FRITZHID
Flashlight Enthusiast
Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.
They use a GE MARC-300/35K projection lamp
They use a GE MARC-300/35K projection lamp
Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.
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Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.
GE Marc300 EZS to be specific but all Marc 300's use the same quartz envelope and gas fill. I should also mention that the Anode is positioned out front in this application - contrary to almost all my other lights where the Cathode is out front.
GE Marc300 EZS to be specific but all Marc 300's use the same quartz envelope and gas fill. I should also mention that the Anode is positioned out front in this application - contrary to almost all my other lights where the Cathode is out front.
Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.
OK, thanks to both of you for the info about that lamp.
As I recall from earlier discussions, these Xe Hg lamps have much more stringent cooling requirements, with both ends needing cooling, and are extreme pressure lamps, with overpressure even when cold, so the cooling needs to be right. Not sure I can pull off using one in my light. What do you guys think, would Xe Hg work for me?
I am going to keep looking for "any position" options I can mount & cool axially in my reflector, and run with my Oriel PS gear, which is DC.
Osram XBO lamps have similar form factor to the HBO, and they work in any position, so these are one clear option. I initially picked HBO instead of XBO due to HBO having about 4-5x more lumens for same power. Sounded good on paper!
Lesson learned: Super high pressure Hg short arc lamps, the Osram HBO variety at least, require you to know, and comply with, the orientation specification. I wish I hadn't seen conflicting specification, indicating S90 orientation in the one source. I allowed that to persuade me it would work. Now, I know it was bad info.
On the positive side, I should already have achieved a good beacon mode, aiming straight up, with the HBO lamp currently installed. When I get more time, I will get some comparison beamshots for HBO vs the 35W HID I initially used. That will be a big moment for my project. I expect the HBO will absolutely destroy the HID in both beam visibility and collimation. It should have about 30x the arc intensity of the HID.
Beacon mode (straight up, not a strobe like with LED beacon mode) was one of my main goals, so this would be a partial success. But, the drawback with HBO of not being able to maintain good brightness when aiming at targets on earth is a big disadvantage. So, maybe that is a new piece of info for the CPF community, from my adventure.
I will also try higher amperage on the HBO in horizontal orientation, to see if it will re-stabilize at rated power with more current. But I don't want to do that in the reflector, in case I pop the lamp. It is clearly risky running a lamp outside recommended parameters like that. I will need to devise a test enclosure. Also, from BVH's recent experience destroying a power transistor when a lamp failed in one of his IR illuminators, I suppose I might hurt the PS if an electrode vaporizes and coats the envelope with a dead short of metal. Since the Oriel is current regulated across a broad range of loads, maybe that less of a risk.
Perhaps I should have taken the MHI route instead (used the MSR400SA lamps I originally bought). Those are any-position lamps, but they are AC lamps. Lightsward had suggested some workable HMI lamps and ballasts by Jenbo. These lamps are interchangeable with the MSR lamps I initially planned to use, and I still have one left. New Jenbo ballasts are priced similar to what I spent on the used Oriel gear. Arc length is about 3x as long as the HBO lamp at similar power, but output is 3x higher. I think that would have been a workable solution. But I can't give up on the DC power supply and ignitor, yet. MHI Lumens are impressive, but they do not develop nearly the same arc intensity as a DC short arc lamp. And spending again for a different PS would hurt!
---
Interim Summary (or TL;DR): I now think MHI lamps would have been easier, lighter/more compact electronics, brighter, and similar cost vs the DC SA lamps. But much lower intensity.
OK, thanks to both of you for the info about that lamp.
As I recall from earlier discussions, these Xe Hg lamps have much more stringent cooling requirements, with both ends needing cooling, and are extreme pressure lamps, with overpressure even when cold, so the cooling needs to be right. Not sure I can pull off using one in my light. What do you guys think, would Xe Hg work for me?
I am going to keep looking for "any position" options I can mount & cool axially in my reflector, and run with my Oriel PS gear, which is DC.
Osram XBO lamps have similar form factor to the HBO, and they work in any position, so these are one clear option. I initially picked HBO instead of XBO due to HBO having about 4-5x more lumens for same power. Sounded good on paper!
Lesson learned: Super high pressure Hg short arc lamps, the Osram HBO variety at least, require you to know, and comply with, the orientation specification. I wish I hadn't seen conflicting specification, indicating S90 orientation in the one source. I allowed that to persuade me it would work. Now, I know it was bad info.
