Re: [ATM] Lurie-Houghton telescope update

["Ukyo Chen" <ukyochen888@hotmail.com>]

It is not easy for an ATMer to make and test convex surfaces, also the 
optical company can provide all lenses with coating in low price, why not?

I will try to find approximate aperture and F ratio APO telescope and do a 
test after I finish the OTA.

I guess the reason why Lurie-Houghton is not popular lies on below facts:
1. Only 20 year ago, in 1975, did Lurie mentioned that same type of glass 
can be used to build 2 elements corrector for Houghton lens inside US Patent 
#2350112 in 1944.
2. Lurie mentioned in the footnote of an optical paper, seldom person will 
notice that, so does ATMer.
3. Houghton's Patent totally contain 4 types of lens, hard to know which is 
better if you do not have enough optical knowledge.
4. Lurie died already and no company support(even known, I guess) his idea, 
More lens means more grinding and testing, more cost, perhaps.
5. ATMer's are making Lurie-Houghtons, but most people will think, too many 
surfaces, less light, more error, more weight, but they may not know 
Lurie-Houghton system has much better tolerance than any other type like 
APO, Cassegrain or Newtonian.
6. Lurie-Houghton owner seldom show their photos to others so that not too 
many person know it really works fine.

Best Regards,
Ukyo Chen

>From: Aki Lötjönen <aki.lotjonen@phnet.fi>
>To: Ukyo Chen <ukyochen888@hotmail.com>
>CC: atm@atmlist.net, 
>atm_free@yahoogroups.com,Make_Your_Own_Telescope@yahoogroups.com
>Subject: Re: [ATM] Lurie-Houghton telescope update
>Date: Tue, 08 Nov 2005 17:55:06 +0200
>
>Ukyo Chen wrote:
>
>>Hi all,
>>
>>Regarding to my 5" Lurie-Houghton telescope project, lenses part finished 
>>already. Now 2 126mm correctors with multi-coating, 1 126 mirror with 
>>Enhanced-Ag coating, 1 diagonal mirror with Enhanced-Ag coating are all in 
>>my hand. Now I am seeking for a company who can do the machine work on my 
>>tube.
>>
>>I had worked out a website to record it, as well as some wonderful photos 
>>taken through Lurie-Houghton by other guys. The address is 
>>http://ukyochen.lamost.org, appreciate if you have any suggestion for me.
>>
>>Best Regards,
>>Ukyo Chen
>>
>>
>>
>>
>Hi Ukyo,
>Congratulations! You already have come far with your LHN project. Just wish 
>you would have done the grinding and polishing work by yourself. Then the 
>achivement would taste even better. On the contrary you might be a wise man 
>by letting others to do the hard work.
>Anyway, now there is a short way to see soon the first views through a new 
>Lurie-Houghton Newtonian telescope! :)
>
>Regards,
>Aki Lötjönen
>


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