Husun Double Sextant
Double sextant by Henry Hughes and Son (Husun)
Obtained from the UK
Product details: Husun Double Sextant | Henry Hughes and Son | Quintant | Survey | Material: Aluminium
This one was on my wish list for a long time untill one showed up in a UK auction. Expecting to have to pay much money I was rather pleased that there was no ferocious bidding on it. This sextant was specifically developed (as well as its predecessor which is still on my wish list) for hydrographic work. With this sextant a single observer can take two readings between three objects; something that would otherwise require two observers. To make this work the sextant has two index arms with mirrors that rotate independently of each other around a central axis. The mechanisms on both arms are very similar to those on the MkIII survey sextant.
Based on the standard method of sextant sounding as described in e.g. Wharton and Field, one mirror would be set to a fixed angle based on the location of the sounding boat (a plotting sheet was prepared for this). The other would then either be set to a fixed angle as well and the coincidence of all three objects would be called out indicating that the survey launch was at a plotted crossing of the two angles. Alternatively one would have been kept fixed and the other moved while at times the changing angle would be called out. This was called surveying the arc (as a fixed angle will give an circle with a radius based on the two given points).
More information / other collections:
Husun double sextant
Data sheet
- Year
- 1948
- Serialnumber
- 56091
- Type of use
- Survey
- Material
- Aluminium
8 other products in the same category:
Double sextant by Henry Hughes and Son (Husun)
Obtained from the UK
Product details: Husun Double Sextant | Henry Hughes and Son | Quintant | Survey | Material: Aluminium