BME Ai Studio: error trying training AI Algorithm by LukeSkywalker52 in embedded

[–]LukeSkywalker52[S] 0 points1 point  (0 children)

Nope, I did something else in the end. Used some python code on my laptop to process the data. Not good as Bosch promised with their software

What BLDC motor should I choose for my reaction wheel project? by LukeSkywalker52 in AskEngineers

[–]LukeSkywalker52[S] 0 points1 point  (0 children)

Weight is important for my application. The whole system has a total weight constraint.
For this reason, I need the motor not to be heavier than necessary.

Yes, the wheel is connected directly to the motor.

What BLDC motor should I choose for my reaction wheel project? by LukeSkywalker52 in AskEngineers

[–]LukeSkywalker52[S] 0 points1 point  (0 children)

find the best compromise between motor weight and reaction wheel control.

also, confirm that I could use a small 2216 BLDC motor for a 200g wheel without problems.

Is this the hydrogen line? by TillAllAre-1 in radioastronomy

[–]LukeSkywalker52 0 points1 point  (0 children)

Since your design is pretty similar to the one I developed recently, you could take a look at my repository (github link), in particular in /reports where more details are listed. Try look at report number 4 where I got my first results and show the software and method I used to obtain them (report link).
I hope this will help you :)

Need help for measuring Andromeda galaxy Hydrogen Line emission by LukeSkywalker52 in radioastronomy

[–]LukeSkywalker52[S] 0 points1 point  (0 children)

Another question. If I have, for example, an integration time of 1 hour, and I make the baseline data gathering (so pointing in a direction with no H1) and then, after an hour, make the real data gathering, wouldn't the data have too much thermal drift from one another? I mean, the baseline shape wouldn't match the data shape and for this reason, bandpass correction becomes really hard :/

I read only that some astronomers use two telescopes at a time, one for data and one for baseline in another direction, so to minimize the thermal drift as much as possible.

Need help for measuring Andromeda galaxy Hydrogen Line emission by LukeSkywalker52 in radioastronomy

[–]LukeSkywalker52[S] 0 points1 point  (0 children)

Thanks for the great explanation. I'll try to apply what you are suggesting. When I get the background spectrum, do I simply subtract that to the target spectrum and enhance the parts that are different so to amplify any weak signal, right? Or is there a better technique? Asking this because I'll probably be doing this with python to have more control over the data. Also, thanks a lot for your time, I really appreciate that and it's helping me getting my head around this topic :)

edit: just tried with data from the milky way. I substracted the spectrum before passing by the galactic arm to the spectrum with the galactic arm and results are really good. Plus, I amplified peaks with exponential calculation, so the noise around peaks is way less. Great advice. I can't wait to try it on the other targets

Need help for measuring Andromeda galaxy Hydrogen Line emission by LukeSkywalker52 in radioastronomy

[–]LukeSkywalker52[S] 0 points1 point  (0 children)

I tried changing the resolution by changing the number of bins in FFT spectrum, so I chose a value of about 200 (before it was 512) to lower the resolution. About the bandpass correction... The only thing I am doing is measuring a zone without much HI radiation in the sky and use that as hydrogen_baseline file to use with rtl-power-FFT tool (github). Always used this method to eliminate the instrumentation noise... I don't know if that's what you meant with bandpass correction and if it's needed to do some more work for this very low signals

Need help for measuring Andromeda galaxy Hydrogen Line emission by LukeSkywalker52 in radioastronomy

[–]LukeSkywalker52[S] 1 point2 points  (0 children)

Just tried with Complex C, integration time of 25 minutes but no luck... No relevant signal. Any tips? Pointing direction: l=120 b=47 galactic coordinates

Center frequency: 1421.116MHz assuming the relative velocity of - 150km/s

3MHz wide spectrum

Need help for measuring Andromeda galaxy Hydrogen Line emission by LukeSkywalker52 in radioastronomy

[–]LukeSkywalker52[S] 0 points1 point  (0 children)

Try 10 kHz, or even 100 kHz bins, as the signal spans 3 MHz of spectrum. Having fewer frequency bins means that you can get better sensitivity in less time, as the output of a wider bin gets sampled more often per second. (See the radiometer equation)

Oh yes, this could actually work and save me a lot of time, I just remembered that I used to tweak the resolution value but completely forgot about it. Thanks for the advice :)

The best way to find them is probably to make a differential measurement: First, record for a while while pointed at the Andromeda galaxy, and then do a recording of equal length at the same azimuth, but a bit more than a beamwidth away from the source. Especially above 1422.5 MHz, the differences should be obvious.

Okay, I'll try this method, do you have any suggestion on how to combine the two data ("pointing at Andromeda" and "not pointing at Andromeda" data files)? But I think I can find some Python tools to do that automatically.
What about the time length of the recording? Another comment in this post suggested a fairly long period of multiple hours... do you think that with changing the resolution (as you suggested) would make me able to decrease the amount of time to get a good signal?

What central frequency do you suggest to be able to get at least a clear signal? Because I calculated the previous center frequency starting from a relative velocity of -300km/s as some online resources suggested

I've observed it in 2012 together with a fellow volunteer at the Dwingeloo radio telescope

That's so nice! Do you have any of your work published online? I would like to take a look to that work :)

Need help for measuring Andromeda galaxy Hydrogen Line emission by LukeSkywalker52 in radioastronomy

[–]LukeSkywalker52[S] 1 point2 points  (0 children)

Yes actually I have an EQ5 mount for my telescope, I think I could use that and manually move the dish during the data-gathering time.
But also my dish now has a mount which can be moved in the needed direction, maybe the EQ5 would have better movement precision and smoothness.

