Rigel SkyLite Mini Red/White - continuously variable brightness

[UnknownVT]

I jumped at the chance to get a Rigel Systems SkyLite Mini in the Group Buy with the CPF sticker..... it arrived today.

I've long been interested in the continuously dimmable Rigel Systems SkyLite (the bigger waterproof version) also in Red/White - and my interest peaked when they introduced the Mini version losing the waterproof but gaining in smaller size and socketed LEDs for easy exchange.

Just when I was on the brink of ordering one - Leon from Rigel posted about the CPF special Group Buy - the timing couldn't have been better, adding the CPF sticker was the real icing.......

As soon as details were confirmed and the stickers ready I ordered one (at 2:02AM 2/02 )

Size -


Components -



Head and LEDs/board -


The LEDs are well recessed in the body behind the square plastic window - this is good detailed design to avoid extraenous light - to least disturb others - remeber this was orignally designed for astronomers who need to preserve their Scotopic human Night Vision. However there is some light leakage through the gaps in the non-sealed parts of the flashlight (I would imagine the full sized waterproof version probably does not have this problem.)

The light levels are controlled by a thumbwheel - which turns the light on and goes from dimmest to brightest. There is a selection switch next to the thumbwheel that changes between Red and White LEDs.

OK, how does this light compare?

vs. eternaLight ergo 3 Red/White - both on Brightest Whites


vs. eternaLight ergo 3 Red/White - both on Brightest Reds


Seems comparable.....

(brightest) Whites vs. Energizer LED HeadBeam (2x Brighter) on Whites


(brightest) Reds vs. Energizer LED HeadBeam on Red


Again pretty comparable.......

Compare the Red (brightest setting) to a coin cell single 5mm Red LED (clone Photon)

Comparable, maybe the Rigel is a bit brighter........

All this is really MISSING the POINT -
it's not how bright are these lights - although obviously they should be bright enough to be practical -
BUT how DIM will this light go to help least disturb whatever dark adaption one can attain.

Let's start with the Red - the correct color to preserve Scotopic human Night Vision -
vs. eternaLight ergo 3 Red/White both on Dimmest Red setting

Man! that is DIM! - the beam doesn't even show up in this comparison photo. But in real-life one can just make out the red light - it is very dim and only really usable close up - but that's EXACTLY what I'd want!

How about white?

vs. eternaLight ergo 3 Red/White both on Dimmest White setting -

The Rigel manages to go noticably lower in brightness - however it is not as dim as the Reds would go.....

Compared to my deliberately Dim 20 for $20 coin cell light - salvaged 5mm white LED on single 2016 (or 2032)

So the Rigel will actually get dimmer than a 5mm white LED on only 3volts (1x 2016 or 2032 coin cell)

Dimmness compared to my semi-dark adapation use of old Photon I Yellow

The old Photon I Yellow LED using an old 2032 is still quite a bit brighter than the dimmest white level of the Rigel SkyLite - so this light probably will help a lot in least dusturbing any semi-dark adaption......

I really like this light - it is a serious purpose built tool for keeping one's dark adpation (or at least minimizing any disturbance) - if the low dimmer levels are used correctly......

Being continuously variable/dimmable this will allow me to adjust the level of light to least disturb any semi-dark adaption; or even true scotopic human night vision (very rare) - using the red LEDs. In other words this kind of light will allow me to get the right amount of light suitable for the situation.

[Kryosphinx]

is it waterproof?

[chmsam]

The Starlite Mini is not water resistant.

[Sub_Umbra]

Thanks for the review.

I've been experimenting with really dim lights lately and this is one of the only games in town.

My palms are sweating.

[Kram]

These are interesting lights, and have been around longer than most of the other LED flashlights. That circuit with the two transistors and two resistors may be a constant current regulator that allows adjustment with the variable resistor. If that's the case, the battery life should be phenomenal given that you can maintain constant brightness all the way down to around 5 volts on the battery. What's interesting about this circuit vs. those used with some of the other 9V LED lights is that you truly only use the current you have dialed in. There is very little energy loss to heat through the resistor.

