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Revolutionary new way of focusing! No less!

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#226 smokin oakum

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Posted 10 September 2008 - 08:25 PM

Will this design also work for Newts? I have a 12" scope on a CGE that I use for astro video astronomy using a Mallincam Hyper Color Plus, and so far I just use the defraction spikes to focas with. I do get good results, but I'm wondering if this might make things even better.

Would the spider veins play havoc with this method?

Neil

#227 isramirez

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Posted 10 September 2008 - 08:29 PM

:sleepy:

#228 snowdragonusa

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Posted 10 September 2008 - 08:31 PM

As someone else posted you will still see some diffraction spiking from the spider but the Bahtinov Mask diffraction spikes should still be very easy to see for focusing. You will just have some extras in there. :)

#229 smokin oakum

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Posted 10 September 2008 - 08:40 PM

As someone else posted you will still see some diffraction spiking from the spider but the Bahtinov Mask diffraction spikes should still be very easy to see for focusing. You will just have some extras in there. :)


Thanks Adam. I should have looked closer to the other posts to find my answer. I must have put isramirez to sleep. Not sure that was most polite way of comming across, but anyway...

I'll look up the program to download the scaled template.

Thanks again.

Neil

#230 snowdragonusa

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Posted 10 September 2008 - 08:52 PM

No worries Neil. Let me know if you run into any issues scaling that file. Just remember the exact measures for your scope could be slightly off but should be OK as long as you don't have a funky FL scope.

I think isramirez is asleep waiting for his skies to clear up. The poor guy has an awesome Bahtinov Mask to use but no clear skies to use it on. :bawling:

Cheers!

#231 isramirez

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Posted 10 September 2008 - 09:28 PM

Sorry guys but i'm bussy creating my Pavel Mask because the previus design was not the correct for my IM715 scope... i just did a minimal effort in this great thread (click's with mouse) and got all the info i was looking for ;)

#232 jimguy08

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Posted 10 September 2008 - 09:47 PM

To Dennis, John or any Russian speakers...

Do you suppose it would be possible to establish a PayPal Donation account for Pavel Bahtinov?

I'd certainly contribute as I'm sure many others here would...
Just a thought.

#233 Podarok

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Posted 10 September 2008 - 10:53 PM

I think you can contact him, here's his account page with e-mail from the Russian forum
http://www.astronomy...n=profile;u=408

#234 John Wunderlin

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Posted 10 September 2008 - 10:56 PM

I actually had the same thought today. We are still trying to work out some issues on that front directly with Pavel which is quite challenging with the language barrier, but hopefully we'll get there. I would be happy to host a link on our site with a 'tip jar' for Pavel. I think it would be a great idea.

#235 John Wunderlin

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Posted 10 September 2008 - 10:59 PM

I think you can contact him, here's his account page with e-mail from the Russian forum
http://www.astronomy...n=profile;u=408


We didn't have any luck with his email directly. Not sure if it was a firewall or what - Jerry finally signed up on his forum and translated everything into Russian! Very creative! :bow:

#236 Podarok

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Posted 10 September 2008 - 11:09 PM

Well I guess another way would be to send him a private forum message by clicking on (hmm, I can't type in Russian here for some reason, it shows up as gibberish) on that page, here's the direct link http://www.astronomy...m;sa=send;u=408
but you probably have to register for that. Or post a message in the thread about the mask itself http://www.astronomy...index.php/topic,10421.300.html I don't think there will be a problem understanding English. Understanding what those automatic translators write might be harder.

#237 cvedeler

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Posted 10 September 2008 - 11:11 PM

Here is my 2nd generation Bahtinov mask. I found some 6mm thick hobby foam at JoAnn's. Cutting it was much more challenging than I thought, but it came out OK. I had some left over to glue-gun a 3cm wide ring around it for easy mounting. No stars tonight so I'll have to wait and see how well it works another night.

Attached Thumbnails

  • 2636125-IMG_3026-800.jpg


#238 FarmerDave

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Posted 10 September 2008 - 11:23 PM

I wanted to play in the Greatest Thread Ever, too, so I threw together a Bhatinov mask generator.

http://astrojargon.net/maskgen.aspx

Put in the numbers, press "submit" and voila, an SVG file appears scaled to the rules I found perusing the thread.

The *big* caveat (other caveats appear on the page) is that I haven't actually tested the results. The second biggest caveat is that while Inkscape *displays* the resulting SVG perfectly, it doesn't *print* it worth a darn. Apparently there are some Inkscape print bugs.

I did actually print a couple from Firefox, and they seemed to be scaled perfectly, but what do I know (see big caveat, above).

You might have to tweak what I call the "Bahtinov Factor" in order to get the lines on the left to show up where they should (i.e., with a gap in the middle), but I don't know if that's super critical.

If you see any issues, or have any suggestions, either PM me here or drop me a line at the e-mail address on that page.

Note, however, that I'm going away Friday morning for a romantic weekend with the wife - no computer (and, sadly, no scopes - tho I might try to sneak the binoculars into the car), so I won't be able to respond for a couple of days.

