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Equipment Discussions >> ATM, Optics and DIY Forum

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magic612
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Reged: 09/30/08

Loc: S. of Chicago's light dome
Re: Optimized Newts vs APOs new [Re: azure1961p]
      #5593569 - 12/28/12 11:43 PM

Quote:

2. It seems odd but maybe somekind of fan intake to carry my breath elsewhere. When the scopes up at that angle my breath trail is like a smokestack.




This may sound (and likely look) goofy but it is the first thing I thought when I read this: What about using a snorkeling breathing tube? It would shoot your breath back out the opposite direction away from you and the scope.


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cheapersleeper
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Re: Optimized Newts vs APOs new [Re: magic612]
      #5593624 - 12/29/12 12:20 AM

Snorkle? I have done that...

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tim53
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Reged: 12/17/04

Loc: Highland Park, CA
Re: Optimized Newts vs APOs new [Re: magic612]
      #5593627 - 12/29/12 12:21 AM

I focus the image on my computer screen and then sit down at the keyboard while making my observations. My 6" f/10.3 Kludegescope cools down pretty quickly. I've not felt the need for a fan before.

-Tim.


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azure1961p
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Re: Optimized Newts vs APOs new [Re: magic612]
      #5593628 - 12/29/12 12:21 AM

Dead airspace. A snorkel has too much rebreathing of the air in the snorkel itself. You don't notice it in swimming but I'm mindful of proper breathing when observing lest things begin to loOk grainy as a result.

Thanks though!


Pete


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robboski2004
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Reged: 01/14/08

Re: Optimized Newts vs APOs new [Re: MKV]
      #5593728 - 12/29/12 02:19 AM

Quote:


If you can make a mirror you can make a window; it's just more work - two sides, and a central hole. No reason for the optics to cost more than $250 in 4 to 6 inch aperture.

But let's even double that and say it'd cost you $500 for optics, is it still worth paying 10 to 20 times more for the same or even inferior performance.

Mladen


Mladen




Mladen, your usual understanding of lens designs seems to have deserted you !!

The lens design , Roland Christen published in the Sky and Telescope , was later corrected , due to being over-corrected
for spherical and not optimised for colour.

These glasses are capable of producing, what in 1981, was considered apo correction. i.e green , red , blue within the airy disc.

Toward then end of the article , he states that his and other amateurs were working on lenses for astro-imaging (photography at the time !)
Which is one of the strengths of apo's.
Another would be their relative ease of use and ability to perform year after year for basically as long as their owner requires .
Possibly one area they excel, would be in their capability of producing , fully illuminated fields in wide field eyepieces.

Just some thoughts?
Ian.


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Jon Isaacs
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Re: Optimized Newts vs APOs new [Re: MKV]
      #5593814 - 12/29/12 05:18 AM

Quote:

Quote:

Quote:

Yet no one has dared to take Ed Turco on his challenge!




A challenge accepted or ignored does not make a victory. I could venture a challenge to arm wrestle all takers. If no one were to accept my challenge, the wise course of action would be to not claim victory.

Jon



True, but then claims to the superiority of APOs should be mum.

Mladen




Again, a challenge accepted or ignored does not make a victory or a defeat. It does not change reality.

My youngest son weighs 208 lbs, does 120 pushups a day, 120 pullups a day, does reps on the bench of 275lbs and can Bench press 400lbs.

If I challenged him to arm wrestle me and he were to kindly decline, it would not make me any stronger or mean that I were the better arm wrestler.

A 6inch apo is what it is, a 6 inch optimized Newtonian is what it is... A challenge, accepted or ignored does not change that. Both are good, both are different. To me it makes little sense to compare a 6 inch f/10 Newtonian to a 6 inch apo because a decent 10 inch f/6 Newtonian will provide superior views to either one and be far more affordable than the apo.

In my mind, telescopes are all open class, you "run what you brung" and enjoy the views for what they are, regardless of aperture...

I will say this... If I had a 6 inch apo, which I don't... I wouldn't be interested in a challenge because a challenge is competitive with an obvious agenda. On the other hand, if someone wanted to compare the views, I would be happy to make a friendly comparison.

