Software for automating Hartmann test?
Posted 17 May 2021 - 01:59 PM
- PrestonE likes this
Posted 18 May 2021 - 01:05 PM
Quoting Dale Eason from 4 years ago:
I eventually realized that just like interferometry air currents disturb the results. The reason all the 2d harman results where different was because of air current in my test area. That could be solved if Jim's program could average several results like DFTFringe can but it can not. So, to use his 2D hartman software and setup you need to control air currents very carefully.
But like others have said interferometry is far more convenient than setting up the 2d hartman test if you optics allow its use.
Was Hartmann test created for a refractor? Anyway it sounds like for mirrors you are better off with foucault or bath.
Posted 18 May 2021 - 02:30 PM
The usual way to overcome the effects of turbulence when doing a Hartmann test (or its interferometric variant which is ~5x more accurate) is to stir the air well and use long (minutes) exposures. The original implementation used photographic plates.
A large number of short exposures can be averaged to achieve a suitably long exposure.
Although the Hartmann test was first initially used to test refractors it was later used to test large reflector primaries.