SteveBz

And here is the maximum intensity in dB returned for each RA vertically overhead. Sorry it's in Excel!! The peak at about ~75 deg is much wider than the peak ~320 deg, which corresponds to the breadth of the curve on the diagram from the H1 survey. Obviously when I get the DEC axis working I'll need to get it into Matplotlib to get the 2D map, and the peak frequency could be false colour to show the doppler effect, like red <1.420 GHz (travelling away from us) and blue >1.420 GHz (travelling towards us). I'd like to show the lobes too where there is more than 1 peak. Not sure how to do this. Sadly, I think the stepper motor I have to drive the dish may not be working, as so far it has resisted all my efforts. I'll try for a bit longer, and then I may need to find a replacement. Not sure how, I may reach out here!! Hope you're having a good weekend. Kind regards, Steve.

Hi Guys, So I still have a noise problem, even with all the electronics powered down. Most of my scans look like this: But then occasionally, I get one of these: And everything seems worthwhile 😀 Maybe it's the central heating system or the fridge. Maybe I can move the dish a bit further away (or just turn the fridge and central heating off - not sure what the family will think). Kind regards, Steve.

Yes. I tried it up to 200 and I felt 75 was an OK value.

I should add that I also split out the 'gif' piece of your code into a spearate program so that I could run 'mogrify' first and then 'gif' it. Like this: import imageio import os # Main method # def main(args): # Generates and saves a GIF of 24H observations def generate_GIF(): arr_txt = [x for x in os.listdir('Spectrums/clean') if x.endswith("png")] dec=51.1 ra='all' ras=[] for fileName in arr_txt: sub1=fileName.find('ra=')+3 sub2=fileName.find('dec=')-1 raFlt=fileName[sub1:sub2] ras.append(float(raFlt)) ras.sort() print('Generating GIF from observations... This may take a while') path = f'Spectrums/clean/ra={ra[0]},dec={dec}.gif' images = [imageio.imread(f'Spectrums/clean/ra={str(raFlt)},dec={dec}.png') for raFlt in ras] imageio.mimsave(path, images) if __name__ == "__main__": generate_GIF() NB, I put all the files I want to 'gif' in a separate directory called 'clean'. Steve.

Hi Victor, Thanks for your kind words. Here is the command line: python3 H-line.py -s 2400000 -r 11 -n 10000 -e 192.168.1.116 -m 75 -i 2.50 -d -c And here is the config file: { "latitude": <x>, "longitude": <y>, "azimuth": 0, "altitude": 90, "low_y": -0.2, "high_y": 1.3 } I've just got 20 of those magnetic collars you recommended in the post this morning. I attached them all to everything in sight, but sadly it hasn't helped. I think I need to step through each device one at a time to see where the noise is soming from. Kind regards, Steve

And here is 24 hour's worth. I had to resize the photos to make it work with: mogrify -resize 960x *.png Which is available from ImageMagick. Ie sudo apt-get install -y imagemagick Now I need to start my campaign against the other sources of noise while waiting for the stepper motor driver to arrive. Kind regards Steve.

So with this one that I took last year of P Cygni and processed with BASS: The width at half intensity (6.0E5 on this plot) goes from 655.0 nm to 657.7 nm giving a width of 3.7 nm. I should probably call that 4 nm. 656/4=164 or 656/3.7 = 177, so it's a bit over 160, say in the range of 160-170. Is that right? Kind regards Steve.

OMG. I just unplugged all the electronics in the observatory! Look how clean it is! No Spikes at all!

Hi Robin, That's very cool - and easy to access. I can see people have been busy! Can I ask: 1) How do you calculate the resolution of those spectra? 2) What is a 'Star - Be' or 'Star - Be Candidate'? Kind regards Steve.

Hi Guys, Although I never got a fully corrected spectrum for Uranus, I was still mighty chuffed to have got as far as I did. Can I ask what ideas people have for the SA100 that I can look for during March and April? In fact is there a spectroscopy calendar that someone has put together somewhere? Kind regards, Steve.