On the positive side, I should already have achieved a good beacon mode, aiming straight up, with the HBO lamp currently installed. When I get more time, I will get some comparison beamshots for HBO vs the 35W HID I initially used. That will be a big moment for my project. I expect the HBO will absolutely destroy the HID in both beam visibility and collimation. It should have about 30x the arc intensity of the HID.
Beacon mode (straight up, not a strobe like with LED beacon mode) was one of my main goals, so this would be a partial success. But, the drawback with HBO of not being able to maintain good brightness when aiming at targets on earth is a big disadvantage. So, maybe that is a new piece of info for the CPF community, from my adventure.
I will also try higher amperage on the HBO in horizontal orientation, to see if it will re-stabilize at rated power with more current. But I don't want to do that in the reflector, in case I pop the lamp. It is clearly risky running a lamp outside recommended parameters like that. I will need to devise a test enclosure. Also, from BVH's recent experience destroying a power transistor when a lamp failed in one of his IR illuminators, I suppose I might hurt the PS if an electrode vaporizes and coats the envelope with a dead short of metal. Since the Oriel is current regulated across a broad range of loads, maybe that less of a risk.
Perhaps I should have taken the MHI route instead (used the MSR400SA lamps I originally bought). Those are any-position lamps, but they are AC lamps. Lightsward had suggested some workable HMI lamps and ballasts by Jenbo. These lamps are interchangeable with the MSR lamps I initially planned to use, and I still have one left. New Jenbo ballasts are priced similar to what I spent on the used Oriel gear. Arc length is about 3x as long as the HBO lamp at similar power, but output is 3x higher. I think that would have been a workable solution. But I can't give up on the DC power supply and ignitor, yet. MHI Lumens are impressive, but they do not develop nearly the same arc intensity as a DC short arc lamp. And spending again for a different PS would hurt!
---
Interim Summary (or TL;DR): I now think MHI lamps would have been easier, lighter/more compact electronics, brighter, and similar cost vs the DC SA lamps. But much lower intensity.
Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.
I was uneasy about the conflicting specs for lamp orientation, so I checked the specification for my HBO200W/2 L1 lamp again to see who said what.
It is the official Osram site which lists the orientation as S90, anode underneath. One would expect Osram to have the correct spec for their lamp. Look at the tab labelled 200W/2 57V (HBO200W/2 L1 variant is rated 57V):
http://www.osram.com/osram_com/products/lamps/specialty-lamps/hbo/hbo/index.jsp
Bulb Connedtion shows S45 for the same lamp. Either this spec is correct, or I am doing something wrong:
http://www.bulbconnection.com/ViewS...ing/Osram_69198_HBO_200_W_2_L1_bulb_item.html
I was uneasy about the conflicting specs for lamp orientation, so I checked the specification for my HBO200W/2 L1 lamp again to see who said what.
It is the official Osram site which lists the orientation as S90, anode underneath. One would expect Osram to have the correct spec for their lamp. Look at the tab labelled 200W/2 57V (HBO200W/2 L1 variant is rated 57V):
http://www.osram.com/osram_com/products/lamps/specialty-lamps/hbo/hbo/index.jsp
Bulb Connedtion shows S45 for the same lamp. Either this spec is correct, or I am doing something wrong:
http://www.bulbconnection.com/ViewS...ing/Osram_69198_HBO_200_W_2_L1_bulb_item.html
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Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.
Been reading up on XBO lamps today. After hours of reading lamp specs, my effort was rewarded. Not so much by new knowledge, but by a wonderful little bit of humor added by whoever wrote this in-depth technical paper on XBO lamps:
http://web.mit.edu/jhawk/tmp/ENGR_BLTN11.pdf
Under troubleshooting, I found this (p. 45):
I also learned today (some might be a repeat if you can remember the whole thread, I cannot, and didn't go back to check):
The XBO75 and XBO100 lamps are specifically rated for horizontal operation. 150W versions (the biggest I can find, and run with the Oriel) are not. There is a 250W version, don't know yet about it's orientation, out of stock anyway.
The larger lamps may be able to run horizontal as well (has been suggested to me), but with reduced life. That above MIT paper describes why - arc deflection causing uneven electrode wear, and internal convection currents causing electrode deposits to appear on the side of the envelope, which is at the top when horizontal.
These 75W and 100W XBO lamps have much lower efficiency than the HBO lamps. 75W is only 1000 lumens. Compare to 10,000 lumens for my HBO200 and 40,000 lumens for the MSR400 lamp I originally planned to use.
