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Veteran Amateurs: Past vs Present

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#51 csrlice12

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Posted 16 September 2013 - 10:55 AM

One day, Pizza commercials will have telescopes that point the right direction........

#52 Geo31

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Posted 16 September 2013 - 11:36 AM

My neck of the woods must have been behind the times. All my observing buddies way back when - I started in the early '70's - had some type of GEM. No Dobs in sight for many years after that.

I've tried mounting an 8" and then a 10" Newt OTA on a GEM. Been there, tried it, didn't like it. The biggest Newt I will ever put on a GEM is a 6".

<snip>

But to each their own. After all, this is still a hobby for our own individual enjoyment. At least that's what it is for me. I'm not doing this to please anyone else. YMMV.


Totally agree with you Mike (and noted so in my post). It's a purely personal thing and of course everyone is entitled to their own preferences. Cheers!

Dobs certainly predate the article in S&T in the late 70s, but I'm not sure how much before that. It was the article in S&T that started the trend.

FWIW, I'm not a big fan of GEMs either. I always prefered the fork mount, especially for large scopes. I went to Stellafane in 75 and 76 and most of the larger newts were mounted this way.

[edit] I just reread my prior response. Please accept my apology for the tone. It wasn't intended that way. Sometimes we write things thinking one way and it seems to come out another. No tone or attitude was intended.

Guys, as a matter of fact the so-called Dobsonian design is hardly something new, or even recent, let alone the creation of John Dobson, something he always readily pointed out. Although few amateurs are aware of it today, these classic "gun-type mounting arrangements" for Newtonian telescopes were in common usage among amateur astronomers during the latter half of the 19th century...and even commercially available.


Alt-Az mounts have of course been around for quite some time. What make the "Dobsonian" unique (a point that has been lost through the years and basically any newt on a simple Alt-Az mount is referred to as a Dob) was the use of large, low mass (thin) mirrors. It brought aperture that previously was generally unheard of in amateur hands to the "masses" (so to speak).

#53 Sarkikos

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Posted 16 September 2013 - 11:44 AM

"Dobsonian" type mounts were originally used for cannon, probably long before Newton invented the Newtonian.

Mike

#54 Geo31

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Posted 16 September 2013 - 01:31 PM

"Dobsonian" type mounts were originally used for cannon, probably long before Newton invented the Newtonian.

Mike


Dobsonian refers to a telescope configuration. What you have called Dobsonian above is simply Alt-Az. They were almost certainly used by Ptolemy for visual observation long before Galileo first pointed a telescope to the heavens.

I've said my apologies. Didn't mean to start a wizzing contest. Just pointed out that Dobsonian telescopes have been around nearly as long (or as long in many cases) people on CN have been looking through telescopes.

http://www.sidewalka...ers.us/id1.html

Dobsonians have probably been around at least since the mid-70s and probably much earlier.

Here's an interesting article about John Dobson. From this I think it's safe to say that what we know as a Dobsonian telescope dates back to the 60s or before. I think it's also safe to say the term "Dobsonian Telescope" was coined sometime in the 70s.

http://www.sidewalka...rs.us/id32.html

Again, while Alt-Az astronomical devices pre-date the telescope, what we know as a Dobsonian telescope dates from the 60s or 70s and was popularized by the easily portable, thin mirror, large aperture scopes at that time.

#55 Sarkikos

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Posted 16 September 2013 - 02:01 PM

"Dobsonian" type mounts were originally used for cannon, probably long before Newton invented the Newtonian.

Mike


Dobsonian refers to a telescope configuration. What you have called Dobsonian above is simply Alt-Az. They were almost certainly used by Ptolemy for visual observation long before Galileo first pointed a telescope to the heavens.


Well, yes, that's why I made the point of putting "Dobsonian" in quotes, to imply that I wasn't using a strict definition of the term. Sorry if I didn't make that clear. Obviously I didn't. :grin:

But look at some old depictions of cannon mounts. I swear if you were to take that cannon off, rig up some altitude bearings for a Newt OTA of equivalent girth, and set that Newt into the mount, you'd have yourself a Dobsonian.

Words have significance, but physical reality has more. Well, let's leave that alone. There's probably enough to debate in that statement to last a few hundred years. :ubetcha:

Mike

#56 csrlice12

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Posted 16 September 2013 - 02:08 PM

Also explains why dobs are often mistaken for rocket launchers or morters.......

#57 Geo31

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Posted 16 September 2013 - 02:13 PM

"Dobsonian" type mounts were originally used for cannon, probably long before Newton invented the Newtonian.

Mike


Dobsonian refers to a telescope configuration. What you have called Dobsonian above is simply Alt-Az. They were almost certainly used by Ptolemy for visual observation long before Galileo first pointed a telescope to the heavens.


