ASTRON SETTINGS PAGE

ASTRON SIGHT LOG AND PLOTTER

ASTRON SIGHT PLANNER & SKY CHART

ASTRON TIME ALMANAC PAGE

ASTRON DAY ALMANAC PAGE

ASTRON SETTINGS PAGE

ASTRON LUNARS PAGE

ASTRON MERIDIAN PASSAGE PAGE

Close X

In order to download Astron's comprehensive User Notes,
1: Copy (Ctrl-C) the below link.
2: Select a new browser tab and paste it (Ctrl-V) to the address bar.
3. Your browser will download the file to your downloads folder.

https://friendsofthevigilance.org.uk/Astron/AstronUserNotes.docx

We use the above indirect link method to avoid occasional browser security issues.
We suggest that you then save the file for easy future access.

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The following link accesses a folder from which you can ...
(a) Run a PowerPoint presentation explaining using Astron's main features
(b) Run a PowerPoint presentation explaining Lunar Lines of Position
(c) Download the entire Astron source code
https://drive.google.com/drive/folders/1-5b9b7ySW5hhXsd4ymlthsB_KHYZ1cqf?usp=sharing
The above PowerPoint presentations are not updated and some differences will be evident.
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You may also be interested in the writer's celestial navigation slide rule emulator programs.

TRADITIONAL BYGRAVE SLIDE RULE emulator.
https://friendsofthevigilance.org.uk/Astron/SlideRules/TraditionalBygrave/TraditionalBygrave.html

MODERN BYGRAVE SLIDE RULE emulator (C) Gary LaPook.
https://friendsofthevigilance.org.uk/Astron/SlideRules/ModernBygrave/ModernBygrave.html

CONVENTIONAL LINEAR SLIDE RULE emulator
https://friendsofthevigilance.org.uk/Astron/SlideRules/LinearSlideRule/SlideRule.html

TYPE OF HORIZON		Default SEA. See User Notes Sections 15 & 16 for other types.
TOO LIGHT SUN Hc		Default and suggested value -3.0° (Mid Civil Twilight). Range 0.0° to -6.0°.
TOO DARK SUN Hc		Default and suggested value -9.0° (Mid Nautical Twilight). Range -6.0° to -20.0°.
TYPE OF START UP		LAST USED: Start with date/time set to last used values. PRESENT: (Default). Start with date/time set to present time.
ANGLE UNITS		Outputs only. (Inputs are always DM.m format.) DM.m: Degrees Minutes and decimal minutes. Default and Recommended setting DMS: Degrees Minutes Seconds. D.d: Degrees and decimal degrees.
SHOW EXTRA DECIMALS		Recommended Value 0. Shows EXTRA decimal places. Range 0 to 3. Formatting (including plotter and planner) may become ragged when > 0.
SHOW LUNAR ARC DISTANCE		Show on legend bar below Astron and Google Sight Plotters YES: Show sextant arc (LDs) between selected body and Moon at cursor position. NO: (Default). Don't show it.
MSL TEMPERATURE AND PRESSURE		YES: (Default). Always enter MSL Temperature and Pressure. NO: If Observer Alt > 0, enter AMBIENT Temperature and Pressure.
DELTA-T		AUTO: (Default.) Astron uses calculated value for ΔT. MANUAL: User can enter a specific value on Home Page. Use 0 for Terrestrial Time. (TT/TD).
MOON CALCULATION METHOD		NORMAL: (Default) High accuracy, valid 1600 - 2200, maybe slow operation. BASIC: Adequate practical accuracy, valid -2999 to 2499. Select this mode on slow devices.
RISE, MP & SET TIMES		Time mode for displaying Rise, Mer Passage and Set times. ALWAYS SHIPS TIME: (Recommended) These times are always shown in Ship's Time. UT WHEN IN UT MODE: Show these times in UT, but only so when in UT input mode.
TIME SYNC OFFSET		When Time Sync selected, time is synchronised with an offset of this amount. Default and recommended value: 0 seconds. Range -200s (Retarded) to +200s (Advanced).
RESET ALL		Resets all settings, inputs and Custom Stars to default values.
INCLUDE CUSTOM STARS		ONE or TWO: All utilities include the CUSTOM STAR(S) detailed in the pop-up table below. NONE: (Default). CUSTOM STARS are hidden.

