Orion and a little bit of milky way - Google Pixel 7 with DeepSkyCamera beta

[ONIKKINEN]

126x 17s untracked exposures taken with DeepSkyCamera beta. Calibrated with darks and flats and stacked in Siril, processing with PixInsight (including BlurXterminator - which is why the stars are nice) and Photoshop. Flats didn't quite work perfectly, still experimenting on flats exposure times.

Its crazy how technology has improved, a few years back would never have believed a phone would take this image. If you look closely you can see the flame nebula, the H-alpha region where the Horsehead would be (not seen at 6.81mm focal length obviously), part of Barnard's loop, the Rosette nebula, some open clusters like M35. Still a short integration yet all those things have pushed through the noise floor - very impressed with the performance of the Pixel 7.

There is also a foreground, which i had to crop as didn't quite figure out yet how to best integrate that to the sky image. Gradient removal especially will be tricky with the foreground visible, i think i need to stack the foreground separately and try to combine that to the star image in Photoshop.

 For a first test shot i will call this a complete success, greatly exceeded my expectations to put it mildly.

[saac]

That's incredible, I would never have thought a mobile phone was that capable. 

Jim 

[ONIKKINEN]

1 minute ago, saac said:

That's incredible, I would never have thought a mobile phone was that capable. 

Jim 

I know right? Its hard to believe a phone can do this, but apparently one can.

I am particularly pleased to see that the phone outputs true raw images with no sRGB gamma or internal meddling with noise reduction to the frames, which is why proper stacking becomes possible.

[saac]

So what format does the Google Pixel use for image file? 

Jim 

[ONIKKINEN]

10 minutes ago, saac said:

So what format does the Google Pixel use for image file? 

Jim 

The built in camera app outputs JPEG and raw .DNG, but there are only a few settings to pick from so i am not sure as to whether they are true raw images or not. DeepSkyCamera beta outputs raw .DNG which are fully linear images, which is easy to see since every image is strongly green as one would expect a colour camera to output if there is no internal meddling with levels. Lots of hot pixels everywhere too, which makes me believe that there is no internal noise reduction applied to the images before saving - so i will call it a true raw image.

[pipnina]

I have tried to do astro with my Pixel 6 in a similar way with the same app. I also ran into the same flat calibration issue.

I suspect the lens suffers too greatly from internal reflections. I also noted that despite the images supposedly being RAW, it appeared as though the camera was still imparting a white balance into the image which may affect matters.

I also struggled a LOT with hot pixels. Did you succeed at removing or handling them in your phone? In my case I was shooting in summer so it was 15c outside.

I also did not have BlurX or NoiseX. Certainly however many differences in technique (or hardware from P6 to P7) your result is miles ahead of what I achieved!

 

[saac]

18 minutes ago, ONIKKINEN said:

The built in camera app outputs JPEG and raw .DNG, but there are only a few settings to pick from so i am not sure as to whether they are true raw images or not. DeepSkyCamera beta outputs raw .DNG which are fully linear images, which is easy to see since every image is strongly green as one would expect a colour camera to output if there is no internal meddling with levels. Lots of hot pixels everywhere too, which makes me believe that there is no internal noise reduction applied to the images before saving - so i will call it a true raw image.

Thanks ONIKKINEN. It looks perfectly matched for astrophotography, certainly produces fine results. 

Jim

[ONIKKINEN]

7 minutes ago, pipnina said:

I have tried to do astro with my Pixel 6 in a similar way with the same app. I also ran into the same flat calibration issue.

I suspect the lens suffers too greatly from internal reflections. I also noted that despite the images supposedly being RAW, it appeared as though the camera was still imparting a white balance into the image which may affect matters.

I also struggled a LOT with hot pixels. Did you succeed at removing or handling them in your phone? In my case I was shooting in summer so it was 15c outside.

I also did not have BlurX or NoiseX. Certainly however many differences in technique (or hardware from P6 to P7) your result is miles ahead of what I achieved!

 

I solved the flat issue just minutes ago, the acceptable exposure time range is quite narrow with my very blue LED panel when the 10-bit sensor has quite a shallow full well depth (have to fit red and blue both into the histogram, which is difficult with my panel). I also found out that there is a median dark value of 64, which i subtracted with a stacked master bias frame. I cant see any internal reflections in the flats, i did see a few in some light frames where a nearby car had lights on just outside the frame illuminating the foreground - horrible streaks across the entire image so it can happen it seems.

20 x 17s darks with aggressive cosmetic correction for hot pixel sigma seems to have eliminated the hot pixels, i also manually dithered every 10-20 exposures or so which kind of happens naturally with untracked imaging when i have to re-center anyway. To be fair it was -7c when imaging, but i think the phone runs much hotter as it was noticeably warm to the touch. It may be the case that your phone was really operating at +30 or more which is much worse. Summer will tell if that is the case for mine as well.

BlurXterminator is really good here, the field is not at all flat and corner stars are kind of banana or cross shaped - far from a perfect lens in the camera. The newest AI can correct these aberrations as long as they are fairly consistent and can be measured from the stars.

[ONIKKINEN]

Another version, this one was stacked with properly working calibration frames:

Pulled out some of the H-alpha regions better. Getting to the point where its spent a little bit too much in the oven, i think this is all i can pull out of the image for now. I am noticing that this kind of very wide field milky way processing is very different from my usual 1-meter focal length telescope images, a whole new game to learn it seems.

The abundance of Ha in a 35 minute image greatly surprises me. Most of Barnard's loop is visible, as is the vast cloud of Ha above it (not sure what this is called, if it has a name). Should be said that the horizon is maybe a thousand pixels from the bottom of the image here, so far from ideal conditions to try and pull out faint stuff from. Will absolutely be doing more imaging with the phone to see what it can do!

[happy-kat]

The image is great lots to see in it. How did you mount your phone or was it propped on something?

[ONIKKINEN]

36 minutes ago, happy-kat said:

The image is great lots to see in it. How did you mount your phone or was it propped on something?

Its mounted on an AZ-5, with all sorts of parts i had at hand. The phone holder part itself is a Celestron smart phone eyepiece adapter that didn't survive the first Finnish winter and some plastic bits broke that prevents its intended use. The holder is ziptied to a Skywatcher L-bracket that i bought years ago but never ended up using and the L-bracket sits on the AZ-5, which sits on top of an EQM35 steel tripod with the polar alignment peg sawed off. I have full alt-az movement this way, but only limited roll control because the ziptie prevents full movement, and forces me to use only portrait mode. So yeah, a monstrosity that MacGyver would be proud of, but it works.

[happy-kat]

Thanks. The L bracket I've used here to similar effect but I'm a rubber band fan for fixings

[Elp]

I've actually cobbled together something robust for this intended use but haven't tried imaging with my phone yet (it was made for using Skeye as an alternative to Starsense, the phone mount can be rotated 90 degrees from the image to be in line with the dovetail and phone can be mounted portrait or landscape and perfect to plonk on top of a tracking scope in a finder bracket):

 

[Jeff-Colorado]

Your image puts mine to shame, but here is my first ever cell phone image.
Bortle 7 skies with Orion near a half Moon (so basically, crap conditions)
Pixel 7
8SE with f/6.3 focal reducer
25 mm X-cel eyepiece
Affinity 2 to darken the image background

As you can see, I've got a camera reflection, a gradient problem, and focus issues. Still, it is surprising to see what a Pixel 7 in night mode can do. Hopefully I will be able to improve on this in the near future.

Edited April 12 by Jeff-Colorado