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Newtonian VS Catadioptric scopes


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In the last 6 months I have had 2 catastrophic telescope disasters (or so I thought). 

I dropped my Skymax 150 Pro destroying the corrector plate and it is beyond economic repair😩

Two weeks ago I had a fall on my deck taking over my whole rig. AZ EQ6 and Bresser 10" Newt. The result was a broken focuser mounting plate and tube with dings, dents and creases. The focuser and EP were in rhe flower bed but had survived. 

After a large gin ( no that was not the cause of the fall) I emailed Bresser UK to see if I could buy a new tube and mounting plate for the focuser. 

They were very helpful but tube not available till about Easter. 😩😩😩😩

Full disassembly of the scope. 

Then started my self taught pannel beating course. 🤔

Tools used

Large roll of Duct tape to bump out the larger dents. 

Just held in hand and banged with the curve of the tube

Wooden mallet and small hammer to gently tap out the smaller dents and sharper crease caused by the edge of the mounting plate. 

I found that the extension bar from the Azeq6 counterweight bar held inside the tube made a perfect anvil and holding it across the inside of focuser hole I could caress the tube back to shape even removing the crease. 

You need to look very hard now to see any  evidence of damage. 

Bresser are sending me a new mounting plate for the focuser. £19.50 delivered. 

Who considers the cost of repair when choosing a scope? I do now. 

Clear Skies

Bigwings

 

 

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Well done! There is something to be said for Newtonians, quite robust, and fixable (as long as the primary mirror survives). And of course easily collimatable without expensive equipment.

I'm very careful with both of my Skymax 127 and 180. The big one is quite challengeing shape and weight  when lifting onto the mounting plate.

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36 minutes ago, johninderby said:

Ah my poor old Bresser dob. 😢

Glad to hear it is on the mend though. 😁

Don't worry John it's going to be fine. It's a keeper as far as I'm concerned. 

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1 hour ago, johninderby said:

Handles should be standard on most scopes. 🙂

So much easier to lift onto a mount. 👍🏻

2FAEAAD0-1BB5-4DA9-A237-C09EF7018DE6.jpeg

I agree that handles make life a lot easier. My de-forked Meade came with a homemade strap and rings - I replaced the strap with a proper metal handle.

IMG_20210925_122420588.jpg

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5 hours ago, Bigwings said:

Who considers the cost of repair when choosing a scope? I do now

Very good point. I’ve got a slight feeling of foreboding about how much it will cost to repair my CPC Goto when it fails, as it surely will and if it will still be supported them. 😬

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On 25/09/2021 at 14:56, Andy ES said:
On 25/09/2021 at 09:31, Bigwings said:

Who considers the cost of repair when choosing a scope? I do now

Very good point. I’ve got a slight feeling of foreboding about how much it will cost to repair my CPC Goto when it fails, as it surely will and if it will still be supported them. 😬

I agree, it is a worry. As mounts are becoming more technically-advanced with wifi, GPS and phone/app connectivity etc., ongoing support and repair costs will probably be a big issue in the not-too-distant future. I bet the optical elements will long-outlast the electronics.  

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Buy Russian!

Some years ago my 20Kg of MN78 slid out of the dovetail while going over the zenith. Bang on the obsy wood floor.
A dent on the tube and a scuff on the paint. I have ignored both.
It didn't even upset the collimation!
Thinking about damaging dropped eyepieces and like, my obsy floor now has gym mats over the wood.

Note to self. Always check the rail clamping screws for tightness. Think about safety end stops.

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My 20+ year old Dob is made from 3/4" oak plywood and sonotube.  Heavy for its size, but both have stood up to being banged into doorways and accidentally kicked without visible injury.

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On 25/09/2021 at 14:50, Merlin said:

It’s been said that a well made, correctly adjusted, Newtonian reflector is superior to any folded-beam instrument.

Newtonians have their advantages but there's a reason that two, and increasingly three-mirror designs are the standard at the high end. More mirrors allow you to have greater correction across the entire field but they obviously cost more to make and collimation is more of an issue.

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10 minutes ago, Andrew_B said:

two, and increasingly three-mirror designs are the standard at the high end.

