Dark sky friendly LED/lights - advice please.

[strongmanmike]

Looking for some advice please :)

I have a small cabin (currently somewhat dilapidated) very near my observatory that will soon be renovated and fitted out to be used for temporary and/or ongoing accommodation (not for me).

A number of light pollution mitigation solutions, like shielding, extended privacy screens and removing windows facing the observatory, as well as decent curtains on other windows, are all being planned in the design of the renovation and fit-out, to prevent/minimise detrimental effects on my observatory operations while the cabin is occupied at night.

Something I was looking for some advice on however, is the best type of readily available (Bunnings/Homehardware etc) LED or normal light bulbs/fittings that could be used in the cabin fit-out (both inside and outside lighting) that would best minimise any effects on the immediate local site light pollution, from an astronomical observations perspective, but still provide adequate amenity for the occupant? The cabin will be on a small to modest solar power system, likely running 240V via an inverter, so conserving energy will be desirable.

Thanks for any feedback :thumbsup:

Mike

[Slawomir]

Sounds like a very exciting project Mike :thumbsup:

I'm thinking going with warm (towards red) colour lighting could be better as red colour is scattered less than blue, so warm light should be better in this regards than cold light.

[strongmanmike]

Yes good idea Suavi, I had thought of that, should incandescent bulbs be used, per current light sockets in the cabin. I was going to go 25W max too, as it is a small cabin and that wattage should be sufficient and conserve the batteries.

Wondering what the specifics are to look for if LED lighting were to be used..?

Mike

[h0ughy]

well there was a study that said orange lights are better for night vision, so can you get one of those led light bars that can produce many colours.... and disco disco......LOL. you can get 12v versions of those

https://www.ebay.com.au/p/733818666?iid=322373247729&chn=ps&norover=1&mkevt=1&mkrid=705-139619-5960-0&mkcid=2&itemid=322373247729&targetid=469489763498&device=c&mktype=pla&googleloc=9071751&poi=&campaignid=1793098937&mkgroupid=74958853368&rlsatarget=pla-469489763498&abcId=1139226&merchantid=116475841&gclid=EAIaIQobChMI2cvJ_8un5QIVR4aPC h3wlQDeEAQYBCABEgL0N_D_BwE



https://www.caravanpro.com.au/products/12v-electrical/12v-lighting/led-interior-lights

[strongmanmike]

Ok orange, yes, probably for any outside lighting, good idea :thumbsup: Maybe not the strip but orange bulbs :question:

I should mention in case it wasn't clear, this isn't going to be accomodation for me but for others, so I can't be too wacky or draconian.

Mike

[AndyG]

Whilst more of a long term thing, planting a row of trees between your cabin and Obs may be a thought. All the things you listed are good, but I worry about the "curtains" bit - that requires co-operation (utilisation) from "tenants"

Picking a species of tree that is dense, and tall enough (but not too tall), may be a thing to offer 99% blockout.

[Wilso]

You could also use contact film or paint the glass to stop the light rather than removing the windows.

[DarkArts]

If the cabin has low voltage DC, that makes it easy as you can wire up anything yourself, legally. (If it uses 240VAC for lighting, you're limited to certified products and need an electrician to do the wiring).

What you do depends on whether you want to protect unaided night vision or eliminate photographic effects.

For the former, try external shutters on the cabin windows.

For the latter, you could try selecting specific wavelengths of LEDs (I've seen plenty on Alibaba) and get a local electronics shop to solder them onto a backplane/project board/diffuser, and wire them up for you with a bias circuit (if you don't want to do it yourself).

Pick the LED wavelengths to fall into the blocked portions of your light pollution filters or simply outside the bands of your narrowband filters if that's all you're using.

I've been thinking about a project like this for some time - to try and produce astro-friendly LED street lighting - assuming we use light pollution filters in our back yards.

[strongmanmike]

Agreed on both accounts Andy, the idea is to create a good wide "V" of blockout/shadow around the observatory, should any inside or outside lights get turned on/left on. The "tenants" will be well aware of the requirements of the neighbouring observatory when in use but anticipating times when closing curtains doesn't happen or is in fact impractical (eg. summer), other forms of mitigation will be needed. The good thing is, full understanding of my needs and a firm willingness to mitigate is at hand from the start :thumbsup:



Yes, something like this will also be done but as you say, takes time (years?) to be effective :thumbsup:

Mike

[xelasnave]

Hi Mike
I have the answer. In Kmart you can buy small lights that take three AA batteries...very bright with new batteries..put them where you like..little magnet at the back...I have found after many years off grid portable lights are less bother.
I will try and post a photo as these are the best I have used...also a stack of garden lights outside so you can grab a couple and bring them in...I also had this approach when on the boat...
I have a few...some with run down batteries for dim light and others that you can read by.
Alex

[blindman]

LED lights are perfect (if you want to damage eyes of cabin nhabitants, of course)
There are numerous issues about LEDs, but it is your call.
Cheers

[h0ughy]

Well Mike so you have a toilet there? Is it air b&b you're thinking of or those seeking solitude and stars

[xelasnave]

Here is a photo of the $2 light.
Alex

Sorry I entirely issued the point..the part that it was not for you.
Alex

[strongmanmike]

Thanks Alex and everyone for the feedback :thumbsup:

The main thing I was keen to understand too was that while I recognise they can have a brightness issue, if LED's were considered, what type/specs/temperature etc are the most astro friendly?

