There are a total of four Faint Constellations. You can not align yourself with them and you can not align your Mantel with them either. To utilize these new Constellations you will need to attune already Attuned Crystals with these new Faint Constellations. This in turn will change the ritual effect of the original Constellations by either boosting them or altering the effects in some way.
In order to attune Crystals with new Constellations you will need to follow the same process as attuning a crystal:
You can look up each of these constellations in the Tome but the descriptions are a bit vague.