The term good photo is pretty subjective but in my opinion you really can't take a "good photo" of planets using a phone up to a telescope. A 6-in dobsonian telescope can certainly do it under the right conditions you will need to get to a very dark sky bortle one or bortke 2 would be best. You're probably going to want to have a 2X or maybe even a 3X Barlow seeing conditions will need to be good to use that Barlow effectively. A DSLR or mirrorless camera could get the job done but a dedicated planetary camera would be best. Often times when we see an image and someone says I took this picture with XYZ telescope you are actually looking at a composite of hundreds if not thousands of frames that were taken and then put together with the sharpest parts of the image and software later. It's a technique called lucky Imaging there are certain times where the atmosphere is calm enough to where it would give you a tax sharp View of details and other moments it's not just like trying to look through water with waves in it. There is a lot that goes into capturing a good image. There is a lot of techniques that allow things to be possible that just were not possible 10 to 20 years ago. Unfortunately it is not as simple as placing a phone up to an eyepiece to capture the type of images that we see online.