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Diffraction spikes

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I did quite a bit of experimenting on spiders before I decided that the curved spider is the best , for example a 4 vane spider gives 4 diffraction spikes ,,,,, BUT ! , a 3 vane gives 6 spikes !!! don't know the science behind it , but it happens yes 6 spikes ! , something to do with the wave nature of light ?

Yes 6 spikes is a real pain , but as Foulksey says pretty to look at and most like that but to do real close and different magnitude double star work ( where a 12 inch excels ) , not so good .

As I said I don't like them , I see them as the reflectors curse , like refractors and their curse'd CA ...


Edited by Brian Nordstrom
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previously I had very large obvious and wide diffraction spikes, now it's totally black around the planet with almost no visible diffraction. I did find the spikes on this particular scope very distracting on Jupiter and Venus, but less so on the 12"

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not sure if i'm correct but..

i had my scope for 6 months now...tweaked and collimated a lot..(SW 300 flex)

I also had a look at the spider..which is a stock model...and seemed fine..

On a rainy night I started tweaking again and decided to re-center my spider...

(the exact reason eludes me..)


I re-centered the whole thing and then started to re-center my secondary..

After this..i moved on to my primary and noticed that the reflection of the spider vanes

had changed (due to my tweaking..).

I noticed that two of the four vanes were barely noticable in the reflection..and I mean

they were a slight smudge of a grey line..

So...I tweaked the other two vanes, by exerting more or less torsion on the vanes by

turning the knobs...

I tweaked them such that their reflection too was a smudge of grey...

I then checked from the front of the scope and saw the vanes were slightly distorted,

but collimation was spot on..

So I left it...and my diffraction spikes have all but dissapeared.

don't know if this is correct or not but, just wanted to tell my story

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