David

#239 Nocturnal

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Posted 10 September 2008 - 11:51 PM

Impressive!

#240 snowdragonusa

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Posted 11 September 2008 - 12:35 AM

Nice work David! I can see where the playing with the 'Bahtinov value' can be tricky in trying to get the center 90 degree line centered. I played with some variations tonight to see if the center 90 deg. cutout needed to be centered and it looks like it is a key component to the success of the "centered" diffraction spike focus pattern.

That is such a seriously cool little generator you made! Can you have a variable to adjust the right side's line angle? Also, can you group the sections together so the 90 degree slits can be unblocked (as the right sides are) so they can be centered more easily?

Cheers!

#241 smokin oakum

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Posted 11 September 2008 - 12:52 AM

Does this look right? I used 315mm for my clear apeture, 85mm for the central obstuction, 1500mm for the focal length, 100 for the Bahtinov factor, 10 for the angled stripe count, and -1 for the angled stripe offset.

Neil

Attached Thumbnails

  • 2636258-bhatinov[6] copy.jpg


#242 Dennis Sakva

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Posted 11 September 2008 - 01:49 AM

Hello everyone!
I sent Pavel a message asking him for a permission to use his design for commercial purposes. He has no objections on using the mask for any purposes, including commercial production. As for royalties, he leaves that to producers :) If you think you can and want - feel free to do so. His only condition is that you have to mention that the mask was invented by him. "Bahtinov Mask" sounds good, and it is also widely used in Russian speaking forums.

John, I also asked him about your e-mail. He said that it was lost in his Spam folder. Seems like he found it now.

#243 akira

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Posted 11 September 2008 - 03:24 AM

i try to print my mask at an a4 size paper but the firefox doesn't center it at the page ( i have a 200mm newton) how can i center it at the a4 page?

#244 Mert

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Posted 11 September 2008 - 07:12 AM

Mert- Your horizontal cuts should start in the center axis and mirror out. I think the odd spacing of the cutouts will make the diffraction spikes wide. they still will be in the center if the axis is centered, but may be too wide to see a clear difference between the angled and straight spikes.


Thanks Jerry for pointing this out, I was out last
night trying the mask I posted.
Never had such a good focus, soo easy and clear in soo
little time, though the spikes were not so clear as
you pointed out!
Still I got FWHM of 2" which is unknown for me
in the area where I live, with the eyes I have to focus.
I will make more masks to try out different setups before
making the final one.

Thanks and regards,

#245 Jerry3672

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Posted 11 September 2008 - 08:09 AM

Glad we could help you Mert.

I have seen several nice images from Spain. FWHM of 2 is not too bad. That is about all I get here. Once on a very good night I was able to get 1.6.

#246 smokin oakum

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Posted 11 September 2008 - 09:02 AM

Does this look right? I used 315mm for my clear apeture, 85mm for the central obstuction, 1500mm for the focal length, 100 for the Bahtinov factor, 10 for the angled stripe count, and -1 for the angled stripe offset.

Neil


Well after I did the first design I thought about what you guys meant by "clear apeture" so I decided to measure the inner opening of my newt, and it came out to 339mm so I redesigned the Mask with those numbers, and came up with this...

Does it look right?

Neil

Attached Thumbnails

  • 2636581-map copy.jpg


#247 FarmerDave

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Posted 11 September 2008 - 11:38 AM

Thanks, Adam and Sander!

Now, the news: The new and improved Bahtinov Mask Generator version 0.2!

Here's a list of changes - I think this will address everyone's issues.
  • Greatly simplified the generated SVG - seems to fix the Inkscape printing issues, as well as letting Adam adjust the left cutouts. See next item.
  • Horizontal stripes now start with a cutout on the center line - since apparently this *is* important.
  • Added parameter for controlling number of horizontal cutouts.
  • Decoupled the structural bar thickness from edge thickness; added a parameter for specifying the thickness of the structural bars (the up/down and left/right bars).
  • Added optional "center line" crosshairs for alignment/testing purposes.
  • Elimated "bumps" on outside of circle at the intersection with the structural bars.
  • Fixed the background/fill colors so they work completely.
  • I changed "Submit" to "Generate!" because I thought it was more exciting that way.
  • Decoupled the margin from the edge thickness; added a parameters for left and top margins. Width and height are now calculated as aperture + (2 * edge thickness) + (2 * appropriate margin).
  • Added a parameter for the angle of the angled cutouts.

Let me know...
David

#248 Dennis Sakva

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Posted 11 September 2008 - 12:38 PM

David this is super cool. I wish I had this before I made my mask :)

#249 John Wunderlin

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Posted 11 September 2008 - 01:51 PM

Now, the news: The new and improved Bahtinov Mask Generator version 0.2!


Simply awesome! :bow: :bow: :bow:

#250 blueman

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Posted 11 September 2008 - 01:55 PM

Thanks to you for this fine mask generator. You are very kind to make this available.
Blueman


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