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5" Refractors

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#76 BillP

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Posted 25 August 2014 - 12:39 PM

It would be an interesting stat to see how many housholds have telescopes in them.  Maybe I can get them to add that to the next Census form :lol:


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#77 SteveC

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Posted 25 August 2014 - 01:04 PM

It would be an interesting stat to see how many housholds have telescopes in them.  Maybe I can get them to add that to the next Census form :lol:

Just a survey amongst ourselves, how many of our friends and professional acquaintances own telescopes and use them at night, aside from an astronomy club? Perhaps it's my fault for never joining a club, so my sample size of friends is a bit skewed. 

 

Maybe I'll join a couple in Florida and Rhode Island, now that I'm retired.



#78 Markab

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Posted 25 August 2014 - 03:02 PM

 

I think Astronomy has slowly become and older persons hobby now. ...  I work in the space industry. We are struggling to get young people interested in this field and fill the shoes of the Engineers and Scientists approaching retirement age.

 

 

IMO it is doomed to shrink.  Today's generation is not the same as previous ones.  They are very plugged-in, so gratification needs to be quick and at the fingertips and access to others has to be rapid and integrated.  So that paradigm does not take well to all the setup and planning and solitude that is typical for observing, or to the very static nature of the many astronomy oriented websites.  So unless the equipment changes to be more a part of the mainstream, interest is not going to swell.

 

 

Bill,

 

I am 38, so probably in the bottom quarter of the age distribution here on CN, but while the points you make are valid, I think there is more to it.  I am a scientist, and it is more than simply a lack of interest among younger people in the hard sciences.  It is also a reflection of what our society values. Good jobs (those that are capable of supporting a family), despite what the talking heads like to tell us, are in very low supply in this country. Relative to the population, perhaps the most dismal state in our history. And in most science fields, there are tons of scientists from abroad who get work visas from American companies to work here...all demanding a much cheaper rate than the local population. This has been going on since the 1990s, so wisely, younger people start to realize that given all the hard work involved in getting a BS in a scientific discipline with few good job prospects, why bother?  I don't agree with the attitude one bit, but there is no doubt this is going on, unfortunately. 



#79 dr.who

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Posted 26 August 2014 - 11:30 AM

Folks, sorry to be a kill joy but the thread is starting to drift. Perhaps a new thread in the Off Topic section would be a good place for these discussions.



#80 Ed Holland

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Posted 26 August 2014 - 11:55 AM

I like my 5" Achro its very good all-rounder scope and has shown me some interesting sights. Long-ish focal length (~1200mm) to help planetary viewing, Decent field of view for many objects, and a useable light grasp for a few feint things. It's kind to my eyepieces too, showing nice star fields at low magnification. Aesthetically, and this might sound a bit daft, but it also has a classical telescope feel - a big long white tube with glass at each end and a finder scope to match. Form and function :)



#81 RAKing

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Posted 26 August 2014 - 01:46 PM

There seems to be a real following of folks here who use 5" refractors (120-140mm). Why 5"?  Is it that a 6" costs so very much more for that one inch gain in aperture? If you use a 5" can you tell us why?

 

The jump from a 5 to a 6 incher is significant, but even though I can afford one, my medical problems won't allow me to carry the heavier OTA around.

 

I have owned quite a few refractors and the 5 inch size is just right for my needs. I like to estimate variable stars and I enjoy the task with my refractor.  It's easy to carry and mount, it cools quickly, and it's big enough to see the dimmer comp stars.

 

Cheers,

 

Ron



#82 jhighfield

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Posted 26 August 2014 - 07:09 PM

5 inch refractors (in this case a Zeiss 130mm) can be quite a handful for two strong people.  I don't know what the Germans were thinking, but it's all two coordinated, strong people can do to set this up, 3 is better yet.  When the tube is in it's case, it's at the threshold of pain for two to carry.  I just finished restoring this for a friend, and made the mobile base for it to make it manageable.  It uses medical grade casters that lock in both rotation and swivel for solid performance.

