[HN Gopher] I tried making artificial sunlight at home
       ___________________________________________________________________
        
       I tried making artificial sunlight at home
        
       Author : fouronnes3
       Score  : 197 points
       Date   : 2025-03-27 19:49 UTC (3 hours ago)
        
 (HTM) web link (victorpoughon.fr)
 (TXT) w3m dump (victorpoughon.fr)
        
       | NotGMan wrote:
       | Those in dark winter places can check this out for a home bright
       | light setup.
       | 
       | Some people report much better mood in dark winter days:
       | 
       | https://meaningness.com/sad-light-led-lux
       | 
       | https://meaningness.com/sad-light-lumens
       | 
       | Buy a cheap lux meter if you will be doing this since otherwise
       | you are flying blind.
        
         | astrange wrote:
         | This definitely helps for me, but it's hard to place the lights
         | without glare, since they can't be anywhere that's ever
         | directly in your vision! I'm also a little worried it's going
         | to burn the houseplant near it.
         | 
         | But it was a big change; my Silicon Valley apartment has little
         | overhead lighting, and I mostly use Hue lights which just don't
         | get very bright, so it turned out I'd accidentally built a
         | depression cave in the winter.
        
           | dylan604 wrote:
           | Personally, I hate overhead lighting and much prefer lamps or
           | wall sconce type of lighting. I did replace my overhead bulbs
           | with Hue bulbs, but I don't feel the not very bright aspect.
           | My overhead bulbs are most often at 25%. Anything over 50% is
           | just too much for me. I love my Hue lights and am trying to
           | switch over to all Hue bulbs. I still have a few regular
           | bulbs in places that just don't get a lot of use, so they get
           | ignored
        
           | J_Shelby_J wrote:
           | The 1600 lumen bulbs are worth it - if they fit your
           | fixtures.
           | 
           | Still nowhere near as bright as a window on a cloudy day
           | though.
        
       | proudestmonkey wrote:
       | This is super cool, and a great project.
       | 
       | As someone more on the software side as well, I'm inspired to
       | take on something similar.
       | 
       | But more importantly, as someone who rented a windowless room for
       | a year, I would have loved to make a smart light like this to
       | wake up to in the morning.
        
         | fouronnes3 wrote:
         | > windowless room
         | 
         | Thankfully that's illegal where I live. I'm even tempted to
         | suppress my own work here, because I don't want it to be used
         | to unlock new levels of dystopic housing.
         | 
         | Just kidding, thanks for the feedback!
        
       | ge96 wrote:
       | The interactive 3D models are nice
        
       | woah wrote:
       | Would it be possible to make it look like the light was coming in
       | at an angle from above and the side like real sunlight?
        
         | fouronnes3 wrote:
         | I've given some thought to this, I agree it's one of the
         | obvious improvements. I think with a refractive design like
         | this one it's difficult, because of the way a lens works. Most
         | other projects like this including commercial ones like CoeLux
         | use a reflective design, and I believe that's partly for this
         | reason.
        
         | hinkley wrote:
         | I've seen the video he links at the top of the article, a few
         | years back. They took an old satellite dish, silvered the
         | surface, and put a giant LED where the receiver had been so the
         | light produced was nearly parallel. Otherwise the shadows look
         | wrong.
         | 
         | In his case he sacrificed a doorway or a closet to make a
         | window with "real light"
        
           | j_bum wrote:
           | I was thinking of the same video! Link:
           | 
           | https://youtu.be/6bqBsHSwPgw?si=nV7nGdRhGvkivc1p
        
         | ericmcer wrote:
         | There was a project posted here awhile ago with something
         | similar, but the light was larger and he positioned it outside
         | a fake window with a curtain across it.
        
         | goda90 wrote:
         | Would moving the box itself help provide that effect? Maybe put
         | it on a track to move throughout the day?
        
       | stephenpontes wrote:
       | DIY Perks also attempted to make artificial sunlight at home,
       | also focusing on things like Rayleigh scattering! This was a
       | great watch:
       | 
       | https://www.youtube.com/watch?v=6bqBsHSwPgw
       | 
       | EDIT: After reading the article, I see the OP calls out DIY Perks
       | specifically - the OPs design is much more compact :)
       | 
       | > It's compact. The total size is 19cm x 19cm x 9cm. This is
       | quite compact for a 5cm focal length and an effective lighting
       | area of 18cm x 18cm. Reflective designs like the DIYPerks video
       | or commercial products like CoeLux do not achieve this form
       | factor.
        
