Simple Calculation of Sunset Time required

On Mar 14, 10:36*pm, "Robert Green"
wrote:
Based on how slowly the photocell and UT approaches emerged from a rather
large group of people, many with profound home automation experience, I
believe it's very likely the OP picked the solution he was most familiar
with and ran with it. *Client-directed solutions are almost never as good as
problem-based solutions. *To that end, a photocell is a better light sensor
than a calendar and lots simpler, too. *It doesn't seem good science to lock
oneself into a single approach and then ride it out to the bitter end simply
because that was where you chose to start.

Bobby G.

Funny,funny,funny !.

52000 years ago,my astronomical timekeeping ancestors were building
monuments representing knowledge of the 365 day 5 hour 49 minute
annual; cycle

http://www.mythicalireland.com/ancie...umination.html

Today,5200 years later, I watch all the participants here dither
around with the calendrical cycle of 3 years of 365 days and 1 year
of 366 days and not know the difference between the core system based
on the difference between the axial daily cycle and the aorbital
annual cycle.

The great men of antiquity could reason out the components needed to
light up the internal chamber based on fixing the annual cycle to Dec
21st and developing a monument to reflect it,Later civilisations
created the core structure which creates the 24 hour cycle out of
variations in the natural noon cycles but today,my fellow human beings
refuse to recognise the core structure which keeps cl;ocks in sync
with the daily cycle at 24 hours/360 degrees -

http://www.xs4all.nl/~adcs/Huygens/06/kort-E.html

What have you done to yourselves when the proposed value is shifted to
an unbelievable value of 23 hours 56 minutes 04 seconds insofar as
nobody bother to check Flamsteed's proof for the assertion .I am
absolutely bewidered that this technologically advanced race cannot
grasp the most basic tenets of timekeeping and structural astronomy
making this generation,which extends from the late 17th century to the
present,as the most uncivilised group ever to set foot on the
planet,the bulk of the errors can be expressed in a single and awful
graphic -

http://upload.wikimedia.org/wikipedi...3%A9reo.en.png

The fact is that none of you could build a monument like Newgrange
owing to your adherence to a calendrically based perspective and as
Newgrange is one of the oldest known building on the planet,it tell
everyone here just how far we have descended as a race.

"Marc_F_Hult" wrote in message
wrote in message
"Chris L Peterson" wrote in message
.. .
On Thu, 21 Feb 2008 05:50:32 -0500, "Robert Green"
wrote:

When I hear hoofbeats, I tend to think horses rather than zebras. I
doubt anyone "into" home automation couldn't string two wires from
their controller to an outside window or location.

(I came back to this thread because I woke up today to find a significant
number of clock-enabled devices to be reporting the wrong time because of
DST. That issue alone highlights the significant benefit of the
photocell
method, especially if the goal is simply to turn the lights on when dark
and off when there's daylight.)

About eight years ago I was asked to design and install a lighting system
for an indoor native fresh-water fish stream/aquarium at an Audubon Nature
Center. To keep the organisms happy, the lighting was needed to mimic
natural daylight.

I considered using a digital microcontroller and calculated values. I
concluded that the limiting factor on accurate lifespan with a
non-networked uC or PC was going to be the long-term accuracy of the
real-time clock and, even for networked controllers, the life of the clock
battery. I didn't want to be in the business of servicing the device or to
have it "fail". So I chose an analog route.

If reliability is an essential requirement, simpler solutions almost always
trump the more complex. In your application, as in the OP's, precise on and
off times are not required so the calculated value method doesn't provide
enough benefit to outweigh the potential problems you've described.

I had been scratching my head trying to think of lighting applications that
demanded a calculated approach and your example brought to mind one of the
few cases where a photocell won't do. If you had been asked to mimic the
lighting requirements of an animal from near the North or South Poles, the
calculated method would really be your only option.

When it's simply a matter of "lights on when it's dark, off at sunrise" I
believe as you do: a photocell will likely prove to be exceptionally more
reliable than a calculated solution. That's in addition to its ability to
provide light when it's unusually dark out because of heavy cloud cover.

