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Author Topic: Bahtinov mask generator  (Read 28628 times)

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Offline jochta

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Re: Bahtinov mask generator
« Reply #15 on: 17:00:24, 01 October, 2008 »
BTW... this animation shows perfectly how it works...

http://www.iceinspace.com.au/uploads/Fomalhaut.gif

Gonna be making mine this evening  :happy:

EDIT :: In fact I just knocked one up using some old OHP film I had in the office, printed via the free software Inkscape to a laserjet and photocopied onto two sheets of transparency. Overlapped and stuck at the edges. I'll let you know how I get on (if it's clear).


Wanna knock one up for me ?


I'll see if it actually works first, but I can do that no probs.
GSO Newtonian - Aperture 300mm - F/4
WO Megrez 72FD APO - Aperture 72mm - F/6
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Offline swashy

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Re: Bahtinov mask generator
« Reply #16 on: 17:17:05, 01 October, 2008 »
providing the transparency dosent shift the focus point like some filters can do!

otherwise it will defy the point of the excercise, unless you start imaging with a transparency in the way  :scare:

Ive just made one from thin black plastic (from the cover of an A4 project folder) I sprayed some glue on the printout and stuck it on the plastic, then carefully cut out the vanes, all 27 of them, with a new blade and then peeled the paper template back off, worked well  :D

so just need to figure out how to mount it now and it should be good for testing on the next available star, just hope its as good as they say, 'cause I really need a working solution to this focus lark
Ade

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Offline jochta

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Re: Bahtinov mask generator
« Reply #17 on: 17:38:24, 01 October, 2008 »
There are about 100 cut outs for my 200mm f/4 - I don't really fancy getting the ruler and craft knife out just yet! And once they are cut out it'll be too floppy to work anyway.
GSO Newtonian - Aperture 300mm - F/4
WO Megrez 72FD APO - Aperture 72mm - F/6
Sky-Watcher NEQ6 Mount
Watec 120N :: Atik 16IC-S :: Nikon D40 :: DMK 21AU04.AS :: QHY22

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Offline Stuart

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Re: Bahtinov mask generator
« Reply #18 on: 23:15:46, 01 October, 2008 »
Well I've created one and viewed it in firefox, all I need to do now is print it onto something durable and spend an hour or so with a craft knife.  It does look like a good idea and I hope it is as effective as it looks to be.

Offline spaismunky

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Re: Bahtinov mask generator
« Reply #19 on: 23:24:00, 01 October, 2008 »
A wee bit wobbly but it's made of polymer clay (FIMO). Baked in the oven and pared a bit. It's not perfect but I'm happy with the result...as long as it works that is! ;)
mojo :D

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Offline swashy

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Re: Bahtinov mask generator
« Reply #20 on: 23:53:51, 01 October, 2008 »
Fantastic Mo!   :canadian:
Ade

Imagine...  above us only sky!

Offline spaismunky

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Re: Bahtinov mask generator
« Reply #21 on: 00:12:56, 02 October, 2008 »
Thanks Ade :embarrass:, and thanks for the measurements.
mojo :D
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Offline janmclare

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Re: Bahtinov mask generator
« Reply #22 on: 02:54:52, 02 October, 2008 »


Interesting way of making one of these mo...  good luck, hope it works.

Jan
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Offline shelleym

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Re: Bahtinov mask generator
« Reply #23 on: 07:32:29, 02 October, 2008 »

Thanks for the heads up on this folks.  Cut my own from cardboard last night for my C11.  Here's a pic and an animated GIF I made showing it in action with my DSLR.  It's just SO easy to use!!

Mark



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Offline Roger B

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Re: Bahtinov mask generator
« Reply #24 on: 08:33:47, 02 October, 2008 »

Thanks for the heads up on this folks.  Cut my own from cardboard last night for my C11.  Here's a pic and an animated GIF I made showing it in action with my DSLR.  It's just SO easy to use!!

Mark



At what point in your gif is this focused ? 

roger
Scopes - TS65q, W/O 110 Triplet
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Offline shelleym

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Re: Bahtinov mask generator
« Reply #25 on: 09:22:21, 02 October, 2008 »

Roger,

It is focused when the vertical line is exactly halfway between the slanted ones.

Mark

Offline Roger B

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Re: Bahtinov mask generator
« Reply #26 on: 09:53:20, 02 October, 2008 »

Roger,

It is focused when the vertical line is exactly halfway between the slanted ones.

Mark

That's what i thought.    Does it work ?

roger
Scopes - TS65q, W/O 110 Triplet
Mount - EQ6 PRO via  Eqmod,  Rowan belt modded
Cameras - SX694, QSI583WSG,Lodestar Guidecam, GP-Cam, QHY5II.
TS 9mm OAG
Quantum 7x1.25 EFW, Baader LRGB,Ha,OIII,SII Filters 
Quark chromo

SGPro, Pixinsight.

************AND NO TIME TO USE IT************

Offline jochta

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Re: Bahtinov mask generator
« Reply #27 on: 10:12:35, 02 October, 2008 »
My bodged transparency version of the mask kind of worked. I guessed the dimensions of my scope and put them in the generator so it wasn't quite the right size.

It gave the diffraction pattern and you could see the focus point, but it was nowhere near as clear as the examples I've seen. I will more carefully make one over the weekend. Problem with a low f-ratio is that there are loads of thin cutouts which makes it much harder to make...

BTW mojo I'd be a bit concerned about the non-sharp edges on yours, AFAIK the diffraction pattern will need nice straight sharp edges to work well, lasercuts work best apparently. Let us know how you get on.

John
GSO Newtonian - Aperture 300mm - F/4
WO Megrez 72FD APO - Aperture 72mm - F/6
Sky-Watcher NEQ6 Mount
Watec 120N :: Atik 16IC-S :: Nikon D40 :: DMK 21AU04.AS :: QHY22

jochta's astro

Offline Dangerous_Dave

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Re: Bahtinov mask generator
« Reply #28 on: 17:26:16, 02 October, 2008 »
This is first class stuff swashy. Could one of UKAI's esteemed sponsors go into business manufacturing these? I am absolutely hopeless at making these sorts of things!
EQ6 Skyscan, Vixen GP, WO Megrez 90FD, WO Megrez 72FD, Vixen R200SS, SXV-H16, Modified EOS 20D, DMK 21AU04.

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Offline KARLOSFD

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Re: Bahtinov mask generator
« Reply #29 on: 19:25:42, 02 October, 2008 »
I've just finished mine tonight, looks great !(even if I say so me sen) I printed 2x halves onto photo paper, cut out the slots then transfered it over to some black mounting board, cut them out again, then used an embroidery hoop to fix it to the scope.
I've just given the reverse side a quick coat of black spray paint now to cover the cut edges and letting it dry off. Tonight is looking reseanably clear so will hopefully get a chance to try it and perhaps even my first go at autoguiding too !

Karlo
C11 CF , Cape 8" F6 & Intes M715 DeLuxe ( shortly to be sold) flea3 mono

 

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