posts: 3893
  • Joined: 01 Apr 2007
  • Loc: South of the Mason-Dixon Line

Posted 18 April 2013 - 11:44 AM

Yes, a lot of experience at the eyepiece will reveal more details. Try this: set an egg on a table and draw it. Try to get the smallest details. This will help your eye "train" itself to see faint details on planets in any scope.

#12 buddyjesus

buddyjesus

    Vanguard

  • *****
  • Posts: 2236
  • Joined: 07 Jul 2010
  • Loc: Davison, Michigan

Posted 18 April 2013 - 11:44 AM

Lastly, time. More experienced deepsky observers can put in a whopping amount of time on objects I wrote off with the same aperture - even the same galaxy. I was amazed Jake Saleronta (spelling) saw details in a face on spiral I gave five minutes and moved on with disappointment . He on the other hand spent well over an hour with the same aperture and began to see clumpy arm shapes. I'm into this for decades - I just recently found out Im too quick to move on. Experience is a progressive thing!

Thanks.

Pete


I am continually learning the same lesson. 5 minutes just isn't long enough to get a deep feel for the features of an otherwise grey fuzzy. I just recently started giving a minimum fifteen minutes for each object even if they are not getting sketched. I find even this amount of time is short for trying all the observing tricks and playing the waiting game with variable seeing.

#13 Eric63

Eric63

    Viking 1

  • -----
  • Posts: 989
  • Joined: 16 Jun 2012
  • Loc: Ottawa, Ontario

Posted 18 April 2013 - 11:46 AM

Very interesting thread and one that could help many newbies with aperture fever. I would love to increase my aperture right now to see more, but I think it would be better to learn to see more with the aperture I have before jumping to the next. This way I will better appreciate that larger scope when I decide to upgrade. (or Perhaps this is another way convincing myself since I’m too cheep to get another scope :))

Eric

#14 csrlice12

csrlice12

    Voyager 1

  • *****
  • Posts: 11243
  • Joined: 22 May 2012
  • Loc: Denver, CO

Posted 18 April 2013 - 12:27 PM

Yes, but your FIRST view of Saturn/Jupiter/Mars, etc... is the one you remember....do you remember your 350th view? The experience will allow you too "see" better (not more), eeking out the fine details; but it's that first view that really determines if there is a 2nd...or 350th....

#15 FirstSight

FirstSight

    Duke of Deneb

  • *****
  • Moderators
  • Posts: 9916
  • Joined: 26 Dec 2005
  • Loc: Raleigh, NC

Posted 18 April 2013 - 12:52 PM

Well, I would certainly like to experience more aperture. Alas, my application for a grant to purchase a 20" reflector to conduct some experiments on the question at hand wasn't approved.
:grin:

#16 Kraus

Kraus

    Apollo

  • -----
  • Posts: 1145
  • Joined: 10 Mar 2012
  • Loc: Georgia.

Posted 18 April 2013 - 02:43 PM

Hmmm...that's a good one. I learned a long time ago not to expect objects to appear bright and colorful unless they're bright and colorful.

Might be why many scopes end up on e-Bay. Look at some of the telescope advertisements. Folks see a telescope in front of or next to a long-exposure photograph. Folks buy the telescope and don't see the 'photograph'. Now they're disappointed.

So to answer your question. I don't think experience or aperture is the issue, it's expectations.

#17 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 44367
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 18 April 2013 - 05:40 PM

So to answer your question. I don't think experience or aperture is the issue, it's expectations.



Expectations are, in many way the key to life. Realistic expectations are the result of experience.

Personally, I just like looking through a telescope at the night sky. Big or small, top notch or not so hot.. I enjoy it.

The whole idea of gauging skill by aperture, I just figure we see what we see. If I with someone who is more skilled than me, hopefully they will help me out. If I am with someone who is less skilled than I, I hope to be able to help them...

But, if one wants to track ones gain in skill or amateur against amateur, probably the "Smallest aperture I saw X" with is a viable measure. Unfortunately, such comparisons can bring out the competitive aspects... I enjoy using smaller scopes because they challenge my skills and help me develop them...