--
Bobby G.

On Mar 15, 12:22*pm, "Robert Green"
wrote:
"Marc_F_Hult" wrote in message
wrote in message
"Chris L Peterson" wrote in message
.. .
On Thu, 21 Feb 2008 05:50:32 -0500, "Robert Green"
wrote:

When I hear hoofbeats, I tend to think horses rather than zebras. *I
doubt anyone "into" home automation couldn't string two wires from
their controller to an outside window or location.

(I came back to this thread because I woke up today to find a significant
number of clock-enabled devices to be reporting the wrong time because of
DST. *That issue alone highlights the significant benefit of the
photocell
method, especially if the goal is simply to turn the lights on when dark
and off when there's daylight.)

About eight years ago I was asked to design and install a lighting system
for an indoor native fresh-water fish stream/aquarium at an Audubon Nature
Center. To keep the organisms happy, the lighting was needed to mimic
natural daylight.

I considered using a digital microcontroller and calculated values. I
concluded that the limiting factor on accurate lifespan with a
non-networked uC or PC was going to be the long-term accuracy of the
real-time clock and, even for networked controllers, the life of the clock
battery. I didn't want to be in the business of servicing the device or to
have it "fail". So I chose an analog route.

If reliability is an essential requirement, simpler solutions almost always
trump the more complex. *In your application, as in the OP's, precise on and
off times are not required so the calculated value method doesn't provide
enough benefit to outweigh the potential problems you've described.


I like exposing squirming pretension.

The answer to this 'problem' is found in Huygens by reworking the
sunrise/sunset observation which centralises natural noon in order for
the Equation of Time correction to be applied or indeed,as Huygens
notes, can be used to determine central natural midnight (as opposed
to the convenience of civil midnight).

http://www.xs4all.nl/~adcs/Huygens/06/kort-E.html

The thread was specifically an astronomical solution,albeit a
geocentric sunsrise/sunset one and it shows just how limited
astronomical timekeeping knowledge is among this present
generation,almost astrological in its flavor.Go ahead and vanish,a
technologically advanced race is hardly the be all and end all
considering what it chooses to believe where matters of intutive
intelligence or 'wisdom' is required.You can get away with pretension
in a forum which displays more of the same but ultimately this thread
has exposed exactly what we have become as a species.

Astronomy is still there for people who are genuine and sincere
despite the pretension which now surrounds it from all sides,it is
there for those who have outgrown the gadgets of modern society and
wish to venture into the arena where astronomers once travelled in
timekeeping and structural astronomy based on the Earth's motions or
even further back to the great timekeeping astronomers.

Good thread this one,it shows the standard between intutive and
inventive intelligence is probably at its widest point ,the former in
a wretched state while the latter fairly advanced.













I had been scratching my head trying to think of lighting applications that
demanded a calculated approach and your example brought to mind one of the
few cases where a photocell won't do. *If you had been asked to mimic the
lighting requirements of an animal from near the North or South Poles, the
calculated method would really be your only option.

When it's simply a matter of "lights on when it's dark, off at sunrise" I
believe as you do: *a photocell will likely prove to be exceptionally more
reliable than a calculated solution. *That's in addition to its ability to
provide light when it's unusually dark out because of heavy cloud cover.

--
Bobby G.- Hide quoted text -

- Show quoted text -

On Sat, 15 Mar 2008 08:22:51 -0400, "Robert Green"
wrote:

I had been scratching my head trying to think of lighting applications that
demanded a calculated approach and your example brought to mind one of the
few cases where a photocell won't do.

This isn't a lighting application, but I use the calculated times of
civil twilight to determine when to automatically start and stop my
meteor cameras. The conditions that would cause differences in actual
light levels for a given time aren't important in my case: if it gets
dark earlier because of clouds, there's generally no advantage to
starting an allsky camera earlier!
_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

On 19 Feb, 01:23, (Perihelion) wrote:
oriel36 wrote:
[...incoherent rant excised...]
I am absolutely intrigued by the ability to ignore the greatest known
astronomical timekeeping mistake,the most fundamental correlation is
all timekeeping astronomy and men are off by a margin of roughly 3
minutes 56 seconds !.

