Return-Path: X-Processed-By: Virex 7 on prxy.net X-Real-To: stagecraftlist [at] theatrical.net Received: by prxy.net (CommuniGate Pro PIPE 4.2) with PIPE id 4557637; Fri, 01 Oct 2004 03:01:03 -0700 X-ListServer: CommuniGate Pro LIST 4.2 List-Unsubscribe: List-ID: Message-ID: From: "Stagecraft" Sender: "Stagecraft" To: "Stagecraft" Precedence: list Subject: Stagecraft Digest #149 Date: Fri, 01 Oct 2004 03:00:52 -0700 MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Disposition: inline X-Spam-Status: No, score=-3.2 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00, MAILTO_TO_SPAM_ADDR autolearn=ham version=3.0.0-pre4 X-Spam-Level: X-Spam-Checker-Version: SpamAssassin 3.0.0-pre4 (2004-08-04) on prxy.net X-prxy-Spam-Filter: Scanned X-TFF-CGPSA-Version: 1.4a3 For info, archives & UNSUBSCRIBE, see --------------------------------------------------- Stagecraft Digest, Issue #149 1. Re: Engineering Grad Schools by Paul Masck 2. Re: Guns by "Paul Guncheon" 3. Blue lightning shoots from hand by "Jared Clarkin" 4. Mythbusters Fresnel "Death Ray" by "Storms, Randy" 5. Re: Blue lightning shoots from hand by Mat Goebel 6. Re: Guns by MissWisc [at] aol.com 7. RE Dorians question on coring by "Riter, Andrew (Head Ltg)" 8. Re: Mythbusters Fresnel "Death Ray" by "Immel,Patrick" 9. Re: Mythbusters Fresnel "Death Ray" by "Scott Boyle" 10. Re: Mythbusters Fresnel "Death Ray" by howie 11. Re: Mythbusters Fresnel "Death Ray" by Nathan Kahn/Look Solutions 12. Re: 24 hour theater... Slightly off topic by Michael Powers 13. Re: Cdn Rules for Coring, x-raying by "Michael Finney" 14. Re: Engineering Grad Schools by "Booth, Dennis" 15. Re: Mythbusters Fresnel "Death Ray" by "Stephen E. Rees" 16. Re: Mythbusters Fresnel "Death Ray" by Steve Larson 17. Re: Mythbusters Fresnel "Death Ray" by "Michael Denison" 18. Re: 24 hour theater... Slightly off topic by "Mike Rock" 19. Re: Mythbusters Fresnel "Death Ray" by Richard Niederberg 20. Re: Guns (Again) by June Abernathy 21. Re: Mythbusters Fresnel "Death Ray" by "will kent" 22. Re: Mythbusters Fresnel "Death Ray" by "Alf Sauve" *** Please update the subject line of your reply to use the subject *** line of the message you are replying to! Please only reply to *** one message subject in each reply. ---------------------------------------------------------------------- In-Reply-To: References: Message-Id: From: Paul Masck Subject: Re: Engineering Grad Schools Date: Thu, 30 Sep 2004 08:46:25 -0400 On Sep 30, 2004, at 6:00 AM, Stagecraft wrote: > Hi, > I'm an undergrad, and I am looking at going to grad school for > mechanical > engineering, specifically robotics/automation and dynamic control > systems. > My hope would be, of course, to be able to go into either mechanical > engineering or use it in a technical theatre career. I was wondering > if > anybody had any suggestions, recommendations, or general comments about > MechEng grad schools specializing in automation. Any help is greatly > appreciated. Also, I'm going to Boston next month on unrelated > business, > but I thought I would take a look at grad schools out there. Besides > MIT > and Boston University, does anyone know about schools in that vicinity? > Thanks. > > Ben Kehoe > Hamline University Hi Ben- With what kind of undergraduate degree are you going to be graduating? What is your dream job/career when you're done with school? Lots of schools have both engineering and theatre programs. The challenge is finding a theatre program that lets you participate fully while still going to school in Engin. I did my undergrad (Electrical Engineering) at the University of Michigan, and was able to spend every spare moment in the theatre. Unfortunately when you're an engineering student, you don't have many spare moments. I'm probably playing devils advocate here, especially in such an education-centered forum, but I think you run the risk of becoming overeducated to do theatre. No theatre in the world will be able to pay you what you are worth as an Engineer, certainly not full time. Masters degree programs in engineering usually take the generalizations of Undergrad Engineering programs and apply them to a single small specialization. Theatre really isn't about specialization. I just don't see the point of spending USD$100,000 or more for a degree that overqualifies you for every job you might want in this industry. Talk to some people that are working in your dream jobs, find out about their backgrounds. Talk to Imagineers and to people at ScenicTech, Showman Fabricators, Feller