So, such a tool looks like: Beginner Jon barely saw NGC ???? in his 10 inch wizbang. Experienced observer Wilbert can see NGC???? in his 4 inch Didley from the same site.. That's a measure of experience, how much aperture can you give up?

Jon

#18 David Knisely

David Knisely

    Hubble

  • *****
  • Posts: 15635
  • Joined: 19 Apr 2004
  • Loc: southeastern Nebraska

Posted 18 April 2013 - 05:52 PM

I got "trained" early on, being forced to put up with observing with a little 2.4 inch f/11.7 refractor for a number of years as a youngster. This experience taught me how to push myself and learn how to eek-out objects and the very faintest detail using proper dark adaptation, averted vision, proper power selection, and other viewing techniques. This was true of several of us in our club who also started in the late 1960's with the small refractors and then eventually worked up to the larger apertures some time later. When I 'graduated' from my little refractor to my 8 inch f/7 a few years later, the amount of detail I could see was astounding, so all that "training" really paid off. Indeed, one night a few years ago, I had my 100mm f/6 refractor out on my driveway testing the 8.5-12mm Speers-Waler eyepiece I was reviewing, and abruptly saw the dust lane in M104, which surprised the heck out of me. Some others I observe with could not see the feature in that aperture, so I began to notice this difference more and more. I could really notice this one night when we were observing the Horsehead at one of our club's star parties. It was quite faint, but after seeing it several times before, I had little trouble getting it in my Nexstar 9.25 inch SCT with the H-Beta filter. However, a friend with a 10 inch couldn't see it in my scope. He hadn't come up through the ranks (started with a 10 inch), so his observing experience hadn't been as fully developed. Eventually, he gained at least some of that experience and closed our observing "gap", but I find that even now, I still tend to have a small but definite edge over others in our group who didn't start out "small". It might be a 20% to 25% gain in "effective observing aperture", but it is hard to judge an exact level of improvement, as levels of observing experience vary widely. On planets, the difference due to experience is less noticeable, but may still be there, especially when looking at the finest low-contrast detail. Clear skies to you.

#19 rdandrea

rdandrea

    Mercury-Atlas

  • *****
  • Posts: 2861
  • Joined: 13 Jun 2010
  • Loc: Colorado, USA DM59ra

Posted 18 April 2013 - 06:30 PM

Percival Lowell had a REALLY big scope (almost even by today's standards)
http://www.lowell.ed...tore-the-clark/

Yet he saw a lot of stuff on Mars that wasn't really there.
There's no substitute for experience and a good eye.

#20 HCR32

HCR32

    Messenger

  • -----
  • Posts: 451
  • Joined: 27 Aug 2010
  • Loc: Melbourne Australia

Posted 18 April 2013 - 06:33 PM

I had a first timer look at Jupiter through a 6" at about 180x and didn't know what he was looking at to the point where he had to google an image of Jupiter to spark off he's imagination. I couldn't believe it. Some people need things to slap them in the face. My guess would be 10" for experience, 16" for novice.

#21 Perigny270

Perigny270

    Mariner 2

  • -----
  • Posts: 201
  • Joined: 23 Oct 2011
  • Loc: Temiscaming, Quebec

Posted 18 April 2013 - 07:14 PM

My best evening of looking at Jupiter was last year when I decided to set up my backlash settings. I aimed at Jupiter with my 13mm and fiddled all evening. Boy, did I see lots of detail that night. The virtues of patience all came out. And I understood how much the more experienced astonomers could see so much. You cannot be in a hurry. And BTW I appreciated the value of my observer's chair.

#22 Asbytec

Asbytec

    Guy in a furry hat

  • *****
  • Posts: 8335
  • Joined: 08 Aug 2007
  • Loc: La Union, PI

Posted 18 April 2013 - 09:35 PM

You know, before I got my 6" Mak I was primarily deep sky with large Dobs and 10/11" SCTs. A quick look a Jupiter now and then, man, I missed so much in those scopes. I see so much more in my 6" these days because the planets have become my primary focus. I study them instead of just glancing.

So, no idea what I was missing earlier. I just know the planets are stuffed with features in that smaller 6" aperture. So, from inexperience to experience, there is a 4" aperture advantage right there. Maybe more so, because I never "observed" the level of detail in those larger scopes that I can see in a 6" MCT.