Aluminum is specifically not recommended for lamp mounting. I suspect this is due to the oxide layer, which could interfere with current flow. I used aluminum. Brass or bronze are recommended.
Magnetic arc correction is recommended for horizontal operation, to counter convective forces that deflect the arc upwards, even in lamps rated for horizontal use. Magnetic fields from the cables can cause unacceptable arc deflection. I can't see the arc from the side well enough, when it's in the reflector, to check this.
Power leads are recommended to be no longer than 50 cm, to reduce high frequency, high voltage losses. Mine are about 150 cm. I can still strike the arc, on Hg at least, but Xe lamps are a lot harder to start. Could be an issue.
XBO100s list for about $420 apiece, lowest I found was 265! There aren't any on the usual auction site. Hmmm, I'm not spending that much to downgrade output to only 1000 lumens; I don't care how sharply it can focus. That is most of the cost of a proper ballast for my 40k lumen MSR lamp.
Been reading up on XBO lamps today. After hours of reading lamp specs, my effort was rewarded. Not so much by new knowledge, but by a wonderful little bit of humor added by whoever wrote this in-depth technical paper on XBO lamps:
http://web.mit.edu/jhawk/tmp/ENGR_BLTN11.pdf
Under troubleshooting, I found this (p. 45):
Continuous burning: XBO lamps that do not go out even after the power supply plug has been withdrawn are extremely rare.
:thinking:
:thinking:
I also learned today (some might be a repeat if you can remember the whole thread, I cannot, and didn't go back to check):
The XBO75 and XBO100 lamps are specifically rated for horizontal operation. 150W versions (the biggest I can find, and run with the Oriel) are not. There is a 250W version, don't know yet about it's orientation, out of stock anyway.
The larger lamps may be able to run horizontal as well (has been suggested to me), but with reduced life. That above MIT paper describes why - arc deflection causing uneven electrode wear, and internal convection currents causing electrode deposits to appear on the side of the envelope, which is at the top when horizontal.
These 75W and 100W XBO lamps have much lower efficiency than the HBO lamps. 75W is only 1000 lumens. Compare to 10,000 lumens for my HBO200 and 40,000 lumens for the MSR400 lamp I originally planned to use.
Aluminum is specifically not recommended for lamp mounting. I suspect this is due to the oxide layer, which could interfere with current flow. I used aluminum. Brass or bronze are recommended.
Magnetic arc correction is recommended for horizontal operation, to counter convective forces that deflect the arc upwards, even in lamps rated for horizontal use. Magnetic fields from the cables can cause unacceptable arc deflection. I can't see the arc from the side well enough, when it's in the reflector, to check this.
Power leads are recommended to be no longer than 50 cm, to reduce high frequency, high voltage losses. Mine are about 150 cm. I can still strike the arc, on Hg at least, but Xe lamps are a lot harder to start. Could be an issue.
XBO100s list for about $420 apiece, lowest I found was 265! There aren't any on the usual auction site. Hmmm, I'm not spending that much to downgrade output to only 1000 lumens; I don't care how sharply it can focus. That is most of the cost of a proper ballast for my 40k lumen MSR lamp.
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Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.
After several more hours of online research, I have been unable to identify a true short arc lamp with high lumen output that will run vertically and horizontally on the Oriel gear (200W DC rated, 300W absolute limit). HBO series is the only design I can find that 'should' work. I can't find any HBO application data about transitioning from horizontal to vertical to learn from, either. They always call for either one position, or the other, not both.
So, I'm stumped for alternate lamp choices, beyond the low output 75 and 100W XBO lamps. Are those really the best I can achieve in a true short arc with my gear? I have researched the Hg and Xe types as much as I think is productive.
Are there DC powered XeHg lamps around 200-250W that I am overlooking?
I would still love to try an XBO 100, at least long enough to get beamshots vs the 35W HID to see what extreme intensity vs 3x the lumens can do! But they are so darned expensive. There isn't a single one on eBay. I would need to pay retail. I'll keep an eye out for a deal, maybe even on a used one. I am torn between buying one of these new, or getting a ballast for my MSR400 SA. If I am going to dump a few hundred more dollars into this light, I suspect getting the ballast would be the smarter route.
I did read up on the GE Marc 300/35k lamps. I don't have quite enough power to run one; they need 300W, my Oriel PS overload cutout is set at 300W. It can deliver 12A, so current is not the issue, power is. It would be close, I might be able to run one at 250 or 275W. Not sure it would work. More importantly, these lamps are discontinued, and if I could find one, they only last 25 hours. 25 hours!
