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Followspot mounting

Discussion in 'Lighting and Electrics' started by squigish, Feb 23, 2005.

  1. squigish

    squigish Member

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    My school currently has four followspots: 3 altman 902 and one that I believe is made by Little Stage Lighting. Two of them are sitting on floor stands at the back of the house, at about a 20-30 degree vertical angle from the stage, and about a 30 degree plan angle (they're on the two sides, because there are architectural obstructions in the center). The other two (both altmans) are not being used. We would like to put two or three of the spots in our catwalk beam position, which has a 40-50 degree vertical angle to the stage.

    My question is threefold:

    1: How do you recommend we mount the suckers? Our catwalk is equiped with a wierd mounting system made by electro controls called a channel mount, it's similar to unistrut, just more of a pain to work with. Basically, we need a way to suspend the spot from a piece of threaded rod or a bolt. Currently, we have three floor stands, but they're open at the top, so they would be completely useless for underhanging the spots with.

    2: This is more a design question, but where do you recommend we place them? We have space to hang two dead center, but without any available circuits (we'd have to run a jumper) and one about 35 degrees left of center with a non-dim circuit, and another the same distance right of center, also with a non-dim. We would like to keep at least one spot located in the house for outside events, so that we don't have to bring people up to the catwalk where they could cause damage, or hurt themselves, or fall through the ceiling, etc.

    3: all three of the altman units have a cooling fan, so they can't be easily placed on a dimmer, but the little stage lighting one is fanless. However, it is currently using a 1500W Quartz-Halogen lamp, and our dimmers are only 1.2kW. The altman that we are using has the same 1500W halogen lamp, and the other two have 1500W incandescant lamps. Would it be feasible to put 1000W lamps in the spots so that they can be dimmed? It occurs to me that since we are greatly reducing the throw distance, the 1500W lamp might be too bright anyways. What kind of lamp would we want to use? They are currently using a mogul pre-focus base. Also, what kind of wiring would we have to do to bypass the fan and allow the lamp to be dimmed in the altman units?
     
  2. Les

    Les Well-Known Member Premium Member

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    I really can't answer your rigging question because I really don't understand the setup. As for placement, I would try to put them at the ends of the catwalk. Not all the way, just about 1/4 of the way in and out. I believe I know what followspot you are talking about. I have a huge 'little' spot in my attic. I'm pretty sure you can get a 1,000 watt lamp in it without any problems. The 1500 watt is quite intense (and hot due to lack-o-fan) so down-grading to 1kw would probably be the most practical choice.
    Good luck with it all!
     
  3. techieman33

    techieman33 Well-Known Member

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    I'm assuming the floor stands are just an upside down youlk(sp) so why not just flip it 180 and have it on the top instead of the bottom.
     
  4. SteveB

    SteveB Well-Known Member

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    There's no good method for modifiying the spots to an overhanging support. Spot yokes usually have slots in them, open at the top to allow ease of installation - lift and drop into place.

    You can explore removing the tripod base and clamping the vertical boom to a structural member on the catwalk - possibly using a set of U bolts to the channel steel ?. And/or cheeseboroughs/Roto-Loks to the catwalk railings ?. Can't advise further without seeing the catwalk.

    It's not a huge issue to isolate the fans - yes, there may be more then one. It's not unusual to see a fan in the back cooling the lamp area as well as one in the front cooling the gel. Best check. In either case, re-wiring both to a dedicated 120v connector is fairly easy for a licensed electrician.
    The 902 isn't listed on the Altman website anymore, so I can't advise about the lamps, other then to recommend getting whatever information is on the lamp, usually there's a 3 letter code called the ANSI designation, EGG as example that tells us what it is. The GE and/or Osram-Sylvania websites could probably tell you what lamps are available, or call Bulbtronics for advise - 800 227-2852.

    I'd leave the LSL spot and 1 902 in the house, then put the remaining 902's on the catwalk at the centerline. This way you alway's have 1 spot (or 2 as needed) available on the centerline where they are most useful.

    SB
     
  5. squigish

    squigish Member

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    No, that won't work. There's a slot on the top of the yoke, so if we flipped it, the spot would fall out, unless we also managed some way to reverse gravity.

    As far as the structure of the catwalk goes, I'll take some pictures on tuesday and upload them.

    The 902 is on the altman website, it's just hiding. I found it in their pdf listing of specs, or something like that. I don't think it included lamps, though.

    Oh, and after consulting a sectional, the sectional angle to the spots in the back of the house is more like 10-15 degrees.
     
  6. techieman33

    techieman33 Well-Known Member

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    Well yes there are slots, but it wouldn't be hard to modify the yolk to make it work the other direction.
     
  7. techieman33

    techieman33 Well-Known Member

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    Well yes there are slots, but it wouldn't be hard to modify the yolk to make it work the other direction.
     
  8. ship

    ship Senior Team Emeritus Premium Member

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    Rigging the yoke bracket to mount to the catwalk floor, or having a yoke made to hang would be a good option. I might consider having the two Altman spots in the house, and only a single third in the catwalk in saving the other one for other usage, but otherwise agree with keeping what must be moved or removed that which is not the standard thus in the house. A lot of it is going to depend upon what lenses and optics are in each of the fixtures. If the other brand has a wider focus, than the shorter throw will be more useful at close range.

    Photometrics Handbook says it's using a DTJ lamp.

    The 1Kw alternative to this lamp is a DPW at 50 hours. It will be about 2/3 the intensity but double the life of the DTJ. A more efficient 1.5Kw lamp would be the DTA at between 100 and 300 hours in life instead of just 25 hours. Intensity is just about as much also.

    GE long ago discontinued the DTJ lamp but Ushio still makes it. Philips might still make it, otherwise Usihio and Fuji.

    On the DTA long life alternative at 1.5Kw, GE should still, Osram might but probably does not any longer, but Ushio should still. It's also become a halogen lamp in explaining why it can have more lamp life but just about as much output for the same wattage. The GE DTA should be the best lamp on the market in being brightest and in having 300hrs of life.





    All this said about mounting the fixtures from the catwalk as possible in making a yoke for hang or in mounting the fixture to the deck, it's also it would seem by way of another note something you don't wnat to be doing with this fixture.
    Something about a wee little note about the lamp in saying at best even for the halogen versions "Base Down ±30°" meaning no less an angle than 30°. If you use it in the truss it can't be done unless perhaps by chance you have the Osram/Sylvania lamp in the fixture which is again probably discontinued if not an error in notes about beang able to burn in any position.

    Don't install the fixtures in the catwalk. The lamps won't have enough support to to filament and will or should have premature lamp failures.
     
  9. techieman33

    techieman33 Well-Known Member

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    I agree with ship on that one, you need to leave 2 of the altmans on the floor. So that you have a balance.
     

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