Author Topic: Bahtinov Mask  (Read 16278 times)

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Mike

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Re: Bahtinov Mask
« Reply #15 on: Mar 09, 2011, 12:44:58 »
Some time next week.

Just give me the numbers for the generator, it will be a lot easier.

I will need to convert the .svg file to .dxf for the laser cutter.

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RobertM

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Re: Bahtinov Mask
« Reply #16 on: Mar 09, 2011, 13:49:56 »
Ok, will do

Fay

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Re: Bahtinov Mask
« Reply #17 on: Mar 09, 2011, 13:52:06 »
I have an 8" one I can sell
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The Thing

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Re: Bahtinov Mask
« Reply #18 on: Mar 09, 2011, 15:11:27 »
I used the web generator (Mac's link below) and printed it on an A4 self adhesive photo sticker, sprayed it with photo shield stuff, then stuck it on an old plastic folder cover then cut it out with a craft knife. I believe sharp edges are crucial rather than perfectly straight lines as its the edge that causes the diffraction. I have tried a couple of configurations and fewer slots seems to be better. 8" masks must be easier to cut than one for Mick's Burgess.
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mickw

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Re: Bahtinov Mask
« Reply #19 on: Mar 09, 2011, 15:40:34 »
Quote
8" masks must be easier to cut than one for Mick's Burgess.

I still see diffraction spikes when I look at a lightbulb  :o

At least I know it's in focus  :lol:
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Carole

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Re: Bahtinov Mask
« Reply #20 on: Mar 09, 2011, 20:27:44 »
Wish I'd seen this revived thread a couple of days ago, might have saved some blisters on my fingers from all the pressing with the cutting blade.

 :(

MarkS

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Re: Bahtinov Mask
« Reply #21 on: Mar 09, 2011, 20:45:33 »
I've just seen the animation at the beginning of this thread.  I was dead impressed until I realised it was my own!
« Last Edit: Mar 09, 2011, 21:42:42 by MarkS »

Carole

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Re: Bahtinov Mask
« Reply #22 on: Mar 09, 2011, 22:08:17 »
 :lol:

Mac

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Re: Bahtinov Mask
« Reply #23 on: Mar 09, 2011, 23:53:47 »
 :cheesy:
Never, ever, argue with an idiot. They'll drag you down to their level and beat you with experience.
If you argue with an idiot, there are two idiots.

Mike

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Re: Bahtinov Mask
« Reply #24 on: Mar 15, 2011, 12:33:41 »
Note that the maximum size of the cutting bed for the laser is 310mm x 585mm so nothing over 310mm in diameter. Suitable materials - thin MDF sheeting or acrylic.

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mickw

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Re: Bahtinov Mask
« Reply #25 on: Mar 15, 2011, 12:42:05 »
So the Lightbridge is out then   :D

When would you want the materials by ?
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Mike

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Re: Bahtinov Mask
« Reply #26 on: Mar 15, 2011, 12:54:34 »
Acrylic can be cut up to 4mm depth and MDF up to 3mm. I can get materials from Hamar Acrylic which is just a short walk from London Hackspace. I'm doing some for Robert tomorrow (if he gives me the dimensions) so I'll let you know an idea of prices then. I know it is £3 per hour to use the cutter plus cost of materials on top.
We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology. Carl Sagan

mickw

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Re: Bahtinov Mask
« Reply #27 on: Mar 15, 2011, 14:58:57 »
PM on it's way
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Mike

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Re: Bahtinov Mask
« Reply #28 on: Mar 16, 2011, 23:52:15 »
Did a few tests today cutting some of the 3mm MDF Mick gave me:



This was using the 80mm dimensions Robert gave me for his scope.

The acrylic Mick gave me was useless though, it just burnt. It needs to be branded Perspex apparently if you want smooth edges. I shall pick up some in black from Hamar Acrylic some time this/next week and do some more tests.
We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology. Carl Sagan

Mike

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Re: Bahtinov Mask
« Reply #29 on: Mar 17, 2011, 00:17:21 »
Just for a laugh I made some planetary gears (tenuous astronomy link) too.

We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology. Carl Sagan