BVH, you have my sympathy and respect; I see now that maintaining your BEAUTIFUL locators must be pretty difficult, with such an unobtanium bulb at their heart! (and the last thing you need is one more guy trying to compete for available lamps).
The HBO lamp would be great, if only it would run horizontally. I am starting to think (hope?) that the Osram position data is probably accurate, and it should work horizontal, but that I am doing something wrong. Sylvania engineers clearly know more about this than I do! But it could still be a typo error.
Brainstorming about what that 'doing something wrong' might be, I came up with the following possible issues and tests to verify:
So, I did come up with a few things I can try with the HBO lamp. I'm not giving up on it yet. I welcome any other theories about what could be going on!
Have any of you guys ever played with super high pressure Hg short arc lamps like the HBO? Experiences?
I still owe you guys (and myself) beamshots of the HBO200 vs the 35W HID. Hopefully, I will have some evening time without rain or snow this weekend.
After several more hours of online research, I have been unable to identify a true short arc lamp with high lumen output that will run vertically and horizontally on the Oriel gear (200W DC rated, 300W absolute limit). HBO series is the only design I can find that 'should' work. I can't find any HBO application data about transitioning from horizontal to vertical to learn from, either. They always call for either one position, or the other, not both.
So, I'm stumped for alternate lamp choices, beyond the low output 75 and 100W XBO lamps. Are those really the best I can achieve in a true short arc with my gear? I have researched the Hg and Xe types as much as I think is productive.
Are there DC powered XeHg lamps around 200-250W that I am overlooking?
I would still love to try an XBO 100, at least long enough to get beamshots vs the 35W HID to see what extreme intensity vs 3x the lumens can do! But they are so darned expensive. There isn't a single one on eBay. I would need to pay retail. I'll keep an eye out for a deal, maybe even on a used one. I am torn between buying one of these new, or getting a ballast for my MSR400 SA. If I am going to dump a few hundred more dollars into this light, I suspect getting the ballast would be the smarter route.
I did read up on the GE Marc 300/35k lamps. I don't have quite enough power to run one; they need 300W, my Oriel PS overload cutout is set at 300W. It can deliver 12A, so current is not the issue, power is. It would be close, I might be able to run one at 250 or 275W. Not sure it would work. More importantly, these lamps are discontinued, and if I could find one, they only last 25 hours. 25 hours!
BVH, you have my sympathy and respect; I see now that maintaining your BEAUTIFUL locators must be pretty difficult, with such an unobtanium bulb at their heart! (and the last thing you need is one more guy trying to compete for available lamps).
The HBO lamp would be great, if only it would run horizontally. I am starting to think (hope?) that the Osram position data is probably accurate, and it should work horizontal, but that I am doing something wrong. Sylvania engineers clearly know more about this than I do! But it could still be a typo error.
Brainstorming about what that 'doing something wrong' might be, I came up with the following possible issues and tests to verify:
- Maybe there is too much convective airflow in my light to maintain temperature.
- I can block off all airflow paths and see if it helps.
- Maybe lack of magnetic arc stabilization is the problem.
- I can play with adding magnets if I can figure out a way to view the arc in operation. I thought about drilling a hole in the reflector, but that seems drastic, and I am afraid I would deform it and wreck it. I'll probably use a mirror on a stick. I would have to violate my 'only run the lamp enclosed' rule, though. Welding mask, gloves, thick jacket....
- Drawback is that any magnet tuning of arc position to improve horizontal operation will have the opposite affect when vertical, pulling the arc out of position. I might find a balance that works for both.
- Maybe the cables are causing a magnetic field that destabilizes the arc.
- I can try inverting the whole light in horizontal position, so the cables are at the top instead of the bottom. I can also try relocating the cables themselves. Heck, I guess I should just remove the lamp from the reflector, put it into something smaller and more airtight, and see how it behaves in different positions.
- Maybe I just need to crank the current, to maintain power at 250W, no matter how low the voltage sags.
- This seems like a bad idea, likely to erode the electrodes. It is my planned last resort, at this time.
- The cool temperatures in my shop may simply be preventing the lamp from running at design temperature.
- Cool shop temp is only about 10-15C below normal room temperature, and for a lamp that wants to be 1000C, that is a pretty small offset. I don't think this is the problem.
So, I did come up with a few things I can try with the HBO lamp. I'm not giving up on it yet. I welcome any other theories about what could be going on!
