Time Setting URLs and Software

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Subject: LX200 Classic Time Setting --part 1 of 2  Top

From: Don Tabbutt <dona_ttabbutt.com>

All the LX200 needs is GMT. However it gets that is up to you. It could care less what the local time is at your location. You could live in California and set it for the local time in Timbuktu, as long as you enter the CORRECT GMT OFFSET for Timbuktu. By time I mean time and date. The location, of course, has to be set to the lat-long of where the LX200 actually is.

The LX200 sums whatever its time is set to with the GMT offset to get GMT. It then uses GMT for various initial alignment settings and to find the planets. Remember it sums it...so the offset will be positive west of GMT and negative east of it.

As I said before, set it to GMT with an offset of zero and be done with it forever.


Subject: LX200 Classic Time Setting --part 2 of 2   Top

From: Brian Grounsell <briana_tmec.co.nz>

To enter a minus sign you use the W key to back over the + sign and press the previous key (prev).

The time entry does work as per the manual ... for those without manuals they can be found at

1. One area that can be confusing is that those of us that are ahead of GMT (UT) enter a minus and those behind enter a plus, illogical but I guess there is a good reason for it?

2. Another problem I've found (and it seems to be common) is that my LX200 classic keeps very poor time. It needs re-entering every viewing day


Subject: Local/GMT Time Offset--part 1 of 2       Top

From: John Oliver <olivera_tastro.ufl.edu> Date: May 2002

RebelPPC wrote:
> messier27 Wrote:
>> We have been using an LX200 Classic for about four years now and I thought
>> I understood this.
>> Central Daylight Savings Time is "+5" hours.

> Only according to Meade's way of thinking is CDST +5. I also went through
> all this when I first got my scope. I set its offset time to what is the
> "standard" offset and nothing worked. Reading the manual plus many messages
> from Mapug members showed me that Meade doesn't use the universal or
> standard offset but uses their own made-up offset. For example.... the
> standard or universal offset for where I live (Eastern Daylight Savings)
> is -4 but Meade's made up offset for my area is +4. The standard universal
> offset for you (Central Daylight Savings) is -5 but Meade's made up offset
> is +5..... totally opposite from the universal standard.
> With this it might make you wonder of the screws and bolts on your Meade
> scope might turn counter-clockwise to tighten and clockwise to loosen.
> Anyway, for a chart of the "Meade" standard, GoTo page 11 of your manual and
> for the real universal standard GoTo greenwichmeantime.com.

While I agree that Meade's time zone sign convention can lead to confusion it is not necessarily "made up". A bit of detail along the lines of an early lecture each fall in my "Techniques of Observational Astronomy" class.

Most of the world follows the convention that time zones are an "O-C" ("observed minus computed") calculation, where the local zone is "O" and GMT/UT is "C". For locations west of Greenwich, this leads to negative zones. At midnight UT, the time in the central standard zone will be 1800 so O-C=1800-2400= -6. For daylight time (Spring forward, Fall back) O-C=1900-2400= -5. This is the opposite of the Meade convention but Meade is not alone.

a) The International Astronomical Union decided in 1982 to define all planetary longitudes to increase in the direction opposite to the planet's rotation (so if you are staring at the central longitude of Mars, longitudes in the center of your field of view will be increasing with time). This leads on Earth to longitudes increasing to the west so that longitudes in the US would be of positive signs. This allows Martians observing Earth to see increasing longitude with time. Time zones are related to longitudes and can also thus be defined as positive going west. This reversal of the long standing convention on terrestrial longitudes has been ignored by most of the astronomical community. The Astronomical Almanac's approach for tabulating observatory longitudes is to tabulate "East Longitude" which increases to the east, making the tabulated longitudes in the US negative.

b) in the computer world some operating systems (Linux for example) have entered the local time zone via a "set TZ" statement in initialization files. The established form for this statement has time zones in the US as positive and this is probably the source of the convention used by Meade. This Linux usage was carried over to Windows 3 where Microsoft forgot to include any provision for time zone but where many programers made use of a "set TZ= ..." statement in the autoexec.bat file to let their program know the desired time zone. The listing below has been extracted from the UFAQ (the Unofficial FAQ run by the Netscape Champions) at: <http://www.ufaq.org/navcom/settz.html>