ASTRON: Integrated Astro Navigation Software				Home Page
Date and Time Input						Watch Corr		Daylight
Year	Month	Day	Hour	Minute	Second	Secs (Slow +ve)		Saving


Body Data		GHA of		GHA of	Dec of	UT:
Body:		Aries				Ship's Time:

						Observation
Apparent Body Position						Windows
Assumed	Assumed						Bearing (°T)	Altitude (°)
Latitude	Longitude					Unidentified body?
Deg	Deg			Calculated	Calculated
M.m	M.m	LHA of	LHA of
		Aries		Azimuth (Zn)	Altitude (Hc)



Altitude Corrections		Observer Alt
Sextant	Index					SD	HP
Altitude (Hs)	Correction (IC)
Deg	(Off Arc +ve)	Eye Height (HoE)			Limb		Parallax Corr	Observed
M.m	M.m							Altitude (Ho)


Azimuth and Intercept					Calculated Hs
			Shore Dist (nm):			Rise	Mer. Passage	Set


Change fix time
Day
Hour
Minute
Second
Change COG/SOG
COG (Degs T)
SOG (Knots)
Mark Location
Latitude
Longitude

Lat
Long


Year	-	+
Month	-	+
Day	-	+
Hour	-	+
Minute	-	+
Second

Set Present Date/Time

Sun Altitude
Moon Altitude
Moon Phase

Lat
Long


Year	-	+
Month	-	+
Day	-	+
Hour	-	+
Minute	--	++
	-	+
Second	--	++
	-	+

Set Present Date/Time







Sun Altitude
Moon Altitude
Moon Phase

Aries
SHA
GHA
LHA

Dec (0° to 90°)	Dec Name	Lat (0° to 90°)	Lat Name	LHA (0° to 360°)

Custom Star Data (Equinox J2000.0 Epoch J2000.0)

Dec (+/-D.d)

pm RA (mas/yr)

pm Dec (mas/yr)

Parallax (mas)

NOTES on using this CUSTOM STARS utility. See User Notes / Settings / "Include Custom Stars" for more detail.
• Astron holds data for two CUSTOM STARS.
• On changing this option to "ONE" or "TWO", the CUSTOM STAR(S) become visible and the upper star (ONE) or lower star (TWO) becomes the currently selected body. Other bodies can be selected as normal.
• On all other pages, the CUSTOM STAR names are preceeded by an asterisk "*" distinguishing mark.
• The CUSTOM STARS are shown as the last two bodies in the body select list and elsewhere. [Keystroke hint: Press "z" then "⯆"]
• When option set to "ONE" or "TWO", the CUSTOM STAR(S) are included in all Astron utilities.
• When option set to "NONE", the stars are excluded and this table hidden.
• When Astron is closed, CUSTOM STARS data are remembered for next use.
• On first use, the CUSTOM STARS are set to Castor (α Geminorum) and Mirach (β Andromedae).
• When entering values, RA and Dec must be in degrees and decimal degrees.
• pm RA values are in milliarcseconds of ARC, not mas of Right Ascension.
• Input data must be referenced to J2000.0 Equinox and Epoch. Astron then adjusts to the selected date and time.
• See User Notes / Settings / "Include Custom Stars" for suggested link to catalogue star data.

Altitude (Hs)	Moon		Moon	Moon
Deg	Limb		Apparent	Cleared
M.m		SD/Aug Corr	Alt (Ha)	Alt (Hcl)

Use calc Hs

Sextant Arc (LDs)	Moon		======= Entered Values =======
Deg	Limb	Limb		Ass Lat	Ass Long
M.m
			==== Lunar Revised Values ====
				Calc Lat
					Calc Long


Corrections for observer movement and rate of change of body declination

COG (degs T)	SOG (knots)	Dec Rate (mins/hour)	Observer Northings	Time Correction

					Latitude	Longitude

All 3 observations