How hot does an exo terra 150W heat glo bulb get?

I have a ball python and I've been using this bulb for awhile. I use a dimmer to lower the temperature when it's obviously too hot but I can't tell if it's too cold. I can't move my thermometer to her hot side because I use astro turf as her substrate and it covers the sides as well. The temperature is obviously off because she doesn't shed in one piece but I'm not sure if it's too hot or cold.