Free lessons

Open teaching, in full and permanently: what light pollution actually costs you, why stars go oval, and what a calibration frame is really for.

A cloudy week reading list

Seven nights of cloud is a reasonable amount of time to fix something that is not the weather. Here is what to read instead of refreshing the forecast.
A cloudy week reading list

What a flat frame actually fixes

Everyone takes them. Fewer people can say what they correct, which is why so many are taken wrongly and then blamed for the result.
What a flat frame actually fixes

You do not need a dark site

The most repeated advice in this hobby is to drive somewhere else. It is true and it is nearly useless, and here is the arithmetic behind why.
You do not need a dark site

Forty-three nights, one galaxy

Nine years running a two-metre telescope did not help. This is the log of the six weeks that followed, including every night that produced nothing.
Forty-three nights, one galaxy