How do I divide a Howeara Lava Burst 'Puanani'?

[Anjohnson]

Hi

I'm new here. I live in northern Victoria, Aus (a couple of hours out of the ski fields, down by the sea). I've got 2 cymbidiums going crazy outside, a crucifix orchid and a recently obtained Phalaenopsis (second attempt at owning and I've got two flower spikes so it's going well).

I also have a Howeara Lava Burst that I've been getting many flowers from for the past 5 years. I want to try dividing it. It's so pretty, I'd love to have another around. It's been chilling in a tea cup (I drilled a drain hole) filled with sphagnum moss and has two what I would call crowns. The spots where the leaves sprout from. How do I divide the plant without losing both? I'm nervous since it was the first orchid I've bought (the others were gifts) and since its flowering so well, I feel like it's a good investment.

Is there a time of year I should do this? We're entering winter so it will get a lot colder soon. It's snowing in the Alps. The orchid lives in my bathroom near a frosted picture window.

Thanks so much for your help.