Re: [ATM] 32" Focal ratio

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

Hi Scott and ATMers,

My design with wynne corrector have a fixed 45 degree diagonal and,
a. Not need to change anything to both for visual and photo.
b. Only 20% diameter obstruction;
c. Corrector only use BK7 glass, which is the most cheap and popular optical 
glass.
d. Only use 1 6" diagonal mirror.
e. coma free!

Is it better than your design? Wouldn't you think about it?

Best Regards,
Ukyo Chen

>From: polaraligned <polaraligned@optonline.net>
>To: Ukyo Chen <ukyochen888@hotmail.com>
>Subject: Re: [ATM] 32" Focal ratio
>Date: Tue, 02 Aug 2005 07:26:32 -0400
>
>Thank you,
>I appreciate your time.  The system is to be folded
>with a 12" flat.  The obstruction ratio will be about
>38%.  You can see a rendering of the scope in here:
>http://photobucket.com/albums/v223/polaraligned/25%20inch%20scope/
>The camera lies between the primary and the flat secondary.
>My thoughts of using a longer focal ratio are for less coma to deal
>with and also easier collimation.  I will be using a removable
>3rd diagonal mirror for visual use, when not imaging.
>
>Thanks for your help,
>Scott
>
>
>
>
>----- Original Message ----- From: "Ukyo Chen" <ukyochen888@hotmail.com>
>To: <polaraligned@optonline.net>; <aplanatic@aol.com>; <atm@atmlist.net>
>Sent: Monday, August 01, 2005 10:03 PM
>Subject: Re: [ATM] 32" Focal ratio
>
>
>>Hi Scott,
>>
>>Basically a fast F ratio will reduce the exposure time, as well as the 
>>tube length and weight.
>>I suggest you use parabolic mirror + wynne corrector. commercial coma 
>>corrector are not designed specially for your system and the performance 
>>may not as good as you can.
>>
>>Below is a 20% obstruction telescope that perform diffract limit image in 
>>whole 24.6x24.6mm area. You can put secondary right behind lens 2 so that 
>>camera or eye pieces can be easily connected after lens 3.
>>
>>If you do not need to connect eye pieces, please let me know and I will 
>>modify the design to get less obstruction.
>>
>>Best Regards,
>>Ukyo Chen
>>
>>F/5 32" wynne corrector
>>SRF      RADIUS      THICKNESS   APERTURE RADIUS       GLASS  SPE  NOTE
>>OBJ  0.0   1.0e+20   4.3633508207e+17             AIR
>>
>>AST  -7135.270890953675 V -3000.0   407.0 AS   REFL_HATCH   *
>>
>>  2   -160.6112693212592 V -15.0   77.8465641180188 S           BK7 C
>>  3   -282.4400424991707 V -40.0   74.2797145556817 S           AIR
>>
>>  4   -427.5044558225438 V -10.0   65.2910476243541 S           BK7 C
>>  5   -144.0836019042825 V -500.0   63.2897662600067 S           AIR
>>
>>  6   -226.6123202207288 V -10.0   25.2464843501938 S           BK7 C
>>  7   -655.2293854027363 S -57.6514303221301 S 24.3649768490518 S AIR
>>
>>  8   0.0   0.0   17.7588378402554 S           AIR
>>
>>
>>
>>>From: Polaraligned <polaraligned@optonline.net>
>>>To: aplanatic@aol.com, atm@atmlist.net
>>>Subject: Re: [ATM] 32" Focal ratio
>>>Date: Mon, 01 Aug 2005 20:17:56 -0400
>>>
>>>>Hi Scott,
>>>>
>>>>What is the largest camera you will be using with the scope?  Are you 
>>>>figuring the mirror or is someone else?  Will you be buying (or making) 
>>>>a focal reducer?  How picky are you about the images at the edge of the 
>>>>field?  Do you plan on doing mosaics?
>>>>
>>>
>>>
>>>Probably a KAF 1001 with a 24.6 x 24.6 mm size.  24 um pixels.  It's
>>>pixel size is a good match for the long focal legnth without binning.
>>>Plan on having someone else make mirror.... Buying a coma corrector....
>>>Well, of course I would like the best possible images to the edge of 
>>>field,
>>>and I can't rule out mosaics.  Am I asking too much?  How will this scope
>>>compare to an RC?  Oh, and the original question: Is a longer f ratio 
>>>going
>>>to help me achieve better images, even with a corrector?
>>>
>>>Opinions appreciated,
>>>
>>>Scott
>>>
>>>
>>>_______________________________________________
>>>ATM mailing list http://www.atmlist.net/
>>
>>
>


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