The ring on the aiming device needs to be moved close to the patient's face and the cone then needs to be close to the aiming device ring.  This helps make a clearer image.  Before placing the aiming device, look at the contacts you are trying to open and make sure the angle of the bar on the aiming device and the cone of the tube head are all on the same horizontal plane.  This will open your contacts.

Can you show us the tips and trick on how to get the open contact on bitewing ? Do you check where the open contact between the teeth first ?can you do show us tips and trick to get open contact ? Can you show us the image you took to see if you get the open contact