Is there a way to start an ATL sequence after the desired 'Start' time? So if I set a 6am – 6pm active period and start the sequence ‘during this time’ it appears to do nothing until the next day.

You can program multiple sequences to start at various times during the day. You don't need to make them contiguous either, you can set them to end at the same time. Once a sequence starts, the DigiSnap doesn't look for any other start times until that particular sequence ends. This means that overlapping sequences are ignored.

Unfortunately when using SLR cameras, as in the Time-Lapse Package, the DigiSnap doesn't know the time of day. When using a Coolpix camera, the camera will report the time of day, which is very convienent. With an SLR, the DigiSnap simply assumes that it's midnight when it is turned on. If you set a sequence to start at 00:01 (one min after midnight), then the time-lapse sequence will start one minute after you power it up.

If you know you are going to be on site, and start the DigiSnap at say, 4 PM, but you want your pics to run from 6 AM to 6 PM, say 1 shot per hour, then you can do this.

Set up a sequence to start at 14:00, taking 13 pics, with a 1 hour interval. The next morning, it will start that sequence at 6 AM (14 hours from the power up), and run all day.

You can also set another sequence to start at 00:01, taking 3 pics, at 1 hr interval. This will then start taking pictures 1 minute later, and take pics until 6 PM. The next day, it will execute the full-day sequence, and ignore this later one.