r/u_DeepSpace1420MHZ

Researching the scans reveals, for a 4.5-meter dish at 1420 MHz, the theoretical half-power beamwidth (HPBW) is typically calculated using:

θ≈D70×λ
With λ≈0.21 meters and D=4.5 meters, its expected beamwidth is right around 3.26∘. The plot's physical span matches this math, confirming the mesh surface tolerance, feed horn illumination, and focus are dialed in optimally to capture the full theoretical resolution of the aperture.

This image created with Python with csv recorded drift scans 5/1 - 5/8/26, from Spectraview, “Hydrogen Line Radio Terrain," represents the results of drift scans performed using a radio telescope. The plot visualizes the detection of the Neutral Hydrogen Line at 1420 MHz as the Earth's rotation allows the telescope's fixed beam to sweep across a portion of the sky.
Breakdown of the Visualization
Vertical Axis (Z): This shows the Relative Hydrogen Signal (dB), indicating the intensity of the hydrogen emissions detected during the scan.
Horizontal Axis (X): Labeled as Drift Time, representing the duration over which the data was collected as the celestial objects passed through the telescope's field of view.
Depth Axis (Y): Labeled as Azimuth, which corresponds to the specific horizontal direction (between 75.00 and 77.00 in this view) the dish was pointed toward during the observation.
Color Scale: The "terrain" uses a heatmap where brighter yellow peaks represent the strongest signal intensities (reaching above 0.7 dB), while darker purple and black areas represent lower signal levels.
Technical Context
This specific data was generated using a 4.5-meter mesh dish. The prominent "mountain" in the terrain map illustrates the concentration of neutral hydrogen, from a section of the Galactic Plane (Milky Way), passing through the antenna's 34 dB gain beam. This type of 24/7 monitoring and data mapping is used to visualize the structure and density of our galaxy.