[UnknownVT]

Kram wrote: "That circuit with the two transistors and two resistors may be a constant current regulator that allows adjustment with the variable resistor. If that's the case, the battery life should be phenomenal given that you can maintain constant brightness all the way down to around 5 volts on the battery. What's interesting about this circuit vs. those used with some of the other 9V LED lights is that you truly only use the current you have dialed in. There is very little energy loss to heat through the resistor."

Thank you so much for that very informative input.

On Rigel System's Page on these lights they claim:

"Energy Efficient -- Up to 320+ hours at the dimmest setting, 12+ hours at the brightest, from one 9V Alkaline."

[Kram]

Craig's LED Museum review (http://ledmuseum.candlepower.us/fourth/skylite.htm) confirms my speculation almost word for word (I promise I didn't see his review before my posting). He says that the manufacturer provided the following input:

"The transistors + resistors are a current regulation circuit, as battery ages & voltage drops, keeps current through LEDs the same (more or less). Will regulate whites from 9-7 volts, reds all the way down to 5 volts or so."

[Coop]

continuously variable brightness ??? I believe they call that flickering


sorry... couldn't resist...

[UnknownVT]

MayCooper wrote: "continuously variable brightness ??? I believe they call that flickering
sorry... couldn't resist..."

Actually I believe that's how the eternaLights achieve their variable brightness
by pulsing the electricity to the LEDs.....

So you're not as - as you seem

[paulr]

I've been wondering for a while where to get 660nm red leds. Typical red led flashlights are 635nm which is more orangey. I guess I gotta order one of these...

[Sub_Umbra]

paulr-

I just noticed that right after I placed my order. I'm going to have to get one to check out...eventually. Until yesterday I was unaware of any easily available "red" lights with wavelengths in that range.

[UnknownVT]

paulr wrote: "I've been wondering for a while where to get 660nm red leds. Typical red led flashlights are 635nm which is more orangey. I guess I gotta order one of these..."

The Red LEDs in my eternaLight ergo 3 Red/White option seems visually very similar to the Rigel system Reds.

I didn't even notice the difference with my other reds like the inexpensive coin cell keychains and the Energizer LED HeadBeam.

Only when made aware of this did I see the difference with the beams side-by-side shone on a white surface.

The Red of this $1.99 LED Club keychain from WalGreens is a bit of a lighter red -
but only very marginally - in this comparison beamshot they almost look the same....

[UnknownVT]

Just something one should be aware of....

The light fell out of my pocket and dropped maybe 3 feet onto carpet - fortunately no damage -
but on that mild impact the light flew apart - the head came off and and innards popped out -
I was somewhat surprised, and would be very careful NOT to drop it onto harder surfaces......

Also I don't think there is even the smidgen of water resistance - from the sheer fact I can see gaps where light leaks (not serious) - like the cutouts for the thumbwheel and for the selection switch - so don't dunk it - and I probably wouldn't even take it out in the rain.......

However I knew this was not waterproof when I bought it (says so right on the Rigel web page), and I still think it is a great light.

I'm having endless fun trying out how low a light level I can still see to navigate round a darkened room or to read by.......
it's surprisingly low -
the lowest level of the eternaLight ergo 3 Red/White are BRIGHT in comparison......

[paulr]

I don't think it's possible to compare red wavelengths from a beamshot. You end up seeing the colors of the red dots on your monitor. Wrt the wavelength, you're looking for sort of a deep cherry red, that's too dim to see at all by normal (day) vision. Maybe you want more like 680nm. Yeah I wouldn't expect much water resistance from an astronomy light. Stargazing in rainy conditions is usually impossible .

[UnknownVT]

paulr wrote: "I don't think it's possible to compare red wavelengths from a beamshot. You're looking for sort of a cherry red, that's too dim to see at all by normal (day) vision."

