I remember J using the "telescope" we have at the zoo (where we went partly as a homeschool excursion and partly to play with the camera). I don't know how long yours is, I thought his was a tad excessive XD
Youngest found a magnetic pet door flyscreen thing that we bought years ago, we never put that one up as the first one that we put up (we'd bought two thinking we could do one for the front and back doors) kept falling down every time my dog went through it. Youngest attached it to the actual flyscreen door rather than using it as a door/curtain but this morning it had fallen off which J was saying he thought was what would happen.
If youngest can be bothered I'll see if he wants to paperclip the top part of the door to the flyscreen as that's what he did at the bottom for some reason in addition to the double sided adhesive provided with the door (he was grouchy at me as I told him he wasn't allowed to use the tacks as I didn't want random holes in the wall).
He was so excited about being able to leave the door open in summer too ^_^; (part of the flyscreen on the actual flyscreen door keeps coming undone despite us attacking it with a tool that's meant to attach flyscreens to doors, I keep lobbying for a security door with those metal flyscreens that are attached to the actual door so they won't come off but keep getting knocked back because expensive)
See! Size does matter.
This reminds me - I have to find a decent solution to stop the dog at the top and bottom of the stairs. There are screens, but nearly all of them require drilling into the wall (for the gap size) and I don't want that! :D
It is really weird in Finland, as pretty much no front/back doors have fly screens, even though mosquitoes are a huge issue here. Even on windows, it is only 50/50 if there are fly screens. We have them on ours though.