       | softbuilder wrote:
       | This is a great build and report. Even though you don't have
       | great photo gear, you should try capturing a picture of steam in
       | the light (as DIY Perks did).
        
         | fouronnes3 wrote:
         | That's a great suggestion, thanks! I'll give it a try. It
         | already works with dust quite well though, hehe.
        
       | brcmthrowaway wrote:
       | Wait, you can order custom fabrication of lenses online?
        
         | fouronnes3 wrote:
         | Turns out you can yeah! I'm not sure the quality would be
         | anything useful for imaging applications though. But for
         | lighting / non-imaging stuff go for it!
        
           | isoprophlex wrote:
           | Well, there goes my idea of DIYing a telescope...
        
             | hatthew wrote:
             | DIY telescope discussion on HN 2 weeks ago:
             | https://news.ycombinator.com/item?id=43351988
        
           | brcmthrowaway wrote:
           | What was the cost details?
        
       | jclarkcom wrote:
       | Very cool. I'm the CEO of Innerscene (https://innerscene.com) and
       | we make a commercial artificial skylight that uses some of these
       | concepts. Actually the coelux ht25 model is almost identical to
       | what you made but using smaller lenses and more LEDs - however
       | the effect they were able to achieve still isn't that great, the
       | sun looks like a giant orb and once you get a few feet away you
       | can make out a sun at all. We spent a lot of time working on
       | perfect collimation and hiding lens edges and making sure the
       | view into the sky was seamless and artifact free. I'd say the
       | last 10% of that problem is 90% of the work. :). I think we
       | successfully cracked the nut but currently using a lot of
       | expensive parts so working on brining the cost down. If you
       | search Innerscene patent many of our approaches are spelled out.
       | We also spent a lot of time on simulation and software...
        
         | fouronnes3 wrote:
         | Are you hiring? I'm looking for a job currently. Contact info
         | is on my website :)
        
           | jclarkcom wrote:
           | Let's chat! Are you the article author?
        
             | fouronnes3 wrote:
             | Yes that's me! Happy to chat :)
        
               | the_arun wrote:
               | This is a great way to pitch for a job & half the
               | interview is already done.
        
         | rambambram wrote:
         | > If you search Innerscene patent many of our approaches are
         | spelled out.
         | 
         | Subtle, nice. Maybe you can give the man a job. ;)
        
         | sheepscreek wrote:
         | "Virtual Sun" looks really cool. How much does one cost today?
         | Say if someone wanted to buy a single piece or a few (2-3).
        
           | dan-robertson wrote:
           | Pricing is 'contact us' and going to be region-dependent. I
           | would expect to pay ca $ 10^4.5 for a panel that produces the
           | 'virtual sun' effect. Same goes for competitors (I know of
           | Coelux but maybe there are others. Not sure how quality/price
           | compares). But maybe GP will reply to you.
        
             | jclarkcom wrote:
             | Yes, it's region specific. In the USA sales generally go
             | through a partner. But it is a fraction of the weight,
             | depth, and cost of the large coelux units that run $40k
             | plus install. We also realized there is a need for
             | producing just the sky with great photo metrics and that is
             | even thinner and less expensive. A lot of interesting
             | reading can be found in our interactive spec sheet here:
             | https://www.innerscene.com/products/circadian-
             | sky/CircadianS...
        
               | kulahan wrote:
               | Make them small, add heat, attack the pet market >:)
        
               | jclarkcom wrote:
               | Haha - actually one of our customers is a doggie hotel
               | chain that has installed them in multiple locations
        
           | anthk wrote:
           | Hope Oracle doesn't sue them somehow ;)
        
         | klysm wrote:
         | How do you guys go about doing sheet metal design? It looks
         | pretty clean
        
           | jclarkcom wrote:
           | Thanks! It's powder coating that gives it a super clean look,
           | great for sales demos but I'd suggest that anything not
           | visible from the room side should be cost optimized
        
             | klysm wrote:
             | Yeah definitely, I'm more referring to the bending process,
             | material selection, fastener types, etc. It seems like
             | quite the art form
        
         | Intralexical wrote:
         | This is simultaneously really cool technology, like a hyper-
         | specialized analog light field display with health benefits,
         | and yet there's also something dystopically unsettling about
         | the sun being faked by a machine in a box.
         | 
         | Please don't have your marketing department destroy the real
         | sun. Doing so would break antitrust regulations.
        
