Joselo
sage
Reged: 02/26/08
Posts: 421
Loc: Texas
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Space,
thanks for your helpful ideas,
this weekend I will try to make my first mask...
Cheers
Jose
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APM 115 design by TMB
SV80S, and bunch of accessories
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WhistleStop
sage
Reged: 09/07/07
Posts: 439
Loc: Grafton, Ontario
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Just a thought on remote focusing...could this mask be etched on a 2" filter holder and placed in a filter wheel for remote focusing ???
Just a thought
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WHISTLESTOP
Whistle Stop Observatory (44N78W)
TV NP101is, C9.25, WO ZS66,
G11 with Gemini, EQ6 with EQMOD
FLI ML8300 with CFW-2-7
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Dale J Martin
member
Reged: 12/07/05
Posts: 41
Loc: MA
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Hi folks,
Just a quick note, a few nights ago I cut out the mask for an ED80 and
the test results were great! The other night I printed one out on a jet ink
printer using 3M transparency film (CG3480 bought at Staples) and the
results were as good. Needless to say the film was much easier... no
cutting!
I used 2 part epoxy to mount the film into a embroidery hoop from Clover
(Art No. 8813) which fit the Orion ED80 scope.
This is an amazing tool!
Regards,
Dale
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snowdragonusa
Pooh-Bah
Reged: 09/04/07
Posts: 1128
Loc: Denver, CO
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I would strongly urge folks not to use transparency film. If anyone has ever had really good focus at the EP and then stuck a low to mid grade filter on you noticed the focus slightly out. In the case of filters their optical quality is a fair bit better than transparency film. If you put one or more sheets in front of your scope the focus WITH the film in place my be perfect, but when you remove the film the focus will most likely be off if only slightly.
I would like to see a comparison of someone using a transparency made mask to achieve focus and then use a cut-out mask right after to see if this is indeed the case.
I would just hate to see folks use transparencies for masks, spend a couple of hours shooting, and find out that the focus was not as good as it could have been.
If I find some transparencies around here I'll give it a go here in the next week.
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Adam
12" LX200R, AT80LE
Lunt 60mm Ha & CaK solar scopes
DMK41.AS, DSI Pro, DSI-C, LPI
Denver Astronomical Society
Brighton Astronomical Group
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snowdragonusa
Pooh-Bah
Reged: 09/04/07
Posts: 1128
Loc: Denver, CO
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Quote:
Hi folks,
Just a quick note, a few nights ago I cut out the mask for an ED80 and
the test results were great! The other night I printed one out on a jet ink
printer using 3M transparency film (CG3480 bought at Staples) and the
results were as good. Needless to say the film was much easier... no
cutting!
I used 2 part epoxy to mount the film into a embroidery hoop from Clover
(Art No. 8813) which fit the Orion ED80 scope.
This is an amazing tool!
Regards,
Dale
Hey Dale,
I should have read a little further.  Did you try focusing with the transparency and then sticking the cutout on to see if the focus was still on? Please try this if you wouldn't mind so we can see if the transparency film really does give an accurate focus.
Cheers!
--------------------
Adam
12" LX200R, AT80LE
Lunt 60mm Ha & CaK solar scopes
DMK41.AS, DSI Pro, DSI-C, LPI
Denver Astronomical Society
Brighton Astronomical Group
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jgraham
Postmaster
Reged: 12/02/04
Posts: 6747
Loc: Dayton, Ohio
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Filters shift the focus because they are placed in the converging/diverging light path. The light entering the telescope is parallel and adding a flat plane across the entrance should not shift the focus. The low optical quality of a plastic sheet may fuzz things a bit, but it shouldn't shift the focus. With respect to the focussing mask I suspect it will make the lines a tad fuzzy, but it shouldn't effect how the mask works or the relative placement of the reference lines. I might give this a try for some of my smaller telescopes where the line spacing makes cutting a mask by hand out of foam core difficult.
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-John
================================================
Homebuilt scopes from 4.25-16.5"
Meade LXD75-N6/SN6/SC8, DSX-90, ETX-60BB, ETX-125PE, DS-2130
Orion StarBlast, BinoViewers, Coronado PST
Rebel XT/XTi, DSI Pro (I, II, & III), DSI, LPI, Electronic Eyepiece, Phillips SPC900NC
Tasco 60mm Refractors
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Elliot
super member
Reged: 09/12/06
Posts: 123
Loc: Medford NJ
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John received my mask but it is the wrong size. You sent me a 12" and I ordered a 13". 
What now?
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Celestron CPC 1100
APT Wedge
Celestron ED80 GuideScope
SkyShed
SBIG ST9XE
Celestron Ultima 2000
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John Wunderlin
Vendor - Spike-a Focusing Mask
Reged: 10/01/04
Posts: 690
Loc: Mineral Point, Wi
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Hi Elliot- sorry about that- my eyesight must be going! I emailed you about that. If you don't receive that, please PM me and I'll get you fixed up.
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John Wunderlin
Vendor - Spike-a Bahtinov Focusing Mask
Empire Ranch Observatory
Iowa County Astronomers
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FarmerDave
sage
Reged: 09/07/07
Posts: 414
Loc: Northern Virginia
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Quick post to say that astrojargon.net was down, but is back up again. Sorry for any inconvenience, and thanks to Marty for giving me a heads-up.