Precision. You might be surprised to learn where they came from. ---------------------------------------------------------------------- Paul Masck paul [at] masck.com www.masck.com slave to the misshapen chaos of well-seeming forms ----------------------------------------------------------------------- ------------------------------ Message-ID: <002601c4a6f1$c3dc9980$0202a8c0 [at] MyLastPC> From: "Paul Guncheon" References: Subject: Re: Guns Date: Thu, 30 Sep 2004 03:31:16 -1000 <> Definitely an apples and oranges comparison here. I find that such hysteria and irrational warnings lead to people (students, actors, whomever) to disbelieve. No matter how many times I hear someone say "Treat all guns as is if the are real and are loaded", if it ain't, and it ain't, then I don't. If I don't know the gun, then yes. There are relatively simple safety rules for using stage guns. The first of which is never to use a real (read "able to fire a projectile") one. there are a lot more which I assume one can find in the archives. Laters, Paul "I know all the wherefores," said Tom wisely. ------------------------------ Message-Id: Date: Thu, 30 Sep 2004 10:39:48 -0400 From: "Jared Clarkin" Subject: Blue lightning shoots from hand Does anyone out there have any suggestions on how to create an effect, triggered by the actor, where blue sparks and a flash of light emanate from the actors hand, and can be repeated multiple times? Any help would be greatly appreciated. Currently I am trying a modified camera flash combined with a device called "makin sparks" however the effect is not reading as strong, or as blue as the director would like. Thanks for your time, Jared Clarkin Production Manager Actors Studio Drama School ------------------------------ Subject: Mythbusters Fresnel "Death Ray" Date: Thu, 30 Sep 2004 08:09:53 -0700 Message-ID: <555928311F8B2943B65FC7197942C3B7323947 [at] es1.bsdnet.wednet.edu> From: "Storms, Randy" Did anybody catch Mythbusters last night? They tried to verify/disprove = the apocryphal story about Copernicus destroying a fleet of Roman = triremes by arranging hundreds of bronze shields to focus reflected = sunlight on a small area, thereby causing a fire... In an attempt to recreate the essential components of the story without = hiring 300+ "soldiers" to stand around aiming their shields, the MB guys = built a large (~12'x12'?) "lens" of mirror segments mounted to a plywood = deck in concentric circles. Each ring of mirrors was tipped out from = the mounting surface a specific number of degrees, with the rings = closest to the center being almost flat and the angle increasing with = each ring thereafter.=20 They called it a fresnel (Adam said "fraynel"; the voiceover guy said = "freznel")and I guess it sort of was - anybody have a good description = of what makes a fresnel a fresnel? Anyway, myth busted - At a distance of 60' they were able to get the tar = on their target ship's hull to smoke slightly, but only raised the = temperature to around 200 degrees Fahrenheit, some 400 degrees short of = inducing combustion. They finally decided it would have been a lot = cheaper and easier for Copernicus to just chuck a bunch of flaming stuff = at the enemy ships. Cheers, -- r. Randy Storms rstorms [at] bham.wednet.edu ------------------------------ Message-ID: Date: Thu, 30 Sep 2004 08:32:34 -0700 From: Mat Goebel Subject: Re: Blue lightning shoots from hand In-Reply-To: References: I believe Disney does something similar to this with fiber optics in their "Fantasmic" show. On Thu, 30 Sep 2004 10:39:48 -0400, Jared Clarkin wrote: > For info, archives & UNSUBSCRIBE, see > --------------------------------------------------- > > Does anyone out there have any suggestions on how to create an effect, > triggered by the actor, where blue sparks and a flash of light emanate > from the actors hand, and can be repeated multiple times? -- Mat Goebel Entertainment Technical Services Paramount's Great America Cell: 510.693.1448 ------------------------------ From: MissWisc [at] aol.com Message-ID: <1db.2bfbee89.2e8d85bf [at] aol.com> Date: Thu, 30 Sep 2004 11:52:31 EDT Subject: Re: Re: Guns Cc: paul.guncheon [at] verizon.net In a message dated 9/30/4 8:32:03 AM, paul.guncheon [at] verizon.net wrote: <> It's not about knowledge, Paul. It's about who accepts responsibility when/if something goes wrong. We agree on many points. Let's say someone does a search of the stagecraft archives, finds the post of "weld a plug to the end of your gun" (not a literal quote) and does