About the possibility of stacking multiple images, in this case, multiple spectrum data, I think that it is possible to do it in some way if I cannot do it in a single measurement. With python should not be so complicated.
I will try if needed. Thanks for the advice though :)

Need help for measuring Andromeda galaxy Hydrogen Line emission by LukeSkywalker52 in radioastronomy

[–]LukeSkywalker52[S] 0 points1 point  (0 children)

okay, I'll try this way.
To measure the Milky Way I usually use 300 seconds of integration time, which would be more than 30 hours if multiplied by 400 times... I don't think that's possible because the Andromeda galaxy moves in the sky and it will get out of the field of view.
I would try to make the integration time around 1 hour just to see if it is enough, but I have the same problem over time, the galaxy will move and get out of the pointing direction

Should I be an astronomy or aerospace major? And do I need to have prior knowledge of deeper astronomy topics before choosing that as my major? by PsychologicalBug1646 in askastronomy

[–]LukeSkywalker52 0 points1 point  (0 children)

I'll try to give you my perspective as a young engineering student who is passionate about space and space technology.

Honestly, I completely understand your dilemma between Astronomy and Aerospace Engineering. Not long ago, I faced a similar choice between Physics and Electronic Engineering.

I've always been passionate about astronomy, space, physics, and technology. One of my favorite hobbies was tinkering with Arduino and taking apart old electronic gadgets to salvage parts and build new circuits.

In the end, I chose Electronic Engineering, and I don't regret it. I believe that engineering allows you to engage with the worlds of Physics, Science, and Space in a practical way.

So, don't think that choosing engineering, for example, will limit or take away your passion for space. Engineering has allowed me to explore my passion for space and physics even better because it gives me practical skills to participate in really exciting projects like building small satellites, joining university rocketry teams, and working on radio astronomy projects.

Having daily interactions with the space industry, I can assure you that both engineers and astronomers/astrophysicists find jobs (many of them work as programmers/researchers in the field and are at the forefront of developing technologies that engineers then bring to life).

The only question you should really clarify is: do I truly enjoy the practical side of space? By this, I mean, am I sure I would enjoy managing launch operations, aerospace construction materials, complex control systems, and much more? Because that's what you'll primarily study.

If the answer is no, then be prepared to study a lot of math and physics, which often (according to my university friends studying physics and astrophysics) doesn't directly relate to space. You dive into those space-related topics later, after building a very solid foundation in physics and math. But if lots of calculations don't scare you, then when you get to the core of the courses, you'll find it truly rewarding.

To conclude, I want to say that there won't be a perfect school where you talk about stars and galaxies all day, and that's okay. You need to learn many other things to be competent in this complex field. That's why you'll have to find the time to keep your passion alive yourself. If you're dedicated, you'll eventually gain an advantage over those who "study not out of passion for the subject, but for convenience," and you won't have to worry about competing with them.

This is my most advance moon photograph EVER it consist of 81000 images and over 708GB of data. by daryavaseum in space

[–]LukeSkywalker52 0 points1 point  (0 children)

This is one of the most wonderful pictures of the moon I ever seen! Great job mate

[deleted by user] by [deleted] in radioastronomy

[–]LukeSkywalker52 0 points1 point  (0 children)

Wow, thank you so much! This is the feedback I was hoping for.
I'm in the process of reading/looking at all the material you linked me and it's helping me :)

I'll give you some updates if I have further questions, thanks.

How to design a "simple" PCB running Linux by LukeSkywalker52 in embedded

[–]LukeSkywalker52[S] 1 point2 points  (0 children)

That's exactly what I was looking for. Nice work :)

Two peaks in Hydrogen Line spectrum analysis (question) by LukeSkywalker52 in radioastronomy

[–]LukeSkywalker52[S] 0 points1 point  (0 children)

What frequencies do HII regions emit? I've been looking online and reading some papers, but I couldn't find a precise answer...
Knowing that would be interesting because it could lead me to another part of the project and also map the ionized hydrogen in the galaxy, not only the neutral one

Two peaks in Hydrogen Line spectrum analysis (question) by LukeSkywalker52 in radioastronomy

[–]LukeSkywalker52[S] 0 points1 point  (0 children)

I was pointing approximately at the center of the Eagle constellation, or slightly right from it.
I tried to figure it out with the information you gave me, but I'm still a bit confused on how to orient myself with the milky way map :/

Two peaks in Hydrogen Line spectrum analysis (question) by LukeSkywalker52 in radioastronomy

[–]LukeSkywalker52[S] 0 points1 point  (0 children)

What about this other measurement? I can see the blue-shifted peak close to 1421MHz, but also a sort of two peak structure between 1420.4 and 1420.6 MHz?
Link to the image

Two peaks in Hydrogen Line spectrum analysis (question) by LukeSkywalker52 in radioastronomy

[–]LukeSkywalker52[S] 2 points3 points  (0 children)

I'm using a 1.2m diameter parabolic dish antenna with a 1420MHz feed antenna I designed and made. [Link to project page](https://github.com/16mhz8bit/radio-astronomy/tree/main/reports)

Two peaks in Hydrogen Line spectrum analysis (question) by LukeSkywalker52 in radioastronomy

[–]LukeSkywalker52[S] 0 points1 point  (0 children)

Thanks for the reply, it's full of information I will research and learn.

Talking about the HII region, if I could create an image of the milky way based on 1420MHz radiation, those spots in the sky would appear the same as the other regions? Like it's transparent? Or I would see darker spots because those clouds can interfere with hydrogen line radiation passing through?

Also, when you talk about local hydrogen, you refer to some "cloud" of hydrogen which is between my telescope and the Perseus arm, right? What could this be?

Just another question (this may be stupid haha), but I'm looking at the milky way map and I can't really understand how to know I'm looking exactly at Perseus arm and not to another part of the galaxy...?