Have any of you guys ever played with super high pressure Hg short arc lamps like the HBO? Experiences?
I still owe you guys (and myself) beamshots of the HBO200 vs the 35W HID. Hopefully, I will have some evening time without rain or snow this weekend.
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Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.
This is from the guys at A.R.C.
It is possible if they use a smaller amount/percentage of Hg than is usual in the gas fill blend. This would not be a production lamp.
This is from the guys at A.R.C.
It is possible if they use a smaller amount/percentage of Hg than is usual in the gas fill blend. This would not be a production lamp.
Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.
Sorry, I'm not sure I am comprehending your comment. Do you mean A.R.C. could make a custom lamp to my requirements, that will have proper fill to achieve temperature at whatever power level I need?
If so, I suppose that falls in to the 'if you have to ask' category for me, in terms of acquiring one personally.
Sorry, I'm not sure I am comprehending your comment. Do you mean A.R.C. could make a custom lamp to my requirements, that will have proper fill to achieve temperature at whatever power level I need?
If so, I suppose that falls in to the 'if you have to ask' category for me, in terms of acquiring one personally.
Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.
I experimented with horizontal running today. I can see the arc well enough to tell it was not sharply deflecting upwards. It seems a little more diffuse than in vertical running, but not drastic.
I realized the 3 small rare earth magnets I had used to attach the light shroud might be affecting the arc. I replaced them with Velcro. There did seem to be a small improvement.
Inverting the light didn't make much if any difference. Neither did moving the cables.
Blocking convection airflow openings didn't make a significant difference, either.
So, on to the last resort. Crank the amps. It takes about 3.3 - 3.4 A to run vertical.
The light will stabilize in horizontal running at 4.6 amps. I ran it like this for about 10 min, after it was already fully warmed up in vertical running. Nothing melted.
This is a breakthrough! I do need to be careful not to aim upwards again without re-setting the current. That will be a minor annoyance. But, it is now apparently functional in any orientation. Note that the manufacturer's spec is only 3.6A, so I am probably using up the lamp life faster than intended. But I'm pretty happy to have found a workaround!!
:twothumbs Woohoo!
I'm off to get a sturdier tripod, and something to lug the power supply and ignitor around in.
There might, perhaps, be an interesting update later tonight.
I experimented with horizontal running today. I can see the arc well enough to tell it was not sharply deflecting upwards. It seems a little more diffuse than in vertical running, but not drastic.
I realized the 3 small rare earth magnets I had used to attach the light shroud might be affecting the arc. I replaced them with Velcro. There did seem to be a small improvement.
Inverting the light didn't make much if any difference. Neither did moving the cables.
Blocking convection airflow openings didn't make a significant difference, either.
So, on to the last resort. Crank the amps. It takes about 3.3 - 3.4 A to run vertical.
The light will stabilize in horizontal running at 4.6 amps. I ran it like this for about 10 min, after it was already fully warmed up in vertical running. Nothing melted.
This is a breakthrough! I do need to be careful not to aim upwards again without re-setting the current. That will be a minor annoyance. But, it is now apparently functional in any orientation. Note that the manufacturer's spec is only 3.6A, so I am probably using up the lamp life faster than intended. But I'm pretty happy to have found a workaround!!
:twothumbs Woohoo!
I'm off to get a sturdier tripod, and something to lug the power supply and ignitor around in.
There might, perhaps, be an interesting update later tonight.
Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.
I'm sure ARC can make just about anything but they prefer not to. They were just saying that with less percentage of Hg fill in the blend of an XeHg lamp, a lamps' performance is less susceptible degrading performance at extreme angles of operation.
Also, they have told me in the past that 10% of current/power can be added and subtracted with no affect on the lamp. So maybe you'll lose a little life with a 25% increase.
I'm sure ARC can make just about anything but they prefer not to. They were just saying that with less percentage of Hg fill in the blend of an XeHg lamp, a lamps' performance is less susceptible degrading performance at extreme angles of operation.
Also, they have told me in the past that 10% of current/power can be added and subtracted with no affect on the lamp. So maybe you'll lose a little life with a 25% increase.
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New Beamshots w/ HBO200 Lamp
Ok, thanks, I see.
Here's the new base - a construction tripod with spikes to stomp into the ground:
Beamshots:
Weather Underground says cloud ceiling is at 6000 feet tonight.
Panasonic Z50 DMC-FZ200, Night Scenery auto mode. The beam appears roughly the same as viewing by eye.
