Sight Folder
Sight Folder: Pub 229 Workbook
Pub 229 sight reduction, every line shown.
Sight Folder helps USCG license candidates find the line they got wrong in a Pub 229 sight reduction.
- Not in the app stores yet
- No signal needed
- No account
- Free to download · Contains in-app purchases
Work a sight, every line shown.
Type the assumed latitude with N or S, the LHA, the declination with N or S, and your Ho if you have it. The form fills in every Pub 229 line in the order you would write it on paper: Tab Hc, d, the d-correction in tens and units, the double-second difference, Hc, Z to Zn and the intercept.
The intercept is stated in words, toward or away, and the rule that turned Z into Zn is printed under it. Your work is saved as you type.
Tap a line to see where it comes from.
The Line Explainer shows where any line comes from in Pub 229 and how to check it by hand.
Table Opening shows the Pub 229 page opening for a latitude and LHA, set the way the printed page reads, with the cell your sight reads marked.
Find the line you got wrong.
In Exam Drill you work each line yourself. A line that disagrees with the table is flagged on that line, and the lines that follow correctly from it are not blamed.
The drill tells a rounding question (one tenth away) from a lookup error (wrong row, column or section), and a value on a rounding boundary is accepted either way. Free on the 18 NGA worked examples; Pro adds practice sights after them, and Check my own sight for your homework. There is no score, no streak and no celebration.
Where the numbers come from.
The engine is checked against 154 values copied from the printed volumes (Vols 1 to 4 and 6): 96 table cells, 40 Interpolation Table entries and 18 worked sights from the volume introductions. All 154 match in the app’s own test suite, and a button in the app runs the same 154 checks on your phone.
Every sight you save goes in the folder, newest first, with its intercept and azimuth, and each one opens the full form again.
What you bring
LHA and declination from your own almanac, and Ho after your own altitude corrections. Sight Folder does not compute the almanac, does not plot a position, and is not a navigation system of record. It is a workbook for reducing, checking and drilling sights.
Table values are from Sight Reduction Tables for Marine Navigation, Pub. No. 229, National Geospatial-Intelligence Agency, a U.S. Government work. Sight Folder is not endorsed by NGA and is not affiliated with the U.S. Coast Guard.
No account, no ads
There is no sign-in and no email address. Your sights stay on your phone, unless your phone’s own backup includes them. No ads, no usage tracking and no permission prompts. Working a sight needs no signal at sea. Buying Pro goes through Google Play, and RevenueCat, the app’s billing service, checks what you own: they see the purchase, not your sights.
What stays free, with no trial and no time limit: Work a Sight with every Pub 229 line, the Line Explainer, Table Opening, About the Tables, your Sight Folder, and Exam Drill on the 18 worked examples.
Sight Folder Pro adds practice sights after the worked examples, aimed at the last line you got wrong; Check my own sight, for your homework; a record of which lines differ most; and new Exam Drill sets about every quarter.
Try Pro free for a week, with no card. It is offered after your first finished drill, and the yearly plan on the Pro screen starts it too. Nothing is charged and nothing renews when the week ends.
Sight Folder Pro is sold through Google Play as a yearly or a monthly subscription.
Not in the app stores yet.