A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Tony Oz
Date: 2021 Jan 22, 01:02 -0800
The ИАС-1(М) is a clone of this well known SOLD KM2 instrument.
The name translates as the "Integrating Sextant for Aviation", the "М" index denotes the "Modified" model. The difference between the ИАС-1 and the ИАС-1М is:
- the mechanical "flag" appearing over the bubble chamber when the intergation interval runs out
- the bubble level is slightly different - a bigger air chamber (a small cylinder popping up from the AH body) is introduced, apparently - to prevent AH damage or leakage if the bubble left small after the sight was taken (to counter the thermal expansion of the liquid)
- several minor details of not so big significance
The "-3" sextant was for marine use, its' proper name is "ИМС-3", which translates as the "Integrating Sextant for Marine". It is said to be the further enhancement of its' aviation "brothers". I plan to buy that as well, the one obvious enhancement is the handle. The ИМС-3 has the left handle as per the Fig.2 (ref the "SOLD" article), while both the ИАС-1 and ИАС-1М have left handle similar to the one on the drum side (ref Fig.3).
All those sextants are featuring the integrators running for 40, 120 or 200 seconds.
I wish the GPS AntiSpoof could accommodate for that.