Well, yes, that's why I made the point of putting "Dobsonian" in quotes, to imply that I wasn't using a strict definition of the term. Sorry if I didn't make that clear. Obviously I didn't. :grin:

But look at some old depictions of cannon mounts. I swear if you were to take that cannon off, rig up some altitude bearings for a Newt OTA of equivalent girth, and set that Newt into the mount, you'd have yourself a Dobsonian.

Words have significance, but physical reality has more. Well, let's leave that alone. There's probably enough to debate in that statement to last a few hundred years. :ubetcha:

Mike


So true Mike. Yeah, I think the written word is getting in the way here. Nuances are being missed all around.

As for the cannon mount analogy, I'm not sure if you know this, but John Dobson uses the same analogy.

Here's another interesting history of the Dobsonian. It jibes with what I remember from that S&T article so many years ago (can I really be that old?).

http://en.wikipedia....onian_telescope

One of the interesting things about the Dobsonian craze is that with the sudden interest in large amateur instruments, also came a revolution in equatorial mounted scopes. Not long after the S&T article made Dobs popular, several companies started producing very large, easily broken down and transported split-ring Eq scopes. It was about that time that I only occasionally kept up with what was going in in amateur astronomy. Some of those huge split-ring Eq scopes have a LOT in common with the Porter Garden Telescope.

I guess we can all agree that the apetures available today were largely unheard of 40 years ago in the hands of an amateur.

#58 Seldom

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Posted 16 September 2013 - 02:25 PM

So what's the difference between a Dobsonian and an Alt-Az Newt? I'm thinking about F. W. Herschel's 47" scope or the Leviathan of Parsontown. Herschel's had all the characteristics of a big Dob except balance. They certainly had to climb ladders. Can't tell from photos if the Leviathan actually had Azimuth adjustment, but it seems unlikely if the supporting walls were masonry.

#59 Geo31

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Posted 16 September 2013 - 03:12 PM

So what's the difference between a Dobsonian and an Alt-Az Newt? I'm thinking about F. W. Herschel's 47" scope or the Leviathan of Parsontown. Herschel's had all the characteristics of a big Dob except balance. They certainly had to climb ladders. Can't tell from photos if the Leviathan actually had Azimuth adjustment, but it seems unlikely if the supporting walls were masonry.


Herschel's 40' scope was certainly a granddaddy of the modern Dob.

Keep in mind, the Dob was not a new "invention." It took several basic things such as the Alt-Az mount, large thin mirror (low mass), simple bearings, and combined them into a previously unheard of level of portability and simplicity for relatively large to large (for the time) apertures. A Dobsonian is probably defined more by the packaging of the telescope than by any one atribute (such as Alt-Az or the fact it's a Newtonian telescope).

It's interesting that there is a Dob in existence that is larger (diameter) than Herschel's telescope (once the largest in the world). It's probably a whole lot easier to operate.

#60 amicus sidera

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Posted 16 September 2013 - 04:43 PM

So what's the difference between a Dobsonian and an Alt-Az Newt?


None. Dobson merely had better press in the form of enthusiastic fanbois making certain that the appellation "D*******n" entered the vocabulary of amateur astronomers.

Fred

#61 semiosteve

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Posted 17 September 2013 - 08:54 AM

Interesting question and good thread.

Let's see I think I first started observing the moon with a spyglass duct-taped to a porch pillar around 1957.


It is far easier to see far more objects with far better equipment today. There is a much wider range of choices.

I think the real game-changer has been digital setting circles (and related software, specialty devices, etc.). This innovation dramatically increased BOTH the number of objects viewable per session AND the amount of time available to ponder those objects (if so inclined).

However, the character and atmosphere of the hobby is very different. Not better or worse, just different.

In the 50's through late 70's amateur astronomy fell under the rise of the space race - now an amateur can take better pictures of Jupiter, Mars or the Moon than the best professional equipment in the world back then (think Damian Peach) and it really doesn't have the same impact as a a great drawing by Inez Beck or Harold Hill or Chick Capen. Likewise, today you can see amateur CCD photos of DSO's that are better than those from the best from professional scopes of the 50's, but the sense of wonder of Walter Scott Houston's musing tends to be missing from today's writers and observers (Sue French does best to bridge both era's however).

That being said, I still love the hobby and still read every page of every issue of S&T. I still observe the way that suits me best - and there are more choices for other ways to observe than ever before (e.g. spectroscopy - what a thrill to see the unique signature lines from the recent nova in Delphinus).

Because the baby boom has peaked and we are heading to retirement and beyond, the hobby will have a smaller base over the next 10 to 20 years. This is just market demographics. So expect to see the hobby change again going forward.

The stars are eternal, viewing them is ever-changing.

#62 Gil V

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Posted 17 September 2013 - 11:11 AM

Although the base may be smaller, we are considerably better connected.

