Rigel SkyLite Mini Red/White - continuously variable brightness

UnknownVT

Flashlight Enthusiast
Joined
Dec 27, 2002
Messages
3,671
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 :D)

Size -
SkyLMiniSz.jpg


Components -
SkyLMiniOpn.jpg
SkyLMiniOpn5.jpg

SkyLMiniOpn2.jpg


Head and LEDs/board -
SkyLMiniHd3.jpg
SkyLMiniCirc.jpg


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
SkyLM_eternaWB.jpg
SkyLM_eternaWB2U.jpg


vs. eternaLight ergo 3 Red/White - both on Brightest Reds
SkyLM_eternaRedB.jpg
SkyLM_eternaRedB2U.jpg


Seems comparable.....

(brightest) Whites vs. Energizer LED HeadBeam (2x Brighter) on Whites
SkyLM_EnerHdBmW.jpg
SkyLM_EnerHdBmW2U.jpg


(brightest) Reds vs. Energizer LED HeadBeam on Red
SkyLM_EnerHdBmRed.jpg
SkyLM_EnerHdBmRed2U.jpg


Again pretty comparable.......

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

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
SkyLM_eternaRedDim.jpg

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 -
SkyLM_eternaWDim.jpg

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)
SkyLM_20f20WDim.jpg

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
SkyLM_PhotonYWDim.jpg

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.
 
Last edited:

Sub_Umbra

Flashlight Enthusiast
Joined
Mar 6, 2004
Messages
4,748
Location
la bonne vie en Amérique
Re: Rigel SkyLite Mini Red/White

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. :D
 

Kram

Newly Enlightened
Joined
Jan 21, 2003
Messages
86
Location
Texas
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

Flashlight Enthusiast
Joined
Dec 27, 2002
Messages
3,671
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

Newly Enlightened
Joined
Jan 21, 2003
Messages
86
Location
Texas
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."
 

UnknownVT

Flashlight Enthusiast
Joined
Dec 27, 2002
Messages
3,671
MayCooper wrote: "continuously variable brightness ??? I believe they call that flickering :laughing:
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 :D :p
 

paulr

Flashaholic
Joined
Mar 29, 2003
Messages
10,832
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

Flashlight Enthusiast
Joined
Mar 6, 2004
Messages
4,748
Location
la bonne vie en Amérique
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

Flashlight Enthusiast
Joined
Dec 27, 2002
Messages
3,671
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....
SkyLM_LEDclub.jpg
 

UnknownVT

Flashlight Enthusiast
Joined
Dec 27, 2002
Messages
3,671
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

Flashaholic
Joined
Mar 29, 2003
Messages
10,832
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

Flashlight Enthusiast
Joined
Dec 27, 2002
Messages
3,671
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

Flashlight Enthusiast
Joined
Mar 6, 2004
Messages
4,748
Location
la bonne vie en Amérique
UnknownVT said:
...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

Flashlight Enthusiast
Joined
Dec 27, 2002
Messages
3,671
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

Flashlight Enthusiast
Joined
Mar 6, 2004
Messages
4,748
Location
la bonne vie en Amérique
UnknownVT said:
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
 
Last edited:

UnknownVT

Flashlight Enthusiast
Joined
Dec 27, 2002
Messages
3,671
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
icon11.gif
.

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
grnTrafficLites.jpg
LEDclub_grnGreen.jpg


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)
 
Last edited:

Spudman

Enlightened
Joined
Jun 19, 2002
Messages
382
Location
Kentucky
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
 
Last edited:
Top