ScottFHall
Newly Enlightened
I've got the ballast, wiring, socket, and bulb comprising a 70 watt high-pressure sodium-vapor arc lamp system and a pretty deep 10 inch diameter parabolic reflector all sitting idle here. This thing measures 6000 lumens according to the specs. Yeah, the sort of thing you'd normally just hang over the door of your barn to light your path while doing your part to not further "pollute" the night sky with stray light. The thing is, though, I'm one of those people who actually like light pollution in carefully contained quantities--long, skinny, vertical beams in any color rising straight up to infinity do not offend me at all! So while staring at these parts, I suddenly had this vision of making a custom spotlight capable of putting that gnarly pink circle normally reserved for the ground right up there onto the high, high cumulonimbi! Hence, this new thread: behold the very first pictures of The Pink Menace! A 70 Watt High-Pressure Sodium-Vapor Arc Cloud Bouncing Spotlight!
The rig you see here--the funny little bookshelf object with clamp--is only for doing initial testing of the parts. I took all this out tonight and aimed it above the treeline. It is a completely cloudless night--cold and dry here lately--so I wasn't able to actually try it on a cloud. What I want to do before proceeding, of course, is confirm that this thing will put a circle of heinous pink right on the clouds (and maybe also cast a treelimb shadow onto the clouds, too).
It's a 120 volt AC circuit and will probably stay that way (I don't really want to lug a DC-AC inverter and auto battery around in a backpack with this one). The lamp takes a minute or two to ramp up to full power. Once it does get there, it's very, very bright and it throws out way too many longwave UVs. Even just a minute or two of exposure in one's peripheral vision will make your eyes feel like you've been swimming in chlorine all day. Note to self: put a layer or two of UV blocking glass over the lamp.
The bulb sits nicely down in the deep dish parabolic reflector. It looks to me like the reflector was well designed to throw a tight beam--the only trouble with that is likely the structure of my HPS bulb itself. These lamps have a 2 inch long tubular section inside where the arc happens. Surely, this is not the best configuration for a really tight beam--I think one gets the best result from the smallest possible point source (i.e. a small ball of light as seen within those new HID lamps which have that little spherical arc zone).
So, here are the initial results from below and behind on ASA 1600, 12 megapixels, 1/2 second exposure.
There is a good tight beam emitted--it's just a wee bit dim. It is much more visible to the human eye than it is to the digital camera here--I tried and tried and could not get the camera to "see" exactly as my eyes were seeing the beam. By the way, it's very good at lighting up "dust motes". You've never seen so many dust motes with a white light beam as with this thing! The air looks downright dirty.
The dimness of the beam is no surprise: I believe HPS lamps are designed with the idea in mind that light passing through thin air should not be very visible. On the other hand, light as it strikes larger objects should be very, very visible due to the narrow-band HPS spectrum (which is why we light our roadways with them, right?) The whole result is a very high contrast of dark to light at the price of odd colored pink lighting. In all, though, this bodes well for actually lighting up overhead clouds (my primary objective with The Pink Menace!--the beam is going to go up there with serious dimness and therefore stealth and yet really blast the cloud surface into major visibility--I think). That ought to look really interesting to me and perhaps pretty scary to those off over the horizon who won't know what the they're looking at up in the sky and won't know where it's coming from.
As you can see, there is some pretty significant spill coming out of the reflector. Surely, this is mostly due to the 2 inch long glowing element inside the bulb--light is not coming from a perfect point source and so some of it is going off on overly acute and obtuse tangents. This fact shouldn't mess up my plans to light clouds up, though. I'm already convinced that the necessary candlepower exists in this system and it does have a tight enough beam.
Regarding this major spill, what do you guys suggest other than replacing the bulb and reflector? If I attach a long, flat black interior-colored cylinder to the output end of the reflector, is spill going to be reduced or eradicated? Is that cylinder going to block and absorb the stray photons?
The rig you see here--the funny little bookshelf object with clamp--is only for doing initial testing of the parts. I took all this out tonight and aimed it above the treeline. It is a completely cloudless night--cold and dry here lately--so I wasn't able to actually try it on a cloud. What I want to do before proceeding, of course, is confirm that this thing will put a circle of heinous pink right on the clouds (and maybe also cast a treelimb shadow onto the clouds, too).
It's a 120 volt AC circuit and will probably stay that way (I don't really want to lug a DC-AC inverter and auto battery around in a backpack with this one). The lamp takes a minute or two to ramp up to full power. Once it does get there, it's very, very bright and it throws out way too many longwave UVs. Even just a minute or two of exposure in one's peripheral vision will make your eyes feel like you've been swimming in chlorine all day. Note to self: put a layer or two of UV blocking glass over the lamp.
The bulb sits nicely down in the deep dish parabolic reflector. It looks to me like the reflector was well designed to throw a tight beam--the only trouble with that is likely the structure of my HPS bulb itself. These lamps have a 2 inch long tubular section inside where the arc happens. Surely, this is not the best configuration for a really tight beam--I think one gets the best result from the smallest possible point source (i.e. a small ball of light as seen within those new HID lamps which have that little spherical arc zone).
So, here are the initial results from below and behind on ASA 1600, 12 megapixels, 1/2 second exposure.
There is a good tight beam emitted--it's just a wee bit dim. It is much more visible to the human eye than it is to the digital camera here--I tried and tried and could not get the camera to "see" exactly as my eyes were seeing the beam. By the way, it's very good at lighting up "dust motes". You've never seen so many dust motes with a white light beam as with this thing! The air looks downright dirty.
The dimness of the beam is no surprise: I believe HPS lamps are designed with the idea in mind that light passing through thin air should not be very visible. On the other hand, light as it strikes larger objects should be very, very visible due to the narrow-band HPS spectrum (which is why we light our roadways with them, right?) The whole result is a very high contrast of dark to light at the price of odd colored pink lighting. In all, though, this bodes well for actually lighting up overhead clouds (my primary objective with The Pink Menace!--the beam is going to go up there with serious dimness and therefore stealth and yet really blast the cloud surface into major visibility--I think). That ought to look really interesting to me and perhaps pretty scary to those off over the horizon who won't know what the they're looking at up in the sky and won't know where it's coming from.
As you can see, there is some pretty significant spill coming out of the reflector. Surely, this is mostly due to the 2 inch long glowing element inside the bulb--light is not coming from a perfect point source and so some of it is going off on overly acute and obtuse tangents. This fact shouldn't mess up my plans to light clouds up, though. I'm already convinced that the necessary candlepower exists in this system and it does have a tight enough beam.
Regarding this major spill, what do you guys suggest other than replacing the bulb and reflector? If I attach a long, flat black interior-colored cylinder to the output end of the reflector, is spill going to be reduced or eradicated? Is that cylinder going to block and absorb the stray photons?
