I am not familiar with the 1000 but on my Durst 138S there is a slot for a heat absorbing glass, UV filter, and VC filters (on mine these mount into a holder). This is located immediately in front of the lamp. The inclined mounting I am not sure about. Could it be where the mirror is mounted? On my enlarger the lamp shines on a mirror and the mirror then reflects the light down through the condensors.