Got flashed by camera for making a right turn on Red

There was a yellow right turn signal when I approached the intersection so I made the right turn. There was no other traffic at all. But the camera caught me and the ticket is about $450 dollars. I'd like to contest it. Any chance of winning? My hu*****and said I should pay for it. The video showed the yellow light but when I was making my right turn, it became red. The ticket for two pictures said "Vehicle behind limit line, light is red." and "Vehicle within intersection, light is red." There was no posted sign there saying no right turn on red. But I didn't stop completely for three seconds before I turned right. I was rushing to my $1500 class--first day and not knowing where the building was. Now the class even cost more!

Please share your experience or suggestions. Thanks.