Andrew, not wishing to be in any way confrontational, but I do think that’s a highly questionable generalisation.  🙂

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34 minutes ago, Andrew_B said:

Newtonians have their advantages but there's a reason that two, and increasingly three-mirror designs are the standard at the high end. More mirrors allow you to have greater correction across the entire field but they obviously cost more to make and collimation is more of an issue.

That's certainly true of observatory class telescopes, but a large Newtonian with a hand figured mirror and Paracorr II is hard to beat dollar for dollar on aperture at the high end of the amateur market.  Most folks dropping $20,000+ on catadioptric designs are purely imagers, not visual observers.  On the other hand, folks dropping $20,000+ on giant custom Dobs with Zambuto or similar mirrors tend to be visual only observers.  It really depends on what you're going to use the telescope for when it comes to deciding on a particular design at a particular price point.

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2 hours ago, JTEC said:

Andrew, not wishing to be in any way confrontational, but I do think that’s a highly questionable generalisation.  🙂

I should have qualified that by high end I mean the kind of optics used in spy satellites and state-of-the telescopes like the ELT. I don't know if there's any three-mirror designs (three curved mirrors, not just a Nasmyth-Cassegrain) on sale aimed at the amateur market.

If you're an amateur and especially one who's interested in visual observing then you'd be hard pressed to beat a good Newtonian.

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2 hours ago, Louis D said:

That's certainly true of observatory class telescopes, but a large Newtonian with a hand figured mirror and Paracorr II is hard to beat dollar for dollar on aperture at the high end of the amateur market.  Most folks dropping $20,000+ on catadioptric designs are purely imagers, not visual observers.  On the other hand, folks dropping $20,000+ on giant custom Dobs with Zambuto or similar mirrors tend to be visual only observers.  It really depends on what you're going to use the telescope for when it comes to deciding on a particular design at a particular price point.

Totally agree, and I should have made it clear that I was talking about designs preferred for very large optics that are far beyond the budget of any amateur that are used for space telescopes and the latest observatory-class instruments.

The great thing about a Newtonian is that your budget only needs to pay for a single large, curved mirror so you should be able to get more aperture and better quality for the money than with any other design.

One of the more interesting concepts I've seen is unobstructed reflectors based on three-mirror designs which could have incredible performance but the need for asymmetric optics would presumably make them expensive and keep them out of the amateur market for a while yet.

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On 25/09/2021 at 09:31, Bigwings said:

Two weeks ago I had a fall on my deck taking over my whole rig. AZ EQ6 and Bresser 10" Newt.

You carried it whole? 😲

I have an EQ6 Pro and a 10" Newt (loaded with cameras etc.). I struggle with the unweighted mount on its own and am now finding the fully loaded OTA difficult to manage. I can't imagine carrying it all together! Well, I simply couldn't...

Yes, gin might not be the cause of most disasters but it's the prescribed treatment for many :)

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No Paul, I can't lift it up and don't need to as its got a scope dolly. 

I did lift it back up after its fall to the horizontal. That was hard enough. 

I tripped on something in the dark and took it over when I fell. 😭

IMG_20210823_141316.thumb.jpg.3c5f89ff29b753f3cf7f50c24970c266.jpg

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13 minutes ago, Bigwings said:

No Paul, I can't lift it up and don't need to as its got a scope dolly. 

Ah, right :)

I could use one of those but powered! Unfortunately I have a big step in/out of the garage so it's all mandraulic for me.

Just thinking over your original disaster, perhaps a way forward and to start a trend is to dent the whole tube uni-formally and go for the hammered Enamel look. You go first... :) 

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  • 2 weeks later...
On 30/09/2021 at 23:03, Paul M said:

Ah, right :)

I could use one of those but powered! Unfortunately I have a big step in/out of the garage so it's all mandraulic for me.

Just thinking over your original disaster, perhaps a way forward and to start a trend is to dent the whole tube uni-formally and go for the hammered Enamel look. You go first... :) 

Mmmm. On this occasion I will pass. 

This lovely Newt is now back in great condition for the sum of less than £30.

Spares service and customer support from Bresser UK was superb. 

For me its a Newt every time. Great performance at a good price and owner repairable at modest cost. IMG_20211011_172141.thumb.jpg.09ce9c776b50421b06b131c1148e7c41.jpg

Love this scope. 

🤗🤗🤗🤗

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