         | cannonpr wrote:
         | I adore the lights by your company, though they seem to be
         | incredibly hard to source in general except for high end
         | architectural projects. I wish there was an easier way to order
         | them directly for DYI inclined engineers willing to pay the
         | price.
        
           | jclarkcom wrote:
           | Yeah - channels can be a pain, reach out to me directly if
           | you run into issues: Jonathan @ Innerscene
        
         | kulahan wrote:
         | It's infuriating that you only have "accept all cookies" and no
         | other options.
         | 
         | Oh but I do absolutely love this concept. I'm curious if you've
         | had lots of interest from these billionaires building bunkers,
         | if that story is even true!
        
         | nmarinov wrote:
         | Hi, I couldn't figure it out on your site but on the picture
         | where you have your hand under the virtual sun[1], do you feel
         | the warmth of the "sun" on your hand as you'd feel it with the
         | real sun?
         | 
         | [1] -
         | https://www.innerscene.com/_next/image?url=%2F_next%2Fstatic...
        
       | huzeifad wrote:
       | Great project! Instead of routing ground traces, I would
       | recommend to use a ground plane on the bottom layer of the PCB
        
       | Const-me wrote:
       | > the main thermal issue when scaling up would be the cooling of
       | the power supply itself, not of the lamp
       | 
       | If I would be scaling up that device, I would consider an ATX
       | power supply. These are relatively large and typically include an
       | active cooler inside, but they can easily supply hundreds of
       | watts at 12V, often have an on/off switch on the back, are
       | relatively inexpensive (at least unless you need much more than
       | 500W of power), and are available everywhere. Usually, you just
       | need to connect the PS_ON wire with the ground to make them turn
       | on once powered.
        
         | brcmthrowaway wrote:
         | Could you wire them in parallel for more watts
        
           | Const-me wrote:
           | Personally, I would avoid it if possible. Even if they are of
           | the same model, small discrepancies may cause their +12V to
           | be slightly different. At the very least, will cause very
           | non-uniform load distribution.
           | 
           | Luckily, seems the OP only needs one. The current light only
           | uses 36W @ 12V, even if they make the new light 10x more
           | powerful, a single 400W PSU should do the job nicely.
        
             | foobarian wrote:
             | It's not like the fixtures consist of a single LED either.
             | Should be trivial to parallelize.
        
             | brcmthrowaway wrote:
             | What about wiring them in parallel with a voltage regular
             | after.
        
               | mystified5016 wrote:
               | Then you waste a ton of energy on the conversion and
               | still have the same problem. You won't ever get two
               | regulators at _exactly_ the same voltage. One will
               | _always_ take most of the load.
               | 
               | You get around this with load balancing resistors, but
               | that comes with its own set of problems.
               | 
               | The way you get around _that_ is to chop up your load
               | into multiple independent power domains. That way each
               | segment is powered exclusively by one supply.
               | 
               | If you can't do that, you will _always_ be better off
               | with a single larger supply.
        
           | wtallis wrote:
           | At that point you might be better off getting a power
           | distributor from an old server that was already designed to
           | operate off redundant 12V power supplies. But you wouldn't
           | want the server PSUs themselves due to the tiny loud fans.
        
       | petsfed wrote:
       | Is there a reason why you went with traces rather than pours? I
       | count 7 signals per board, and they're all meant to be low
       | impedance. You could even expose copper on the back of the board
       | to be used as ad hoc heat sinks without spending any extra money.
       | The weird little triangle loops on the back really stand out to
       | me, even though you probably don't need to worry about the
       | impacts of a loop in your circuit.
        
         | fouronnes3 wrote:
         | Thanks for the feedback. Everything I know about PCB design is
         | self-taught. I'm a total beginner, so I'm sure there's a lot to
         | improve!
         | 
         | There's only 2 routes per board, VCC and GND. I initially
         | planned for SMD header pins that I didn't end up using, because
         | soldering wire on bare pads was good enough. I also planned for
         | 8 connection pads per PCB, but only used 2 to 4 in the final
         | assembly. So yeah, lots of room for improvements in the PCB
         | design! Definitely would need to spend some time on it for a
         | higher power version 2.
        