Yeah, you're right - but it was easy to see (once I knew there was a difference) ....
and I was hoping it could be shown in a side-by-side beamshot....

paulr wrote: "Yeah I wouldn't expect much water resistance from an astronomy light. Stargazing in rainy conditions is usually impossible ."

True, but the original full-sized version is actually claimed to be water resistant - see the Rigel webpage

I may consider that if I were to use it for outdoors field work.

[Sub_Umbra]

...I'm having endless fun trying out how low a light level I can still see to navigate round a darkened room or to read by.......
it's surprisingly low -
...

I'm looking forward to doing just that... I've been playing with my NV Green Photon Freedom (on a 2032 instead of 2X2016s) the same way.

[UnknownVT]

Sub_Umbra wrote: "I've been playing with my NV Green Photon Freedom (on a 2032 instead of 2X2016s) the same way."

NV - is that the pure green or the turquoise (blue-green)?

Hope I'm not just telling you something you already know well.

Green and blue-green are used for compatibility with Night Vision EQUIPMENT.

Human night vision - or Scotopic vision - red is the correct color to use to preserve it - as Scotopic vision uses the Rods of the eyes only, and the Rods are INsensitive to Red light above about 650nm - so one's Scotopic (human) night vision is preserved.

Light of any other color will flood/over-saturated the very sensitive Rods. Anytime one can actually see color (other than red) it's TOO BRIGHT and will affect scotopic night vision.

Please see this Sticky reference thread - Human Night Vision Preservation

Also the USAF Flight Surgeon's Guide Chapter 8
(section on Night Vision starting about 3/4 way down the page)

My apologies if you know all this already.

[Sub_Umbra]

Sub_Umbra wrote: "I've been playing with my NV Green Photon Freedom (on a 2032 instead of 2X2016s) the same way."

NV - is that the pure green or the turquoise (blue-green)?

Hope I'm not just telling you something you already know well.

Green and blue-green are used for compatibility with Night Vision EQUIPMENT.

Human night vision - or Scotopic vision - red is the correct color to use to preserve it - as Scotopic vision uses the Rods of the eyes only, and the Rods are INsensitive to Red light above about 650nm - so one's Scotopic (human) night vision is preserved.

Light of any other color will flood/over-saturated the very sensitive Rods. Anytime one can actually see color (other than red) it's TOO BRIGHT and will affect scotopic night vision.

Please see this Sticky reference thread - Human Night Vision Preservation

Also the USAF Flight Surgeon's Guide Chapter 8
(section on Night Vision starting about 3/4 way down the page)

My apologies if you know all this already.

It's blue/green. With the stock 2016s it's supposed to be ~495nm and because of the PWM it seems to hold that color no matter how far it is dimmed. With a 2032 it looks like about ~505nm and again, it holds that color well at all levels. (I'm not really good at judging colors but I have a turquoise Pak-Lite which is supposed to be ~505nm and with the 2032 the Freedom looks the same color to me.

I've been interested in Dark Adaptation and NV compatable lights for some time. I first started reading your posts in a thread I started a while back called, "How Red is Red?" All of the regular Dark Adaptation guys showed up for that one. I learned a lot. I read all the links and most of the secondary links. After Katrina I went back and read a lot of it again. (We were using NV compatible lights for six weeks during the K event.)

Most of my lights are green (SEE avatar) or blue/green and the blue/green is what I use the most of. I'm also interested in seeing how much color shift I'll have with my green Rigel Mini with it's current regulation.

Sounds like we're both into some of the same things.

Regards,

Sub

[UnknownVT]

Sub_Umbra wrote: "It's blue/green.
Most of my lights are green (SEE avatar) or blue/green and the blue/green is what I use the most of. I'm also interested in seeing how much color shift I'll have with my green Rigel Mini with it's current regulation."

Cool! I've always been interested in blue-green (turquoise) - but they seem to be relatively uncommon - at least inexpensively .