Not quite sure what your point is,

Of course you are not sure what my point is because you have an
illness,a genuine disability to grasp basic astronomical principles
such as the unequal natural noon cycle.You get the point of the
following graphic which affirms your illness -

http://upload.wikimedia.org/wikipedi...3%A9reo.en.png

Alter any component is that graphical fiction and it disintegrates
including your belief that the noon cycles are 24 hours exactly.


but the OP doesn't care about the
sidereal day. To know what time the sun sets, you need care about only
the solar day; which does, indeed, have a mean value of 24 hours.

The calculations of sunrise/sunset are based on the Ra/Dec calendrical
offshoot which means you are using the sidereal day framework
anyway.The system which creates the average 24 hour cycle and keeps
these cycles elapsing seamlessly into the next cycle is based on a 365
day 5 hours 49 minute system while you creatures work off a 3years of
365 days and 1 year oif 366 days.

You do not know what my point is,indeed !,a bunch of cretins who
cannot turn on a porchlight using an easy to understand Equation of
Time system ebvven with the whole treatise by Huygens in front of you
-

"Here take notice, that the Sun or the Earth passeth the 12. Signes,
or makes an entire revolution in the Ecliptick in 365 days, 5 hours 49
min. or there about, and that those days, reckon'd from noon to noon,
are of different lenghts; as is known to all that are vers'd in
Astronomy. Now between the longest and the shortest of those days, a
day may be taken of such a length, as 365 such days, 5. hours &c. (the
same numbers as before) make up, or are equall to that revolution: And
this is call'd the Equal or Mean day, according to which the Watches
are to be set; and therefore the Hour or Minute shew'd by the Watches,
though they be perfectly Iust and equal, must needs differ almost
continually from those that are shew'd by the Sun, or are reckon'd
according to its Motion."

http://www.xs4all.nl/~adcs/Huygens/06/kort-E.html

I have to suffer a cretinous viewpoint ,even in its geocentric
form,where the Sun has an actual motion corresponding to 24 hours
exactly in order to justify axial rotation in 23 hours 56 minutes 04
seconds,a perspective that is so chronically bad that only a person
with an illness could not get the point.

Do you get this point?, the most stupid,the most ridiculous group of
people ever to set foot on the planet in astronomical matters can
justify axial rotation through 360 degrees in 23 hours 56 minutes 04
seconds,not even the creationists reach that level of stupidity.I
would prefer to believe that you have a severe inte;llectual
disability because the other option is unthinkable.

"oriel36" wrote:

Of course you are not sure what my point is...

Oh, that one is easy. You're a troll.

[plonk]

--

Regards,
Robert L Bass

==============================
Bass Home Electronics
4883 Fallcrest Circle
Sarasota · Florida · 34233
http://www.bassburglaralarms.com
Sales & Tech Support 941-925-8650
Customer Service 941-870-2310
Fax 941-870-3252
==============================

On Mar 17, 2:06*am, "Robert L Bass" wrote:
"oriel36" wrote:

Of course you are not sure what my point is...

Oh, that one is easy. *You're a troll.

[plonk]

--

Regards,
Robert L Bass


Being roughly 3 minutes and 56 seconds off for the value of axial
rotation through 360 degrees is no joke and the fact that there is an
organisation (IERS) in existence to maintain that terrible error makes
it even worse.This is what happens when a technologically advanced
society loses touch with the intutive intelligence needed to
appreciate timekeeping and structural astronomical principles.

How difficult is it to acknowledge that the 24 hour cycle is a product
of the natural noon cycle via a correction known as the Equation of
Time which keeps the 24 hour day fixed to natural noon and
subsequently is the reason why the 24 hours of Monday elapse into the
24 hours of Tuesday.This is basic stuff that nobody should dispute
unless they suffer from a severe intellectual disability.

