Lens recommendations for Canon DSLR?

Hi everyone! I'm looking for a new lens for my Canon 70D that suits what I want.

I need- a lens that is a wider angle, under a 20mm, is great in low light (I'll be using it to take long exposures of the stars in the night sky), also a lens that is great for daytime landscape shots as well.

If anyone can please recommend a good lens that fits those requirements that isn't too pricey, please respond! It would be well appreciated! Thank you!

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Want an honest, unbiased lead and advice on what camera and computer to buy?

hey, I ve been want to pick up on photography and videography so I ll be amateur to the fullest. Not sure where to start when it comes to cameras because I hear all types of things and don t want to be mislead and buy into something marketing scheme. Also looking for a computer for in depth editing that can glorify and magnify the photos/videos I want to capture. Also, don t want to spend an arm and a leg (picky picky, I know) but was hoping for some advice. Was look at a Nikon D7000 for camera choice and a MacBook Pro. Thanks for reading!

Read more: Want an honest, unbiased lead and advice on what camera and computer to buy?