       | null_name wrote:
       | Really neat, thank you for posting. I took a different angle when
       | trying to figure this out - my goals were high spectral
       | similarity to the sun, high brightness, adjustable warmth, and
       | low cost. The existing lower-cost solutions people have posted
       | about end up with high brightness, but the lights are evil.
       | 
       | I ended up with a photography light that's /alright/. It's not
       | nearly as bright as I want, and I can't automate changing the
       | warmth. When I next take a crack at this, I'll look deeper into
       | some of what you've posted about here.
        
         | fouronnes3 wrote:
         | Thanks! Feel free to reach out, I love to chat about this
         | stuff. Contact info is on my website.
        
         | jddj wrote:
         | What were you missing for the colour temp control?
        
       | sberens wrote:
       | Really cool! I'm working on a lamp that gives you daylight levels
       | of light indoors (albeit no raleigh scattering and columnated
       | light). On the bright side (pun intended), it's 50,000 lumens
       | instead of ~4500. https://getbrighter.com/
        
         | polishdude20 wrote:
         | Oh this is cool! Reminds me of led grow lights. You can get a
         | panel with hundreds of LEDs on it for growing plants for like
         | $200
        
         | izuchukwu wrote:
         | Had the chance to see one of these in person - did not believe
         | you could achieve "daylight indoors" before I did.
        
       | polygot wrote:
       | Very cool! I'd be curious to see an HDR version of it using
       | bracketed exposures--it might give a better sense of how it
       | actually looks in person. It seems really bright in the photos,
       | so the shortest exposure would probably need to be very low to
       | capture a good dynamic range for the HDR.
        
       | alejohausner wrote:
       | For me, the problem with this setup (and with most high
       | efficiency LED lights) is the lack of red wavelenghts. Real
       | sunlight has a substantial amount of energy in the very red end
       | of the visible spectrum (700 nm) and also of course quite a bit
       | in the infrared. These lamps have two spectral peaks: a narrow
       | peak in the blue range, around 450 nm, a broader peak in the
       | green, centered around 580 nm. That greenish peak falls off
       | sharply, and has almost no energy in the red end.
       | 
       | The color sensitive cones in our eye have three peaks of
       | sensitivity, the S cones in the blue range, the M cones in the
       | green, and the L cones in yellow. The L cones are what your brain
       | uses to see red colors, but they are actually pretty insensitive
       | to deep reds like 700 nm. That's why you THINK that LED lamps
       | produce red, because they stimulate your L cones, but they do so
       | without actually emitting much red energy at all!
       | 
       | Our bodies are sensitive to deep red light. The cytochrome in our
       | mitochondria respond to it. There's an experiment where shining
       | red lights on the skin improved sugar metabolism. That makes
       | sense, because we naked apes evolved under red-rich sunlight.
       | 
       | So these lamps may look like sunlight, but they're missing some
       | crucial wavelengths.
        
         | fouronnes3 wrote:
         | That's a good point, but not much I can do about that. Such a
         | DIY project is limited to off the shelf LED suppliers. It would
         | be cool to do such a lamp with both the high CRI and some
         | infrared, also for heating (infrared lamps are a thing after
         | all).
        
         | crazygringo wrote:
         | > _So these lamps may look like sunlight, but they're missing
         | some crucial wavelengths._
         | 
         | Which means they're also not going to give me a tan... bug, or
         | feature?
        
           | lll-o-lll wrote:
           | Tan is the other end of the spectrum (UV)
        
             | crazygringo wrote:
             | They said crucial wavelength _s_ , plural. I took that to
             | its natural conclusion. ;)
        
           | TeMPOraL wrote:
           | It also won't be a great disinfectant, both in literal and
           | figurative senses of the phrase.
        
         | drewolbrich wrote:
         | My issue with this setup is that it doesn't emit as many
         | neutrinos as the Sun.
        
           | ketralnis wrote:
           | Have you considered taking neutrino supplements?
           | 
           | The nice thing about them is that they're flavour changing
        
           | aljgz wrote:
           | Good that you get your sunborn nutrino fix even in cloudy
           | days (and much of it even at night)
        
         | ankitml wrote:
         | Yep, that was my first assessment. Cant call it sun without
         | NIR.
        
