Looking for a working Bahtinov Mask Generator

[nick lamendola]

Hi folks,

Can anyone point me to a working Bahtinov Mask Generator?

The one on astrojargon.net is no longer working. I have a few masks I generated from this page a few weeks ago, but now I wanted to generate one with a much finer slot pattern, suitable for a 105mm focal length.

The generator on astrojargon.net worked great in the past, but not so much now. I tried sending an e-mail to David, but got no response,

Thanks,

Nick

 

[Sittatunga]

Hi folks,

Can anyone point me to a working Bahtinov Mask Generator?

The one on astrojargon.net is no longer working. I have a few masks I generated from this page a few weeks ago, but now I wanted to generate one with a much finer slot pattern, suitable for a 105mm focal length.

The generator on astrojargon.net worked great in the past, but not so much now. I tried sending an e-mail to David, but got no response,

Thanks,

Nick

The last mask generator I looked at gave 1mm slots at 2mm centres for a 300mm focal length (i.e. 1mm bar, 1mm slot, 1mm bar etc.). The spacing was proportional to the focal length so that would work out as 0.35mm slots at 0.7mm centres for a 105mm lens. That's tricky even if you were to print them on transparent film rather than cut them from foil.

 

[nick lamendola]

Thanks for that information, I agree that is pretty fine. I was going to try and print a transparency and use that to etch or print a pattern on a UV lens filter. What generator did you use for that?

Thanks

Nick

 

[Sittatunga]

Thanks for that information, I agree that is pretty fine. I was going to try and print a transparency and use that to etch or print a pattern on a UV lens filter. What generator did you use for that?

Thanks

Nick

I actually just drew them in DraftSight, a free 2D CAD program working in the AutoCAD .dwg file format. If you draw the bars as polylines you can assign a width to them.

 

[Lyle Aldridge]

Nick, before you drive yourself crazy printing or precisely cutting teeny little slits and bars, I would suggest experimenting with down- or up-sized copies of some of the masks you can find already prepared online. I don't believe there is anything magical or critical about precise sizing of the slits and bars in a Bahtinov mask. Most of the masks produced by generator programs, as well as those you see available commercially, have far smaller and more numerous slits and bars than the mask that Pavel Bahtinov created and used for himself.

If you're not too skittish about connecting with Russian websites, you can find a link to Bahtinov's 2005 forum post with an image of his mask on the Wikipedia Bahtinov Mask page, in the references section.

 

[Sittatunga]

Nick, before you drive yourself crazy printing or precisely cutting teeny little slits and bars, I would suggest experimenting with down- or up-sized copies of some of the masks you can find already prepared online. I don't believe there is anything magical or critical about precise sizing of the slits and bars in a Bahtinov mask. Most of the masks produced by generator programs, as well as those you see available commercially, have far smaller and more numerous slits and bars than the mask that Pavel Bahtinov created and used for himself.

If you're not too skittish about connecting with Russian websites, you can find a link to Bahtinov's 2005 forum post with an image of his mask on the Wikipedia Bahtinov Mask page, in the references section.

There's a problem where theory meets practice. The mask generators are purely theoretical and for focal lengths shorter than about 2-300mm it's better to make the smallest spacing you can make reliably, precisely and that's going to be robust enough to actually use. A too coarse mask may be better than a rough one with ideal spacing. I find that magnified Live View is easier to use than a Bahtinov mask for a 200mm lens.

 

[nick lamendola]

Hi Lyle,

Thanks for your suggestion, I may try that. The two pictures below show what I trying to do. I hand cut the one mask and before it stopped working I was able to generate a little finer mask that I used to make a small silk screen to use to make the mask I printed on a 77mm UV filter. I had hoped to try and generate a even finer pattern. I could never cut by hand something this fine. The mask generator at astrojargon.net was really nice, it's too bad it's down.


hand cut mask vs screen printed - which one will work best for 105mm - 180mm lens


not perfect, but not bad

I haven't yet determined for myself which mask will work better for 105mm or 180mm lens, but I will test them both if we ever get some clear skies here in western NY.