it. They end up with a very dangerous device. They use that device and it injures someone. Who pays for that injury? The person who modified the device - yes, but also the person who said to do it that way, the special effects/stunt supervisor, the director/producer who permitted it to be done, the set guardian (if the injured person was a minor), and so on. When it comes to guns/weapons or flying people, the chances of death or injury is great and thus the stunt design, equipment selection, and training of the actors involved should be done by competent professionals who specialize in those areas. That's simple fact. Paul, you're working on a TV set for an action show... would the director allow the actors to bring in their guns from home? Of course not! I'd bet you have someone who's in charge of the guns, the guns are specifically made by a professional gunsmith for stage use (which you stated in your post), they're stored in a locked place when not in use, the actors have been trained in their use, and each usage is safely choreographed. That's standard practice in the professional world. The amateur one should use that same standard of care. It'll never be 100% safe. But it is worth it to take time to make it as safe as possble. Last time I needed guns for a show (Bugsy Malone) we used silly string with the gun shaped triggers for spray cans. Even with a "safe" item as weapon, I consulted with someone who stages fights professionally and we carefully blocked the shots to minimize the chance for injury. Kristi "Swift?? Isn't that a brand of HAM?" asked Tom. ;) (OK Paul, you've got me WHUPPED on these!!!!) ------------------------------ Message-ID: <297C9E3B63B2D3119C8100508B5ED28F1601FEF2 [at] exchange2.ubc.ca> From: "Riter, Andrew (Head Ltg)" Subject: RE Dorians question on coring Date: Thu, 30 Sep 2004 09:19:46 -0700 Dorian asked: >I am displaying my ignorance here. Could someone please explain about >X-Ray coring? Although it might be common practice here in the UK, I have >never come across it. I asssume by 'coring' you mean diamond drilling >through slab RC. to make access for vent or electrics trunking. Is it a >specialist job? What power are the X rays? Do the operators need special >protection, lead aprons, do they have to leave the room, wear dosimeters >etc? And why does it have wheels? > >How big an area is scanned, is it the whole diameter of the core or just a >representative hole in the centre or what? Drilling, or boring, as I refered to it is a standard hammer drill with a masonary bit, used for cinder block, concrete/cement, etc. It is a dry process. Coring makes bigger holes than drilling, much like a hole saw in the carpentry shop. It involves water that washes the "sawdust" mud out the hole (and down the wall, onto the floor, and fabric, stage, etc). It is not a "specialist" job, except that the operator needs to know what they are doing. The coring machine looks like a drill press, but is mounted to the wall, tipped 90 deg from the standard drill press position (working horizontal, rather than vertical). The wheels on end allow it to be rolled across the ground to get to the work site. X-raying a wall is a separate job. I know only how it was described to me: a piece of "film" is mounted on one side of the wall, and a box with the isotope is on the other side. The box has a hose/nozzle which is placed on the wall. The box is "opened" allowing isotopes to go through the nozzle, out the end, through the wall, and against the film. The film is then developed, and you see what is in the wall (re-bar, conduit, Jimmy Hoffa). The other specifics (lead aprons, meters), I have no knowledge of. Once you know what is in the wall and where, you can place the coring machine to cut through the wall without cutting conduit, data lines, etc. What is Slab RC? Re-inforced concrete? Andrew M. Riter Head Lighting Technician Chan Centre ------------------------------ Message-ID: <147CF8DFB9C5D41187300001FA7EE390213D72DD [at] mail.nwmissouri.edu> From: "Immel,Patrick" Subject: RE: Mythbusters Fresnel "Death Ray" Date: Thu, 30 Sep 2004 11:27:34 -0500 > -----Original Message----- > From: Storms, Randy [mailto:rstorms [at] bham.wednet.edu] > Sent: Thursday, September 30, 2004 10:10 AM > To: Stagecraft > Subject: Mythbusters Fresnel "Death Ray" > > They called it a fresnel (Adam said "fraynel"; the voiceover > guy said "freznel")and I guess it sort of was - anybody have > a good description of what makes a fresnel a fresnel? > What makes a fresnel a fresnel? I