I have a single solitary blue-green - it's really green with a slight tendency toward blue-green in the form of an LED Club $1.99 Keychain LEDs bought from WalGreens -

The Blue-green is kind of like the difference between some
Traffic lights .................................................. .......................LED Club $1.99 Keychain LEDs Blue-green vs. pure green


I found that (other than maybe blue) the Blue-green seems to dazzle me more - oh, I do see well using blue-green - but it tends to leave more after images when I switch it off. A typical practical experience is driving under blue-green traffic lights into a darkened street - there is a momentary "blindness" for me while my eyes recover. Whereas (not exactly the same condition - turning right on Red into a similarly dark street doesn't seem to give me as much problems.

A shorter wavelength LED on a single 2032 (or 2016) ie: on only 3.0V is dim, in comparison to it on 2x 2016 (ie: 6.0V) - but it is still pretty bright relatively speaking when we're talking about being able to see in the dark.

The eternaLight ergo 3 Red/White on its lowest white setting is pretty dim but not quite as dim as an average 5mm white LED on a single 2016 coin cell.
The Rigel SkyLite Mini lowest white setting is substantially lower than either of those - the comparison beamshots show that the Rigel can get quite a bit lower.

However at even that low white level on the Rigel I can easily navigate round a dark cluttered room - and easily read 10pt print with the light at a typical hand-held distance - about 6-8" away.

The lowest Red on the Rigel - however is MUCH dimmer -
it didn't even register in my comparison beam shot against the eternaLight on lowest Red.

The is NO way I could navigate around a darkened room with that level of red. I had to turn the light up quite substantially before I could do that.

To read 10pt print I literally had to have the light about 1" away from the paper - which meant I was illuminating about a word at a time - to be able to read more comfortably the light held at about 6" away - meant I had to turn up the brightness by quite a bit - perhaps not as high as for navigating around a room - but it was quite a bit more......

Please do let us know how you get on with your Rigel SkyLite....

The more I use (OK, play) with it the more I like it - but beware of its limitations in ruggedness - try not to drop it, and definitiely don't get it wet.

BTW - you might be interested in this unscientific ad-hoc experiment -

LED Colors and Vision (pics)

[Spudman]

Got my mini today. Shipping was super fast. Here are my first impressions:

Red leds go very dim. This is a big plus for astronomy use. Variable output will let you use the least amount of light necessary for the conditions.

Lanyard does not have a breakaway. This one is for wrist use only. I will switch it with another lanyard if I use it for neck carry.

Not super-robust. This has been covered but I don't think it will be a problem for the intended uses.

Has cool CPF sticker on it.

Bottom line: I like it. I didn't know this was made by the same Rigel systems that makes the quikfinder for telescopes. I've had one of those for years and I prefer it over the telrad, another 1X finder that it is often measured against. This is my new go-to light for astronomy.

Gary

[rigelsys]

I've been wondering for a while where to get 660nm red leds. Typical red led flashlights are 635nm which is more orangey. I guess I gotta order one of these...

Yes we do use 660nm deep red leds, for better scotropic (sp?) response. I have found the 635nm too orangy. Because 660nm is a deeper red, they are usually quoted as having lower candlepower (lower mcd) compared to 635nm not because they put out less watts, but because the eye's sensitivity drops quite a bit between 635 and 660nm

Leon Palmer
Rigel Systems

[rigelsys]

It's blue/green. With the stock 2016s it's supposed to be ~495nm and because of the PWM it seems to hold that color no matter how far it is dimmed. With a 2032 it looks like about ~505nm and again, it holds that color well at all levels. (I'm not really good at judging colors but I have a turquoise Pak-Lite which is supposed to be ~505nm and with the 2032 the Freedom looks the same color to me.

I've been interested in Dark Adaptation and NV compatable lights for some time. I first started reading your posts in a thread I started a while back called, "How Red is Red?" All of the regular Dark Adaptation guys showed up for that one. I learned a lot. I read all the links and most of the secondary links. After Katrina I went back and read a lot of it again. (We were using NV compatible lights for six weeks during the K event.)

