Astronomic Time Clocks

[arnettda]

Looking at replacing some old time clocks for parking lot lighting. Are time clocks with the Astronomic feature worth it? Can I do the same thing with a time clock and a photocell? In my mind it should work but I have a doubt. A Astronomic time clock would adjust for day light savings like alot of programable units do but then would compensate for the different sunrise sunset times each day?
Thanks

 

[Joe.B]

I believe you program in your latitude, longitude, date, and time, and the timer accounts for all of that. So yes, theoretically it compensates for the variation in sunrise and sunset. I've never used one though so I can't say how good they are.

 

[hillbilly1]

You can do the same thing with a photocell and time clock, but usually the astronomical time clocks have battery backup. The cost difference between an astronomical and a regular digital time clock with battery back up should be the close to the same. So if you don’t need the battery backup, A T101 and a photo cell will work fine.

 

[gadfly56]

One of the forum members patented and markets exactly this. His name escapes me at the moment.

 

[Little Bill]

I believe the product is called GPS Lightlock.

 

[gadfly56]

I believe the product is called GPS Lightlock.

I think you're right, I recall the member being in FL.

 

[Strathead]

They work well, but they have to be programmed properly. I prefer them, especially when weighed against getting a photocell installed above the roof facing south.

 

[K8MHZ]

I like the photocells better. We get some nasty weather in Michigan and sometimes it gets so dark during the day the streetlights come on. That means it's also real dark in the parking lot and with Astronomic 'feature' none of the lights would come one. I, for one, don't see the benefit.

 

[drcampbell]

An astronomic light timer doesn't need to adjust for Daylight-Saving Time. DST goofs up only the clocks, not the daylight.

Once you program in the latitude, longitude, date, and real (not daylight-saved) time, it calculates each day's time of sunrise & sunset and switches the lights on & off accordingly. It doesn't know or care when DST takes effect in the spring. (if you don't mistakenly reset the timer's clock while you're resetting all the other clocks)

I installed an early version of one in my house. It worked well for a while, but its internal clock isn't very accurate and isn't synchronized to anything. It drifted several hours, (over several years) by which time I had lost the instructions and can't figure out how to reset it. One nice feature is that you could program it for (iirc) 0, 20 or 40 minutes before sunset and after sunrise.

The idea implementation would synchronize the clock to an external source. (and maybe this has been implemented while I wasn't paying attention) Either a time reference such as WWV or a local wifi, or it could use one outdoor photocell and tally up a running average. (to eliminate short-term weather effects)

 

[hillbilly1]

I know one thing, I hate Intermatics ET 90000 series. Sitting here right now programming one that somebody else screwed up, and I can see why. The instructions are horrible, and after I figured out what the instructions didn’t say, and got it all set, it will not run the program!

 

[dpcarls1598]

Someone had a clock that you just had to input the zip code and enter yes or no if you observe DST. I dont have any left after moving everything to our BAS…. Think i could remember the name though????

 

[gadfly56]

An astronomic light timer doesn't need to adjust for Daylight-Saving Time. DST goofs up only the clocks, not the daylight.

Once you program in the latitude, longitude, date, and real (not daylight-saved) time, it calculates each day's time of sunrise & sunset and switches the lights on & off accordingly. It doesn't know or care when DST takes effect in the spring. (if you don't mistakenly reset the timer's clock while you're resetting all the other clocks)

I installed an early version of one in my house. It worked well for a while, but its internal clock isn't very accurate and isn't synchronized to anything. It drifted several hours, (over several years) by which time I had lost the instructions and can't figure out how to reset it. One nice feature is that you could program it for (iirc) 0, 20 or 40 minutes before sunset and after sunrise.

The idea implementation would synchronize the clock to an external source. (and maybe this has been implemented while I wasn't paying attention) Either a time reference such as WWV or a local wifi, or it could use one outdoor photocell and tally up a running average. (to eliminate short-term weather effects)

GPS Lightlock uses the atomic clock reference from the GPS network. And you don't program the lat/lon, it does that on its own.

GPS Timers Home

gpslightlock.com

 

[spark master]

The best ones are at the Home Depot. Easy to program. The supply house ones loose time, impossible to program, etc, etc.
I have 4 at my house. 2 Home Depot, and 2 supply house. The 2 supply house ones area always 10 minutes apart, no matter how often I correct them.

 

[hillbilly1]

Yeah, this one was off by two hours and a few minutes when I got there, reset it, after going through the program, set a test output, when it didn’t trigger, went back through the program, noticed it jumped back an hour again. Chunking that piece of junk!

 

[hillbilly1]

The best ones are at the Home Depot. Easy to program. The supply house ones loose time, impossible to program, etc, etc.
I have 4 at my house. 2 Home Depot, and 2 supply house. The 2 supply house ones area always 10 minutes apart, no matter how often I correct them.

Which Home Depot ones did you use? The one that fits a single device box?

 

[SSDriver]

GPS Lightlock is the way to go. Hook up line and load, no programming. It automatically adjusts based on your GPS location and doesn't care about cloud cover. No GPS service fee either.

 

[hillbilly1]

GPS Lightlock is the way to go. Hook up line and load, no programming. It automatically adjusts based on your GPS location and doesn't care about cloud cover. No GPS service fee either.

Will it work in a parking garage though? The electrical room is on an outside corner, but four deck levels above it. Probably will not connect with the satellite signal.

 

[hillbilly1]

GPS Lightlock is the way to go. Hook up line and load, no programming. It automatically adjusts based on your GPS location and doesn't care about cloud cover. No GPS service fee either.

Looked it up, didn’t have any pricing. Too bad it only goes to 277 volts, I have an application it would work great on, but it’s 480 volts. Probably could use four per job, at around 50+ jobs. Would eliminate needing a bucket truck or boom lift rental. Bookmarked it for future reference.

 

[SSDriver]

Looked it up, didn’t have any pricing. Too bad it only goes to 277 volts, I have an application it would work great on, but it’s 480 volts. Probably could use four per job, at around 50+ jobs. Would eliminate needing a bucket truck or boom lift rental. Bookmarked it for future reference.

One of the members here makes them in Florida, I only see 277v on the site. The 120v units I've used are right about $60. Might want to reach out to him and see if he has a 480v version.

 

[gadfly56]

One of the members here makes them in Florida, I only see 277v on the site. The 120v units I've used are right about $60. Might want to reach out to him and see if he has a 480v version.

The back of the catalog says they do custom work. If hillbilly1 has that many units (200) he'd like at 480 it couldn't hurt to call.