would say the lense and the ability to forward or backward to change the size of the beam of light. Or is this too simple? Maybe *I'm* missing something as well! :-) Pat Immel Northwest Missouri State University ------------------------------ From: "Scott Boyle" Subject: RE: Mythbusters Fresnel "Death Ray" Date: Thu, 30 Sep 2004 11:43:08 -0500 Organization: Carroll College Message-ID: <000a01c4a70c$91d889b0$73db688c [at] cc.edu> In-Reply-To: No, it really is about the lens. Augustine-Jean Fresnel invented the step lens to convert the optics of a thick plano-convex lens into a thinner format. I was always told, it was originally used for lighthouses, but that could be an old wives' tale. Scott M. Boyle Technical Director Department of Theatre Arts Carroll College 262-524-7308 -----Original Message----- From: Stagecraft [mailto:stagecraft [at] theatrical.net] On Behalf Of Immel,Patrick Sent: Thursday, September 30, 2004 11:28 AM To: Stagecraft Subject: Re: Mythbusters Fresnel "Death Ray" For info, archives & UNSUBSCRIBE, see --------------------------------------------------- > -----Original Message----- > From: Storms, Randy [mailto:rstorms [at] bham.wednet.edu] > Sent: Thursday, September 30, 2004 10:10 AM > To: Stagecraft > Subject: Mythbusters Fresnel "Death Ray" > > They called it a fresnel (Adam said "fraynel"; the voiceover > guy said "freznel")and I guess it sort of was - anybody have > a good description of what makes a fresnel a fresnel? > What makes a fresnel a fresnel? I would say the lense and the ability to forward or backward to change the size of the beam of light. Or is this too simple? Maybe *I'm* missing something as well! :-) Pat Immel Northwest Missouri State University ------------------------------ Message-ID: <415C37D0.8090601 [at] hillinteractive.net> Date: Thu, 30 Sep 2004 12:44:00 -0400 From: howie Subject: Re: Mythbusters Fresnel "Death Ray" References: In-Reply-To: Immel,Patrick wrote: > What makes a fresnel a fresnel? the stepped lens. http://www.lanternroom.com/misc/freslens.htm ----------------h ------------------------------ Message-Id: <5.0.0.25.2.20040930124726.017abc90 [at] 212.86.129.164> Date: Thu, 30 Sep 2004 12:53:25 -0400 From: Nathan Kahn/Look Solutions Subject: Re: Mythbusters Fresnel "Death Ray" In-Reply-To: At 08:09 AM 9/30/2004 -0700, you wrote: >anybody have a good description of what makes a fresnel a fresnel? Fresnel is the name of the French guy who invented the fresnel lens. He invented it for use in lighthouses. Fresnel is also the term given to a stage light that's comprised of a lamp and a fresnel lens, in a housing. Can any light that incorporates a fresnel lens be called a fresnel? Dunno . . . Nathan ------------------------------------------------------------ Look Solutions USA, Ltd. 114 W. Third St., Waynesboro, PA 17268 Phone: 1-800-426-4189 Fax: 1-717-762-7366 Email: usa [at] looksolutions.com Web: www.looksolutions.com ------------------------------ Date: Thu, 30 Sep 2004 12:53:59 -0400 From: Michael Powers Subject: Re:24 hour theater... Slightly off topic Message-id: <415C3A27.2090300 [at] theater.umass.edu> "CATHERINE BRUMM" wrote: <> Catherine, UMass has done this the last two years and we have found it to be very exciting and interesting. I however, am not the person who has the information you are looking for. You should contact Anna-Maria Goossens and or Julie Fife . They are our Publicity Director and Production Manager respectively. Between the two of them, the program has run smooth as silk both years and of course we are looking forward to doing it again this spring. I have copied this note to both Anna-Maria and Julie, so if you decide to contact them it won't be a surprise. HTH! Michael Michael Powers, Technical Director UMass Amherst 112 FAC West Amherst, Ma. 01003 413-545-6821 Voice 413-577-0025 Fax mfpowers [at] theater.umass.edu mptecdir [at] aol.com ------------------------------ Subject: Re: Cdn Rules for Coring, x-raying Date: Thu, 30 Sep 2004 10:38:49 -0700 Message-ID: From: "Michael Finney" On Thu, 30 Sep 2004 Dorian Kelly wrote: <> =20 Dorian - To be honest, I'm kind of surprised nobody asked those questions yet, as sub-surface surveys of walls are actually not a *terribly* common practice (especially not in the entertainment industry). Good questions, all...... We're actually talking about two separate things here - one is the concrete coring, and the other is subsurface survey (the term we're using ("x-ray survey") can be a bit of a misnomer. More on that in a second). Concrete