How to know the progressive state of mind in insight meditation While  doing  meditation thoughts  developing on cittarupa and the what is appearing  on the field too disappears together feel like anattma(non self).At that moment citta goes out into the field and light appears from  the point it has gone.no attachment it is freed and moved towards. No sensations of body has appeared. (Eg sound ....,...,)what is this experience?
I believe the speed of letting go of things is one of the indicators from Indriya-bhavana Sutta


  There is the case where, when seeing a form with the eye, there arises
  in a monk what is agreeable, what is disagreeable, what is agreeable &amp;
  disagreeable. He discerns that 'This agreeable thing has arisen in me,
  this disagreeable thing... this agreeable &amp; disagreeable thing has
  arisen in me. And that is compounded, gross, dependently co-arisen.
  But this is peaceful, this is exquisite, i.e., equanimity.' With that,
  the arisen agreeable thing... disagreeable thing... agreeable &amp;
  disagreeable thing ceases, and equanimity takes its stance. Just as a
  man with good eyes, having closed them, might open them; or having
  opened them, might close them, that is how quickly, how rapidly, how
  easily, no matter what it refers to, the arisen agreeable thing...
  disagreeable thing... agreeable &amp; disagreeable thing ceases, and
  equanimity takes its stance.