Jon

Edited by Jon Isaacs (12/29/12 05:36 AM)


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

Re: Optimized Newts vs APOs new [Re: MKV]
      #5593875 - 12/29/12 07:49 AM

Quote:

Using Aberrator(R), I constructed this collection of Jupiter shots starting from 0% obstruction (APO) all the way to 45% (for Newotnians). I intentionally chose a picture that resembles the kind of image reaching the eye rather than the Photoshop(R) art that is commonly used. I think this is a much more realistic portrayal of what an observer can expect to see.




I realize the images were for the purpose of comparing obstructions, but if I saw images that bad, I'd quit observing planets. Why cares about the differences if that's what one should expect to see. What is it that observers really care about? Images or numbers? Seems like the numbers mean more to observers. To me, it just appears to be a numbers game.

I've seen jaw dropping images of Jupiter with telescopes that had 15%, 20%, 25%, 30%, 35% obstructions, but if you see Jupiter images that looked like that with a telescope that had 0% obstruction, why bother. Maybe this explains why there are so many conflicting and confusing reports from others that make absolutely no sense.


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MKV
Carpal Tunnel
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Reged: 01/20/11

Re: Optimized Newts vs APOs new [Re: Jon Isaacs]
      #5593884 - 12/29/12 08:04 AM

Quote:

Quote:

My youngest son weighs 208 lbs, does 120 pushups a day, 120 pullups a day, does reps on the bench of 275lbs and can Bench press 400lbs. If I challenged him to arm wrestle me and he were to kindly decline, it would not make me any stronger or mean that I were the better arm wrestler...



I think you're mixing apples and oranges. Your son's benchpressing abilities are a fact, and if you claimed the same or superior abilities then his declining the challenge would raise some questions.

There are a lot of (fairy)tales circulating in the ATM community, all based on anecdotal "evidence" and personal impressions. How many times have you read or heard a "testimony" that such and such a scope gave the "best views" (whatever that means) or that it was the "ultimate telescope"?

One of those tales is that APOs are better than Newotnians of equal aperture and focal ratio. How else could anyone convince people to buy a telescope of the same size as another one, but costing 10-20 times more? Because everyone is swearing APOs are "much" better, yet there is no objective data to back it up, nor will anyone submit their APOs to a test.

Ed's challenge was based on the fact that theory disagrees with eyewitness accounts. For that reason it would have been a good thing if someone had accepted his challenge, so that people may know instead of believe other people's impressions of exactly zero scientific value.

I guess you're just one of those people who'd rather believe someone's story than know the facts. That's cool. Why don't you just say so? It's everyone's world. But let's not try to rationalize this issue as "not important".

Mladen


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dpwoos
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Reged: 10/18/06

Loc: United States
Re: Optimized Newts vs APOs new [Re: MKV]
      #5593899 - 12/29/12 08:22 AM

And how does this test, if it occurred, produce anything more than anecdotal evidence? You are kidding yourself if you think that this kind of "test" is going to produce any "facts". Furthermore, who cares enough to engage in such a test? Do you not think that APO owners have had the chance to look through zillions of dobs, SCTs, and other designs at club events and star parties, and even their own other scopes? They have made a choice, and some folks will continue to make that choice, and I don't understand why that bothers anybody else.

Edited by dpwoos (12/29/12 08:24 AM)


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MKV
Carpal Tunnel
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Reged: 01/20/11

Re: Optimized Newts vs APOs new [Re: Daniel Mounsey]
      #5593910 - 12/29/12 08:31 AM

Quote:

I've seen jaw dropping images of Jupiter with telescopes that had 15%, 20%, 25%, 30%, 35% obstructions, but if you see Jupiter images that looked like that with a telescope that had 0% obstruction, why bother. Maybe this explains why there are so many conflicting and confusing reports from others that make absolutely no sense.



One of the reasons is intellectual dishonesty, reliance on anecdotal tales rather than factually provable claims, ulterior motives (maximizing profit), i.e. promoting business as "hobby" to increase sales, etc.

BTW, Questar is not an unobstructed telescope. And you're absolutely right, such images on astronomical objects would be worthless - except for Photoshop artists and maybe after stacking hundreds of frames. As it turns out 1/4 inch lacense plate numbers are still too small for a Q3.5 even if we're talking about "extended" objects. Questar is an elitist product and makes elitist claims.

How else can you hope to sell a telescope the size of an ordinary finder scope (89 mm clear aperture) for $5K, or a used one on eBay for $3500?