coring is being used in this instance as a generic term for boring a hole in a concrete wall. This construction task actually falls into the general construction category of concrete drilling, coring, saw-cutting, and chipping. These are all methods of making holes in concrete - "drilling" is just like any other kind of drilling (with a diamond tipped, water cooled bit usually); "coring" is the same thing, using a "hole saw" in place of the bit and producing a concrete cylinder; "saw-cutting" is using a large, usually diamond tipped, water cooled circular saw; and "chipping" is using power or manual chisels (and other tools) to remove the concrete material. All are loud, messy activities - and there are companies that specialize in this sort of activity. Most of us could do a certain amount of this work, but specialist firms are much quicker (and not actually all *that* expensive in the long term - it was actually cheaper to hire a firm last week to punch a hole here in the office than it would have been to rent the equipment and do it myself...go figure!). Performing a sub-surface survey of an area before cutting is done in the construction industry when there is a good chance that sub-surface utilities (conduit, buried cables, fiber optic runs, plumbing, gas pipes (yikes!), sewer (yikes again!), tension cables, rebar, etc.) may be encountered. To be honest, x-rays (normally using gamma radiation rather than x-radiation) are not always the first choice for subsurface survey's, as it isn't always possible to get the necessary access - or budget (x-ray surveys can be expensive due to the cost of equipment, protection, etc). =20 A good site explaining a bit about x-ray surveys is: http://www.iinspect.com/concrete_x-ray.htm These guys are very, very good at this, and other pages on their site explain other subsurface survey options...as well as talking about the general guidelines for performing an x-ray survey. I've used them for a number of inspections over the years - including mailing them metal assemblies to be checked for flaws within the welds or castings. Another option these days is often ground penetrating radar or subsurface interface radar, used with an outboard imaging and image enhancement system. Another great link to several articles on the subject is: http://gpr.articleinsider.com/49167_subsurface_exploration.html In fact, this site has a number of great short, basic articles on construction: http://www.articleinsider.com/construction/ I love this kind of stuff! It's the coolest part of my job - getting to play with all sorts of odd toys! Michael Finney Thinkwell Design & Production mfinney [at] thinkwelldesign.com =20 http://www.thinkwelldesign.com =20 ------------------------------ Subject: RE: Engineering Grad Schools Date: Thu, 30 Sep 2004 13:48:37 -0400 Message-ID: From: "Booth, Dennis" North Carolina School of the Arts Design and Production has an MFA = degree program in Stage Automation. Please contact Jack Miller millerj [at] ncarts.edu for more information. Our = website is listed below, also. DGB Dennis Gill Booth Technical Faculty & Assistant Dean for Operations =A0 North Carolina School of the Arts=20 =A0 School of Design and Production=20 =A0 1553 South Main Street=20 =A0 PO Box 12189=20 =A0 Winston-Salem, NC=A0=A0 27117-2189=20 * Voice:=A0 (336)770-3232 x105=20 * FAX:=A0=A0 (336)770-3213=20 * Email: boothd [at] ncarts.edu=20 * D&P URL: http://www.ncarts.edu/ncsaprod/designandproduction/=20 * Faculty=A0URL: http://faculty.ncarts.edu/dandp/booth/ -----Original Message----- From: Stagecraft [mailto:stagecraft [at] theatrical.net] On Behalf Of Ben = Kehoe Sent: Wednesday, September 29, 2004 12:49 PM To: Stagecraft Subject: Engineering Grad Schools For info, archives & UNSUBSCRIBE, see --------------------------------------------------- Hi, I'm an undergrad, and I am looking at going to grad school for = mechanical engineering, specifically robotics/automation and dynamic = control systems. My hope would be, of course, to be able to go into = either mechanical engineering or use it in a technical theatre career. = I was wondering if anybody had any suggestions, recommendations, or = general comments about MechEng grad schools specializing in automation. = Any help is greatly appreciated. Also, I'm going to Boston next month = on unrelated business, but I thought I would take a look at grad schools = out there. Besides MIT and Boston University, does anyone know about = schools in that vicinity? Thanks. Ben Kehoe Hamline University ----------------------------------------------=20 This message has been scanned for viruses and dangerous content and is believed to be clean. ---------------------------------------------- ------------------------------ Message-ID: <415C5040.7020301 [at] fredonia.edu> Date: Thu, 30 Sep 2004 14:28:16 -0400 From: "Stephen E. Rees" Subject: Re: Mythbusters Fresnel "Death Ray" References: Hi, Light houses lenses are not just "old wives tales". Although it is kind of hard to make a direct comparison between the theatrical version and the light house version of a Fresnel lens, the principle of refraction is exactly the same. BTW, it isn't a step lens in the strict sense of the term as step lenses have the plano side removed and Fresnels have the convex side of the lens removed. Steve Rees, TD SUNY-Fredonia Scott Boyle wrote: > For info, archives & UNSUBSCRIBE, see > --------------------------------------------------- > > No, it really is about the lens. Augustine-Jean Fresnel invented the > step lens to convert the optics of a thick plano-convex lens into a > thinner format. I was always told, it was originally used for > lighthouses, but that could be an old wives' tale. > > Scott M. Boyle > Technical Director > Department of Theatre Arts > Carroll College > 262-524-7308 > > -----Original Message----- > From: Stagecraft [mailto:stagecraft [at] theatrical.net] On Behalf Of > Immel,Patrick > Sent: Thursday, September 30, 2004 11:28 AM > To: Stagecraft > Subject: Re: Mythbusters Fresnel "Death Ray" > > For info, archives & UNSUBSCRIBE, see > --------------------------------------------------- > > > > >>-----Original Message----- >>From: Storms, Randy [mailto:rstorms [at] bham.wednet.edu] >>Sent: Thursday, September 30, 2004 10:10 AM >>To: Stagecraft >>Subject: Mythbusters Fresnel "Death Ray" >> >>They called it a fresnel (Adam said "fraynel"; the voiceover >>guy said "freznel")and I guess it sort of was - anybody have >>a good description of what makes a fresnel a fresnel? >> > > > > What makes a fresnel a fresnel? I would say the lense and the ability > to > forward or backward to change the size of the beam of light. > > Or is this too simple? Maybe *I'm* missing something as well! :-) > > Pat Immel > Northwest Missouri State University ------------------------------ Date: Thu, 30 Sep 2004 16:05:08 -0400 Subject: Re: Mythbusters Fresnel "Death Ray" From: Steve Larson Message-ID: In-Reply-To: For a biographical look at Fresnel go to: http://www-gap.dcs.st-and.ac.uk/~history/Mathematicians/Fresnel.html If you ever get to D.C., go to the "castle" at the Smithsonian. They used to have a lighthouse unit set up with a large fresnel lens. Steve on 9/30/04 2:28 PM, Stephen E. Rees at Rees [at] fredonia.edu wrote: > For info, archives & UNSUBSCRIBE, see > --------------------------------------------------- > > Hi, > Light houses lenses are not just "old wives tales". Although it is kind > of hard to make a direct comparison between the theatrical version and > the light house version of a Fresnel lens, the principle of refraction > is exactly the same. BTW, it isn't a step lens in the strict sense of > the term as step lenses have the plano side removed and Fresnels have > the convex side of the lens removed. > Steve Rees, TD > SUNY-Fredonia > > Scott Boyle wrote: >> For info, archives & UNSUBSCRIBE, see >> --------------------------------------------------- >> >> No, it really is about the lens. Augustine-Jean Fresnel invented the >> step lens to convert the optics of a thick plano-convex lens into a >> thinner format. I was always told, it was originally used for >> lighthouses, but that could be an old wives' tale. >> >> Scott M. Boyle >> Technical Director >> Department of Theatre Arts >> Carroll College >> 262-524-7308 >> >> -----Original Message----- >> From: Stagecraft [mailto:stagecraft [at] theatrical.net] On Behalf Of >> Immel,Patrick >> Sent: Thursday, September 30, 2004 11:28 AM >> To: Stagecraft >> Subject: Re: Mythbusters Fresnel "Death Ray" >> >> For info, archives & UNSUBSCRIBE, see >> --------------------------------------------------- >> >> >> >> >>> -----Original Message----- >>> From: Storms, Randy [mailto:rstorms [at] bham.wednet.edu] >>> Sent: Thursday, September 30, 2004 10:10 AM >>> To: Stagecraft >>> Subject: Mythbusters Fresnel "Death Ray" >>> >>> They called it a fresnel (Adam said "fraynel"; the voiceover >>> guy said "freznel")and I guess it sort of was - anybody have >>> a good description of what makes a fresnel a fresnel? >>> >> >> >> >> What makes a