Mike

[gary]

Hi Mike,

Bugger all that.

Just get one of these war-surplus clocks left over from the London blitz
along with an Air Raid (ARP) Warden helmet and shout at visitors if you
see any stray light.

[xelasnave]

That cracked me up. :rofl:Great to have such a good laugh so early sets up the rest of the day.
And get a siren run it for five minutes before opening the dome.
Alex

[Sunfish]

Lamps are rated in degrees K with warm white being 3000K . I think you can get them down to 2500K without too much trouble or even variable. So if more red is better then you could try that. Also a dimmer circuit to reduce light power with programmable control based on time might work but you would have to ensure the lamps in the fittings are correctly rated for the dimming control and don’t buy cheap systems which may interact with other electronics.

[vlazg]

Mike, i use these when i go camping, they can be either white or orange and are dimmable.


https://www.korrlighting.com.au/product-category/led-camp-lighting/led-camping-light-bars/


George

[strongmanmike]

Thanks Ray, all good to know :thumbsup:



Thanks George, apart from being good for maintaining night vision, the less bugs under orange light makes good sense too and I think we will definitely go this way for any outside lighting :thumbsup:

Mike

[Startrek]

The colour rendering index CRI is what you look for in LED lamps
A CRI between 85 to 90 is technically equivalent to natural daylight in the light spectrum
Colour temperature in Kelvin K is what our eyes perceive to be a warmer colour ( red) or a cooler colour (blue )
Incandescent lamps were phased out by the Australian government a number of years ago , although you can still buy them at some retailer ??
The answer to your dilemma, turn off your lights and wear a red led head set with switch to operate everything

[strongmanmike]

Thanks Martin

Yes the turn off and have local/head red lights only is obviously the best approach but this soon to be renovated dwelling will be occupied and not by me, so I need to have mediation in place to cover the potential night antics of non astronomers being so nearby :)

So a lower Kelvin rating will be a warmer white I take it..?

Mike

[xelasnave]

Mike show them a photo of you pulling a truck and tell the new occupant you do astronomy to keep your aggression under control and how you hate light.
Or tell them if they leave any lights on you can't help singing.
But I am such the small amount of light from one cabin won't cause any problems.
Good luck.
Alex

[Sunfish]

Yep . Lower number equals a spectral profile with more infrared I think. So 3000 warm like incandescent, 6000 cool like daylight or old school flouro office tubes.

Lamp makers publish the light performance.

This is the rating of the Lamp or bulb, not the light fitting or lamp holder although with lower cost LED they can be one unit and non replacable lamps.

But there are many frequencies involved and I don’t know whether Warmer would neccessarily be better and the answer might be , it depends , on many other variables.

Lower wattage also and non reflective colours and surfaces with directional shielding may be even more important . Paint it black or at least dark and flat.

Interesting thought that fire light may allow better night vision.

[strongmanmike]

Ummm...yeeeah, problemo is, I can no longer pull trucks, well not big ones anyway :question: :lol:

Being in the position to direct initial design and construction should produce a good result :thumbsup:



All good feedback, thanks :thumbsup: Shielding will feature strongly.

Mike

[xelasnave]

Mike as we all know folk think I am crazy but my idea (And The Hubble) of extending you tube in effect with a baffled dew tube helps with stray light..even star light.
(Have a look at how Hubble is set up and how far the baffled tube extends) really does help..I may be crazy but the folk who designed Hubble hopefully are not.
The main thing as you say is being involved...is it a rental? If so rent it yourself.
Alex

[gregbradley]

Well I am going to be different here.

I would mainly not want those outside, motion detector type lights that are very bright.

But I doubt a few lights in a nearby cabin will affect your astro photos.

I used to be hot on lights but at home if a car pulls up with lights on or if the outside light was left on etc it does not seem to make any difference to my images.

What the real problem is with light pollution is the general city glow that lights up the sky and forms a light dome. Not so much a nearby room. My home observatory has a small house next to it that was being occupied. Made no difference to images. Just not direct light shining onto the scope area.

Light leaking out between curtains and windows that lights up the ground is more an issue when doing a nightscape but that it not what you usually do there.

I wouldn't sweat it too much.

Greg.

[cwjohn]

I used arlec strip lighting from Bunnings. 5m costs around $60. I set it to red and can control the intensity from my mobile phone. Works great in the observatory.

[strongmanmike]

All quite true Greg :thumbsup: Thing is, I like to do visual observing sometimes too, so while preventing sustained washes of light across the observatory is probably all that is required to prevent issues while I'm imaging inside a protective dome, making sure DOH!!! :scared: moments dont occur while enjoying the dark sky environment outside, is the goal too :thumbsup:

Mike

[strongmanmike]

Cheers Chris...I have a flexable roll of Red tube lighting sitting in a box somewhere actually...:question:

Mike