imhotep
Pooh-Bah
Reged: 02/14/07
Posts: 1426
Loc: Tampa, FL
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Marty, I had the exact same experience when I tried to use Illustrator with my SVG file. Even when I print from Mozilla using the SVG plugin it misses the mark by about %-6% in terms of the sizing.
By the way, I did try my mask for the first time two nights ago using an Orion 80ED. It worked great in Nebulosity using the Fine Focus tool. I need to post a screen shot later today.
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Curt
8" F5 Newtonian Astrograph
Orion 80ED CUSTOM
Edmund Optics 4.25" 'Palomar' Newtonian, 1968 vintage
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J.P.M
Pooh-Bah
Reged: 11/14/06
Posts: 1225
Loc: 65"01'N25"47'E
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Hi,
I made the mask by using laser printer and the transparent
media.
There is no need to cut off holes! Just use it as it is
on front of the telescope.
I was not able to see any visual defects by clear plastic.
(not the inkjet one, it's more or less matte)
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PER ASPERA AD ASTRA
J-P Metsavainio, Finland
LX200 GPS 12", SkyWatcher ED80, Canon 200mm EF f1.8L, Tokina 300mm AX f2.8, SXV-AO, QHY9, QHY8, QHY5, Lodestar
http://astroanarchy.blogspot.com/
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FarmerDave
sage
Reged: 09/07/07
Posts: 412
Loc: Northern Virginia
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Quote:
Unfortunately, the SVG is not scaled correctly when I load it with Illustrator - it was about 13.5" diameter instead of the 280mm (11") I requested in the generator.
If I had to guess (which I do, since I don't own Illustrator), I'd say this is a 72 dpi v 90 dpi (the standard for SVG) problem.
If you end up doing another mask for one of your other scopes, you might try poking around in Illustrator and seeing if you can change it to 90dpi.
David
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Celestron C6/C9.25/CG-5GT Mount
Orion 80ED/EON 72/Supercharged Atlas EQ-G
Garrett Optical Signature Series 10x50
Canon XTi (soon to be modded)/Canon 40D (unmodded)
Meade DSI/Meade DSI Pro/Philips SPC900N
1944 Ford 2N/1948 Ford 8N
Bahtinov Mask Generator * AstroCataLink * 40DShutterCount
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imhotep
Pooh-Bah
Reged: 02/14/07
Posts: 1426
Loc: Tampa, FL
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Thanks David I'll give it a try.
I must say I like the idea of using matte transparent media. This probably works best on small apertures though. Maybe I'm wrong but I can see something that flimsy being a problem if it has to span say 8" or more.
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Curt
8" F5 Newtonian Astrograph
Orion 80ED CUSTOM
Edmund Optics 4.25" 'Palomar' Newtonian, 1968 vintage
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J.P.M
Pooh-Bah
Reged: 11/14/06
Posts: 1225
Loc: 65"01'N25"47'E
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I joint together four transparents with stampler and placed them to a wooden frame. I tested it with 12" Meade.
I printed smaller as well for camera lenses.
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PER ASPERA AD ASTRA
J-P Metsavainio, Finland
LX200 GPS 12", SkyWatcher ED80, Canon 200mm EF f1.8L, Tokina 300mm AX f2.8, SXV-AO, QHY9, QHY8, QHY5, Lodestar
http://astroanarchy.blogspot.com/
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MartyT
professor emeritus
Reged: 09/28/07
Posts: 682
Loc: Kansas City
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Quote:
If I had to guess (which I do, since I don't own Illustrator), I'd say this is a 72 dpi v 90 dpi (the standard for SVG) problem.
I'll check that out this evening if I have time. Sounds like that might be the issue.
As long as I've got your ear... 
Is there any way you could render output direct to a PDF instead of SVG? Seems like that would solve a lot of issues with scaling, etc.
Also looking for recommendations as to how I might convert the SVG to an AutoCad compatible drawing. I have a friend with a whiz-bang CNC milling machine but he needs the input in AutoCad format before he can use it.
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Celestron CGE / C-11 (CGE-1100)
Megrez 90 FD APO / 0.8x FR/FF vIII
QHY8, 350D, DSI Pro, SPC900NC
KWIQ Guider (QHY5)
ETX-125AT
12" Lightbridge
My Astrophoto Gallery
Astronomical Society of Kansas City
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imhotep
Pooh-Bah
Reged: 02/14/07
Posts: 1426
Loc: Tampa, FL
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Marty, I think what you need is to export your .SVG as a .DXF. I'm also going to be working with a similar machinist who can take a CAD file and use it to guide a flo-jet machine. AutoCAD can read a .DXF file and this format may in fact be the prefferred one by your guy. The shop I'm working with specifically asked for a .DXF file.