fresnel a fresnel? I would say the lense and the ability >> to >> forward or backward to change the size of the beam of light. >> >> Or is this too simple? Maybe *I'm* missing something as well! :-) >> >> Pat Immel >> Northwest Missouri State University > > > > ------------------------------ Message-ID: <415C4378.25050.54C7DF6 [at] localhost> From: "Michael Denison" Date: Thu, 30 Sep 2004 17:33:44 -0500 Subject: Re: Mythbusters Fresnel "Death Ray" In-Reply-To: Sort of...my understanding is that a Fresnel lens is a step lens flattened out. If you chopped up a Fresnel lens into concentric circles and then fit all of the convex surfaces together in one smooth curve, you'd have a step lens. The idea was to get the same light bending qualities from a thinner piece of glass that would be less likely to break under heat stress. Yes? No? BTW, it isn't a step lens in the strict sense of > the term as step lenses have the plano side removed and Fresnels have > the convex side of the lens removed. Michael A. Denison Technical Director Cottey College 1000 West Austin Nevada, MO 64772 (417) 667-8181 x 2265 FAX: (417) 667-8103 mdenison [at] cottey.edu www.cottey.edu ------------------------------ Message-ID: <004f01c4a73f$1ebdccf0$80fea8c0 [at] Fred> From: "Mike Rock" References: Subject: Re: 24 hour theater... Slightly off topic Date: Thu, 30 Sep 2004 17:44:58 -0500 This sounds rather intresting, I did a rather quick search and I came up with some results mostly about schools that have done it, very little real info is there a site where I could get some details? Mike ------------------------------ Date: Thu, 30 Sep 2004 16:48:01 -0700 Subject: Re: Mythbusters Fresnel "Death Ray" Message-ID: <20040930.164813.1112.3.ladesigners [at] juno.com> From: Richard Niederberg Another purpose of placing a rotating array of Fresnel lenses in light houses is that from a relatively fixed position, such as miles away at sea, the light appears to flash a certain amount of times per minute; this rate appears on nautical charts, and is a at a different rate than that of adjoining lighthouses. Lighthouses, then and now, do not just mark the shoreline as an aid to navigation. The primary reason for the introduction of the Fresnel lens was to cut down on the weight of a plano-convex lens that had to be supported dozens of feet in the air and be rotated continuously. Before electrification, it was the Lighthouse keeper who had to wind a spring or lift a weight up the tower on a strict schedule. Also, Fresnel lenses were less likely than a plano-convex lenses to crack when exposed to rapid temperature changes, because they are much thinner. /s/ Richard > Hi, > Light houses lenses are not just "old wives tales". > Steve Rees, TD ________________________________________________________________ Get your name as your email address. Includes spam protection, 1GB storage, no ads and more Only $1.99/ month - visit http://www.mysite.com/name today! ------------------------------ Message-ID: <20041001001808.95394.qmail [at] web14124.mail.yahoo.com> Date: Thu, 30 Sep 2004 17:18:08 -0700 (PDT) From: June Abernathy Subject: Re: Guns (Again) Frank writes: >I should have thought that the reason was obvious >even to someone of your limited understanding. A >weapon with an open muzzle can be used for >firing live rounds. I don't know what rules you >operate under, but, here in the UK, this is >explicitly forbidden. Blank firing weapons MUST have >the barrel blocked, and vent the charge sideways. I >could not, legally, implement my proposed solution >over here. Frank, Be careful of slinging around that "limited understanding" thing. Or at least, consider having a mirror handy. First, there is not, to my knowledge, any national law in the US that prevents anyone from using a real, unmodified weapon capable of firing live rounds in a stage production where it is fitted with blank rounds. You may think that this is unsafe or crazy, and you would not be alone in this thinking, but it is nonetheless true. I've worked on a couple of shows where this was done. There are a LOT of schools, theaters, municipalities, and maybe even states that prevent the use of a "real" weapon on stage, but no universal rule, as I take there is in England. Second, there is a middle ground - actually, a couple middle grounds - between a plugged barrel weapon and the real McCoy. These alternatives have been mentioned before, on this list. Recently. Probably by me. Let me say up front that I believe that all modifications to weapons should be done by a reputable and qualified gunsmith. If you don't want a plugged barrel weapon for some reason (like, because you WANT the gasses to vent mostly forward, as in the example that sparked this), you can: 1) get a weapon whose barrel has had a pin, or crossed pair of pins inserted to prevent a projectile from exiting, although it still allows gasses to vent. The danger with these, of course, is that if somehow a projectile WAS fired, the gun would probably blow up in your hand. (Much the same thing that would happen if a projectile was fired from a plugged barrel weapon). 