Sight Reduction Tables for Astro Navigation.

small sextant iconSight Reduction Tables

These Sight Reduction Tables have been condensed into as compact a form as possible. Each set of tables covers seven degrees of Latitude, which should satisfy the needs of most people. Simply download the set, or sets, that best matches your cruising latitude.
The files are ~750KB each.

Latitudes 0-6
 Latitudes 7-13
   Latitudes 14-20
   Latitudes 21-27
   Latitudes 28-34
   Latitudes 35-41
   Latitudes 42-48
   Latitudes 49-55
   Latitudes 56-62
   Latitudes 63-69
   Latitudes 70-76
   Latitudes 77-83
   Latitudes 84-90

Taking a leaf out of the Air Tables, pub 249, here are a set of sight reduction tables that return Integer values for Hc, d' and Z. They are easier to read and should make the whole sight reduction process a little easier with minimal impact on accuracy.

Latitudes 0-6 Integer
 Latitudes 7-13 Integer
   Latitudes 14-20 Integer
   Latitudes 21-27 Integer
   Latitudes 28-34 Integer
   Latitudes 35-41 Integer
   Latitudes 42-48 Integer
   Latitudes 49-55 Integer
   Latitudes 56-62 Integer
   Latitudes 63-69 Integer
   Latitudes 70-76 Integer
   Latitudes 77-83 Integer
   Latitudes 84-90 Integer

Declination in these Sight Reduction Tables is limited to 23 Degrees. The rationale being these tables are for reducing a Sunsight where the declination never exceeds 24 Degrees.

Most of us amateurs sail in the summer when Latitude and Declination are the SAME. These tables make the transition from SAME, at the front, to CONTRARY towards the rear, as seamlessly as I could contrive. No flicking through SAME/CONTRARY/SAME/CONTRARY page after page.

Where in the tables the transition from SAME to CONTRARY occurs depends on your selected Latitude and LHA. It should all become clear when you start using the tables.

It's also worth pointing out that Sight Reduction Tables do NOT go out of date. Download them once, print them, bind them with nice covers and they're yours forever.

These Sight Reduction Tables include pages for GHA minutes and seconds interpolation, Declination interpolation and Sextant corrections.