Thanks,

Nick

 

[aramgrg]

Hi Lyle,

Thanks for your suggestion, I may try that. The two pictures below show what I trying to do. I hand cut the one mask and before it stopped working I was able to generate a little finer mask that I used to make a small silk screen to use to make the mask I printed on a 77mm UV filter. I had hoped to try and generate a even finer pattern. I could never cut by hand something this fine. The mask generator at astrojargon.net was really nice, it's too bad it's down.


hand cut mask vs screen printed - which one will work best for 105mm - 180mm lens


not perfect, but not bad

I haven't yet determined for myself which mask will work better for 105mm or 180mm lens, but I will test them both if we ever get some clear skies here in western NY.

Thanks,

Nick

That's a very nice print on the UV filter, except it won't work . Filter is glass, which is more dense than the air, it shifts the focal point if you put in front of the lens ever so slightly, but potentially enough to render the mask useless.

--

Aram Grigoryan

Explore Aram Grigoryan’s 84 photos on Flickr!

www.flickr.com

 

[nick lamendola]

OK, thanks for that information. It won't hurt if I still give it a try to see if I notice any shift at the 105mm to 180mm lens I intending to use it with.

William Optics and LonelySpeck both sell clear plastic Bahtinov masks. Maybe the plastic they use is not dense enough to affect the focus?

Loading…

williamoptics.com

SharpStar2 Precision Focusing Tool by Lonely Speck

SharpStar2 by Lonely Speck Precision Focusing Tool for Astrophotography Achieve perfect focus on the stars with SharpStar. SharpStar is a simple tool created by Lonely Speck to help astrophotogra…

www.lonelyspeck.com

-Nick

 

[Sittatunga]

OK, thanks for that information. It won't hurt if I still give it a try to see if I notice any shift at the 105mm to 180mm lens I intending to use it with.

William Optics and LonelySpeck both sell clear plastic Bahtinov masks. Maybe the plastic they use is not dense enough to affect the focus?

https://williamoptics.com/products/...80mm-120mm-ed-skywatcher-and-other-refractors

https://www.lonelyspeck.com/sharpstar/

-Nick

The difference would be noticeable at macrophotography distances. The difference between infinity and infinity minus about 1⅓ mm won't be significant. Just make sure that the printed side is closest to the lens if you're really worried.

 

[nick lamendola]

Yes, the printed side faces the lens in an effort to protect it. The UV filter glass was very thin, I didn't measure it but I bet is wasn't even 1mm thick.

In the past I've always just used live view and zoomed in on a dim star and adjusted focus for the smallest star, slowly going past both sides of focus and gauging the middle of the rotated motion. Most of the time this has worked fine, occasionally it looks like I was off just slightly. I know to recheck focus as the night goes on and temperature changes. I'm looking to see if using a Bahtinov mask will prevent the occasional miss-focus.

Thanks to all for the comments and information.

Nick

 

[aramgrg]

OK, thanks for that information. It won't hurt if I still give it a try to see if I notice any shift at the 105mm to 180mm lens I intending to use it with.

William Optics and LonelySpeck both sell clear plastic Bahtinov masks. Maybe the plastic they use is not dense enough to affect the focus?

https://williamoptics.com/products/...80mm-120mm-ed-skywatcher-and-other-refractors

https://www.lonelyspeck.com/sharpstar/

-Nick

The difference would be noticeable at macrophotography distances. The difference between infinity and infinity minus about 1⅓ mm won't be significant. Just make sure that the printed side is closest to the lens if you're really worried.

No offense, but I bet you haven't tried deep sky astrophotography. To get correct focus is very hard with bare hands, even with 100% magnified view and masks(that's why feather touch focusers cost much). The focus even shifts with the temperature changes, let alone entire lens element added or taken off.

 

[Sittatunga]

OK, thanks for that information. It won't hurt if I still give it a try to see if I notice any shift at the 105mm to 180mm lens I intending to use it with.

William Optics and LonelySpeck both sell clear plastic Bahtinov masks. Maybe the plastic they use is not dense enough to affect the focus?

https://williamoptics.com/products/...80mm-120mm-ed-skywatcher-and-other-refractors

https://www.lonelyspeck.com/sharpstar/

-Nick

The difference would be noticeable at macrophotography distances. The difference between infinity and infinity minus about 1⅓ mm won't be significant. Just make sure that the printed side is closest to the lens if you're really worried.

No offense, but I bet you haven't tried deep sky astrophotography. To get correct focus is very hard with bare hands, even with 100% magnified view and masks(that's why feather touch focusers cost much). The focus even shifts with the temperature changes, let alone entire lens element added or taken off.