Most of my lights are green (SEE avatar) or blue/green and the blue/green is what I use the most of. I'm also interested in seeing how much color shift I'll have with my green Rigel Mini with it's current regulation.

Sounds like we're both into some of the same things.

Regards,


Sub

the blue greens we use were tested and approved by the AFRL (Air Force Research Lab) Night Vision folks in Arizona for use around military night vision equipment.

Leon Palmer
Rigel Systems

[rigelsys]

And if any body's interested in the early history of LED flashlights (from our perspective anyway) download the history of Rigel Systems on the customer care tab on our website at www.rigelsys.com

If enuf interest is posed, I will regale the assembled multitude with my story of being contacted for prior art during the great LED patent wars a few years ago

Leon Palmer
Rigel Systems

[UnknownVT]

rigelsys wrote: "And if any body's interested in the early history of LED flashlights (from our perspective anyway) download the history of Rigel Systems on the customer care tab on our website at www.rigelsys.com

If enuf interest is posed, I will regale the assembled multitude with my story of being contacted for prior art during the great LED patent wars a few years ago"

Many thanks for the input.

I, for one, would be very interested in hearing your story.

I've taken some current draw readings from my sample of the Rigel SkyLite Mini Red/White -

.................... Max ........... Min
Red ............. 55.9mA ..... 1.75mA
White .......... 55.6mA ..... 1.75mA

[Sub_Umbra]

the blue greens we use were tested and approved by the AFRL (Air Force Research Lab) Night Vision folks in Arizona for use around military night vision equipment.

Leon Palmer
Rigel Systems

Wow. This is really interesting. Thanks for mentioning that. I've kinda been really itchy to see what color the green lights are.

Do you know the dominant wavelength of the blue/greens you use?

EDIT: I'd like to hear the story, too.

[Sub_Umbra]

Hey Leon,

I just read the brief history on your site. The lineage of your lights is interesting. Since I'm not an astronomer it was also cool to see just what those other products are for that I keep seeing on your site.

Sub

[PeterW]

Regardless of the white/green/red debate......
I am about to put together my own light. I will have red (>650nm) and white LEDs in it. I plan to put a 1Mohm pot in there too, so I can get microamps current. A 10kohm pot didn't make it dim enough.

I found that I could 'short' out a microswitch in my prototype with my skin resistance (>>Mohm) and the LED die would JUST begin to glow and I could STILL read text in a pitch black room (from an inch away). So my philosophy is that if in doubt, make it dimmer!! If your eyes are struggling, then they aren't going to be so affected.

I feel that most red 'Astro'lights are probably too bright, but I'd love someoone to test their night vision with some lights as a test. Keep the 'contol' eye covered during 'exposure' to the test light.

Cheers

PEterW

[UnknownVT]

PeterW wrote: "Regardless of the white/green/red debate......
I am about to put together my own light. I will have red (>650nm) and white LEDs in it. I plan to put a 1Mohm pot in there too, so I can get microamps current. A 10kohm pot didn't make it dim enough.

I found that I could 'short' out a microswitch in my prototype with my skin resistance (>>Mohm) and the LED die would JUST begin to glow and I could STILL read text in a pitch black room (from an inch away). So my philosophy is that if in doubt, make it dimmer!! If your eyes are struggling, then they aren't going to be so affected.

I feel that most red 'Astro'lights are probably too bright, but I'd love someoone to test their night vision with some lights as a test. Keep the 'contol' eye covered during 'exposure' to the test light."


Cool - please keep us informed of your experiments.

However in mitigation

Rigel Systems have been making these astronomy lights for years and have a very good reputation among astronomers -
so I personally would give them at least the benefit of the doubt that they DO know what they are doing.....

If you please look at Post #19 above the Red LEDs on dimmest setting is pretty low - I could only manage to read 10pt print with the light about 1" away from the paper - which meant it would only illuminate about one word at a time........

