Pathfinder Sorcerer/Oracle Spell Selection

[Baroncognito]

I've got a concept building towards Mystic Theurge.

Stargazer Oracle with the Heavens mystery
And Starsoul Bloodline Sorcerer

The curse is a homebrew, wherein I am effectively blind at distances less than 15 feet (though, by wearing goggles of minute seeing, I am able to read). At first level, the bonus is that the distance for perception check penalties is reduced by 30 feet.

I'm having a little trouble picking thematically appropriate useful spells.

[Corlindale]

First of all, a word of caution. While combining Oracle and Sorceror for a Mystic Theurge might seem like a good idea because of the Charisma-synergy, remember that you will be 4(!) caster levels behind for most of your career, and that you will be restricted to 2nd-level spell until level 10. That's a massive disadvantage in play, and I would advise against such a build myself.

Maybe you could achieve something with similar fluff by playing an Oracle and taking the Eldritch Heritage feat line to get some of the powers of the Starsoul bloodline, without crippling your spell progression? Of course you should play what you want, but just be warned that this build might be really frustrating to play at low levels, and will never get 9th level spells in either class unless you have some early-entry trick.

As for thematic spells, your obvious focus as an Oracle of the Heavens are Illusion: Pattern spells, because of the power of the Awesome Display revelation. Color Spray can actually be your most potent offensive spell for a huge part of the game, though remember to slap Heighten and/or persist on top of it later on to keep the dc high.
Since it might be good for you to take Spell Focus and Greater Spell Focus: Illusion to take advantage of this, other illusion spells would be obvious picks too - unfortunately there are few of those on the cleric list, which I guess could be one advantage of doing the Sorceror/Oracle MT.

Otherwise there are a lot of spells that are star-, moon- or night-themed, though they probably appear more often on the Sorceror list as well.

[Baroncognito]

I'm aware that colour spray is actually a very nice spell, but Stargazers don't get it. The Stargazer bonus spell list is slightly different.

And, while Eldritch Heritage is a nice feat, I wouldn't really be taking levels of Sorcerer to get the bloodline feats.

I'm aware that Mystic Theurge has its drawbacks, but that's the concept. I'm trying to get advice on spells to make the character a bit more useful despite that.

[Corlindale]

I'm aware that colour spray is actually a very nice spell, but Stargazers don't get it.

Your sorceror side could simply take it as a spell known if it came to that. I still think it's your best means of offense for your first 10 levels if you take Awesome Display and crank up its save DC a little. Glitterdust is also nice, but Stargazer gets that for free. Silent Image and the like will also remain useful for much of the game, and have very little dependence on your caster level.

On that note, you may want to look into some more SR: No spells, since your caster level will be relatively low for most of the game.

[Baroncognito]

Well, I do have Magical Knack: Oracle, which improves my caster level by two. I'm also going to ask the DM if I can take the 3.5 feat Practiced Magician (I think it is) which improves a caster level by 4.

[Oncoming Storm]

the problem is not the CL for effects--plenty of spells don't even care about CL. it's being unable to cast all the really good spells. Sure, you can spam all the searing rays you like, but you'll be 10th level before you can so much as stone shape anything. You're essentially a subpar blaster.