           | fouronnes3 wrote:
           | Can't call it sun without gravitational confinement nuclear
           | fusion either.
        
         | firju55 wrote:
         | If the metric you're looking for is most accurate spectrum
         | including deep red, near and far infrared (heat), then a good
         | old incandescent filament light is the most efficient device.
         | Not LEDs.
        
       | ludicrousdispla wrote:
       | Nice, Mojang should set one of these up at their headquarters.
        
       | vincekerrazzi wrote:
       | Honestly this area is so interesting to me because of how
       | incredibly strongly light (or lack thereof) affects in the
       | winter. It also seems to affect me more strongly than most in
       | regards to sleeping patterns. Too much blue light in the evening
       | and bam, brain refuses to sleep until 2am or later.
       | 
       | So for me the biggest factor missing in these kinds of projects
       | is a dynamic color temperature. While we get that from products
       | similar to apples adaptive lighting, that's missing in products
       | like this. It seems we can only really have one or the other.
       | 
       | My dream is something like this build but with full adaptive and
       | programmable color temperatures based on time and seasons.
       | 
       | Honestly I want to build something like this but my area of
       | expertise is too far into the software domain, and not very far
       | into the hardware or electrical engineering domain.
        
         | fouronnes3 wrote:
         | This is the reason I decided to use 4000K instead of the more
         | physically accurate 5400K. I picked a less middle of the day
         | color temperature and closer to evening time, basically.
         | 
         | I spent a lot of time looking at LED suppliers and there's
         | quite a range of options in terms of color temperature. Some
         | manufacturers even have 2 color temps on the same LED package,
         | meaning you can sort of do what you describe by mixing two
         | light sources at a distance less than a millimeter.
         | 
         | > Honestly I want to build something like this but my area of
         | expertise is too far into the software domain, and not very far
         | into the hardware or electrical engineering domain.
         | 
         | That was me last year before starting this project! You'd be
         | surprised what you can achieve with time and effort!
        
       | johnea wrote:
       | Yea, I can relate. I tried making an artificial Big Bang at home.
       | 
       | But my neighbors kept complaining 8-/
       | 
       | Haters!
       | 
       | Probably the same people that keep flagging comments on the
       | articles I'm interested in...
        
       | hubraumhugo wrote:
       | That's the most HN headline I've read in a while
        
       | 14 wrote:
       | Very cool. I do think the DIY perks version just pops a little
       | nicer but it could also be the photography of the project. But
       | the firm factor if your project is much nicer as well. I think
       | both projects would be better suited for different needs so again
       | very cool. If you had lots of space the diy perks would be the
       | way to go. If you only have a thin wall or ceiling then yours
       | would be best. All in all thanks for posting this.
        
         | fouronnes3 wrote:
         | It's partly the photography but definitely the reality as well.
         | Mine is only 0.03m2, the DIYPerks parabolic reflector is 1.13m2
         | :)
         | 
         | One of my goals was to explore the feasibility and scalability
         | of a refraction based design.
        
       | trallnag wrote:
       | I've just mounted tons of full spectrum LEDs in my home office.
       | Off the shelf, fairly cheap, easy to replace. My plants like it,
       | except for the Goeppertias that keep dying on me
        
       | davidw wrote:
       | Ah... the intensity, not actual nuclear fusion. Well, still a
       | nice project!
        
         | simonebrunozzi wrote:
         | At first I thought the same! Well, we're safer now.
        
       | Molitor5901 wrote:
       | Sunrise alarm clock lamps are a really great way to wake up,
       | especially if you have a larger room.
        
       | spl757 wrote:
       | I'd be interested in seeing the optical spectrograph of the LEDs.
       | If you want to simulate sunlight you want a full-spectrum LED
       | like a Samsung LM301 series LED which are popular in grow lights.
       | Not all LEDs are created equal, and even the LEDs in many "grow"
       | lights only show two sharp peaks at red and blue wavelengths. A
       | full-spectrum LED will output colors across the visible spectrum
       | of light. You can't tell by looking at them, so you can either
       | buy ones from which you trust the manufacturer or do what I did
       | and build a cheap optical spectroscope using a raspberry pi with
       | a small camera attached, a spectroscope lens, and some python
       | code. I'm sure there are guides you can find with a quick web
       | search if interested in making one.
        
