Entry level/Nightscapes:

• DSLR or mirrorless camera, ideally with at least a 16 megabyte sensor.
              Nikon D7500 or D750, Canon 7D II or Rebel T7, Sony a6400 or a7S
• Sturdy tripod
• Fairly fast wide-angle lens (f/2.8 or faster, 35mm or wider.)
              Sigma 24 or 35mm f/1.4, 14mm f/1.8, Rokinon 14mm f/2.8, 24mm f/2.8
• Recommended but not essential to start
              Intervalometer
              Star tracker
                          iOptron SkyTracker Pro, Move-Shoot-Move, Sky-Watcher Star Adventurer

Intermediate- deep sky imaging:

• DSLR or mirrorless camera as above or more advanced
• Sturdy tripod
• Fast telephoto lens, f/5.6 or faster, prime lenses generally better
• Tracker essential
              iOptron Sky Guider Pro, Sky-watcher Star Adventurer, Fornax Light II
              Note: these are not GoTo trackers. Knowledge of the night sky is necessary to find targets

The next step:

• GoTo mount EQ mount
              Sky-watcher EQM-35, EQ6-R, HEQ5, Celestron AVX
• Telescope
              William Optics Redcat 51 or Gran Turismo 71, Sky-watcher Evostar 80ED

Advanced—the sky is the limit:

• Dedicated cooled astro camera
• Large telescope
• High-end EQ mount
• Narrow-band filters
• Astro-specific software—Pixinsight, AstroPixelProcessor, Deep Sky Stacker
• Private observatory

Caveats: Although some try to take deep sky images without using a tracker (by taking up to 1000 1 or2 second exposures), I do not recommend this. Neither does my computer. Likewise, there is a growing interest in doing astrophotography with a cell-phone. It can be done, but the small sensors make achieving detailed, noise-free images challenging.

At the intermediate level of deep sky imaging, there are trade offs in terms of a prime telephoto lens vs a wide-field telescope. At a similar focal length, 250-400mm, prime telephoto lenses are more expensive than telescopes, but they can also be used for wildlife and sports photography.

The above examples are not meant to be all-inclusive. Many similar models from other brands are available.

Although there are many specialized software programs available, most experienced photographers are familiar with Lightroom and/or Photoshop. Deep sky images can be opened as Layers in PS, aligned, stacked, and processed without additional software.