Horological Science Newsletter Archive

Since 1999 I have published a number of articles on my clocks and pendulum research in HSN the 'Horological Science Newsletter.'

HSN's website has a list of all authors.

Below are pdf files for all my articles ordered from newest to oldest:

Signal and Noise (HSN2015-3)

Detailed analysis of cycle-by-cycle period measurements from an experimental pendulum. Description of many statistical techniques used to remove short term noise and show longer term environmental factors.

Full paper in pdf format can be downloaded here. (pdf 629 KB)

Tidal Effects on Pendulums at Various Latitudes (HSN2015-2)

Two independent methods are used to model the change in period of a pendulum located at a given latitude. The average daily effect from the position of the sun and the moon on a pendulum is only zero at latitude 35.2644° (north or south.) Above or below this latitude seasonal variation can cause time variations of many milliseconds. Over the full 19-year cycle of the moon's orbit, time variation could reach hundreds of milliseconds. Both empirical and mathematical methods are used to describe the effect.

Full paper in pdf format can be downloaded here. (pdf 293 KB)

Results of Proportional Digital Drive with #8 Pendulum (HSN2009-4)

Method and results for switching from drive and coast to proportional drive. Optical sensor accuracy.

Full paper in pdf format can be downloaded here. (pdf 248 KB)

Exploring Buoyancy (HSN2007-2)

Air's density changes pendulum period because buoyancy can slightly reduce gravity's restoring force. Daily changes in temperature, barometric pressure, and relative humidity all change air's density and therefore clock rate. Methods are given to compute air density from environmental measurements and to compute the magnitude of the effect in most pendulums. A design for a pendulum free of buoyancy error is given. Real environmental data is applied to a hypothetical clock to show rate variation.

Full paper in pdf format can be downloaded here. (206 KB)

An Earthquake Observed (HSN2007-1)

One pager showing a Hollister CA earthquake's effect on pendulum #8.

Full paper in pdf format can be downloaded here. (pdf 65 KB)

What I've been up to (HSN2006-3)

Describes the building of clock 2/7 in 2003 and the work to date on Clocklab. An experiment shows circular error when a pendulum coast down to zero angular displacement.

Full paper in pdf format can be downloaded here. (pdf 141 KB)

Crystal Oscillator Temperature Calibration via WWVB (HSN2001-3)

One pager show the result of using a WWVB receiver to find the temperature coefficient of a timing crystal.

Full paper in pdf format can be downloaded here. (pdf 76 KB)

Clockquakes (HSN2000-4)

One pager showing sudden changes in period from mechanical stick/slip.

Full paper in pdf format can be downloaded here. (scanned pdf 451 KB)

Measuring a Clock's Temperature Response (HSN2000-3)

Temperature effects and thermal lag.

Full paper in pdf format can be downloaded here. (scanned pdf 451 KB)

Period Variation in an Electronically Maintained Clock (HSN1999-4)

How drive may effect period.

Full paper in pdf format can be downloaded here. (scanned pdf 1,147 KB)

Quantifying Temperature and Barometric Effects in Free Pendulum Clocks (HSN1999-3)

Many details about measuring pendulum period and environmental data. Barometric effects are not actually seen in this experiment but temperature is clearly shown.

Full paper in pdf format can be downloaded here. (scanned pdf 1,078 KB)

(Some of earlier papers refer to website 'casaalta.com' which is no longer mine.) (rlb)