The next part is even easier to grasp.When Copernicus discovered that
axial rotation is the cause of the daily cycle,they adapted the
Equation of Time creation of the 24 hour day and transfered it to
axial rotation as a 'constant' thereby allowing 4 minutes of clock
time to represent 1 degree of longitudinal/geographical seperation
making 24 hours/360 degrees.They never needed an external reference
for keeping clocks in sync with terrestrial longitudes and the daily
cycle at 24 hours/360 degrees ,it was just assumed that axial rotation
is constant as a convenient principle rather than a direct
observation.

Then Flamsteed came along and adopted a strange position of tying
axial rotation directly to the return of a star in 23 hours 56 minutes
04 seconds obligating an explanation for where the missing 3 minutes
56 seconds goes\.They came up with this monstrosity which has the
natural noon cycles at 24 hours exactly -

http://upload.wikimedia.org/wikipedi...3%A9reo.en.png

It is though an enormous joke has been played on humanity and it is no
longer funny.I could understand it if the actual principles which
create the 24 hour cycle out of the natural noon cycle were difficult
to understand but they are a joy to behold as seen in the treatise of
Huygens.The intricate transfer of the 'average' 24 hour cycle to
'constant' axial rotation is probably the only intricate point where
people can get lost but a little familiarity demonstrates the genius
of the timekeeping astronomers.

The framework Newton built on is of course the 'sidereal time' one
borrowed from Flamsteed which has an astrological core and exists
only in the imagination.I don't know how long people intend to keep
the proper principles which link clocks to terrestrial longitudes and
the daily cycle at 24 hours/360 degrees but being roughly 3 minutes
56 seconds off is perhaps the worse condition a person can find
themselves in and really unhealthy.

Easy to rip Newton's agenda asunder but that is not the point,a lot of
productive work is going unattended while that monstrosity of a
framework prevails.It is as much for the benefit of dynamicists as
anyone else but so far all they do so far is cling to the coatails of
the late 17th century numbskull who never spotted the error in
Flamsteed's reasoning.







==============================
Bass Home Electronics
4883 Fallcrest Circle
Sarasota · Florida · 34233http://www.bassburglaralarms.com
Sales & Tech Support 941-925-8650
Customer Service 941-870-2310
Fax 941-870-3252
==============================

On Sat, 15 Mar 2008 08:22:51 -0400, "Robert Green"
wrote in message
:

"Marc_F_Hult" wrote in message

About eight years ago I was asked to design and install a lighting system
for an indoor native fresh-water fish stream/aquarium at an Audubon Nature
Center. To keep the organisms happy, the lighting was needed to mimic
natural daylight.

I considered using a digital microcontroller and calculated values. I
concluded that the limiting factor on accurate lifespan with a
non-networked uC or PC was going to be the long-term accuracy of the
real-time clock and, even for networked controllers, the life of the clock
battery. I didn't want to be in the business of servicing the device or to
have it "fail". So I chose an analog route.

I hooked up a Panasonic PNA4603H light sensor
http://rocky.digikey.com/WebLib/Pana...a/PNA4603H.pdf
to a Crydom 10PCV2450 analog-input solid-state dimmer.
http://www.crydom.com//userResources...crydom_pcv.pdf
through a simple home-brew op-amp buffer to adjust signal offset, span and
gain.

The setup was a success because it required no maintenance on the part of
the Nature Center staff. It just works. And it was (I assume!) smart
enough to 'account' for the solar eclipse in 2002 and is ready for 2012.
Unless someone paints over the sensor or causes some other situation that
I would consider 'breaking' it, the arrangement will continue working
no-fuss/no-muss as long as the lamps that the device dims are replaced
when they burn out.

If reliability is an essential requirement, simpler solutions almost always
trump the more complex. In your application, as in the OP's, precise on and
off times are not required so the calculated value method doesn't provide
enough benefit to outweigh the potential problems you've described.