On its dimmest setting the current draw was only 1.75mA.

A very important point - Red above about 650nm is the correct color to preserve Scotopic human Night Vision - there is NO debate - it is simply human physiology - don't take my word for it - please read the the USAF Flight Surgeon's Guide Chapter 8 (section on Night Vision starting about 3/4 way down the page).

So establishing that - it is NOT that important how bright the Reds are - as the vision Rods of the eyes (used for Scotopic human vision) are not sensitive to Red above about 650nm -
within reason of course - as too high a light level even in Red will start to affect the Cones or Phototopic vision of the eyes and leave one temporarily blinded.

Even though it is admairable to have such a dim Red level - it is probably done to help least disturb other people - rather than the pure scotopic human night vison preservation.

[UnknownVT]

I've been EDC'ing at home the Rigel SkyLite Mini so have used it more (OK, played )

Back on more of a flashaholic tangent - I thought the light was pretty bright on white LEDs - and although in my comparisons above I noted it was "comparable" to the eternaLight ergo3 Red/White on its brightest whites and the Energizer LED HeadBeam 2x Brighter - I think the Rigel SkyLite Mini Red/White on brightest White level is a bit brighter than the eternaLight.

In comparison it seemed at about the same level as my other at home EDC the AdvancedMart 0.5w 1AA - so I thought I'd do a side-by-side comparison beamshot of the two.

Rigel SkyLite Mini Red/White on Brightest White vs. AdvancedMart 0.5w 1AA

[rigelsys]

PeterW wrote: "Regardless of the white/green/red debate......
I am about to put together my own light. I will have red (>650nm) and white LEDs in it. I plan to put a 1Mohm pot in there too, so I can get microamps current. A 10kohm pot didn't make it dim enough.

I found that I could 'short' out a microswitch in my prototype with my skin resistance (>>Mohm) and the LED die would JUST begin to glow and I could STILL read text in a pitch black room (from an inch away). So my philosophy is that if in doubt, make it dimmer!! If your eyes are struggling, then they aren't going to be so affected.

I feel that most red 'Astro'lights are probably too bright, but I'd love someoone to test their night vision with some lights as a test. Keep the 'contol' eye covered during 'exposure' to the test light."


Cool - please keep us informed of your experiments.

However in mitigation

Rigel Systems have been making these astronomy lights for years and have a very good reputation among astronomers -
so I personally would give them at least the benefit of the doubt that they DO know what they are doing.....

If you please look at Post #19 above the Red LEDs on dimmest setting is pretty low - I could only manage to read 10pt print with the light about 1" away from the paper - which meant it would only illuminate about one word at a time........

On its dimmest setting the current draw was only 1.75mA.

A very important point - Red above about 650nm is the correct color to preserve Scotopic human Night Vision - there is NO debate - it is simply human physiology - don't take my word for it - please read the the USAF Flight Surgeon's Guide Chapter 8 (section on Night Vision starting about 3/4 way down the page).

So establishing that - it is NOT that important how bright the Reds are - as the vision Rods of the eyes (used for Scotopic human vision) are not sensitive to Red above about 650nm -
within reason of course - as too high a light level even in Red will start to affect the Cones or Phototopic vision of the eyes and leave one temporarily blinded.

Even though it is admairable to have such a dim Red level - it is probably done to help least disturb other people - rather than the pure scotopic human night vison preservation.

Green vs Red has been argued quite a bit in the Astro hobby. The gist is, visual acuity in red is pretty bad, to read one has to crank the red up to the point that it decreases dark adaptation. Visual acuity in the green is so much better, that the green can be used at much lower levels than red to read by and so green doesn't affect night vision as much. Our position is, that if you don't need to read fine print, then red is the best. If you need to read fine print in the dark, then green is better.

I have done the comparison between green and white, and it's amazing how much sharper vision is in the green.

Leon Palmer
Rigel Systems