It was shooting at ISO1600, f2.8, 1/2 second:
This tree is almost exactly 50 yards, horizontal distance:
Ok, thanks, I see.
Here's the new base - a construction tripod with spikes to stomp into the ground:
Beamshots:
Weather Underground says cloud ceiling is at 6000 feet tonight.
Panasonic Z50 DMC-FZ200, Night Scenery auto mode. The beam appears roughly the same as viewing by eye.
It was shooting at ISO1600, f2.8, 1/2 second:
This tree is almost exactly 50 yards, horizontal distance:
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Re: New Beamshots w/ HBO200 Lamp
Now, for reference, the original 35W HID: This one is f2.8, 8 sec, ISO100. So, it is same exposure as the HBO shot just below it, but was taken on different night, way out in the dark country::
HBO200 again, equivalent exposure, but in bright city, tonight:
One more of the 35W HID:
This is one of my favorites so far, even though it was the old lamp - shooting the stars really makes the beam look impressive! This one is ISO1600, f2.8, 8 sec. So, 16x (4 stops) more exposure than the two above shots. Much wider view, from a lot further away, clear, dark sky. That HID really does shoot a nice, long, tight beam:
I will eventually take real A-B shots. I ran out of time tonight. And, it was freezing out.
Oh, one more thing. This Oriel power supply is regulates current, not power. While I was taking photos running the HBO horizontal at about 4.4 amps, the lamp voltage crept up while I wasn't watching it (lamp getting hotter). Maybe 5 min time. When I checked the meter, it was pegged! Well over 240 watts. Turned it back down quickly. So, it may seem stable in horizontal, but it isn't, quite. Needs monitoring.
There! Your patience has been rewarded with semi-comparable beamshots of the HID vs a true Short Arc lamp. 2700 ish, HID lumens, vs. 10,000ish HBO lumens.
Now, for reference, the original 35W HID: This one is f2.8, 8 sec, ISO100. So, it is same exposure as the HBO shot just below it, but was taken on different night, way out in the dark country::
HBO200 again, equivalent exposure, but in bright city, tonight:
One more of the 35W HID:
This is one of my favorites so far, even though it was the old lamp - shooting the stars really makes the beam look impressive! This one is ISO1600, f2.8, 8 sec. So, 16x (4 stops) more exposure than the two above shots. Much wider view, from a lot further away, clear, dark sky. That HID really does shoot a nice, long, tight beam:
I will eventually take real A-B shots. I ran out of time tonight. And, it was freezing out.
Oh, one more thing. This Oriel power supply is regulates current, not power. While I was taking photos running the HBO horizontal at about 4.4 amps, the lamp voltage crept up while I wasn't watching it (lamp getting hotter). Maybe 5 min time. When I checked the meter, it was pegged! Well over 240 watts. Turned it back down quickly. So, it may seem stable in horizontal, but it isn't, quite. Needs monitoring.
There! Your patience has been rewarded with semi-comparable beamshots of the HID vs a true Short Arc lamp. 2700 ish, HID lumens, vs. 10,000ish HBO lumens.
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Re: New Beamshots w/ HBO200 Lamp
Very nice shots! Thanks for braving the cold to get them. If I'm remembering correctly, my newer generation 69920 Oriel gives the option of regulating Current OR Watts/power. (Still have not found a reasonably priced ignitor/lamp housing) I'm currently looking to find a 69910 (200-500 Watt) for cheap so I can run 300 Watt and under lamps. The 69920 floors out at 350. I have two very nice ILC 100-500, POT adjustable PS's but they do not seem to be as "beefy" as the Oriels. They are built for the Cermax ceramic body lamps specifically and they sometime balks at igniting conventional SA lamps. Once running, they work fine.
Very nice shots! Thanks for braving the cold to get them. If I'm remembering correctly, my newer generation 69920 Oriel gives the option of regulating Current OR Watts/power. (Still have not found a reasonably priced ignitor/lamp housing) I'm currently looking to find a 69910 (200-500 Watt) for cheap so I can run 300 Watt and under lamps. The 69920 floors out at 350. I have two very nice ILC 100-500, POT adjustable PS's but they do not seem to be as "beefy" as the Oriels. They are built for the Cermax ceramic body lamps specifically and they sometime balks at igniting conventional SA lamps. Once running, they work fine.