#63 BrooksObs

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Posted 17 September 2013 - 12:05 PM

"Because the baby boom has peaked and we are heading to retirement and beyond, the hobby will have a smaller base over the next 10 to 20 years. This is just market demographics. So expect to see the hobby change again going forward." - Steve

An astute observation and something not yet widely recognized among hobbyists here. The Boomer Generation was very much into hobbies, while subsequent ones have not been nearly so much so. The passing of the Boomers over the next 10-20 years will have a considerable impact not only on amateur astronomy, but hobbies all across the board in years to come.

This fact is already becoming quite apparent in several other hobby areas I pursue. One is seeing the host of former manufacturers and suppliers either consolidating, or just plain closing up shop. At the same time, many previously commonly available products, some of them the staples of those hobbies, are now being produced in only limited batches whose availability comes and goes. Other items are offered increasingly on a pre-order/limited run basis, forcing a "buy now or miss out" situation.

So far the astronomy hobby hasn't yet seen much of this sort of thing, but it will invitably surface here. Only the severity of its overall impact on hobby participation remains yet to be determined.

BrooksObs

#64 hbanich

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Posted 17 September 2013 - 12:06 PM

So what's the difference between a Dobsonian and an Alt-Az Newt?


None. Dobson merely had better press in the form of enthusiastic fanbois making certain that the appellation "D*******n" entered the vocabulary of amateur astronomers.

Fred


Actually, the main distinguishing feature between a Dobsonian and an alt-az mount is the use of formica and Teflon bearings - that made the movements of a Dobsonian possible and helped fueled its expolsive growth. That, along with "thin" primary mirrors and using inexpensive plywood where Dobson's major innovations. For instance, my 28 inch scope looks a lot like a Dob but because it rides on ball bearings it's not a Dob - it's an alt-az Newtonian.

This is splitting hairs, but it good to remember what Dobson came up and why it caught on fire.

#65 csrlice12

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Posted 17 September 2013 - 12:10 PM

Youo mean I can't call my dob a dob no more since I installed a lazy susan???? :bawling:

#66 Sarkikos

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Posted 17 September 2013 - 12:27 PM

Didn't philosphers get into long debates over terms, such as the difference between a "ball" and a "sphere?" Well, at least they no longer argue about how many angels can dance on the head of a pin.

Wars were fought over such things as whether the Holy Ghost proceeds through the Father and the Son (filioque) or only through the Father. Just sayin'.

Thus began the Dobsonian Wars. :tonofbricks:

:grin:
Mike

#67 Geo31

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Posted 17 September 2013 - 12:50 PM

Youo mean I can't call my dob a dob no more since I installed a lazy susan???? :bawling:


Put Susan to work... ;)

#68 Geo31

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Posted 17 September 2013 - 01:06 PM

Didn't philosphers get into long debates over terms, such as the difference between a "ball" and a "sphere?" Well, at least they no longer argue about how many angels can dance on the head of a pin.

Wars were fought over such things as whether the Holy Ghost proceeds through the Father and the Son (filioque) or only through the Father. Just sayin'.

Thus began the Dobsonian Wars. :tonofbricks:

:grin:
Mike


All too true Mike.

I think what we are seeing is the definition expanding. That happens in all areas of life where a name of something describes a fairly narrow definition, but if said object becomes popular enough, many variations on the theme get lumped in. To that extent, things "are" what we define them to be (uh-oh, getting a bit philosophical here...).

That said, I do think it's true that a classical Dobsonian telescope is defined by simple bearings such as Teflon and Formica (or equivilent since those are brand names - there's that evolving language thing again), Alt-Az mount, thin mirrors, and "tubes" that break down into smaller sections for easy transport. Those were Dobson's innovations - the packaging and simplicity. Prior to that, not only did amateurs not generally possess large scopes (over 12.5"), but to haul said large scopes to a start party was lunacy! :shocked: Thanks to Dobson, it's commonplace to see a 20" or larger scope at a star party. Absolutely we can thank him for that. Prior to, amateurs didn't typically own such scopes and if they did, you had to be invited to their observatory to get a look through it.

#69 Geo31

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Posted 17 September 2013 - 01:14 PM

So what's the difference between a Dobsonian and an Alt-Az Newt?


None. Dobson merely had better press in the form of enthusiastic fanbois making certain that the appellation "D*******n" entered the vocabulary of amateur astronomers.

Fred


Actually, the main distinguishing feature between a Dobsonian and an alt-az mount is the use of formica and Teflon bearings - that made the movements of a Dobsonian possible and helped fueled its expolsive growth. That, along with "thin" primary mirrors and using inexpensive plywood where Dobson's major innovations. For instance, my 28 inch scope looks a lot like a Dob but because it rides on ball bearings it's not a Dob - it's an alt-az Newtonian.