Just open your mask in Inkscape and go to Save As and select .DXF from the dropdown. Hope that helps.
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Curt
8" F5 Newtonian Astrograph
Orion 80ED CUSTOM
Edmund Optics 4.25" 'Palomar' Newtonian, 1968 vintage
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Joselo
sage
Reged: 02/26/08
Posts: 387
Loc: Texas
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Hi all,
which transparent media are you using specifically?
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APM 115 design by TMB
SV80S, and bunch of accessories
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FarmerDave
sage
Reged: 09/07/07
Posts: 412
Loc: Northern Virginia
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Quote:
Is there any way you could render output direct to a PDF instead of SVG? Seems like that would solve a lot of issues with scaling, etc.
I *could,* I'm just not convinced it would be worth the time and effort. SVG is fairly straightforward to generate as it's a flavor of XML. PDF is a rathole unto it's own - which is why several companies sell components for generating PDFs. I have a license for one, but I'm not sure it's a panacea, because I've always had issues with PDFs and margins - especially if we're spanning pages. I'm not saying I won't do it, but it's not terribly high on my list.
Quote:
Also looking for recommendations as to how I might convert the SVG to an AutoCad compatible drawing.
Curt [imhotep] is on the right track - or would be except for the fact that I'm using some advanced features of SVG that don't translate to DXF quite right. I mentioned a ways back in this thread that I tried converting some of the generated masks to DXF, and it was actually quite ugly.
Amusingly, the best conversion I got (admittedly, I only tried a handful) was from Visio 2003, but I still had to do significant editing.
I've actually *completely* rewritten the generation portion using some different technologies that I hope will actually create a "flatter" SVG - thereby making the translation easier. I completed that last week, and it displays great, but now the SVG->DXF export in Inkscape bombs, so I'm trying to figure out that issue. I'm also looking at outputting in XPS, which is sort of like PDF as far as generating consistent output.
If/when I get these changes completed, I'll post here.
David
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Celestron C6/C9.25/CG-5GT Mount
Orion 80ED/EON 72/Supercharged Atlas EQ-G
Garrett Optical Signature Series 10x50
Canon XTi (soon to be modded)/Canon 40D (unmodded)
Meade DSI/Meade DSI Pro/Philips SPC900N
1944 Ford 2N/1948 Ford 8N
Bahtinov Mask Generator * AstroCataLink * 40DShutterCount
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MartyT
professor emeritus
Reged: 09/28/07
Posts: 682
Loc: Kansas City
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Quote:
If I had to guess (which I do, since I don't own Illustrator), I'd say this is a 72 dpi v 90 dpi (the standard for SVG) problem.
Apparently the dpi scaling difference between the SVG you generate and what Illustrator uses is the problem.
There's no way to change that in Illustrator as far as I can tell, but when I scaled the SVG down to 80% of original (72 / 90 = 0.8), it was *exactly* the right size on screen and in print.
So it's an easy enough fix I guess.
--------------------
Celestron CGE / C-11 (CGE-1100)
Megrez 90 FD APO / 0.8x FR/FF vIII
QHY8, 350D, DSI Pro, SPC900NC
KWIQ Guider (QHY5)
ETX-125AT
12" Lightbridge
My Astrophoto Gallery
Astronomical Society of Kansas City
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J.P.M
Pooh-Bah
Reged: 11/14/06
Posts: 1225
Loc: 65"01'N25"47'E
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Quote:
Hi all,
which transparent media are you using specifically?
Hi,
Actually I don't know! I think they are old overhead projector transparents for laser printer. Not very thick ones, but if you use frame of some kind, they works ok.
--------------------
PER ASPERA AD ASTRA
J-P Metsavainio, Finland
LX200 GPS 12", SkyWatcher ED80, Canon 200mm EF f1.8L, Tokina 300mm AX f2.8, SXV-AO, QHY9, QHY8, QHY5, Lodestar
http://astroanarchy.blogspot.com/
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imhotep
Pooh-Bah
Reged: 02/14/07
Posts: 1426
Loc: Tampa, FL
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Quote:
There's no way to change that in Illustrator as far as I can tell, but when I scaled the SVG down to 80% of original (72 / 90 = 0.8), it was *exactly* the right size on screen and in print.
