Some food for thought.
When it comes to photographing the planets it takes a lot of focal length (think f22), however the sky is full of objects that fill a 200mm on a crop . 600 works well on the smaller objects, 800 and galaxies are doable . I have a scope like you are looking at and find it less than appealing for daytime , remember you are magnifying the air also and they are not color corrected and coated like your lens, it is however great for the moon , Jupiter and seeing the rings of saturn. There are really only 3 planets and the moon that are realistic for most without very deep pockets. A newtonian at about 200mm f4 opens up the entire the universe very affordably. I would find what you want lens wise for birding and point that skyward. Samyang make a 300mm cat that is cheap if you just want something to play with.