Diffraction Spikes for a small Refractor

JohnG (John) · #1 08-09-2006, 02:06 PM

For those with a small refractor and would like diffraction spikes on their photo's, something I made up.

Piece of 1/2 inch ply, use your refractor's dew shield as a template, cut out the hole so it slips over the end, 2 pieces of fishing line and 4 small screws.

The fishing line holds it in place and you can change the angles to suit.

Cheers

JohnG

Lee · #2 08-09-2006, 02:25 PM

You should submit it as a mini DIY for the projects section - looks good.....

RB (Andrew) · #3 08-09-2006, 03:38 PM

Great idea John, thanks for sharing.

Adrian-H · #4 08-09-2006, 07:40 PM

test shot test shot!

can i see a test shot?

dose it really work like diffraction spikes from a newtonian?

i aint a huge fan of them but i think they do look nice when they you got some razor sharp ones, i guess it kind of sharpens the image, or it makes it look like you can see the imaginary beams from the star, you know what im talking about im sure.

Thanks.

Adrian

RB (Andrew) · #5 08-09-2006, 08:32 PM

Quote:

Originally Posted by Adrian-H

test shot test shot!

can i see a test shot?

dose it really work like diffraction spikes from a newtonian?
Thanks.

Adrian

Adrian I did the same thing when I took the M45 shot in this thread.
I used fishing line crossed over the refractor's due shield.

JohnG (John) · #6 08-09-2006, 08:47 PM

There you go, 15lb breaking strain fishing line, Antares with a 4"Takahashi FS-102.

Cheers

JohnG

Striker (Tony) · #7 09-09-2006, 09:47 AM

Nice little project John.

Garyh · #8 09-09-2006, 12:43 PM

Hi John always wanted to try that with my refractor..
Here is a pic I took of a 1st mag star...

Used m3 threaded rod...

won`t try that again but looks pretty!!!
Cheers Gary

Garyh · #9 09-09-2006, 12:46 PM

Forgot the pic..

Adrian-H · #10 09-09-2006, 06:18 PM

WOW

very nice, those are super sharp, its even sharper looking then newt diffractions, skyrocket and wow john!

thats interesting looking garyh, its strange how you can see that squared abberations around it? im wondering what is that and what caused it? its interesting that!

i will make one of these! i want to try it when the sky clears up, anyways its something to do while the clouds are covering

just thin fishing line works fine? cause ive only got one fishing line laying around!

thanks!

Adrian

JohnG (John) · #11 09-09-2006, 07:27 PM

Hi Adrian

Dont forget to put a small saw cut in each corner to keep the fishing line in place and at right angles in the centre, the line will slip otherwise.

Hey Gary, interesting effect. lol

Cheers

JohnG

Roger Davis · #12 11-09-2006, 11:47 AM

I know the aesthetics of the diffraction spike, but why dump light out of the Airy disc? More information in a star image in focus than diffracted everywhere!

ving (David) · #13 11-09-2006, 11:53 AM

i was wondering that too roger... sure it looks pretty but do you really need it?

nice little project tho

lol @ gary's. thats a stunner

JohnG (John) · #14 11-09-2006, 12:11 PM

This was purely for aesthetics when taking cluster shots, nothing more, saves mucking around with elastic bands and loose bits of fishing line.

To each their own.

JohnG

ving (David) · #15 11-09-2006, 12:14 PM

sweet

Adrian-H · #16 12-09-2006, 01:54 AM

it makes it look like your using a hubble space telescope RC optics, and gives it the classical hubble picture look!

so when you show the people that dont know anything about astronomy, they think you image from a full scale size observatory!

infact i think that they draw attention on star's, like if you use them on single star double star and open star clusters they kind of have the effect of drawing attention to the subject, well thats what i think anyway, not that ive took any yet, by looking at pictures with them!

rmcpb (Rob) · #17 12-09-2006, 08:58 AM

Funny isn't it, about half the reflector types are trying to get rid of diffraction spikes and then some with refractors want them!!

Can never tell.........

Adrian-H · #18 13-09-2006, 03:08 AM

here i had a go at it, theres thin line through the mid of them though and little dots in the mid of stars, dose that mean i need thinner wire or?

thanks

Adrian.

rmcpb (Rob) · #19 13-09-2006, 03:47 PM

Adrian,

Try painting the line black, it looks to me that you are getting the light going through the middle of the line and reflections off each side of the line.

Try black thread??

Looks great though but then I am used to diffraction spikes even if they are only single ones

Adrian-H · #20 14-09-2006, 12:05 AM

thanks rob ill give it a go soon, probly on the weekend, i will be away accouple of days starting tommorow