Annette that’s not really an image of Venus - what you have captured is the out-of-focus disk of light from Venus. If you had the iPhone exactly at focus the image (and what you’ll see using your eye) is a bright disk filling the aperture of your scope, not an image of Venus !
To obtain an image you need an eyepiece to produce an afocal beam - exactly as you would see looking into a telescope.
The next issue is that if you can get an eyepiece onto the back of that mirror lens you’re going to find the image of Venus is disappointingly small - the focal length and resolution of that mirror lens are both hopelessly too small and you DO need a rather larger telescope.
Now THIs is a nice picture of Venus
https://artsandculture.google.com/as...Vg?hl=en&avm=2