 

 

That isn't a refractor...

 

It's one of the "Guns of Navarone"



#83 nicknacknock

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Posted 27 August 2014 - 04:53 AM

 

There seems to be a real following of folks here who use 5" refractors (120-140mm). Why 5"?  Is it that a 6" costs so very much more for that one inch gain in aperture? If you use a 5" can you tell us why?

 

The jump from a 5 to a 6 incher is significant, but even though I can afford one, my medical problems won't allow me to carry the heavier OTA around.

 

I have owned quite a few refractors and the 5 inch size is just right for my needs. I like to estimate variable stars and I enjoy the task with my refractor.  It's easy to carry and mount, it cools quickly, and it's big enough to see the dimmer comp stars.

 

Cheers,

 

Ron

 

 

Same here. My 6" was 25 lbs and my 120mm is only 9 lbs. I prefer the larger aperture, my back prefers the smaller aperture. Back wins.



#84 JimP

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Posted 27 August 2014 - 09:18 AM

And, if you think an AP 130 GT is expensive check out the Alvan Clark 5" for $15,000 in the classified section. The value of a scope has to do with more than just the quality of the optics. Collectors ALAWYS drive the market. If an object is collectable, then the collector who wants a pristine or as pristine as possible example, will pay a premium price for that example and will therefore set the price for an excellent but not pristine, good example and so forth on down. This of course depends upon rarity and availability. If you can buy a brand new TOA or TEC  or ATM LZOS there is little collector value. But, with AP, it is extremely difficult to buy a new example. The easiest ( I did not say easy) way is to pay a premium price to get one on the second hand market.

 

I hope that makes some sense...


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#85 Scott99

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Posted 27 August 2014 - 06:28 PM

And, if you think an AP 130 GT is expensive check out the Alvan Clark 5" for $15,000 in the classified section.

 

 

 

Wow - apparently they were under-mounting scopes in the 1870's - that thing's going to be shaking like crazy during viewing.  



#86 drollere

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Posted 31 August 2014 - 02:59 AM

I don't think it's that bad. Some of us are drawn to astronomy, just as some are drawn to stamp, book, and coin collecting. It's something that just clicks, you either have it or you don't. Of all the people I've associated with in my entire life, socially or professionally, I'm only one to have owned a telescope. None of those people grew up in the "plugged in" age. Amateur astronomy is a small circle, always has, always will be, so to declared it dying, I think it's a bit premature. As people age, I believe the solitary nature of observing the universe becomes more attractive and a distraction from our regular routines. That's why many of us start at an early age, drop out to start a life, and then gravitate back to astronomy later in life.

 

there is a life stage aspect and there is a tribal aspect too, i agree with all that and especially as a counterweight to "doom". on the other side there's encroaching light pollution everywhere, people are still moving from the country into the cities, and i don't care what the scientists have to say about it, i'm convinced that climate change also means worsened seeing from thermal turbulence. why look through the tube when you can get all the hubble photos on a single CD? put them up on your cinema display, fire up some new age ambient music, and stroll the galaxy. the whole infrastructure lifestyle headline retail muck that we all swim in is very different from the 1950s and 60s.

 

and then, there's that thing called the great recession, which for some reason just isn't going away ...

 

edit: sorry, mod, i copy replied to a post previous to your drift warning.


Edited by drollere, 31 August 2014 - 03:02 AM.


#87 BigC

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Posted 31 August 2014 - 09:06 AM

The irony is that the people living in the country with dark skies are less likely to have access or be exposed to astronomy and telescopes ;and those in the city struggle to see the stars because of wasteful lighting.

 

Returning to 5" versus 6" I think the responses have pretty well covered the reasons which are physical and financial.

 

You could do a thread with why prefer 4" instead of 5",or 3" instead of 4" and get similar responses;the answer is that different situation lead to different solutions.