Dang it! Wish I had known, but deep sky was my primary interest at the time. No regrets, kind of...

#23 Astrodj

Astrodj

    Viking 1

  • *****
  • Posts: 591
  • Joined: 24 Aug 2011
  • Loc: Missouri

Posted 18 April 2013 - 10:31 PM

I got "trained" early on, being forced to put up with observing with a little 2.4 inch f/11.7 refractor for a number of years as a youngster. This experience taught me how to push myself and learn how to eek-out objects and the very faintest detail using proper dark adaptation, averted vision, proper power selection, and other viewing techniques. This was true of several of us in our club who also started in the late 1960's with the small refractors and then eventually worked up to the larger apertures some time later. When I 'graduated' from my little refractor to my 8 inch f/7 a few years later, the amount of detail I could see was astounding, so all that "training" really paid off. Indeed, one night a few years ago, I had my 100mm f/6 refractor out on my driveway testing the 8.5-12mm Speers-Waler eyepiece I was reviewing, and abruptly saw the dust lane in M104, which surprised the heck out of me. Some others I observe with could not see the feature in that aperture, so I began to notice this difference more and more. I could really notice this one night when we were observing the Horsehead at one of our club's star parties. It was quite faint, but after seeing it several times before, I had little trouble getting it in my Nexstar 9.25 inch SCT with the H-Beta filter. However, a friend with a 10 inch couldn't see it in my scope. He hadn't come up through the ranks (started with a 10 inch), so his observing experience hadn't been as fully developed. Eventually, he gained at least some of that experience and closed our observing "gap", but I find that even now, I still tend to have a small but definite edge over others in our group who didn't start out "small". It might be a 20% to 25% gain in "effective observing aperture", but it is hard to judge an exact level of improvement, as levels of observing experience vary widely. On planets, the difference due to experience is less noticeable, but may still be there, especially when looking at the finest low-contrast detail. Clear skies to you.


Great thread Pete,

I had a similar "starting out" experience to David's. 11 years old, 3" f/10 Edmund newt, useless finder, sliding cardboard tube focuser, wobbly mount that wouldn't point straight up without tilting the whole scope/mount together.

I observed for four years with that scope and learned much. Then I got my 10" f/7 newt and was, like David, blown away with what it could reveal.

I too think how you start off can impact the training of the eye. By the time I got my 10" I was already observing individual targets for 20 minutes to an hour before moving on to something else.

I had also developed a very deft hand at focusing, and recentering objects. Modern dobs are a breeze compared to a scope like I started with in this regard.

One of my current scopes is a 5" newt with what is generally accepted as a very poor focuser, and it is. I would have killed for that focuser on my first scope though, so I don't mind it so much compared to what others say. I still have a very deft touch.

And I still have a trained eye. I developed both when very young and they still serve me well.

I look through other people's scopes on the field all the time and see details clearly they can barely detect. These are people with bigger scopes than I will likely ever own who have been observing for 10 or more years in many cases. I get told I "must have very good eyes" all the time and I did when I was young, but now they are just average eyes.

I don't know if there is an answer to your question Pete, at least not one better than the ones above in the thread. I do know that I "see" more than much less experienced folks do through their own scopes.

At the same time, there are a bunch of folks in this forum that could show me a thing or two through mine!

#24 chaoscosmos

chaoscosmos

    Mariner 2

  • *****
  • Posts: 247
  • Joined: 26 Jan 2013
  • Loc: Mission Viejo CA

Posted 19 April 2013 - 12:11 AM

While acknowledging all that has been said here, it doesn't necessarily take too much astronomical observing experience to enjoy viewing stars of unending variance of brightness, color, and pattern in a wide field across the night sky. In that case I think an awareness, curiosity, and appreciation of nature is just about all one needs.

#25 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 44367
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 19 April 2013 - 03:51 AM

While acknowledging all that has been said here, it doesn't necessarily take too much astronomical observing experience to enjoy viewing stars of unending variance of brightness, color, and pattern in a wide field across the night sky. In that case I think an awareness, curiosity, and appreciation of nature is just about all one needs.


Ray:

:waytogo:

I envy those just getting started, the big thrills, the excitement, the learning and understanding, it's all in front of them...

Jon






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics