53 replies to this topic

[KaStern]

Hi folks,

 

in the last weeks I have recognised that many small refelctors that hit the market

did only have the quality of toys.

There are fast small newts that lack collimatability.

Everyone who knows that the diffraction limited field of a fast newt is very small

is surprised when he recognises that he cannot collimate the primary mirror.

 

A telescope like this sthrows away much of it's resolving and contrast transfer capabilities. 

To me it seems as if toy-quality telescopes now enter the regular telescope market.

You find even a 6"f/5 newt on a computorised mount that is not fully collimatable.

 

I wonder if that trend will continue and all new economy newts will be nothing but toys?

 

A strongly recommend to stay away from any fast newt that lacks collimatability! 

 

Severely disgrunteled, Karsten

Edited by KaStern, 02 May 2016 - 04:47 PM.

[jim kuhns]

I started out with a Gilbert reflecting telescope which had only a two and half mirror, with a focal length of F/10. That was 1962, cost was around $30.00 if I remember right and could be collimated. That amount of money was hard to come by, would put 3 days of groceries on the table for my 2 sisters and 3 brothers  counting me plus Dad and Mom.
The mirror was spherical and though the scope was a toy in many respects it was just enough to wet my curiosity to see more. I guess as long as people by theses toy like telescope there will always be a market for them.

[Jon Isaacs]

I think the market has been heading in that direction for the past 25 years.  Thinking back, what is the last quality, small Newtonian on a nice mount?  Arguably the 150 XLT could qualify but i am thinking 4 and 5 inch scopes.

 

I can't think of anything since the C-4.5, a 4.5 inch F/8 on the Vixen Polaris mount.  

 

Jon

[ed_turco]

A 4" reflector can only be considered a toy when the manufacturer makes it a toy.   A decently made 4" reflector isn't going to do much on deep sky objects but point it at the Moon and you won't be calling it a toy, believe me!

 

In CN's classifieds, an optical outfit in Japan advertises 4" mirrors in f/6 and f/10 configurations.  Anyone who wishes to be enterprising and make a 4" telescope will agree with my comments about toys versus decently made telescopes.

 

Its all in how you make it.

 

 

 

Ed

[hyia]

I think the market has been heading in that direction for the past 25 years.  Thinking back, what is the last quality, small Newtonian on a nice mount?  Arguably the 150 XLT could qualify but i am thinking 4 and 5 inch scopes.

 

I can't think of anything since the C-4.5, a 4.5 inch F/8 on the Vixen Polaris mount.  

 

Jon

 

Hello Jon.  It is a dob mount, but the Orion xt4.5 is not bad at all.  I know you would probably recommend the 8" f6 in that line-up, but the 4.5 has its appeal.  It is quite easy to pick up and move around with one hand which can be good if you have a lot trees/obstructions in your yard.  If you are an adult, you do need to sit down to use it, and having something like a crate to set it on can help too.  The mirror is supposedly spherical, but I have split the double-double, Izar, etc. with good seeing.  Regards.

[Pierre Lemay]

Canadian telescope maker Steve Dodson ("Stargazer Steve") has been selling 4¼" telescopes for years and they are anything but toys. Lots of people started observing with them and have enjoyed these simple instruments.

 

See here for details: http://stargazer.isy...owtochoose.html

[KerryR]

I've always admired, and wanted, an SGR-4. Looks like a really nice grab and go scope on a really nicely made/engineered mount.

[KaStern]

Hello Folks,

 

I own and use a 114/500mm (wich is in fact a 112/450mm) Newt with parabolic mirror.

(Edit: Fully collimatable, Label: Skywatcher, 33% central obstruction)

This is a capable telescope. It surpasses my 70/900mm achromat on every object.

 

No doubt, my 150/600mm and 200/1200mm newts are more powerful,

but the little one does what one can expect from it.

 

But unfortunately I see more and more small newt hit the market wich lack collimatability.

It mightb be at the edge of acceptable for a 76/900mm newt, but it is inaceptable for scopes

like 100/400mm / 130/650mm / 150/770mm.

To me this is a very bad trend

 

Cheers, Karsten

Edited by KaStern, 03 May 2016 - 03:16 PM.

[Laika]

Hi folks,

in the last weeks I have recognised that many small refelctors that hit the market
did only have the quality of toys.
There are fast small newts that lack collimatability.
Everyone who knows that the diffraction limited field of a fast newt is very small
is surprised when he recognises that he cannot collimate the primary mirror.

A telescope like this sthrows away much of it's resolving and contrast transfer capabilities.
To me it seems as if toy-quality telescopes now enter the regular telescope market.
You find even a 6"f/5 newt on a computorised mount that is not fully collimatable.

I wonder if that trend will continue and all new economy newts will be nothing but toys?

A strongly recommend to stay away from any fast newt that lacks collimatability!

Severely disgruntled, Karsten

Actually I'm grunteled about this situation
(That is the opposite of disgruntled, I guess, lol)
A friend picked up the Orion 76mm, think it's like f8, and it can be collimated but these fast ones I don't think so

Edited by Laika, 03 May 2016 - 03:58 PM.

[BDS316]

Edmund made some nice 3 and 4 inch newts back in the day.  Not sure if Stargazer Steve still makes his altaz Newt but it's a nice scope.  Nowadays the AWB One Sky 5 inch f/5 mini dob rules IMO. 

 

Edit:  Stargazer Steve SGR-4

Edited by BDS316, 03 May 2016 - 04:25 PM.

[Starman1]

I think the market has been heading in that direction for the past 25 years.  Thinking back, what is the last quality, small Newtonian on a nice mount?  Arguably the 150 XLT could qualify but i am thinking 4 and 5 inch scopes.

 

I can't think of anything since the C-4.5, a 4.5 inch F/8 on the Vixen Polaris mount.  

 

Jon

I was impressed with the optical quality of the Vixen R130 on a Vixen Porta-Mount II.  It has a fairly cheap focuser (though functional) and I found the tripod too tall for comfortable seated viewing,

But the scope is definitely not a toy, and a strong step up from the typical Starblast category.

It is not, however, in the quality range of the Celestron Omni XLT 6" newtonian on a CG4 mount.  That scope is an outright bargain, IMO.

[Max T]

Just to add a countering viewpoint, in a way we should hope that small reflectors are made as cheap (yet functional) as possible.

 

A $20 package containing: 5" reflector telescope with planisphere and brightest top 20 objects will really drive newcomers into astronomy.

 

Later they will then buy a Synta, GSO scope with collimatable cell, parabolised mirror reflector etc.as they learn about 2" focussers, collimation and parabola's tack sharp views.

This in turn drives the premium telescope purchase some years later (when they learn what TV, CC and pv means ).

 

So lets consider how to remove the 2 worst barriers to a newcomer: "what is collimating?" and "how do you find stuff beyond the planets?"

Edited by Max T, 04 May 2016 - 07:36 AM.

[Jon Isaacs]

 

I think the market has been heading in that direction for the past 25 years.  Thinking back, what is the last quality, small Newtonian on a nice mount?  Arguably the 150 XLT could qualify but i am thinking 4 and 5 inch scopes.

 

I can't think of anything since the C-4.5, a 4.5 inch F/8 on the Vixen Polaris mount.  

 

Jon

I was impressed with the optical quality of the Vixen R130 on a Vixen Porta-Mount II.  It has a fairly cheap focuser (though functional) and I found the tripod too tall for comfortable seated viewing,

But the scope is definitely not a toy, and a strong step up from the typical Starblast category.

It is not, however, in the quality range of the Celestron Omni XLT 6" newtonian on a CG4 mount.  That scope is an outright bargain, IMO.

 

 

When compared to refractors and CATs, well made, small Newtonians are just not available.  

 

Imagine a 5 inch F/5.5 that was built to the standards of a William Optics or Astro-Tech refractor.  Aluminum tube, proper baffling/flocking, quality end caps, rotating rings, a nicer focuser and all the rest  Every so often I see one used on Astromart.  They're always Japanese and their quality is obvious.

 

Jon

[Astrojensen]

 

When compared to refractors and CATs, well made, small Newtonians are just not available.

Really? 

 

http://www.teleskop-...ord-Auszug.html

 

It may not be a Takahashi, but compared to scopes available 30 years ago, it's *far* better. S&T would have been running around on the walls, screaming how good it is, if they had reviewed it 20 - 30 years ago. I've seen one in person and it's solid and very well made, incredibly so, for the ridiculous price. The optics are amazing.  

 

 

Clear skies!

Thomas, Denmark

Edited by Astrojensen, 04 May 2016 - 10:26 AM.

[ed_turco]

Oh, they're out there all right.  It all depends on how hard you look.  Or, to use an old expression, with a little gumption, one could easily make a 4" telescope far better than those toys out there.  I may be accused of pushing too hard on this topic, but I am infuriated with these ****ed toy telescopes out there making it difficult for budding amateur astronomers to enthuse about astronomy!  In some cases they pay some real bucks and get nothing for it, except disappointment and frustration.

 

 

Ed

[Jon Isaacs]

 

 

When compared to refractors and CATs, well made, small Newtonians are just not available.

Really? 

 

http://www.teleskop-...ord-Auszug.html

 

It may not be a Takahashi, but compared to scopes available 30 years ago, it's *far* better. S&T would have been running around on the walls, screaming how good it is, if they had reviewed it 20 - 30 years ago. I've seen one in person and it's solid and very well made, incredibly so, for the ridiculous price. The optics are amazing.  

 

 

Clear skies!

Thomas, Denmark

 

 

Thomas:

 

I am aware of those scopes and maybe they have better optics than the standard Syntax/Skywatcher/Orion/Celestron 130 mm F/5's.  I have owned a number of them, currently own 2. They have decent optics.  Mechanically that scope appears to be of similar quality to the basic Orion refractors, decent but spartan.

 

 

I am trying to raise the level of expectations for these small Newtonians.  Ed Turco's comments fit right in.  Ed's 6 inch is a perfect example. Certainly his scope or something of similar quality could be manufactured for a fraction of what a 6 inch color free refractor costs.

 

Where are those scopes?

 

Jon

[Starman1]

Parks made just such a reflector for years, but they didn't sell at all.

First, they were way more expensive than other, similarly-sized scopes.

Second, they didn't meet the definition of portable for most observers.

Third, for the same price as a 6" OTA, one could buy a complete 10" dob, and I don't need to tell you which one people picked.

Fourth, the small refractors were more amenable to widefield astrophotography.

Fifth, they required larger, heavier, mounts than most small refractors.

Sixth, they weren't computerized, and the sales of the company I worked for were 98% computerized--even at $300.

 

I could go on and on.  For every customer of a great 6" reflector on a decent mount, there are over 1000 customers for 4" Maksutovs on computerized mounts.

 

If someone wants a really nice 6" scope, you have to build it yourself, as I did in the '80s.  Back then, though, you could buy a 5" reflector on a GEM with tracking motor.

I haven't seen a scope like that for years.  Computerized scopes own the lower priced niches.  Non-computerized 4-6" scopes are typically a second scope purchased by an experienced amateur.

And I still see dobs as the visual observer's scope if you look at what shows up at star parties.  There is still also a healthy smattering of SCTs showing up.

I see a lot of refractors, but 95% of them have cameras attached and aren't being used for visual use.  And I almost never see a 6" or smaller reflector.

If what I see at star parties attended by 250 scopes or more is any example, sub-8" newtonian reflectors are pretty much non-existent.

Edited by Starman1, 04 May 2016 - 12:37 PM.

[Astrojensen]

 

I am aware of those scopes and maybe they have better optics than the standard Syntax/Skywatcher/Orion/Celestron 130 mm F/5's.

Here's a lunar shot taken with one, by my friend Rudi Rasmussen: 

 

http://b-rasmussen.d...oon_cassini.png

 

It's pretty good, I think. 

 

 

Mechanically that scope appears to be of similar quality to the basic Orion refractors, decent but spartan.

I don't think I would call a 2" crayford focuser with 1:10 gearing "spartan"... The focuser honestly seem to be a cut above the early Synta/Sky-Watcher 2" crayfords and doesn't seem to have any issues with a 2" Powermate and a DSLR. The build quality of the whole scope is arguably just as good, if not better on several points, than the Vixen reflectors of the 1980'ies. 

 

Again, it's not a Takahashi, but it's certainly a very good little 5" newtonian. 

 

 

Clear skies!
Thomas, Denmark

[KaStern]

 

 

When compared to refractors and CATs, well made, small Newtonians are just not available.

Really? 

 

http://www.teleskop-...ord-Auszug.html

 

It may not be a Takahashi, but compared to scopes available 30 years ago, it's *far* better. S&T would have been running around on the walls, screaming how good it is, if they had reviewed it 20 - 30 years ago. I've seen one in person and it's solid and very well made, incredibly so, for the ridiculous price. The optics are amazing.  

 

 

Clear skies!

Thomas, Denmark

 

 

Hi Thomas,

 

Günther, a fellow stargazer of me has one of these.

It is better than some others in that 5" range.

For example it has a 2" focusser wich is acceptably sturdy, but:

 

1) the focal plane is far too high above the tube wall.

For viewing you need the extension tube showns in the picture.

That leads to either a bigger secondary mirror (=> contrast loss)

or

a very small 100% illuminated field of view

or

both of this.

 

2) the tube front end is too short to prevent light from street lamps to come into the tube.

The tube is not baffled or flocked, it is just painted "black" wich means that is reflects light.

The tube is only thin iron metal sheet.

 

3) the mirror quality is o.k., about diffraction limited, but no high quality optics. 

 

I think that newt is a nice basis to build an atm newt from it.

A longer tube made from good material, internally flocked,

smaller secondary, that focusser without an extension,

that would make a good small newt.

 

Cheers, Karsten

Edited by KaStern, 04 May 2016 - 02:58 PM.

[CharlieB]

A 4" reflector can only be considered a toy when the manufacturer makes it a toy.   A decently made 4" reflector isn't going to do much on deep sky objects but point it at the Moon and you won't be calling it a toy, believe me!

 

In CN's classifieds, an optical outfit in Japan advertises 4" mirrors in f/6 and f/10 configurations.  Anyone who wishes to be enterprising and make a 4" telescope will agree with my comments about toys versus decently made telescopes.

 

Its all in how you make it.

 

 

 

Ed

Here are a pair of superb small reflectors - LN-3E and LN4-E.  Made by Astro Optical in the 1960's.  The LN3 is an f/9 and the LN4 is an f/10.  Both give excellent views.  The LN3 has a very peculiar EQ mount which renders it useless, but if you mount it on a more modern mount, it's just fine.  Both mirrors are parabolic.  The motor drive on the LN4 is quite good. The LN3 is 84mm/760mm and the LN4 is 100mm/1000mm.

Attached Thumbnails

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Edited by CharlieB, 04 May 2016 - 05:13 PM.

[Jon Isaacs]

I think that newt is a nice basis to build an atm newt from it.
A longer tube made from good material, internally flocked,
smaller secondary, that focusser without an extension,
that would make a good small newt.
 

 

 

Of the various 130 mm F/5s I have owned, the first Space Probe 130ST had the best optics and it was fitted with a 2 inch focuser.

 

It did a good job for what it was but I always had it in the back of my mind to rebuild it much as you suggest. A longer OTA, aluminum or maybe phenolic and well flocked, a low profile, high quality two speed, a smaller secondary..  

 

Also, these scopes cool rather slowly even after removing the rear cell cover.  Getting 300x to split near Dawes limit doubles takes most of an hour.  A proper mirror cell along the lines of the RV-6 was what I was thinking, minimal blockage, a nice free air path.

 

Regarding the Parks scopes: when we moved our current home, in 1999,Scope City was just a few blocks away. Their Newtonians, large and small were probably very good for the 1980s technology but they didn't seem to have embraced the changes that were happening.  I remember going in the store and asking for a laser collimator.."We don't believe inlaser collimators.". I don't think they believed in two speed focuser, thinner mirrors etc.

 

So, the scope I am imagining is a 5 inch, maybe a 6 inch, built to high standards. A scope where design decisions are not made on the basis of cost but rather based on making the best scope possible..  

 

But I think in the final analysis, Don is likely correct, such a scope would not sell and small high quality Newtonians are ATM projects.

 

Jon

[Laika]

I think most refractors in the same price range are in the same class, in fact I'd recommend the cheap newt.

[Jon Isaacs]

 

My point is there are no small Newtonians that are comparable in quality to the better refractors.  The decision to buy a Newtonian does not have to be based on the fact that its the least expensive, but as the market is configured, that's the way it is.  

 

Jon

[Astrojensen]

 

 

My point is there are no small Newtonians that are comparable in quality to the better refractors.  The decision to buy a Newtonian does not have to be based on the fact that its the least expensive, but as the market is configured, that's the way it is.  

 

Jon

 

If you think of more high-end visual stuff, I think that's true. At least if we're talking about true newtonians, as the INTES mak-newtonians are pretty darn high quality. Takahashi used to make small 100mm and 130mm newtonians of impeccable quality, but they're not in their program anymore. I can't think of any others right now, that I would categorize as really high-end in the small aperture end of the spectrum. The Vixen newtonians were very good, but more a no-frills concept, like the Sky-Watcher newtonians. 

 

 

Clear skies!
Thomas, Denmark

[SpaceConqueror3]

Edmund made some nice 3 and 4 inch newts back in the day.  Not sure if Stargazer Steve still makes his altaz Newt but it's a nice scope.  Nowadays the AWB One Sky 5 inch f/5 mini dob rules IMO. 

 

Edit:  Stargazer Steve SGR-4

 

I had a Edmund 3" f/10 reflector growing up for a few years before adding a Chicago Optical 4 1/4" f/4 in the last of my high school years. Between the two, I found over 3/4's of the Messiers in my edge of suburbia backyard.