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Is it worth buying a mirror from aliexpress or ebay?

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#1 ujak

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Posted 19 January 2019 - 08:38 AM

Me and my friend are trying to build our first telescope (8" dob), and we are looking for a mirror. We can`t make our own telescope so we`ve been looking for one on the internet. We could get a mirror set for quite cheap on ebay and aliexpress, but are those really worth it or should we get more expensive ones from somewhere else? And if so then where?



#2 Augustus

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Posted 19 January 2019 - 09:16 AM

The eBay and aliexpress mirrors are spherical junk. Avoid.

 

Get a mirror from GSO or look at used on the Classifieds or Astromart.


Edited by Augustus, 19 January 2019 - 09:16 AM.

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#3 sg6

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Posted 19 January 2019 - 10:09 AM

Can be difficult to say.

Have no knowledge of Aliexpress, they seem to be uncommon here but ebay is used.

Since ebay is often "shops" then it depends on the shop and the source. Hubble Optics sell some of their sandwich mirrors via ebay and they seem reasonable mirrors. They also sell hyperbolic mirrors and they are better.

 

So you need to investigate then decide. ebay will be a case of one online shop and almost world wide exposure. Minimum is the country they go via as in .com covers the US. They do not need to take a few years to get known as ebay presents just about everything to everyone.

 

Aliexpress is as said more of an unknown, some items appear fair others questionable. You need to be sure of the mirror and if possible the source.

 

One thing you need to ask yourself is are the "cheap" mirrors even if they carry a recognisable name are they of decent quality. I suspect that optical components are checked and catagorised and the poor ones get sold off. These days it will be a few seconds to check any optical item and get a result. It also prevents the recognised names getting poor items - they buy only the grade A items.



#4 geyes30

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Posted 19 January 2019 - 01:17 PM

The eBay and aliexpress mirrors are spherical junk. Avoid.

 

Get a mirror from GSO or look at used on the Classifieds or Astromart.

Second that. Aliexpress is quite the labyrinth and it can be impossible to figure out what they are actually selling. In fact, it seems some of the sellers intentionally obfuscate. I bought my first mirror from Aliexpress because it was so cheap, but when it arrived, I was shocked to find out that it was spherical. You also have absolutely no recourse. Made for a pretty crappy experience. 

 

eBay, on the other hand, has been good. Many US shops are on eBay and I bought 2 mirrors this way. Wait around a bit and you may even get complete 8" mirror+cells from makers like Orion or Skywatcher for only 80 bucks. Not superb mirrors, but quite a bargain, in my opinion.


Edited by geyes30, 19 January 2019 - 01:19 PM.

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#5 ccaissie

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Posted 19 January 2019 - 07:02 PM

https://www.cloudyni...ific-8-f-5-ota/

 

What f # are you looking for?  This one listed will have other useful parts...can't beat that!


Edited by ccaissie, 19 January 2019 - 07:04 PM.

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