How do you make widefields with landscape background?

[Amra]

Hey guys, after mainly doing a bit of DSO imaging so far I have been drooling over many of the widefields of constellations and whatnot posted by members.

So I have ordered a 'nifty fifty' Canon 50mm lens & a ball head I can attach to my smaller dovetail bar so I have tracking with my HEQ5 mount & good framing.

We have some beautiful landscapes here in the Faroe Islands that I would like to include in the bottom of my images, but I'm not sure how to go about it. I was wondering how do I combine having landscapes in my images + stacking images of the stars above the landscape? Do you just take a single image of the star field + landscape untracked & then point the camera on the star field exclusively, track, and take your photos and crop them later to fit with the landscape image? Or should I perhaps not track at all?

How long exposures would you do with the 50mm lens when you have tracking?

I think I read somewhere on these forums that APT can focus the 50mm lens for you, is this a reliable method of focusing?

[ollypenrice]

I would take tracked images of the sky, without a doubt. At that FL you don't need accurate tracking, really. Assuming you are pointing south (so the objects will be setting) I would take a run of subs then switch off the mount and get one good image of the horizon/landscape at the optimal exposure settings. Try to do this quickly after finishing the tracked run.

Stack and process the stellar image. The horizon will, of course, be blurred. Then place your good horizon shot on top of the stellar image, adjust it so that it just covers the blurred horizon, and carefully use the Magnetic Lasso tool in Photoshop to trace round the sky part of the top Horizon layer and erase it. Then you have sharp stars and a sharp horizon. It might help to increase the image size while tracing round the horizon. The Magnetic Lasso can be slightly infernal to use and the Escape key is the only way to be rid of it!!

Olly

[Amra]

Thanks Olly, that's exactly the kind of tip I was looking for!

[Amra]

I wonder what kind of settings I should use for the horizon image though? Everything on my camera has been configured as much as possible for DSOs and it's a full spec camera.

[laser_jock99]

The STARTRAILS software is also worth a look.

http://startrails.de/