Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.
I have been truly impressed with the variety and performance of the searchlight builds here, so I have been watching for a quality reflector, cheap. As you all probably already know, this is not easy! Well, I finally found one that seems pretty great for less than $100, shipped. I am excited. Now, I need to decide what to do with it. I would like the community's help to select a lamp/power supply, and with various other build questions that will come up. I hope this thread will be interesting to you, as well.
Goals:
I want to be able to put an obvious spot on clouds as first priority, and maximize visibility of the beam as second priority. I want to minimize spill. I live a mile from a small city with all its outdoor lighting, so I am working with a fairly bright nighttime sky.
--
EDIT to add a constraint on power, per post 18:
Constraint:
Run from car 12V battery power for at least 5 minutes. Run from idling car power for as long as I want to. Big, clamp on inverter or 12V direct are both OK.
--
I would love to have 20k lumens or more! But the 8000 or so (?) lumens from a '100W' HID is very accessible and easy. Would fewer lumens with a smaller source like a projector short arc be better for my goals?
While I have studied many of your beautiful builds and learned what I can, this seems to be a unique project. I am leaning towards salvaging a lamp and ballast from a DLP projector. But not sure.
My budget for a lamp & ballast is hopefully <$250. I could go higher for significantly better value. Portability is not terribly important, as this will go on some kind of tripod/turret mount, so anything heavy can go on the stand. 12V is preferred over mains power, but I do have an inverter. Modified wave. 750/1500W. Vector VEC043.
From what I have learned here, I think the relatively large reflector means it can collimate a proportionally larger light source, so maximum surface brightness might not be so important for my goals. Maybe HID will be better for this, and short arc overkill that unnecessarily compromises beam power. I know it's a tradeoff, but for my goals, what do you think is the optimal lamp technology?
Here's what I know about the reflector:
From the markings, I think maybe it is an electroformed reflector from Phoenix, or similar. Can you help me ID it?
As soon as it arrived, 2 days ago, I had to play. I started on an adapter to house a spare 35W HID to test it. I found that an old Air Conditioning R/D I had was a perfect OD to fit the reflector ID, so I cut it down on my Smithy and pressed my lamp into it:
This fits nicely, and I use 2 o-rings to retain it while allowing adjust-ability.
Note the AA battery for scale:
The lamp is from a Harbor Freight Off Road HID that was on sale a while ago at 2 for $49. I think the outer glass tube is a UV filter. Is that correct?
Here are a couple of beamshots.
From about 100' away, not quite dark out yet:
From about 4' off-axis:
Zoomed in on cloud. Small spot already, so I am very encouraged! The spot is deformed here. If I hold the light by its base, the spot is round. But here, it is set into my sunroof opening, which slightly distorts the shape. Very sensitive!
This light throws very much better than the 9" Autozone spotlight I modded with the matching HID. And I think it looks rather well collimated. So, already it makes HID seem like it might have a small enough source to work well.
What do you think? What lamps should I consider for the final build? What would you do?
I'm off to try to source a tempered cover lens, and then to the shop to start fabricating a mounting system.
I have been truly impressed with the variety and performance of the searchlight builds here, so I have been watching for a quality reflector, cheap. As you all probably already know, this is not easy! Well, I finally found one that seems pretty great for less than $100, shipped. I am excited. Now, I need to decide what to do with it. I would like the community's help to select a lamp/power supply, and with various other build questions that will come up. I hope this thread will be interesting to you, as well.
Goals:
I want to be able to put an obvious spot on clouds as first priority, and maximize visibility of the beam as second priority. I want to minimize spill. I live a mile from a small city with all its outdoor lighting, so I am working with a fairly bright nighttime sky.
--
EDIT to add a constraint on power, per post 18:
Constraint:
Run from car 12V battery power for at least 5 minutes. Run from idling car power for as long as I want to. Big, clamp on inverter or 12V direct are both OK.
--
I would love to have 20k lumens or more! But the 8000 or so (?) lumens from a '100W' HID is very accessible and easy. Would fewer lumens with a smaller source like a projector short arc be better for my goals?
While I have studied many of your beautiful builds and learned what I can, this seems to be a unique project. I am leaning towards salvaging a lamp and ballast from a DLP projector. But not sure.
My budget for a lamp & ballast is hopefully <$250. I could go higher for significantly better value. Portability is not terribly important, as this will go on some kind of tripod/turret mount, so anything heavy can go on the stand. 12V is preferred over mains power, but I do have an inverter. Modified wave. 750/1500W. Vector VEC043.
From what I have learned here, I think the relatively large reflector means it can collimate a proportionally larger light source, so maximum surface brightness might not be so important for my goals. Maybe HID will be better for this, and short arc overkill that unnecessarily compromises beam power. I know it's a tradeoff, but for my goals, what do you think is the optimal lamp technology?
Here's what I know about the reflector:
From the markings, I think maybe it is an electroformed reflector from Phoenix, or similar. Can you help me ID it?
- P/N P60-08
- 16" Diameter
- Focal length is about 2". You can see this in the pics - bulb is focused.
- Rhodium plated from the RH marking.
- Very smooth image, not a spun reflector, I think.
- About 1mm thick at edge. Can measure if helpful
- Outer surface looks to me like the ED reflectors. But I think they are Nickel, and a magnet will stick to mine. Are ED reflectors magnetic?
As soon as it arrived, 2 days ago, I had to play. I started on an adapter to house a spare 35W HID to test it. I found that an old Air Conditioning R/D I had was a perfect OD to fit the reflector ID, so I cut it down on my Smithy and pressed my lamp into it:
This fits nicely, and I use 2 o-rings to retain it while allowing adjust-ability.
Note the AA battery for scale:
The lamp is from a Harbor Freight Off Road HID that was on sale a while ago at 2 for $49. I think the outer glass tube is a UV filter. Is that correct?
Here are a couple of beamshots.
From about 100' away, not quite dark out yet:
From about 4' off-axis:
Zoomed in on cloud. Small spot already, so I am very encouraged! The spot is deformed here. If I hold the light by its base, the spot is round. But here, it is set into my sunroof opening, which slightly distorts the shape. Very sensitive!
This light throws very much better than the 9" Autozone spotlight I modded with the matching HID. And I think it looks rather well collimated. So, already it makes HID seem like it might have a small enough source to work well.
What do you think? What lamps should I consider for the final build? What would you do?
I'm off to try to source a tempered cover lens, and then to the shop to start fabricating a mounting system.
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