The Minor Planet 2 Pallas will pass within 20 arc minutes of T CrB from June 22-25, with the closest approach of ~12 arc minutes on the evening of the 24th June. Pallas will be travelling from the NE to SW at magnitude nine or thereabouts.
And here’s a colour wide-field image from tonight (Jun 24/25). The bright star at the top is epsilon CrB which is mag 4.2. T CrB should be brighter than this when it goes off.
I’ve been following this visually and remotely for a while now.
Image below is from last night (June 24.95 UT), and is a truncated image taken with SLOOH Canary 2 Ultra Wide field 85mm Teleview riding on the main telescope.
Unfiltered magnitude 9.4CV using the BAA T CrB sequence.