2) You can get a weapon whose chamber has been modified so that it will not accept a full length cartridge with bullet. These will only accept a blank round. We used (and AFAIK, they still use) a weapon like this on the national tour of LES MISERABLES. It allows you to have a clear barrel that can be properly cleaned, front venting, and basically no chance of ever accidentally loading a real round. Of course, Frank could not use either of these solutions, as I understand it, because in his area, ONLY plugged barrel stage weapons are allowed. I understand that. (Whether the pin(s) are considered a legal "plug" is probably an AHJ question). There are, in the US, many schools, theaters, cities, and maybe even states where this is true as well. They ONLY allow plugged barrel weapons, if they allow blank firing at all. In that case, you might use a plugged barrel weapon and a little air in a tube or suchlike to move dirt, or one of the other 6000 suggestions that was put forward on this identical thread recently. The thing is, there are times when an open barrel IS more desirable, and yes, even safer, than a plugged barrel weapon. Like, if the shooter's proximity to other actors, flammable or delicate scenery, or the audience is such that side venting would constitute a danger to them. Or,if you were in an intimate space, or a thrust or arena space where the actor's proximity to the audience would make a plugged barrel in a weapon glaringly obvious and detract from the play. You CAN use an open barrel weapon onstage in a safe manner. Whether you MAY, is another question. June Abernathy IATSE #321 (Tampa, FL) FOH Electrician The Lion King National Tour (Gazelle) __________________________________ Do you Yahoo!? Take Yahoo! Mail with you! Get it on your mobile phone. http://mobile.yahoo.com/maildemo ------------------------------ From: "will kent" Subject: Re: Mythbusters Fresnel "Death Ray" Date: Fri, 01 Oct 2004 00:33:12 +0000 Message-ID: I did a report my 10th grade english class Augustine-Jean Fresnel and it was infact used originaly for lighthouses. If I rember right they increased the visibility to up to a mile. Another cool thing is that they would spin the lenes around the lamp to creat blinks and each light house would have a differnt pattern of blinks so that ships could navigate at night. Will Kent Owner/Operator/LD Kent Production Services www.kentlighting.cjb.net _________________________________________________________________ Express yourself instantly with MSN Messenger! Download today - it's FREE! hthttp://messenger.msn.click-url.com/go/onm00200471ave/direct/01/ ------------------------------ Message-ID: <05d601c4a754$8fc28d40$0600a8c0 [at] alf> From: "Alf Sauve" References: Subject: Re: Mythbusters Fresnel "Death Ray" Date: Thu, 30 Sep 2004 21:11:44 -0400 The "steps" on a Fresnel lens aren't flat. They are curved. So a mirror made of a bunch of smaller flat mirrors couldn't strictly be compared with a Fresnel lens. The "thickness" of mirrors isn't an optical factor. So what Fresnel accomplished with a lens isn't applicable to mirrors. One could build a parabolic mirror that was much "flatter" than normal by stepping it. But the reason to do so would be to save space (depth) not weight as in Fresnel's case. ----- Original Message ----- From: "Storms, Randy" To: "Stagecraft" Sent: Thursday, September 30, 2004 11:09 AM Subject: Mythbusters Fresnel "Death Ray" In an attempt to recreate the essential components of the story without hiring 300+ "soldiers" to stand around aiming their shields, the MB guys built a large (~12'x12'?) "lens" of mirror segments mounted to a plywood deck in concentric circles. Each ring of mirrors was tipped out from the mounting surface a specific number of degrees, with the rings closest to the center being almost flat and the angle increasing with each ring thereafter. ------------------------------ End of Stagecraft Digest #149 *****************************