Piggy back astrophotography

[kon1966]

Hi guys, going to delve into the world of astrophotography(gulp). I want to start with piggyback option first and later with reducer.

Equipment is celestron 8se with starsense and have the camera piggtback mount. Camera is canon 7d and lens is tamron 17-55 f2.8.

I want to start off with southern targets, eta carina etc. What is a good start to set my camera at, Iso, F ratio, exposure time. I will also have to stack the photos asI have read in the forums.

Regards
Kon

[Garbz]

Settings will depend on your sky and your lens. I believe there's an ideal ISO setting somewhere around ISO800 which is optimal for astro imaging, but I'm not sure of the specifics.

The aperture will depend on how good your lens is. You want to shoot as wide open as possible, but lots of lenses suffer from sharpness and chromatic aberration at lower f ratios, so you want to stop the lens down to the point where the image quality becomes acceptable. I would start around f/4 or f/5.6

Exposure will depend on all the above and on what you're shooting. Rule of thumb is go as long as you can without over saturating parts of the image. Watch your histogram and back off the exposure if you start hitting the right hand side as you will lose colour in bright objects like stars.

[kon1966]

Thanks Garb,
will try f4 at 1000 iso as a start. What about seconds, begin with 20 to 30 sec exposures and how many shots to start and also dark frames.

Regards
kon

[Garbz]

As long as you can while getting an acceptably sharp image without over saturating and clipping the highlights in the stars. Again look at your histogram. You want to ensure you don't hit the right hand side, as soon as you do you'll lose colour in the stars.