Where will you be in relation to the camera, in front, behind, on top or where?? If in front, you should be able to see the aperture blades close down which is good enough an indicator/confirmation that the shutter has fired?
If you are far enough away not to hear the shutter opening and closing then that could be problematic with a standard bulb.
An idea would be to adapt the bulb from a blood pressure cuff for the purpose. The bulb can be locked after squeezing via the screw valve that is part of it. When the time period is done then open the valve to complete the exposure.
This, of course, depends on an air tight connection to all components. Otherwise leak down will cause a failure to remain open for the indicated exposure.
The mirror slap issue with long exposures is negligible. During the last full moon I made landscape exposures using a SRT 101b with and without MLU. There was no noticeable difference. All negatives were sharp with an 8X loupe.
Cheers. I went out on Friday night to give it a try...but:
- Before I went out, I gave things a try - Idiot....the mirror is always reset by the winding action, not the photo taking, so when the bulb is released all you get is the click....face palm...
- It was too windy when I got to my location (about 50 metres walk)...so there was no point.
As mentioned elsewhere, I have plans to make an electronic remote release....but I have spent a bit too much over the last month or so.
Cheers for everyones advice!