And as for "raw" images, here's an example of a Q3.5 shot of Jupiter in one of archived CN 2005 posts. So much for that.

Mladen


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David PavlichAdministrator
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Reged: 05/18/05

Loc: Mandeville, LA USA
Re: Optimized Newts vs APOs new [Re: MKV]
      #5593987 - 12/29/12 09:27 AM

Ok, guys...back on topic.

David


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Pinbout
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Reged: 02/22/10

Loc: nj
Re: Optimized Newts vs APOs new [Re: David Pavlich]
      #5594029 - 12/29/12 10:01 AM

I'm still trying to find someone to make a:

-a 6inf10 parabola 1/20~ pv
-a 7in optical window that's 1/20~ pv flat on bothsides and parallel to sub arcminutes with a hole
-and a 1" secondary mirror that's 1/30~ pv

for under $250 cause I would buy those optics right now if someone would make them at that price.

WOW, I could have ostensibly perfect optics in a scope that I'll build, way better than I could ever dream of making. heck with the challenge I would just like the optics with those specs at that price.


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

Re: Optimized Newts vs APOs new [Re: David Pavlich]
      #5594033 - 12/29/12 10:02 AM

The "optimized" newt is a strong force. I've made side by side comparisons with my high quality 10" f5 Newtonian 10" f12 DK. I even had a 10" stock production 10" f6. I've compared them all to 8" apos and 6" apos. I've seen times when the 10" reflectors were superior on planets and I've seen times where the smaller apos were better on planets. Anyone who makes blanket statements or resorts to numerical figures as an answer is obviously inexperienced, because if they were in fact hands on and experienced in the claims they make, they would know reality does not work that way. If people spent as much time at the eyepiece as they do making numerical claims, they'd learn a thing or two about how telescopes actually perform in reality.

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dpwoos
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Re: Optimized Newts vs APOs new [Re: Daniel Mounsey]
      #5594060 - 12/29/12 10:13 AM

Thanks - great post.

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MKV
Carpal Tunnel
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Reged: 01/20/11

Re: Optimized Newts vs APOs new [Re: Pinbout]
      #5594187 - 12/29/12 11:20 AM

Quote:

I'm still trying to find someone to make a:

-a 6inf10 parabola 1/20~ pv
-a 7in optical window that's 1/20~ pv flat on bothsides and parallel to sub arcminutes with a hole
-and a 1" secondary mirror that's 1/30~ pv

for under $250 cause I would buy those optics right now if someone would make them at that price.

WOW, I could have ostensibly perfect optics in a scope that I'll build, way better than I could ever dream of making. heck with the challenge I would just like the optics with those specs at that price.



Danny, anyone who would make them just for you would be foolish to sell them for $250! I was talking glass cots for someone who can and is wiling to make them. Ed Turco is certainly one who has the skill. We weren't talking about selling.

Mladen


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dan_h
Carpal Tunnel


Reged: 12/10/07

Re: Optimized Newts vs APOs new [Re: Daniel Mounsey]
      #5594205 - 12/29/12 11:33 AM

Quote:

I've made side by side comparisons with my high quality 10" f5 Newtonian 10" f12 DK. I even had a 10" stock production 10" f6. I've compared them all to 8" apos and 6" apos. I've seen times when the 10" reflectors were superior on planets and I've seen times where the smaller apos were better on planets.



I don't think anyone questions these statements but such conclusions are the result of seeing conditions, not telescope characteristics. You would not come to these same conclusions under ideal observing conditions.

Quote:

Anyone who makes blanket statements or resorts to numerical figures as an answer is obviously inexperienced, because if they were in fact hands on and experienced in the claims they make, they would know reality does not work that way.



The reality is that the larger percentage of folks with scopes live in areas where ideal observing conditions are rare or non-existent. Still, they have the right to discuss how a given telescope may function in comparison to another under ideal observing conditions and I think that is really the topic here. (The race car driver is not necessarily qualified to determine the best suspension design although he may well be aware of the end result. A winning team works together to share knowledge.)

Quote:

If people spent as much time at the eyepiece as they do making numerical claims, they'd learn a thing or two about how telescopes actually perform in reality.