Cool. If it works, it works. Thanks for figuring that out as I will probably use this work-around myself.
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Curt
8" F5 Newtonian Astrograph
Orion 80ED CUSTOM
Edmund Optics 4.25" 'Palomar' Newtonian, 1968 vintage
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imhotep
Pooh-Bah
Reged: 02/14/07
Posts: 1426
Loc: Tampa, FL
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Dave, in case this hasn't been said enough already, you're the man for making that generator. Thanks for providing this hobby with another free tool!
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Curt
8" F5 Newtonian Astrograph
Orion 80ED CUSTOM
Edmund Optics 4.25" 'Palomar' Newtonian, 1968 vintage
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imhotep
Pooh-Bah
Reged: 02/14/07
Posts: 1426
Loc: Tampa, FL
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--------------------
Curt
8" F5 Newtonian Astrograph
Orion 80ED CUSTOM
Edmund Optics 4.25" 'Palomar' Newtonian, 1968 vintage
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tonyb
sage
Reged: 07/27/05
Posts: 498
Loc: WA, USA
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I made mine from the mask generator here http://astrojargon.net/maskgen.aspx - converting to a BMP and then scaling in PS. I then printed out the mask and used black foamboard and a super sharp, super fine X-acto knife http://www.xacto.com/ProductDetail.asp?id=169 to cut the board. It's not a super-accurate mask as you can see some of edges were rough. That said, for me, the mask worked great. See in-focus and out-of-focus images and foam board mask.
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* Astro Site
* Blog
* Celestron C9.25" Carbon SCT
* WO FLT 110 Refractor.
* Atlas EQ-G mount.
* QHY8/Q453 color CCD.
* QSI 583CS color CCD.
* Lumenera SKYnyx2-0 color webcam
* Philips ToUCam840K color webcam
* Meade DSI II + PHDGuiding + WO66mm
* wxAstroCapture/Registax/CCDSoft/Nebulosity/PS CS4.
* Dell Latitude D830 notebook w/ Windows 7 32-bit
* Canon EOS 5D MkII DSLR.
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anat
sage
Reged: 06/03/04
Posts: 235
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My materials are ready! Embroidery hoops are available in various sizes to fit dewshields.
Anat
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Astro-physics 155EDT
Borg 60ED
Losmandy G11 Gemini
Hypermodded Canon 450D
LVI SmartGuider
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imhotep
Pooh-Bah
Reged: 02/14/07
Posts: 1426
Loc: Tampa, FL
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Quote:
My materials are ready! Embroidery hoops are available in various sizes to fit dewshields.
Anat
Now that's a great idea. I was trying to think of a premade product that would fill this gap.
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Curt
8" F5 Newtonian Astrograph
Orion 80ED CUSTOM
Edmund Optics 4.25" 'Palomar' Newtonian, 1968 vintage
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Joselo
sage
Reged: 02/26/08
Posts: 387
Loc: Texas
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Anat,
what was your procedure? I think you laminated your paper print of the mask. are you then going to cut it?
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APM 115 design by TMB
SV80S, and bunch of accessories
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anat
sage
Reged: 06/03/04
Posts: 235
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I will cut and paint it before attaching the mask to the hoop.
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Astro-physics 155EDT
Borg 60ED
Losmandy G11 Gemini
Hypermodded Canon 450D
LVI SmartGuider
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Spacewalker
member
Reged: 10/05/07
Posts: 45
Loc: Scottsbluff, Nebraska
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Here are a couple of helpful ideas for making a mask
1. Use generator to make mask pattern.
2. Print on transparency film for laser printers. Works for scopes up to @ 8"
3. Cutout pattern with Exacto knife and steel ruler using a piece of glass for cutting surface. (No grain lines to grab blade)
4. Cutout a circle in a piece of 3/4 pink/blue/yellow foam about a 1 inch larger in diameter than your scope, then cutout scope diameter. This will look like a donut. It does not have to fit tight on scope.
5. Paint your pattern with flat black paint.
6. Tape or glue the pattern to the foam.
This mask will not scratch scope and it weights almost nothing. Works really good.
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www.panhandleastronomyclub.com/StarGaze.htm
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