Here is a shortened and compressed gif of a the period. It's a bit noisy, but the central region around 1.4 is not too bad. I've ordered a box of ferrite clips to put on everything in sight! Steve.

Also a good idea, as maybe the noise is comming from all the electronics in the observatory!!

So if that means 2 minutes exposure and 6 minutes download, it means there is less 'star-trailing'

Trying to upload the GIF, but it's crashing. It's 213 MB, so I guess there's a size problem. I might try again later.

Interesting. I may try that. The problem is that I don't have much space left on my RPi.

But Victor, the 24 hour scan is nearly done and it worked quite well. If I ignore the spikes there are some nice patterns. Can I ask, are you both using the NooElec H1 Premium LNA and the RTL-SDR v3 Blog SDR? If I add another LNA, it will increase the background noise together with the signal, but not the SDR spikes, I guess. I could also increase the n= number from 10,000 to even higher. The problem is that it means fewer increments, so the time is now 8.5 minutes per sample of 10,000 which is 144 steps of 2.5 degrees. As the beam-width is about 10-12 degrees, the longer the sample time, the less accurate the resolution. 2.5 degrees is 20-15% of the beam width, so I don't really want to make it less precise. If I had a longer sample time I think I'd need tracking! Not sure what to do next. Kind regards Steve.

So I did try shortening the coax from 25 m to 5 m, so maybe it improved. It was before I found the missing pins Maybe I could buy a handfull of ferrite clips and put them everywhere. Steve

So I have almost the same spikes as you. How can you tell if the rtl-sdr is genuine or not? Steve

Hi Zi Hao, How did you get to be so beautifully clean and without noise spikes? What software did you use? Have you stacked several images? Maybe I should put a wire fence around the scope like a chicken run! Kind regards Steve.

So the 24 hour mode is performing quite nicely. You can see the bumps corresponding to Cygnus, more or less. It's still quite noisy with those big spikes. Does anyone have any idea what is causing them? Maybe I should just truncate the data. This one here seems to be showing me three spiral arms. One at 1.4205 GHz, and then two more a bit further away. Have I read that right, or is it just noise? I don't know whether that is 'Perseus', 'Outer' and 'Centaurus, or Sag, Per and Outer. Any ideas. And even is that a fourth out at about 1.4212GHz? In which case I could answer the question. But really, I need to improve the data. Steve

So here's a quick update of the rig with it's 'hat' to keep rain off the electronics. Is it enough? What about condensation? Secondly (and it's dark here now), I've just added a superjack actuator to the DEC axis. It seems to be a bit under-powered. 36 v and 1 amp. Maybe 1 amp is not enough. What do people think? Kind regards Steve

Just restarted with: python3 H-line.py -s 2400000 -r 11 -n 10000 -l 51 -g 0 -z 0 -a 90 -e 192.168.1.116 -m 10 -i 2.5 -d Note n=10000, m = 10 and i = 2.5 (same as every ten minutes). I've hacked the 'd' option to dump in 24 hr mode too. Tx for the ongoing help!! Kind regards Steve.

Hi People, So amazingly I found the problems. Both were manufacturing faults: 1) My RTL-SDR was not an original model and the DC Bias never worked. The second one had all the manufacturers details and worked perfectly (apparently). 2) My elbow connection had no pins in it, so there was no current!!!! Both have now been fixed and look at the result. But I have these huge spikes (at about 1420.0 & 1420.8) which distort everything. What to do? Otherwise there seems to be a mild hump which I feel I can built on. I'm running a 24 hour scan now with i=1.25, m = 10 and n = 1000. Advice please. Tx Steve.

Tried it with no success. I'll try the new cable tomorrow and then I'll try Tx.

It's like this: python3 H-line.py -s 2400000 -r 11 -n 1000 -l 51 -g 0 -z 0 -a 90 -e 192.168.1.116 -m 3 -i 0 I gradually ramped up m to 200, which smoothed the line, but still no signal. I've got a new cable on order, should arrive tomorrow. Otherwise I managed to get the DEC motor working today, so that should help. I don't have a spare LNA, so I can't really check the SDR without shorting it again! Unless you think I should do it by turning off the bias T? Kind regards Steve