I had been scratching my head trying to think of lighting applications that
demanded a calculated approach and your example brought to mind one of the
few cases where a photocell won't do. If you had been asked to mimic the
lighting requirements of an animal from near the North or South Poles, the
calculated method would really be your only option.

When it's simply a matter of "lights on when it's dark, off at sunrise" I
believe as you do: a photocell will likely prove to be exceptionally more
reliable than a calculated solution. That's in addition to its ability to
provide light when it's unusually dark out because of heavy cloud cover.

Note that the analog installation I settled on was not ON-OFF, because that
would not have met the requirements. The light incident on the stream table
ramps up imperceptibly from OFF in the morning and dims to OFF in the
evening. Heavy cloud cover can cause the light to dim during daylight hours.
The latter cannot be calculated based on time alone because it depends on
weather, not time. In that sense, it is 'better' than a calculated solution,
not just an expedient substitute.

Your point about mimicking a non-local environment is well taken. Doing this
as well as a with the local analog solution I outlined would a hybrid
approach, perhaps substituting local for remote weather effects, or using a
statistical/stochastic (not deterministic) component. There are also other
approaches for remote simulation with rapidly increasing complexity. (A
remote webcam comes to mind.)

... Marc
Visit my ongoing Home Automation and Electronics Internet Porch Sale at
www.ECOntrol.org/porch_sale.htm

Marc_F_Hult
www.ECOntrol.org

"Chris L Peterson" wrote in message
...
On Fri, 14 Mar 2008 09:55:58 -0400, "Robert Green"
wrote:

Whether it's called the principle of parsimony or Occam's Razor or
methodological reductionism, the bottom line is to "make no more
assumptions
than needed to solve the problem." What number would you assign to the
probability that the OP can't reach daylight easily?

There's no way to know. Anything would be just a guess. In a home
situation, reaching daylight is probably fairly easy. In a commercial
environment, it could be very difficult (the controller could easily be
installed in a control room, and there could be many restrictions on
running wires).

There are clues in what he's told us. There's a clue in his choice to also
post his question in the computer.home.automation group. I'm sorry but I
don't see any reason to assume he's a automating a commercial establishment.
I think those are biases being injected that really have no basis in the
facts we already know. You've heard hoofbeats and interpret them as zebras.
I say that because the OP never gave us any reason to believe he was
automating a store or factory with what he's already described as an
under-powered automation controller. He has, however, given us good reason
to believe this a "home automation" project by posting in the home
automation group. When you don't have a lot of facts, you have to make
reasonable use of the ones you do have. The principle of parsimony.

But all of that is irrelevant, really, because the photocell solution is so
far superior to the calculated version in so many dimensions. You would use
a calculated method only if you wanted to emulate a different diurnal cycle
than your current location or you lived in a mineshaft. We know the first
is not true because of the OP's own words. The second not being true is
just a damn good guess because few of us know *anyone* who lives in a crypt
that can't reach daylight with a pair of wires. In other words, you're
hearing hoofbeats and thinking zebras.

Another possibility is that the OP already has a controller, and it
doesn't have any kind of input supporting a light sensor. Many
controllers can't accept that sort of input.

Name two. No home automation controller I am familiar with is so limited in
its abilities (especially those that can do trig functions, which we know
the OP's can perform), that they can't accept a simple binary input, even if
it means multiplexing an existing input. Once again, it's a zebra because
it's so unlikely to be the case that he can talk to all his household lights
(with X-10 or some other HA protocol, one must assume) but be unable to
accept any inputs. It's a near perfect example of hearing hoofbeats and
thinking zebras. The fact that the OP never returned might easily be
because after Mr. Stockton made his photocell post, the OP realized he was
on the wrong track and spent $20 on an X-10 Sundowner controller or a X-10
Hawkeye motion sensor with a built in photocell. No wires required, either!

In the end, my interpretation of parsimony is that the OP asked for a
particular solution to the problem (and got some good answers).

