Astral Blast and Thunder Mine

Astral Blast and Thunder Mine are Jupiter single-target Psynergies, available to the Page and Apprentice Class series. As such, Isaac (Apprentice), Felix (Apprentice), Garet (Page), and Jenna (Page) can use them if they have enough Jupiter Djinn to be in their respective class series.

Astral Blast
An "attack with celestial force", Astral Blast appears as a group of stars being fired from the user's attack, striking the foe at a distance. In the Page series, Astral Blast is usable by the Page, Illusionist and Enchanter classes; in the Apprentice series, it is usable by the Apprentice, Illusionist and Enchanter classes (note that the latter two classes are different from their counterparts in the Page series). Astral Blast is also usable in both versions of the Conjurer class in the first Golden Sun. Astral Blast isn't as strong as others like it, such as Heat Wave, but it does serve its job quite well, especially against Venus-based enemies such as Tret. Astral Blast costs 5 PP to use and strikes the target with Jupiter power equal to the user's own attack power with 32 base Attack added. It is obtained at level 11.

Thunder Mine
As all Psynergies like it do, Astral Blast is replaced by the more powerful Thunder Mine after the wielder reaches the Conjurer class in The Lost Age. An "attack with ball lightning", Thunder Mine appears as a large ball of plasma-like energy with a heavy electrical charge slowly crashing into the foe. Unlike other, more commonly used counterpart attacks, such as Diamond Berg, which carry the burden of belonging to a class that has very low Psynergy, Thunder Mine is supported by a somewhat decent supply. Thunder Mine costs 16 PP to use and strikes the target with Jupiter power equal to the user's own attack power with 85 base Attack added.

Analysis
Astral Blast can be one of the more useful Psynergies for Felix to possess in The Lost Age, because in most cases, going through the game and acquiring the Djinn as they are found, the player is subject to unequal amounts of Djinn distribution until Piers is in the party, and even then the Djinn distribution can be a problem. The reason it is a problem is because of the fact that the power the Djinn give when set is well needed at the early stages of the game, and not everyone sets their Djinni constantly, thus, if one is to change Felix to an Illusionist class, Astral Blast is the most useful spell he possesses. A good strategy to go along with the Early Illusionist Felix, is to have Jenna become a Brute, as the increase in attack power eliminates the need of using too much Psynergy (In most cases she becomes stronger than Felix), and Sheba use the remaining Djinn to decide her class, or have her equip the Mysterious Card, or later, Trainer's Whip.

Thunder Mine, as it is acquirable much later in the game, is not as readily used, as the power of the Venus Psynergy possessed by Felix greatly overpower the usage of Thunder Mine by the same character.