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Astrophotography

Vizy applications
#1

Took delivery of the camera today, pretty much purchased for the sole purpose of astrophotography. Has any ground been broken on the official app? Suspect that’d be a “No”. In the meantime, I might have a go. Thoughts so far:

  1. Forget talking to my SkyWatcher WiFi alt-az mount for now, it can look after itself, and keep pointing at the object of interest.
  2. Churn out something quick and dirty-ish that will just capture some darks, then a series of (hopefully) RAW images at regular intervals.
  3. Take the images home to mess with in scikit-image/numpy.
  4. Subtraction of darks, field-rotation and stacking of images shouldn’t be All That?!

https://www.mathworks.com/help/vision/ug/find-image-rotation-and-scale-using-automated-feature-matching.html
https://scikit-image.org/docs/dev/auto_examples/features_detection/plot_censure.html

Are there any UI/API docs around? I’ve already had a look at G.H?

1 Like
#2

I would concur some basic function as suggested would be helpful. not so much interested in squirrels.

#3

Hi augeas,
The UI docs aren’t available yet (sorry). The power board API is here. The examples provide some ideas of what you can do inside an app. Most of the UI is based on Dash. Feel free to ask any specific questions.

It sounds like (for starters) a simple app that allows Vizy to take some exposures would be useful. I’m guessing it would be nice if it were controllable from your phone over a browser interface. Is that what you were thinking?

Edward

#4

would be a helpful start, some basic functionality to capturing some basic image information background data and raw images that can be stacked and being able to view real time for focusing and tracking the view from my perspective

#5

I’ll have a poke around, see if I can throw together an “example” and come home with some Beehive Cluster or Orion Nebula pics taken in the field, and have a play with those…

As disappointing it is not to be auto-stacking straight out of the box, it’s still cool to have a light camera one can ssh into…

#6

Maybe I can help out here. I’m an aspiring astrophotographer. If you guys are willing to give some code a whirl, I’ll see what I can cobble together in the next week or so. :slight_smile:

#7

I had dabbled with a Github astropicam application by I believe Louis-e.
It was written for the 8M pi cam I had modified it to work with the HQ pi cam just some minor changes. I was running it on a pi zero with some lag issues and instability. It was intended to be a compact small device with a VNC streaming. But it would allow some imaging albeit too slow to allow the focusing or effective tracking in field of view or reliable image storage. It also used the older legacy camera applications unlike vizy. I will see what I have it could be a starting place. The pi 4 would likely work better especially with the newer cam apps. It did achieve some of the intent if not well enough.

#8

But happy to try out anything for the vizy.

#9

I’d be happy to test some things too.

#10

Cool – I’ll try to get something ready by this Friday. :slight_smile:

#11

Hello,
I spent some time on this. It’s kind of a hack. It runs the libcamera-still utility with some configurable arguments – shutter time and analog gain, which are both sliders.

Image 648

When you want to take a picture click on “Take pic” and it will take a picture and show you the picture. There are two “tabs”: Preview and View. The preview tab gives you a live view of what Vizy sees. It’s good for focusing. There are two sliders “Preview brightness” and “Preview framerate” which you can adjust if preview exposure needs to be adjusted.

To install download the file below and copy to the home directory on Vizy (/home/pi). This page will help you get files on/off your Vizy.

Then run “tar xvfz pictaker.tgz”. This page will help you run commands. It should then install in the ~/vizy/apps directory.
Hit refresh on your browser before bringing up the “apps/examples” dialog and you should see it un apps:

Image 649
Image 649480×566 176 KB

Hopefully this could be useful for playing with and taking pics through a telescope. Let me know how it goes. We will come out with a less hacked and more feature-rich version, but hopefully this is helpful in the meantime. :slight_smile:

pictaker.tgz (2.0 KB)

#12

I downloaded, installed, and ran it with no issues. It seems to work as advertised.

The long exposure capability is great. I’m not sure how well the preview will work for focusing.

It’s cloudy here (of course) so I can’t try it on any stars. I’ll see if I can play with it a little more this weekend.

Thanks edge!

#13

Hello downloaded and installed looks pretty good! I will give it a try and see how the preview works for me for focusing and spotting.

Future things to think about might be:
the ability to allow binning
Multi image capture sequencing
Is there an ability to get raw images?

I will let you know how I male out. May take for a warmer weather spell and a clear night too of course :wink:

#14

Hi McAndrew,
This all sounds good. Regarding raw images, it’s something we can try to target for the next version of the python-libcamera library (kcamera). Which raw format? Let me know which processing programs you want to use so we can be sure to get it right :slight_smile:

Edward

#15

I am no expert on the various image file formats to be sure the RAW format is uncompressd and larger and is essentially unprocessed in any substantive way. They are reputed to give the maximum ability to post process and edit image information. For stacking and background subtraction. When converted to JPG the processing and compression reduces information in exchange for smaller size = Los of information. This is a synopsis of the various formats: https://digital-photography-school.com/understanding-all-the-different-image-file-formats/

Additionally, there is the concept of binning pixels that effectively reduces resolution but sums several adjacent pixels into one sum.
The astropicam program I referred to earlier incorporates this concept. I believe it is an inherent capability of the camera chip, if I recall correctly. Again, I am very new to dabbling and not proficient, to say the least. There may be something to learn from that application; it is based on the older camera routines rather than the libcamera one in more recent releases.

#16

  1. I played with RAW format a bit using this project: https://github.com/schoolpost/PiDNG.
    It did work, although that was before the switch to libcamera, so I don’t know if it still works or not. It generated AdobeDNG format RAW files which can be processed by lots of different software.

  2. By the way, I have tried to image the sky with pic taker. I tried focusing on the moon and wasn’t able to get it very sharp (my lens isn’t the best). I think focusing on a distant subject during the day would be the best approach. Also, I had trouble with the exposure for the moon - it’s very bright and I couldn’t lower it enough to see any detail. It’s probably something I’m doing wrong.

#17

Hi Ed,
Do you remember the exposure settings? You should be able to adjust the exposure and gain lower enough to get a decent exposure, although the slider might be a little fiddly with the lower exposure values.

Edward

#18

No, I don’t remember the exact settings.

Actually, thinking about this, over exposure shouldn’t be an issue - we can always just stop down the lens.

It looks like it’s going to be clear again here tonight. I’ll try to do a more controlled experiment and report back.

#19

I tried again last night and was able to focus on a bright, distant light with preview and take some long exposure photos.

A couple of questions:

  1. The WiFi signal in my back yard is weak. Once Vizy lost WiFi, it never re-connected to the network even when I brought it back inside. Should it reconnect automatically?

  2. I was powering the Vizy through the USB C connector and this worked fine. But when I tried to do a safe shut-down by holding the button, I think it worked - but the button was still lit. Is this normal?

#20

Hi Ed,
Glad you got some pics :slight_smile:

Currently Vizy will try to connect to the last network it successfully connected to. It will attempt to connect only one time upon boot up. If it’s unsuccessful, it will go into access point mode.

If Vizy connects successfully and then loses connection, it doesn’t do anything. It should probably do something… it should probably go into AP mode. (AP mode is a good fallback because it allows you to connect and reconfigure networking, etc.) There are some challenges with these kinds of things because losing the network can be difficult to detect. But for now at least you can power cycle Vizy and it will reconnect.

That’s correct – when powering through the USB C port, you’re bypassing the power board and Vizy can’t switch off power. It can still shut itself down cleanly though. The beep will tell you that things are shut down and you can safely remove power.

Edward