 

And those without either limitation can enjoy bigger if they choose.


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#88 BillP

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Posted 02 September 2014 - 07:21 AM

The irony is that the people living in the country with dark skies are less likely to have access or be exposed to astronomy and telescopes ;and those in the city struggle to see the stars because of wasteful lighting.

 

 

All that is needed is to place a suitable telescope on the east coast of the U.S. and have a Mallincam or similar attached to it (adjust its integration time so it does not show things much more differently than an 8" scope - or vary it throughout the evening or step it on each object).  Then starting at dark on the east coast and running through until 11pm on the west coast have it run through a variety of objects and have the output streaming to the Internet for all to watch.  Have this run by a foundation that is set up by the astronomy community.  This way people could get exposed to astronomy everywhere so it would peak their interest to possibly get their own telescope.  Run this twice a week with narration.



#89 Byron

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Posted 02 September 2014 - 09:50 AM

I regularly reach for my simple 102mm f/10 achromat instead of my even easier to handle 6" SCT . . . I prefer the views and, chromatic aberrations aside, I find the SCT view less satisfying (although it's pretty awesome in other ways). I do use either the Fringe Killer or Contrast Booster filters, sometimes in combination. Of course I also have my aperture fever scope, a 12" dob . . .

 

I'm currently awaiting arrival of a new achromat, the 127mm f/5 Petzval design from Astrozap, which I've picked up with a deep discount. I'll give folks my impression of this scope after it arrives. Should my early retirement income somehow magically increase, I will give serious thought to a large apochromat . . . who wouldn't love to have a 5 or 6" apo? 



#90 bremms

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Posted 02 September 2014 - 03:50 PM

I find the views in SCT's "funny". Don't know what it is. I have a 5.5" Maksutov that I really like. My SCT's perform well, but I prefer my 6" F10 Jaegers and reflectors to my SCT's the C8 is portable for an 8" that's a big plus.  The combination of off axis aberrations and field curvature must not be to my liking.



#91 jrbarnett

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Posted 02 September 2014 - 10:17 PM

Man on the moon?  Hmm...remember when Luke Skywalker first used the force to deflect the stinger laser attacks of the remote, with the helmet blast shield down?  :grin:

 

- Jim



#92 dr.who

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Posted 03 September 2014 - 12:24 AM

I do, Jim. That said please keep it on topic. ;)



#93 Jim Curry

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Posted 03 September 2014 - 06:33 AM

"The jump from a 5 to a 6 incher is significant"

 

Whadya mean?

 

Left to right on the floor: 140 x 800, 60 x 900, 6" x 1,800, 100 x 1,200, 75 x 1,200

Jim

 

Attached File  Ferguson-20121022-00258s.jpg   131.56KB   0 downloads

 



#94 JJK

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Posted 03 September 2014 - 08:07 AM

"The jump from a 5 to a 6 incher is significant"
 
Whadya mean?
 
Left to right on the floor: 140 x 800, 60 x 900, 6" x 1,800, 100 x 1,200, 75 x 1,200
Jim


The differnce in the lunar/planetary views (at the EP) through high quality 5" and 6" scopes is significant.
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#95 Jim Curry

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Posted 03 September 2014 - 09:53 AM

True enough, JJK.  My 6" Istar build is loafing at 300x when the atmosphere allows.  I was referring to size and mount req'mts as had been mentioned earlier :>)   This shot gives a little perspective.

 

Jim


Edited by Jim Curry, 03 September 2014 - 10:58 AM.


#96 JMW

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Posted 03 September 2014 - 08:04 PM

I bought the TEC 140 because they have a great reputation and they come up used several times a year. It is a reasonable size to carry and setup and fits nicely on the DM6 mount I already had. I originally thought I would hold out for the TEC 160 but decided 140 is more than good enough and saves me lot of money compared to the TEC 160. After a few years I am still in love with it and it gets out under a lot of dark skies. 








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