Correct lenses for different objects
Hey I have a 130 mm Newtonian telescope. I’ve been able to look at the moon a few times with good focus. I’ve tried looking at a few planets but they always come out blurry. What size lens should I used for them? I only have a couple: 20mm, 15mm, 10mm, and 9mm. I also have a red, blue and “moon” lenses. Also, should I even attempt looking at the planets and such in the summer? I heard it’s a lot better to look at them in the winter time. What are some good summer objects to look at? Is it possible to look at stars and clusters with my telescope with the lenses I have available? I’m pretty much a newbie but I’m excited to learn! Any advice is welcomed and appreciated!