What primary observational tools are necessary to pierce the dust barrier and map the galaxy?
Answer
Radio astronomy and infrared astronomy.
These techniques utilize longer wavelengths (radio waves and infrared light) that can pass through interstellar dust much more effectively than visible light.

Related Questions
What causes the Milky Way to appear as a faint, glowing band when viewed from Earth?Why is it difficult to map the Milky Way's structure using only visible light?What primary observational tools are necessary to pierce the dust barrier and map the galaxy?What specific feature do astronomers target using radio astronomy to map the distribution of gas clouds?What is the role of the Doppler effect in constructing a three-dimensional map of the spiral arms?Where is the Solar System located relative to the galactic center and the major features?What structural feature distinguishes the Milky Way as a 'barred spiral galaxy'?How do astronomers confirm the internal findings about the Milky Way's overall shape?What specific structural detail of the galactic bulge has been clarified using X-ray data?What makes the definition of where spiral arms begin and end often fuzzy in scientific models?