Greenpassion, I found this explanation with google:
Oncostele is a man made hybrid composed of species and hybrids of the genera Rhynchostele (rink-oh-STEE-lee) and Oncidium
Oncostele (on-co-STAY-le)
Oncostele Aloha Sparks is a cross of Ons. Lorraine's Fourteenth Woc x Onc. Redhot Spark)
And here's a link to a grower which shows a pic though it is not the same cultivar as yours:
Mauna Kea Orchids | Aloha Sparks 'Pele's Glow'
Hope this helps you out!
Judi