Radiotelescope news

Examples
3/ 2025

Example of one program run. Data is collected for around 2 minutes, then the observed frequency is shifter and dark frame is taken. To get the final data, we subtract light and dark frame.
Sometimes the final data will be at an angle, so we do a linear regression on edge data, and correct all data to get nice flat noise level at the bottom. We also need to calculate noise level and if it's above or under zero, we correct for that as well. The result is data with flat background noise level across observed frequencies. We sum all the values in the graph to get total noise power of the signal. That value is then placed on the map on the appropriate RA, Dec coordinates.
An example of first run of the data collection: The graph above only shows total noise power in RA, Dec coordinates.
The rotational speed of the galaxy can be determined from extracting graph peaks frequencies and comparing them to 1420.4MHz, calculating Doppler shift and the speed of the hydrogen cloud.

Data collection phase
10/ 2024

After working through network issues, and then Orange Pi burning out, the radiotelescope is finally in data collection phase. I'm doing the scans of the sky with the duration of 48 hours per scan, then moving 3 degrees in altitude and collecting for 48 hours again.
First sky map is expected to be finished in March-April 2025.
Further improvements to the radiotelescope include connecting the motor on the mount to be able to move it remotely.

First light
2/ 2024

First light of the telescope. The feedhorn was mounted, connected to the LNA and raspberry pi was placed in main cabinet. Hydrogen line was detected but there is a lot of interference in the signal in the form of narrow spikes. Interference was traced to the RTL SDR receiver under the dish, which was not enclosed in metal foil. After enclosing it in aluminium foil the interference was mainly gone. I plan to move the SDR to near the edge of the dish to further reduce interference it emits.

Various work
8-12/ 2023

The main electrical cabinet was mounted on radiotelescope pillar, new N-type connector replaced SMA connector on feedhorn, main electrical conduit was burried in the ground, wifi repeater was setup and Raspberry pi Zero was placed in the main cabinet.

Mounting the dish
7/ 2023

The parabolic reflector was mounted and welded onto a mount. Counterweights were installed

Feedhorn supports
6-7/ 2023

Welding of the feedhorn supports and painting them white. Building of the feedhorn ring clamp and attaching it to feedhorn supports.
I finished the new aluminium feedhorn as the last one was of questionable quality. Using a wooden mould and concrete, I made two dish counterweights.

Feedhorn supports
5-6/ 2023

Making of the feedhorn supports. I mounted them and checked the feedhorn alignment. The supports were a bit flimsy as they were only secured with 1 bolt each, so I decided to weld the 4 supports with the upper flat ring.

Building of the dish
3-5/ 2023

Filling the dish with 6mm steel wire. Purpose of it is to act as a wire mesh support. Next, I put a wire mesh with 8mm spacing inside the dish to complete it.

Concrete pillar
2/ 2023

Building of the concrete pillar. I also put the dish mount on top of it, securing it in concrete before it hardened.

Building of the dish
9/ 2022

Mounting the wooden arcs on the center plate that holds them together. Aligning them, and mounting a flat steel tape around them, securing them together.

Building of the dish
6-8/ 2022

Making of the wooden half-parabola arcs. 8 of them will make up the parabolic reflector dish.
They were painted with wood primer, then with several white top coats. I also cut and drilled holes into central metal plates that the wooden arcs will be bolted onto. I welded two pieces of square metal tube on one plate to be able to mount it on the mount. The Cat approves.

Making of the mount
3/ 2022

I made the mount by taking a wheel hub for azimuthal rotation. I welded a "U" metal bracket on top of it and added two bearings on the sides for altitude rotation. I also added a flywheel teeth ring to be able to rotate the mount with a motor.
Lastly, I painted it with primer for metal.