 

[aramgrg]

OK, thanks for that information. It won't hurt if I still give it a try to see if I notice any shift at the 105mm to 180mm lens I intending to use it with.

William Optics and LonelySpeck both sell clear plastic Bahtinov masks. Maybe the plastic they use is not dense enough to affect the focus?

https://williamoptics.com/products/...80mm-120mm-ed-skywatcher-and-other-refractors

https://www.lonelyspeck.com/sharpstar/

-Nick

The difference would be noticeable at macrophotography distances. The difference between infinity and infinity minus about 1⅓ mm won't be significant. Just make sure that the printed side is closest to the lens if you're really worried.

No offense, but I bet you haven't tried deep sky astrophotography. To get correct focus is very hard with bare hands, even with 100% magnified view and masks(that's why feather touch focusers cost much). The focus even shifts with the temperature changes, let alone entire lens element added or taken off.

I'm very much a beginner but an UV filter such as the one Nick's printed his mask on shouldn't have any power as a lens element. I know it's incredibly difficult to focus with bare hands and how difficult it is to centre the spikes from a Bahtinov mask in magnified Live View even with a 300mm f/4. I've not tried a Bahtinov mask with anything shorter as I think the pattern would be even smaller and harder to make out. Have you used one with a 105mm lens?

Well, not 105mm, but I can confirm uv does make a difference on 300mm.

 

[atigun]

Hi folks,

Can anyone point me to a working Bahtinov Mask Generator?

The one on astrojargon.net is no longer working. I have a few masks I generated from this page a few weeks ago, but now I wanted to generate one with a much finer slot pattern, suitable for a 105mm focal length.

The generator on astrojargon.net worked great in the past, but not so much now. I tried sending an e-mail to David, but got no response,

Thanks,

Nick

A post on Cloudynights (https://www.cloudynights.com/topic/654574-bahtinov-mask-generator/ ) had a link to the Bahtinov mask generator that now worked for me (using Chrome):

http://astrojargon.net/MaskGen.aspx?AspxAutoDetectCookieSupport=1

--
Atigun valley, a place north in Alaska

 

[nick lamendola]

Hi,

Thanks, yes it just started working again over the weekend. I was able to generate a finer mask and made a silk screen, but I haven't printed a new Bahtinov mask with it yet.

I was happy to see the generator was working again, it pretty nice.

-Nick

 

[Pera K]

Hi, do you have a PDF template or a CAD file for the mask? I'm looking for a template to print on my filter too. It would be great if you could help me out.

Cheers,

Pera

 

[nick lamendola]

Hi,

I'm not sure what you are looking for. The last time I checked, the generator started working again, it was down for a time, but then it was back up. Try going to the the web site, if its still working you should be able to generate and print what ever mask you want to design. Hope this helps.

I did end up making a fine line (at least as fine line as I could print) mask and silk screen printed it on a UV filter. It works reasonable well on a 105mm macro lens , but not very well on a 35mm lens. Using the mask with the 105mm it's much easier to get a good focus than just using live view mode. Here's one of the masks I made:





I could probably find the file the generator created that I used to make this mask, if you really need it. Let me know.

Thanks

-Nick

 

[Sittatunga]

Hi, do you have a PDF template or a CAD file for the mask? I'm looking for a template to print on my filter too. It would be great if you could help me out.
Cheers,

Pera

If you've got AutoCAD or similar it's not too difficult to draw one yourself. For a 300mm focal length it would ideally be arrays of 1mm wide polylines at 2mm centres, horizontal for half the mask and rotated + 20° for the other two quarters. Bar width and spacing is directly proportional to focal length.

 

[nick lamendola]

Here's an image I took after I adjusted the focus with the printed Bahtinov mask with a 180mm lens. I find it much easier to get a good focus this way than just relying on how small I can make a star in zoomed in live view mode. The mask also works with a 105mm lens, but I have to take a picture, and then zoom in using image preview, can't zoom in far enough in live view mode, to see how well the centered the spike is.

Does it give me perfect focus? Probably not, I don't know for certain, but it's better than I can do any other way.

Will focus change with temperature, yes, I found that out the hard way. It's best to check focus several times in a session if you care about a constant focus. I found this in 17deg f temps. My focus was good at the start, but an hour later it was off. My camera/lens must have cooled to ambient temps and changed focus.


Bahtinov mask printed on a UV filter, 180mm lens