Very true. But let's not discount the value that an experienced glass pusher and a qualified mathemetician can bring to the discussion. I for one, have learned a great deal regarding obstructions, Strel, MTF, and numerous other topics, by those who have taken the time to post an explanation behind the theory that I could not otherwise comprehend. I welcome their contribution.

I will probably remain an uncurable skeptic. I enjoy learning about telescopes and their attributes. My scopes and eyepieces are modest. While I don't have a great deal of experience with superb instruments under ideal conditions, I have enjoyed the views I have had when folks have shared their eyepiece time with me. In my experience, Ed's statement that a well made 6" Newt can match a similar sized APO is a fair statement. I have enjoyed following the discussion.

Happy New Year to all,

dan


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MKV
Carpal Tunnel
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Reged: 01/20/11

Re: Optimized Newts vs APOs new [Re: Daniel Mounsey]
      #5594213 - 12/29/12 11:35 AM

Quote:

The "optimized" newt is a strong force. I've made side by side comparisons with my high quality 10" f5 Newtonian 10" f12 DK. I even had a 10" stock production 10" f6. I've compared them all to 8" apos and 6" apos. I've seen times when the 10" reflectors were superior on planets and I've seen times where the smaller apos were better on planets. Anyone who makes blanket statements or resorts to numerical figures as an answer is obviously inexperienced, because if they were in fact hands on and experienced in the claims they make, they would know reality does not work that way. If people spent as much time at the eyepiece as they do making numerical claims, they'd learn a thing or two about how telescopes actually perform in reality.



First, it's not clear what you mean by "optimized", but the OP specifically mentioned a Newtonian, same aperture as the APO, and with an optical window so as to eliminate spider vane diffraction effects. IOW, cparing two identical same diameter, same focal ratio, closed tube telescope to one another, except for the central obstruction of 15% or less in the Newotnian.

Second, when you say you have "seen time where the smaller APOs were better on planets", are you saying they were some much better the difference was worth the price difference? Are you aware that a 6-inch APO can cost anywhere from $7,000 to $19,000? Were the views that much better? Just asking.

Of course, to some, that may be pocket change...

As for the disdain that seems so popular for numerical and theoretical, do remember that the numerical and theoretical created these configurations. No one made them by trial and error and anecdotal evidence.

Regards,
Mladen


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Pinbout
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Reged: 02/22/10

Loc: nj
Re: Optimized Newts vs APOs new [Re: MKV]
      #5594218 - 12/29/12 11:37 AM

Quote:

anyone who would make them just for you would be foolish to sell them for $250! I was talking glass cots for someone who can and is wiling to make them. Ed Turco is certainly one who has the skill. We weren't talking about selling.





but everyone is talking about the sale price of an apo compared to material costs of a newt with a >$1k window sale price not even mentioning the sale price of build the scope.

that's not a fair sale price/performance vs material cost/performance comparison.


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MKV
Carpal Tunnel
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Reged: 01/20/11

Re: Optimized Newts vs APOs new [Re: azure1961p]
      #5594228 - 12/29/12 11:46 AM

Quote:

evertyime I exhaled or had my hand on the edge of the tubes secondary end, this awful disruptive heat plume would enter the field.



Pete, that's why even reflectors can benefit form some extra tube length in front of the eyepiece. And it also helps if the tube is made of something other than aluminum (one of the most heat conductive metals). Try Texereau's wooden tube. I know, it doesn't have the snob appeal, but it works, and is much easier to mount things on it, as well as the tube itself.

Mladen


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MKV
Carpal Tunnel
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Reged: 01/20/11

Re: Optimized Newts vs APOs [Re: Pinbout]
      #5594246 - 12/29/12 11:56 AM

Quote:

but everyone is talking about the sale price of an apo compared to material costs of a newt with a >$1k window sale price not even mentioning the sale price of build the scope.

that's not a fair sale price/performance vs material cost/performance comparison.



Well, since there are no commercially available windowed Newts, you'd have to make one. And since there are very, very few if any amateur-built apos, we can only compare what is cost-wise.

If you can buy a 6-inch SCT for under $1K, there is no reason a windowed Newt of the same size would cost more. There is so much more to putting together an SCT then a Newt.

If windowed Newts became popular, I am sure, initially, the price would be hiked, but eventually they would end up being competitively priced way under $1K for a 6-inch scope.

Mladen


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