Tuesday, 19 October 2021

Smartphone Astrophotography

 Evening all.  A few weeks ago, I was fortunate enough to attend my first Star Party for 2 whole years.  The famous AstroCamp was back with a bang.  Every camp I have been to in the passed, I have summed up in a blog post when I got home.  Not this time though.  For once I decided to give the blogging part a miss.  But that doesn't mean I didn't love the whole experience as usual.  This camp was obviously different and truth be told, for me wasn't necessarily about the astronomy, but an excellent chance to meet up with all my friends who I hadn't seen for the last two years.

The forecast for the weekend was generally quite poor, so I took the unusual decision of not taking any astronomy equipment with me.  I know that there would be others there with their telescopes, so I could always visit someone else's eyepiece for any views.  In what turned out to be one of the wettest AstroCamps I can ever remember, the most bizarre happened.  Despite all the cloud, all the wind and all the rain, we still got quality time under the quality sky of Cwmdu for 3 evenings.  Typical.  Stuck at a star party, under clear sky with no astro kit.  What was I going to do?

I started thumbing through my phone and I decided to read up on how people manage to get some quality images just off their smart phones.  At the moment, I use a Google Pixel 4, so I started my search there and it was soon obvious that unbeknownst to me, the Pixel 4 is actually rather good at this astrophotography landscape thing!  From using it before, I knew that the phone had 'Night Mode' which has always been an option when working through the camera settings.  I thought that was it.  But I couldn't understand why all my efforts only come out mediocre at best...

Ursa Major in 'Night Mode' with the Google Pixel 4

Don't get me wrong, it's kind of impressive that a smartphone can pick out any stars with a sensor and lens as small as that at all.  But it's no where near the type of photo I had seen elsewhere.  It was while I was swiping through some web page about smartphone photography that I found an article written on astrophotography specifically with a Pixel 4 and it presented me with an answer which was annoyingly so simple that I can't believe I hadn't found it before.

Once the phone's camera is in 'Night Mode' the phone then starts monitoring for any sort of movement caused by the phone being held in the hand.  I set the phone down on the top of a near by post, and propped it up against a half drank bottle of beer.  Lining it up roughly where the Milky Way was visible all the way down to the horizon, I then left it.  Once the phone detected no movement, it automatically switched into the magic 'Astrophotography' mode.  Then, it is just a question of pushing the shutter button (being careful not to nudge or disturb the phone) and leaving the phone do it's thing.  Over a period of 5 minutes, the phone starts taking a whole series of images, aligning them and stacking them as it goes.  After the 5 minute counter reached zero, the phone produces two things.  The final stacked and aligned image, and also, a very short time lapse of the whole series of images.  The results were so pleasing, and actually even better than I had though possible.

My first test shot taken with the Google Pixel 4, looking across my pitch towards my camp neighbours.



The second test shot, this time from 'The Common'  There's slight evidence of trailing if you look at some of the starts closely, but this was much more in line with what I expected.


Now, getting more used to how the settings work, I started looking for more of a classic portrait Milky Way shot.  The phone now even started to pick up dust lanes.  This image hasn't been processed at all.  It's come straight off the back of the phone.


This was taken around 3am of the second night of camp.  After going to bed while it rained, the forecast was for a clear sky in the early hours of the morning.  I got up and managed to get this image of Orion, the Hyades and the Pleiades.  

The last of my images taken from camp, complete with red light lighting up some of the caravans on site.


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