         | atoav wrote:
         | This is covered by the CRI95+ value, note that the LM301 you
         | mentioned only has a color rendering index of 70. Maybe it has
         | predominant wavelengths that are relevant for plant growth, I
         | don't know, but a CRI of 70 isn't impressive at all.
         | 
         | For an accurate rendering of the suns spectrum you basically
         | would like to simulate the spectrum of a blackbody radiator
         | with a surface temperature of 5500degC minus the absorption
         | bands of water vapors, atmospheric gases thst are typically
         | inbetween the sun and us. Also note that the suns spectrum
         | extends both above and below the visible range, which gives you
         | the feeling of warmth (infrared) and tan/sunburn (ultraviolet).
         | 
         | In reality most commercially available LEDs still have a
         | extremely spikey spectrum compared to sunlight -- this can be
         | somewhat fixed by mixing different LED types and adding
         | filters. But this is only done in extremely expensive movie
         | lights like Arri skypanels.
        
       | nayuki wrote:
       | Nice project. A few miscellaneous notes:
       | 
       | > Kinda cool that you can see a lens flare effect in the shape of
       | the lens grid array.
       | 
       | A lens flare is just a copy of the scene you are photographing,
       | but strongly attenuated in brightness, and possibly rotated
       | 180deg.
       | 
       | > 100,000 lux
       | 
       | Your notation is correct, and there are other ways to write it.
       | The SI unit "lux" has the symbol "lx". Your quantity can also be
       | written as 100 kilolux or 100 klx.
        
       | reaperman wrote:
       | I saw "artificial sunlight" and thought "oh wow I'd love to see
       | the spectrogram of the lighting solution this person came up
       | with". I was disappointed to merely see "CRI 95+".
       | 
       | https://www.youtube.com/watch?v=lH_owRxupC0
       | 
       | This is great video on the shortcomings of "CRI" - it explains in
       | detail CRI, CRI extended, TLCI, TM-30, and SSI.
       | 
       | Brightness and color temperature are only two small parts of
       | lighting - more people should start investigating the utility of
       | taking their own spectroscopy measurements to figure out what
       | lighting works best for them personally. My friends have very,
       | very diverse opinions on what spectral distributions they
       | like/hate, but they lack the language and experience to identify
       | or communicate their preferences except for "Ooh I like/hate this
       | bulb".
       | 
       | I mostly use LED bulbs to keep heat generation down (I pay for
       | the heat twice in Houston: once to generate it and again for the
       | A/C to negate it). But I always mix in a bit of incandescents /
       | halogens (2400-3000K) which provide full-spectrum blackbody
       | radiation to see ALL the wonderful colors in my world.
        
         | kulahan wrote:
         | I think most people at least know the difference between warm
         | and cool light, which helps a lot, but otherwise I agree. As
         | I'm reading this, I'm realizing I have no vocabulary for this
         | topic. That's... kinda strange to experience!
        
         | fouronnes3 wrote:
         | Do you have any insight on how to take spectroscopy
         | measurements at home on a <1kEUR budget? And how to select an
         | LED manufacturing supplier when CRI is often the only thing
         | available on the datasheet?
        
           | reaperman wrote:
           | Starting points for first question: Look into i1Pro (later
           | models of the first generation), which can be had for
           | $200-400. Combine with some free or $99 Windows/Mac/Android
           | software [0] [1].
           | 
           | Second question: It is still too hard even to find CRI for
           | most offerings. It's pretty much a "buy, test, return the
           | ones you don't like" situation. If independent reviewers
           | start publishing spectrograms and making YouTube/etc videos,
           | perhaps the industry will move forward some day.
           | 
           | 0: https://www.argyllcms.com/doc/instruments.html#i1p2
           | 
           | 1: https://rmimaging.com/spectrashop_brochure.pdf
        
       | Vox_Leone wrote:
       | This project is fantastic, but you also deserve congrats for the
       | 'Lens Maker'[0].
       | 
       | "If we have a compound optical system made of a series of lenses,
       | mirrors, etc., we can treat each optical element as the layer of
       | a neural network." Kudos.
       | 
       | [0]https://victorpoughon.github.io/torchlensmaker/
        
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       (page generated 2025-03-27 23:00 UTC)