why are there no stars showing in that pic ...over the horizon....?
Resolution/sensitivity is probably far too low.
Because it’s the lunar daytime.
Because NASA forgot to turn on the Star Lights in the Lunar Landing Studio in that picture??
Pullllease.
Perhaps also filters such as that seen on the visor of the astronaut.
The earth’s atmosphere filters out a substantial amount and cross section of EM radiation (allowing some of that portion which we see here). These filters are strong enough to block stars as well.
There is no atmosphere on the moon. Stars are not visible without an atmosphere.
Try taking a picture of someone outside at night. If you can photograph someone clearly, stars shouldn’t appear unless you have it set for a long exposure. The light from stars is very faint.
Stars are dim and the moon in full sunlight is bright. An aperture and shutter speed which allow the astronaut to be seen as anything other than a pure white blur means that not enough starlight is coming in to expose the film.
Notice the very deep depth of field in the picture. That means the aperture is very small, so less light is getting to the film.
Even from earth a shot showing both the stars and the moon is usually a double exposure because it is very difficult to shoot both.