When this is done, insert the eye-piece, and the star will be seen in the field.
But the telescope is out of focus, therefore we must turn the small focussing screw.

Observe the charming chromatic changes--green, and red, and blue light, purer than the hues of the rainbow, scintillating and coruscating with wonderful brilliancy.

As we get the focus, the excursions of these light flashes diminish until--if the weather is favourable--the star is seen, still scintillating, and much brighter than to the naked eye, but reduced to a small disc of light, surrounded (in the case of so bright a star as Sirius) with a slight glare.

If after obtaining the focus the focussing rack work be still turned, we see a coruscating image as before.

In the case of a very brilliant star these coruscations are so charming that we may be excused for calling the observer's attention to them.