Re: New Beamshots w/ HBO200 Lamp
Power regulation would be really handy! I just double-checked the manual for my 68805. It regulates current to a user set value, with no option to regualte power. Interestingly, it DOES have an output power limit, but the latter is not user adjustable. It's factory set at 300W. If I were more knowledgeable, or had the calibration documentation, perhaps I could reset that at 200W, crank the amps, and run on the safety power limit all the time. The remote connector on the PS has power out and current control signals, so an external controller should be feasible, too.
Or, if I had a 300W lamp, it should theoretically be impossible to overpower it. I've never seen a 300W Hg SA lamp, and only one 250W. The ceramic Xe SA lamps seem to come in 300W.
Short excerpt from the Oriel 68805 user manual here. (Credit Oriel Corporation):
I'm looking around for 300W Hg lamps now. I did find several brand new ARC 200W Hg lamps for auction at a mere $25 each. They look a lot like my HBO, but seem to have a sharp, thin protrusion on the Cathode, whereas my HBO cathode tip is shaped about like it's fatter Anode. I may buy one as a spare.
Power regulation would be really handy! I just double-checked the manual for my 68805. It regulates current to a user set value, with no option to regualte power. Interestingly, it DOES have an output power limit, but the latter is not user adjustable. It's factory set at 300W. If I were more knowledgeable, or had the calibration documentation, perhaps I could reset that at 200W, crank the amps, and run on the safety power limit all the time. The remote connector on the PS has power out and current control signals, so an external controller should be feasible, too.
Or, if I had a 300W lamp, it should theoretically be impossible to overpower it. I've never seen a 300W Hg SA lamp, and only one 250W. The ceramic Xe SA lamps seem to come in 300W.
Short excerpt from the Oriel 68805 user manual here. (Credit Oriel Corporation):
Arc lamp sources will be operated in constant current mode by the Oriel Model 68805 power supply
with the output voltage being dependent on the arc lamp's impedance. The Oriel Model 68805 power
supply will provide a constant current of up to 11 amperes with a load voltage range of 0 to 100 volts.
A power limit, which limits the product of output voltage and current to 300 watts, protects the unit
from output overloads. A constant current power supply regulates current even into a short circuit,
and themodel 68805 is safely limited to 12 amperes or 300 watts.
with the output voltage being dependent on the arc lamp's impedance. The Oriel Model 68805 power
supply will provide a constant current of up to 11 amperes with a load voltage range of 0 to 100 volts.
A power limit, which limits the product of output voltage and current to 300 watts, protects the unit
from output overloads. A constant current power supply regulates current even into a short circuit,
and themodel 68805 is safely limited to 12 amperes or 300 watts.
I'm looking around for 300W Hg lamps now. I did find several brand new ARC 200W Hg lamps for auction at a mere $25 each. They look a lot like my HBO, but seem to have a sharp, thin protrusion on the Cathode, whereas my HBO cathode tip is shaped about like it's fatter Anode. I may buy one as a spare.
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Re: New Beamshots w/ HBO200 Lamp
Thinking about the testing I did last night...some not unexpected, but interesting observations:
The effect of focus was greater with the SA lamp. Meaning that refocusing for every target distance made a big improvement in the shape of the spot. With the HID, focus was less critical.
I could not get a perfect, round, concentric pattern in any case. It had a few minor lobes - 3 skinny ones at roughly 120 degrees apart, actually. This can be best seen in the above cloud spot photo, post 131, 3rd pic.
The SA beam seems more tenuous. By that, I mean 'stringy' looking, with really bright regions, and dim regions, like the pictures of stellar Nebula. The HID beam seems to have more uniform density. Even de-focusing the SA lamp didn't smooth it out like that HID beam, it just widened the pattern. The central core of the focused beam is more intense and better defined with the SA.
I know that a smaller arc requires better optics. I suspect that I am seeing dimensional variation in my reflector which was less evident with the larger HID arc. I also suspect that this would be worse with a really compact arc, such as with the HBO100 lamp. I may be near the practical limit for arc compactness on this reflector?
While fabricating the reflector frame, I had the reflector supported on 3 points, 120 degrees apart, then tack welded the frame together. I was as gentle as I could be, but there may have been thermal stress induced by welding 1/2 inch from the reflector at these points. I might have induced a slight tri-lobed deformity in the reflector, hence the beam pattern. Just guessing...
Spill from the SA lamp makes RAZOR sharp shadows. Neat.
That $35, 5' tall, collapsible tripod was a great deal, too. It is really firmly planted in the grass, with no real risk of the lamp falling. Sale 50% off at Lowes for a few more weeks. If anybody needs a stable outdoor lamp mount, and doesn't mind having to adapt something to fit the cast aluminum tripod head, think about grabbing one.
