Star Trails Help Please

[johnb]

Hi

I’m trying star trails and have  followed a few tutorials but am getting really confused over settings

I’m using a Cannon450d with an external intervalometer

If set the Camera to Manual and the Shutter speed to 20 sec and then manually start the camera takes a 20 sec shot as expected

So if I  then set the camera to Bulb set the intervalometer Long- 20 Secs and the interval to 1 sec it simply seems to take a shot that’s 21 Seconds is Long +the interval

Any pointers appreciated

Kind regards
John B

[happy-kat]

Hi, I think the interval is the length of exposure plus any gap you want, so 21.