6 replies to this topic

[max.leeyl]

Hi,

 

I am planning to use my Panasonic G9 camera with Sky-Watcher MAK127 and AZ pronto mount to start my journey into planetary imaging. After studying through the Youtube tutorials and forum discussions, I cannot understand why there is (almost) no one using hi-speed burst still images for planetary imaging.

 

Using the electronic shutter, my G9 has the capability to take still images at the burst rate of 60 frames per second with 20M pixels for image resolution. On the other hand, it can take 4K60P videos. Therefore, for the same amount of recording time, you can get the same amount of frames using both modes to take still images and videos. But the resolution per frame is very different - 20M for still images and 8.3M for 4K videos. This, in theory, means by taking still images should yield better picture quality for the final result.

 

I just cannot see why there seems no one chooses to take still images for planetary imaging. I guess there must be something I didn't understand. Can you please help me figure out what I am missing here ?

Edited by max.leeyl, 27 March 2025 - 11:41 AM.

[Tapio]

Because the number of pixels mean very little in planetary imaging.

People still use ASI224MC camera which has 1.2 megapixels and get excellent images.

I recommend you to read the excellent FAQ.

[jeffry7]

I have done high speed burst for lunar. It is a pain

Burst, fill buffer, wait for buffer to clear, repeat.

How many frames can the g9 actually take before the buffer fills?

How many images do you want to collect? How long are you going to stand there pressing burst?

Do you have to touch the camera to start a burst? How long does the setup shake if you do. (Get a remote for your camera.)

While I don't recommend using compressed video for astro, I do understand how much more convenient it is than burst.

Oh yeah,while you are fiddling with the camera throughput trying to get enough frames, the target is drifting out of frame.

Pro tip if you want to use burst:
Get an intervalometer. Read how to use the bulb mode of the intervalometer. (NOT bulb mode on the camera!) Use the intervalometer to trigger the burst at intervals that allow the buffer to clear. In bulb mode, the intervalometer will let you set how long to hold down the shutter for the burst. Pick a time long enough to fill the buffer.

Or get a Planetary camera.

[bobzeq25]

Keeping it simple. High speed burst mode is limited to a relatively small number of frames before the buffer fills. Video is essentially unlimited.

People often take thousands of video frames.

Edited by bobzeq25, 27 March 2025 - 01:22 PM.

[RedLionNJ]

Hi,

 

I am planning to use my Panasonic G9 camera with Sky-Watcher MAK127 and AZ pronto mount to start my journey into planetary imaging. After studying through the Youtube tutorials and forum discussions, I cannot understand why there is (almost) no one using hi-speed burst still images for planetary imaging.

 

Using the electronic shutter, my G9 has the capability to take still images at the burst rate of 60 frames per second with 20M pixels for image resolution. On the other hand, it can take 4K60P videos. Therefore, for the same amount of recording time, you can get the same amount of frames using both modes to take still images and videos. But the resolution per frame is very different - 20M for still images and 8.3M for 4K videos. This, in theory, means by taking still images should yield better picture quality for the final result.

 

I just cannot see why there seems no one chooses to take still images for planetary imaging. I guess there must be something I didn't understand. Can you please help me figure out what I am missing here ?

There are two basic requirements for a good planetary imaging camera:  raw data (not compressed, not interpolated) and a pixel size commensurate with optimal sampling.

 

With a 5-inch scope (which is significantly under-sized for serious planetary work, as possible levels of detail capture are proportional to aperture), a planet like Jupiter, when optimally sampled, might cover 150 pixels at most. Let's just assume a square capture area, so 150 x 150 = 22,500.   So a 22 kilopixel sensor (if kept on-target) would suffice to capture all the detail possible.

 

The 3.34 micron pixel size means one should be capturing at about f/20 in order to optimize the sampling. Reaching around f/20 with a Mak may be problematic.

 

But the death-knell for the concept is really the way data is interpolated (and in many modes, lossily compressed) for the video modes. Interpolation is a major no-no for planetary imaging, as is lossy compression.  Perhaps the G9 has a video capture mode which does not interpolate or compress, but the manufacturer does not mention this in the marketing specifications.

[Tulloch]

What do you think a video is? It's just a collection of still frames in a "box".

 

The key point is (as mentioned above) is that the frames need to be uncompressed so that stacking will work without introducing artefacts. So while we take "videos" of the planets, these videos are huge, multi-gigabytes in size. 

 

For instance, I capture Jupiter at 150 fps for 3 minutes with an image size of around 400x400 pixels using a C9.25" SCT @ f/12 (focal length about 5000mm). This corresponds to a video file around 5 GB in size, but in actuality it is around 27000 uncompressed still frames. So I do capture stills (as does everybody else) in "burst" mode (to use a DSLR term) but they are not compressed into a movie format that most people are used to.

 

More info in the FAQ at the top of page (or linked to below).

https://www.cloudyni...d-january-2025/

 

Andrew 

 

P.S. Mind you, you can use "burst" mode on the Moon (where you need a full frame image), here's an example with my Canon 700D and only taking 50 frames in 10 seconds.

https://www.cloudyni...in-sports-mode/

Edited by Tulloch, 27 March 2025 - 06:04 PM.

[max.leeyl]

Thank you all for the very informative and helpful feedbacks. Now I understand the point of choosing to take videos for planetary imaging. Much appreciated.

 

The good thing is that I just verified G9 has a 1:1 pixel mode. By enabling the ex. teleconverter function, I will be able to shoot at 4K60P with 1:1 pixel resolution. I will use this as the starting point to see how far I can go. 

 

Thank you again for all your kindly help.