After reading about some collectors attempting to run 700W H35 mercury vapor lamps on 1000W M47 probe start metal halide CWA ballasts by derating the series capacitor value from 24 microfarads down to 18.5 microfarads with relatively good results, I am interested in trying to find an appropriate capacitor value that is appropriate for running the rare 425W H40-17 mercury vapor lamps on 1000W M47 probe start metal halide CWA ballasts.

For reference, the 425W H40-17 mercury vapor lamps have an arc voltage drop of about 265V and an operating current of about 1.7A and is NOT interchangeable with 400W H33 mercury vapor lamps. So far, my initial guess is a capacitor value somewhere around 10 to 12 microfarads if I am not mistaken. I am interested in answering this question because I am looking for easy ways to help collectors safely run 425W H40-17 mercury vapor lamps just in case they find any in the future, but they are extremely hard to find as they appear to have only been produced during the 1960s and would like them to make sure that those lamps would run properly.

The source that I used to find the electrical characteristics of the 425W H40-17 mercury vapor lamps can be found on the link below on page 15 of the following document:

https://www.scribd.com/document/394833080/Westinghouse-Mercury-Lamp-Brochure-1961

I've noticed it is quite random. Sometimes, there is lots, and sometimes there is none. I have lamps that flash a lot and some that almost never flash. Sometimes the flashes are long and intense, other times they are brief and not too bright. I've even had some flash after running for a few hours (although less intense).

When I was in high school, the 400W halides in the gym would each flash once. They would warm up to the clear mercury phase, stay like that for a little bit, and then have a single, intense, bright pink flash that lasted about 1-2 seconds before fading. When it did fade, the lamp acquired its normal colour (sort of like a signal to the end of the warmup period).

Strangely, I have noticed, like suzukir122, that when one lamp flashes, it seems like the others do as well. Like they all flash or none flash. I also noticed it with preheat fluorescent that are all on the same switch. Sometimes they are blink-happy and sometimes they barely flash, but it seems like all the lamps on the circuit do the same at the same point in time.

Never. I filtered through lots of CFLs at the thrift shops here, spectroscope in one hand and a mini tesla coil in the other, but i've never encountered any halophosphate CFL.

The discussion about power factor and the 'capacitive' load of LEDs brings up a point. Many years ago, I recall it being speculated on here that the proliferation of CFLs and their less-than-high power factor would cause a noticeable strain on the grid. Has this been absolved in the age of LED?

LEDs make the situation better, because they're such small consumers. For extremely small power consumption levels - think phone charger, LED lamp - there are no demands for power factor, at least not in the EU.
For bigger power consumers like PCs, you'll often find the words 'Active PFC' on the box of the power supply. One basic desktop PC draws as much power as 10 LED lamps of >1000 lumen. One gaming PC as much as 50 LED lamps. So therefore, it's much easier and more affordable to focus on those devices that really make an impact.

Nicer LED bulbs have a power factor correction circuit despite not needing one per law. There are driver chips that do it automatically. Big Clive has reviewed a couple of those.

In the past, capacitive loading of the grid has never been an issue. Inductive loads have been much more important to compensate. Our inductive street lighting ballasts are supposed to come with a compensation capacitor, and professional power users with giant motors also have to have giant banks of capacitors to compensate. So if individuals would use CFLs, it would only be beneficial because fewer of those expensive capacitor banks would be needed.
If there would be an excess of capacitive load on the grid today, the operator can just say 'Hey company, i see you have a big 500kW motor. Usually we demand you compensate that for 100%, but because of local grid conditions, we would like you to only compensate it for 50%'.

the news outlets will also get priority routing to the weather service and like posted above the site will have load balancing and parallel content servers likely under heavy traffic the content servers are NOT all up to date and getting updated slowly and that causes "jerking" / stutters

@RRK

No Sony Trinitrons mentioned?

Sony Trinitrons were one of the best tallies but we never had any in our shop other then the one we owned our self so cant talk to the build quaity except OLD SONY electrical gear was top notch and newer less so (around 2000)

look at it "wrong" and you get 3 OV-50s
that is the worst lean I have ever seen but out my way the ground is all big so a pole with that lean is going the rest of the way the moment it got bumped
to me looks like the office doors to a mall over a "big box" type store

the DRL thing and "drivers" forgetting there lights is such a big issue in Canada they passed a LAW  that tail lights come on with DRLs OR full lighting turns on at night unless there is NO cluster lighting on without headlights
got a bunch of MACK AN trucks at work and had to reprogram that feature on to be "legal" for sale as the factory did not do it and I have now taken to turning on on all of our mack and Volvo tractors at work
I can back a lorry up using the mirrors and get the trailers straight but if I look through the back window I cant even get the tractor straight to the trailer to hitch up on the first try )-:

BC Canada and BC hydro had BIG campaigns for CFL change over and loads of commercial pot lights were installed during 90s reno jobs that took PL lamps and PL lamp flood lights and "yard lights" where quite common
and Hydro would give away CFL GLS lamps all the time
but Canada predominantly having globally LOW power rates it was a "hard sell" to rip out existing for CFL outside of reno projects
the electrodeless induction lamps in the early 2000's saw more success with some stores retrofitting there mercury high bays to them OR older T12 liniers for high bays

Sometimes I have nothing to say, and feel like commenting "I like this" on every picture it'd be post farming, so I say nothing. Perhaps other members feel the same and that's why you're not getting a ton of engagement.

I agree with Laurens in that 'big' social media is all about the likes, the points or whatever... not to mention all the bots that are used to inflate the numbers. If you comment on popular posts your comment will be one between hundreds or even thousands and the OP will never read it, so it's like screaming into the void.
Echo chambers. Twitter is an extremely toxic site because the algorithm "learns" (pattern recognition) from your likes and in exchange shows you posts that you WON'T like, it's an engagement bait to keep you posting and being part of endless debates, and apparently views generate money, so there's millions of rogue bots posting and making comments to get revenue, some are good enough you don't know it's a bot that's posting until you make a comment and it replies you back with nonsense.

tiktok traps you in a downwards spiral of doomscrolling that shows you worse and worse content the further you go down the rabbit hole

I've never liked that, hence why I'm not in any of those sites and prefer forums or even chill discord servers. The lighting community is apparently pretty niche, I knew when I saw photos of Photonic Induction's house and read one of the admins here actually knows him, that's nice. But, you won't find millions of people interested in lighting, I'm the weird one of the bunch, my "normie" friends have no clue what a diode is, or what CRI is, or why the light produced by an incandescent bulb isn't the same as the one produced by LEDs, but that's how the world is, they're my friends because we share other interests, like... dancing, or pizza, or manga, idk, not like I have dozens of friends either it's only 4 people lol

Just wanted to say I don't ignore posts, I just don't know what to say. This is just me in general, I do the same irl as in I don't know how to respond to certain things, so I stay quiet.