I'm planning to switch hosting companies tomorrow, then DNS propagation may take a couple of days, so please forgive any hiccups over the next few days.
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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ub0423
member
Reged: 04/01/08
Posts: 69
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I made a mask out of a turbo tax box with tapes, staplers only. It looks super ugly but works great!!
The mask
Edited by ub0423 (10/07/08 03:10 AM)
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ub0423
member
Reged: 04/01/08
Posts: 69
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and here is the star test!
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Peace and Clear Skys
Billy
Location: Wildcat Canyon Backyard Observatory, San Pablo, CA
http://picasaweb.google.com/leungjc4231/MyBackyardAstrophotography#
FSQ106ED, Atik 16HR, AT66Ed,Orion Autoguider,CGE
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cvedeler
Carpal Tunnel
Reged: 12/20/05
Posts: 2151
Loc: Scottsdale, AZ
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ub0423 I think you win for the ugliest mask. But in the dark they all work the same! 
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Chris Vedeler
Astro-Physics 160EDF
Astro-Physics 900GTO
Q453HR / QHY8 CCD camera
Canon 450XSi
----------------------------
www.aznightsky.com
Scottsdale, AZ
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Poochpa
professor emeritus
Reged: 02/12/05
Posts: 503
Loc: Buffalo Burbs, NY
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A local company can laser cut me a mask out of 1/4" acrylic, the only thickness they carry in black. Is that too thick for the mask? Thanks.
Mike
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Televue NP101
Vixen GPDX/Skysensor 2000PC
Meade 8" LX200GPS
WO Zenithstar 66SD
Modified Canon Rebel XSi
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snowdragonusa
Pooh-Bah
Reged: 09/04/07
Posts: 1128
Loc: Denver, CO
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Quote:
A local company can laser cut me a mask out of 1/4" acrylic, the only thickness they carry in black. Is that too thick for the mask? Thanks.
Mike
Naw, it should be just fine.. and super sturdy!
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Adam
12" LX200R, AT80LE
Lunt 60mm Ha & CaK solar scopes
DMK41.AS, DSI Pro, DSI-C, LPI
Denver Astronomical Society
Brighton Astronomical Group
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Dale J Martin
member
Reged: 12/07/05
Posts: 41
Loc: MA
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Quote:
Quote:
Hi folks,
Just a quick note, a few nights ago I cut out the mask for an ED80 and
the test results were great! The other night I printed one out on a jet ink
printer using 3M transparency film (CG3480 bought at Staples) and the
results were as good. Needless to say the film was much easier... no
cutting!
I used 2 part epoxy to mount the film into a embroidery hoop from Clover
(Art No. 8813) which fit the Orion ED80 scope.
This is an amazing tool!
Regards,
Dale
Hey Dale,
I should have read a little further. Did you try focusing with the transparency and then sticking the cutout on to see if the focus was still on? Please try this if you wouldn't mind so we can see if the transparency film really does give an accurate focus.
Cheers!
Hey Adam,
I switched out both the cutout and the transparency the night I posted and as I stated it was as good..... and much easier to make 
Here is an image I shot the other night the Heart Nebula
Dale
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John Wunderlin
Vendor - Spike-a Focusing Mask
Reged: 10/01/04
Posts: 690
Loc: Mineral Point, Wi
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Wow- fabulous image! I guess a picture is worth a thousand words!
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John Wunderlin
Vendor - Spike-a Bahtinov Focusing Mask
Empire Ranch Observatory
Iowa County Astronomers
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snowdragonusa
Pooh-Bah
Reged: 09/04/07
Posts: 1128
Loc: Denver, CO
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Nice work Dale! Thanks for posting that there should not be any focusing distortion with a transparency mask!
Cheers!
--------------------
Adam
12" LX200R, AT80LE
Lunt 60mm Ha & CaK solar scopes
DMK41.AS, DSI Pro, DSI-C, LPI
Denver Astronomical Society
Brighton Astronomical Group
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John Wunderlin
Vendor - Spike-a Focusing Mask
Reged: 10/01/04
Posts: 690
Loc: Mineral Point, Wi
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Quote:
Nice work Dale! Thanks for posting that there should not be any focusing distortion with a transparency mask!
Just make sure you mount it in a rigid frame as he did. Handholding does NOT work- at least it didn't for me. The embroidery frame is a terrific idea!
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John Wunderlin
Vendor - Spike-a Bahtinov Focusing Mask
Empire Ranch Observatory
Iowa County Astronomers
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riha
newbie
Reged: 10/14/07
Posts: 1
Loc: Sweden
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Would this work on an camera with lens as well?
Can it be made to fit an lens on an camera for focusing as well?
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//Rickard Hansson
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dsnay
sage
Reged: 07/02/06
Posts: 271
Loc: Massachusetts
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Quote:
If anyone needs a scaled drawing of the one I made up let me know. I can try it out with your particular focal length and see if it scales properly. Download and install InkScape and you will be able to printout the vector based image and not have to worry about those nasty stair step edges caused from the jpg I posted earlier.
Cheers!
I'll take you up on that offer. I have an 80mm refractor whose focal length is 480mm when not using a 6.3 focal reducer. Would I need two different masks for when I use the scope with and without the reducer?
Thanks,
Dave
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