  • (GMT ) set TZ=GMT000 Greenwich Mean Time; London, Edinburgh, Dublin, Casablanca, Monrovia =0
  • ( -1:00) set tz=+01+01 Azores, CapeVerde Is. =60
  • ( -2:00) set tz=+02+02 Mid-Atlantic =120
  • ( -3:00) set tz=+03+03 Buenos Aires, Rio de Janiero, E. South America =180
  • ( -3:30) set tz=Nwf+03:30 Newfoundland =210
  • ( -4:00) set tz=AST+04ADT Atlantic Time (Canada), Caracas, la Paz =240
  • ( -5:00) set tz=EST+05EDT Eastern Time (US & Canada), Bogota, Lima, Indiana (East) =300
  • ( -6:00) set tz=CST+06CDT Central Time (US & Canada), Mexico City, Tegucigalpa, Saskatchewan =360
  • ( -7:00) set tz=MST+07MDT Mountain Time (US & Canada), Arizona =420
  • ( -8:00) set tz=PST+08PDT Pacific Time (US & Canada), San Francisco, LA, Tijuana =480


Subject: Local/GMT TIme Offset --part 2 of 2      Top

From: Ralph Pass <rppassa_trppass.com>

At the risk of more flames on this topic:

  • CDST is GMT - 5
  • GMT is CDST + 5

The two statements are the same. The sign difference is due to converting from GMT to local time or from local time to GMT. If you know GMT then you subtract 5 to get to local time. This is why you see CDST as -5 on sites that are GMT based.

However, on the LX200 you enter the local time. The LX200 wants to know the GMT. In this case you are converting from local time to GMT. In this case GMT is CDST plus 5.

So the rule for the entering of the 'Hours from GMT' on the LX200 is: What number do I add to the time that I have entered into the LX200 to get the equivalent GMT time? (Sorry for those that have something other than a whole hour difference!).


Subject: Time Setting Software--PC & Mac     Top

From: Doug Stracener <ka5ysya_tix.netcom.com>

There is an excellent time sync utility which is called Dimension4 which has a file of all the atomic clocks operational on the internet, so you can pick which one you want. IT IS ALSO FREEWARE !!!! check it out for download at:


Besides being free, its a small program that does not interfere with other software at all that I have found. It is also very easy to configure.

Also many to chose from for a host of platforms at: <http://www.ntp.org/jump.html?link=ntp.isc.org/Main/ExternalTimeRelatedLinks>

For the Mac, here a small application called Vremya (Russian for time) that uses the Net to update the internal clock via NTP (Network Time Protocol). Very cool. Easy to set-up.--Ed Stewart

LX200 Time Sync V 1.0.3  (Download link)

July, 1995, Copyright © Southern Stars Software, 1994-1995.

Southern Stars Software, Joe Longo
12525 Saratoga Creek Drive
Saratoga CA 95070
E-Mail: sthnstarsa_taol.com
Phone/Fax: (408) 973 1016

This program is provided as-is and royalty free. It can be distributed freely so long as the Copyright notice in the program remains intact. Commercial distribution of the program is not permitted.

"LX200 Time Sync" is a Mac program written for LX200 and compatible telescope controllers. My goal in releasing this program is to provide Mac owners with a Mac utility for performing a handful of useful tasks with the LX200.

The following list summarizes the program capabilities:

  1. . The scopes time and date can be set (synchronized) to the Mac's system time/date.
  2. . Scope motion can be controlled by on-screen buttons.
  3. . Variations in R.A. tracking can be monitored over extended periods.
  4. . Vital data is displayed and updated continuously, including the scope's RA & Dec, Altitude & Azimuth, Longitude and Latitude.

The scope can be connected to either the modem or printer port of any Mac. A specially-wired cable is required for this connection. The LX200 manual describes the pin-outs. If all else fails, contact me at the addresses listed above for information on buying a cable.


Subject: Time Setting URLs     Top

From: Bill Arnett <billaa_tznet.com>
A good web source for accurate time to re-set the clock on the LX200:


Editor's note: Also Time/Date World Clock at: <http://www.timeanddate.com/worldclock/>


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