But not the best answers, and that's the primary issue here. He
artificially narrowed his solution universe prematurely by asking for too
specific a solution. He also asked it of a group that would be predisposed
to give an astronomically related answer. Go to a carpenter, get a hammer
solution, go to an astronomer, get an astronomical solution. That's what I
am trying, somewhat unsuccessfully, to get across. I found myself surprised
at how long it took for someone like me, with an HA predisposition, to
realize that the calculated solution had some serious drawbacks. It's easy
to get drawn into the flow of the discussion, even if it's going in the
wrong direction. (-:

Are you sure you are not injecting your own preferences here? Is it really
logical to assume that someone asking for help doing something he has
(apparently) never done before (automating lights to dawn/dusk) would have
the correct answer right out of the starting gate? These are all questions
of probabilities and I believe we can logically assume from what the OP has
told us that:

1) He's not automating a commercial establishment
2) He does not live in a windowless mineshaft, crypt or bunker
3) He was probably unaware of the superiority of the photocell solution over
the calculated one when he first posted.

It's obvious that I put more weight in the correct solution to the problem
than I do in the OP's proposed solution. I base that assumption on the OP
needing help solving the problem in the first place. If he knew all
solution paths beforehand, he probably wouldn't be asking about calculated
solutions. I also believe that he innately knew that the solution universe
could be larger than his particular calculated approach and that's why he
hedged his bets by cross-posting in to CHA.

A lot of unlikely constraints have to align in order for the calculated
solution to even come up equal to the photocell for this task, let alone
surpass it. I'm not the OP, but I am always thankful when someone points
out the best solution to a problem and not just the one I asked for. In
CHA, that happens quite frequently because the technology changes so
rapidly.

--
Bobby G.

"Paul Schlyter" wrote in message
...
Thanks for your long and illuminating post!

You're welcome. (-: If I wanted to make people groan I'd add "I hoped I
shed some light on the problem!" groan!

However:

In article ,
Robert Green wrote:

How much discussion has there been here about DST compensation and
programming issues when, as you've shown us, it really was virtually
irrelevant to the problem? Smart people often get lost in the weeds. As
a
result, it frequently takes some "quiet time" and conversational exchange
before the proper solution emerges. IMHO, that's one of the greatest
strengths of the WWW: allowing this sort of interaction and
collaboration.

This isn't the WWW, it's Usenet! Usenet predated the WWW by several
decades....

Yes, this particular exchange is occurring on Usenet, but the collaboration
of people around the world takes place in many other venues as well. That's
why I thought the more inclusive term WWW was appropriate. Perhaps the term
"internet" would have been more taxonomically accurate.

Last month I learned about adhesive-filled (a.k.a. dual wall) heat shrink
tubing from a Yahoo HomeVision automation controller group user. It's great
for anyone who needs to install solder-type sensors in outdoor environments.
I imagine that includes astronomer/engineer types with their own
observatories. Now I wouldn't use anything else for even general soldering
because it adds a extra layer of protection.

Pardon that excursion but the point is that Yahoo certainly isn't Usenet by
any stretch of the imagination yet it serves a similar, collaborative
function. For me, that group and a number of others form a part of my
"team" of specialists that I can call on when I get stuck and who advance my
knowledge of the world on a daily basis.

Now, granted, I'm not fond of writing things that Yahoo owns, I much prefer
Usenet for a variety of reasons except one: net psychos. The sad truth is
that unmoderated Usenet groups have notoriously poor psycho control
mechanisms. As a result, a lot of people who don't want to put up with
random abuse by anonymous nimrods, pimple-faced pizzwits and troglodyte
trolls chose other venues. So places like Yahoo and web-based "interaction"
mechanisms are beginning to proliferate. The biggest problem I've found
with those lately is that organizations like MS apparently pay employees to
talk up their products so the information found there is likely to be more
suspect than what survives in the fiery crucible of Usenet.

So maybe I should have said 'Internet' instead of 'WWW,' but I think you get
the drift. Collaborative efforts abound, from IM to mailing lists to web
based forums and not just on Usenet.

--
Bobby G.