[ATM] Difraction Spikes

[Jack Swaton @ Starry Host]

All,
I thank you for your input. As always it is thought provoking, sometimes
antithetical and frequently humorous.

After careful consideration, I think...I'll not lose sleep over the issue
anymore and just continue to build spiders in different configurations until
I hit one that is simple for me to build, simple to use and holds alignment
for a long time while taking bumpy rides in the trunk of my civic. I can
live with a little more or a little less diffraction. I'm no purist!

Jack

-----Original Message-----
From: atm-bounces at atmlist.net [mailto:atm-bounces at atmlist.net] On Behalf Of
Marco
Sent: Friday, October 30, 2009 3:24 PM
To: Peter De Baan De Baan; Richard Schwartz; mjc5 at psu.edu
Cc: atm at atmlist.net
Subject: Re: [ATM] Difraction Spikes

That's the window frame that the telescope is pointed through.

----- Original Message ----- 
From: "Peter De Baan De Baan" <pdebaan at hotmail.com>
To: "Richard Schwartz" <richard1941 at gmail.com>; <mjc5 at psu.edu>
Cc: <atm at atmlist.net>
Sent: Friday, October 30, 2009 8:28 PM
Subject: Re: [ATM] Difraction Spikes


>
> What causes the 4 poined spike around brighter stars oncamera pictures 
> made with refractor telescope ?
>
> baffled without the obsrtuction
>
>
>
> Peter
>
>> From: richard1941 at gmail.com
>> To: mjc5 at psu.edu
>> Date: Fri, 30 Oct 2009 09:15:11 -0700
>> CC: atm at atmlist.net
>> Subject: Re: [ATM] Difraction Spikes
>>
>> What if the spider vanes are relocated to the edge of the aperture, so
>> as th reduce the diameter? I think any reduction in aperture "blurs"
>> the image.
>>
>> Consider, for a moment, the Allen Telescope Array-- it has huge
>> obstructions (the space between the dishes).
>>
>> I apologize in advance for questioning dogma and trying to provoke
>> thought and fourier series. Note that i have long advocated piano
>> wire spyders and given up on Art Leonard (PBUH) technology.
>>
>> Sent from Richard's iPhone
>>
>> On Oct 30, 2009, at 5:52, Michael Coslo <mjc5 at psu.edu> wrote:
>>
>> >
>> > On Oct 30, 2009, at 12:23 AM, Jack Swaton @ Starry Host wrote:
>> >
>> >> Do diffraction spikes actually blur the object causing them? For
>> >> instance,
>> >> is the view of Jupiter less sharp because of the spikes or the
>> >> thickness of
>> >> the spikes?
>> >
>> > They tend to lower the contrast of the image, mostly through light
>> > scattering. And humans tend to interpret lower contrast as less sharp.
>> >
>> > -73 de Mike N3LI -
>> >
>> >
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