This is splitting hairs, but it good to remember what Dobson came up and why it caught on fire.


Bingo.

#70 ADW

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Posted 17 September 2013 - 02:08 PM

That said, I do think it's true that a classical Dobsonian telescope is defined by simple bearings such as Teflon and Formica (or equivilent since those are brand names - there's that evolving language thing again), Alt-Az mount, thin mirrors, and "tubes" that break down into smaller sections for easy transport. Those were Dobson's innovations - the packaging and simplicity. Prior to that, not only did amateurs not generally possess large scopes (over 12.5"), but to haul said large scopes to a start party was lunacy! :shocked: Thanks to Dobson, it's commonplace to see a 20" or larger scope at a star party. Absolutely we can thank him for that. Prior to, amateurs didn't typically own such scopes and if they did, you had to be invited to their observatory to get a look through it.


You are giving John Dobson credit for not only his significant innovations, but for those of other ATMs who greatly advanced the Dob. John Dobson's scopes were massive, heavy, long focal length crudely built beasts with a solid tube made from a Sonotube (a form for pouring concrete).

Other ATMs invented collapsible tubes made with trusses.

When John Dobson brought his 17.5-inch to the 1986 Mount Kobau Star Party here in British Columbia it was an f/7 I believe and required several people to load and unload it. It was crudely built (he used cedar shingles for his spider, for example), but the views were outstanding according to my logbook.

If I recall correctly, the San Francisco Sidewalk Astronomers transported Dobson's 24-inch by something like an old school bus.

Changing topics, I greatly enjoyed Steve Verba's (semiosteve) thoughtful post in this thread.

Best,

Alan Whitman

#71 Chuck Hards

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Posted 17 September 2013 - 02:39 PM

John Dobson was responsible for a paradigm shift, of sorts, more than a specific design. Alt-az scopes were held in disdain back in the old days and equatorial mounts had to assume massive proportions to adequately hold large aperture telescopes. The value of Dobson's idea was to prove that large-aperture, inexpensive telescopes could be built and well-used in an alt-az configuration. Like any other aspect of this hobby, others built upon his work and refined it. But he was the one who started people thinking differently.

Would the modern truss-tubed alt-az light bucket exist today had it not been for Dobson back then? Probably, but it might not be at the state it's at now. Could have taken a few decades longer for the light bulb to come-on in someone else's head.

Don't forget Poncet, who gave us tracking for these big scopes in a pre-digital, or infant digital age. The equatorial platform and Dobsonian scope coming together at about the same time was a great stroke of luck for the amateur astronomer.

I started observing the skies with a telescope around 1968 and have seen many changes over the years. The skies I have access to now are actually darker than they were back then because I grew-up on a hill overlooking a metropolitan area. I can drive long distances now to dark skies that I couldn't when I was ten years old.
In our club, the percentage of folks doing real science at the telescope is about the same now as it was then. Heck, it's the same people, just a lot older, lol. Most of the rest are visual observers and imagers- "nature lovers". The ATM percentage is about the same. Probably more new, young blood in that category than any other.

#72 Michael Rapp

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Posted 18 September 2013 - 08:01 AM

Other items are offered increasingly on a pre-order/limited run basis, forcing a "buy now or miss out" situation.


I was actually thinking about this the other day, in regards to a G11. I've always wanted one, but I don't need one, and quite possibly in the not-so-distant future, the demand for it may go down substantially and Hollywood General Machining may get out of the business if it is not lucrative. (Of course, Scott Losmandy could also retire.)

It has also amazed me a little that our hobby has a large enough base with enough discretionary income to allow the premium mirror and dob makers to turn a hobby into a career and make a very good living. Maybe it will be a all good things must come to an end situation in another 15-20 years.

Okay, I just depressed myself before 9 am. Bleh.

#73 bunyon

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Posted 18 September 2013 - 08:31 AM

Do the premium mirror makers and scope builders make a nice living at it? I've not looked into it but I thought most (or all) of them had day jobs.

I'd be happy to find out otherwise.

#74 csrlice12

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Posted 18 September 2013 - 08:33 AM

Might make a nice retirement "additional income".

#75 BrooksObs

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Posted 18 September 2013 - 09:45 AM

Paul, I think that your question is well founded. While I have no direct information, I would observe that most highly respected mirror makers don't have a long history in the industry. Those with a good rep usually come from an established telescope making company and start out well. But sooner or later they allow themselves to become hopelessly over booked and a backlog builds. People start cancelling their orders. The mirror maker hires assistants, the quality drops and he vanishes from the scene. I have seen this scenario played out so many times during my long association with the hobby that I can pretty much conclude no one individual makes a fortune out of mirror making. Even well known companies these days seem to have a patchy history of profiting and not.

BrooksObs






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