I'm going to design and perhaps build a travel case for the power gear today.
Thinking about the testing I did last night...some not unexpected, but interesting observations:
The effect of focus was greater with the SA lamp. Meaning that refocusing for every target distance made a big improvement in the shape of the spot. With the HID, focus was less critical.
I could not get a perfect, round, concentric pattern in any case. It had a few minor lobes - 3 skinny ones at roughly 120 degrees apart, actually. This can be best seen in the above cloud spot photo, post 131, 3rd pic.
The SA beam seems more tenuous. By that, I mean 'stringy' looking, with really bright regions, and dim regions, like the pictures of stellar Nebula. The HID beam seems to have more uniform density. Even de-focusing the SA lamp didn't smooth it out like that HID beam, it just widened the pattern. The central core of the focused beam is more intense and better defined with the SA.
I know that a smaller arc requires better optics. I suspect that I am seeing dimensional variation in my reflector which was less evident with the larger HID arc. I also suspect that this would be worse with a really compact arc, such as with the HBO100 lamp. I may be near the practical limit for arc compactness on this reflector?
While fabricating the reflector frame, I had the reflector supported on 3 points, 120 degrees apart, then tack welded the frame together. I was as gentle as I could be, but there may have been thermal stress induced by welding 1/2 inch from the reflector at these points. I might have induced a slight tri-lobed deformity in the reflector, hence the beam pattern. Just guessing...
Spill from the SA lamp makes RAZOR sharp shadows. Neat.
That $35, 5' tall, collapsible tripod was a great deal, too. It is really firmly planted in the grass, with no real risk of the lamp falling. Sale 50% off at Lowes for a few more weeks. If anybody needs a stable outdoor lamp mount, and doesn't mind having to adapt something to fit the cast aluminum tripod head, think about grabbing one.
I'm going to design and perhaps build a travel case for the power gear today.
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Re: New Beamshots w/ HBO200 Lamp
OK, I got a crate built for the power gear. The PS does not have illuminated controls, so I put 2 sets of LED strip lights inside. 36 LEDs with 200 mA @12.5V. WAY too bright, I need to dial 'em down.
The PS is angled for easy viewing, and recessed for protection. Ignitor on top, power strip above that in back. Storage compartment on bottom. The lid is a trap door. Front will get 2 more doors. There is foam around the air exits on the sides to prevent recirculation to the fan inlet:
This shows how bright they are - those are warm white rope lights along the pool fence:
OK, I got a crate built for the power gear. The PS does not have illuminated controls, so I put 2 sets of LED strip lights inside. 36 LEDs with 200 mA @12.5V. WAY too bright, I need to dial 'em down.
The PS is angled for easy viewing, and recessed for protection. Ignitor on top, power strip above that in back. Storage compartment on bottom. The lid is a trap door. Front will get 2 more doors. There is foam around the air exits on the sides to prevent recirculation to the fan inlet:
This shows how bright they are - those are warm white rope lights along the pool fence:
Re: New Beamshots w/ HBO200 Lamp
Finally, here are 3 shots with bracketed exposure, to show how it affects the look of the beam. First one is normal, then +2 and +3 stops overexposed:
There, I bet that's plenty. I wish I had further targets. After I test out the 12V inverter, if that works, I will be mobile and can find a better spot.
Finally, here are 3 shots with bracketed exposure, to show how it affects the look of the beam. First one is normal, then +2 and +3 stops overexposed:
There, I bet that's plenty. I wish I had further targets. After I test out the 12V inverter, if that works, I will be mobile and can find a better spot.
Re: New Beamshots w/ HBO200 Lamp
Have you determined from how far away you can see the beam clearly enough for it to be a usable beacon as your original intention was?
Have you determined from how far away you can see the beam clearly enough for it to be a usable beacon as your original intention was?
Re: New Beamshots w/ HBO200 Lamp
In the cold air, with the fire burning and bright exterior house lights on behind that, it was pretty faint from 100 paces away. The HID was just as visible from a twice that far, but in a very dark area with higher humidity. So, it varies, a lot. I'll need more experience and testing to give a more accurate assessment.
In the cold air, with the fire burning and bright exterior house lights on behind that, it was pretty faint from 100 paces away. The HID was just as visible from a twice that far, but in a very dark area with higher humidity. So, it varies, a lot. I'll need more experience and testing to give a more accurate assessment.
