› Forums › Spectroscopy › What wavelength error is acceptable with an Alpy? › Filly lamp
6 November 2018 at 6:39 pm
#580192
![](https://britastro.org/wp-content/uploads/2019/12/picture-5132-1575710618-80x80.png)
Participant
Hi Robin could you try the filly lamp at 90 deg to the correct position to see if the off axis lines mirror the behaviour of the star.
Regards Andrew