Esa Hi. I too, after taking a not-dissimilar picture to your first effort, had similar thoughts and determined to see if I could improve. I'm still on that "journey", loving every minute of it, and I think improving. Funnily enough I am half Finnish, I have family in Lahti, Helsinki, Turku and Kuusamo, and have a brother called Esa.
Some good stuff in the existing replies. Initially as a newbie I just linked to my blog, but I was told that's not acceptable, so here's an extract:
(link to my full blog here http://www.slidingseat.net/stars/stars.html#startingout )
Taking My First Nightscape Pictures:
I often visit Baltimore in South West Cork, about as SW as you can get in Ireland. Walking back from the pub one November night, I was SHOCKED by the sheer blackness of the night sky and the dazzling array of stars. Constellations were not even recognizable, drowned out in the sea of stars. My interest in astronomy suddenly resurfaced.
Round 1 – a Horrid Mess
As of summer 2016 I hadn't really seen the Milky Way for donkey’s years! Out there, the Milky Way is easily visible to the naked eye even straight after leaving a bright room. One evening looking up I thought “I wonder if I can photograph that?”. Being a keen photographer, I reckoned I ‘knew a bit’ about photography – it turned out “you know nothing, Jon Snow”.
Nonetheless I quickly retrieved my camera, attached my fastest wide zoom lens, plonked it onto a tripod and pointed it up. Only then did I think: “Er, what settings to use?”. Obviously the widest aperture and its widest angle (24mm f/2.8) and ISO 3200 (because it seemed "about right"). I chose 30 seconds exposure, but was aware that stars might streak, as the earth rotates noticeably over even as little as a half-minute.
The result, from early August 2016, is here, my first Milky Way image, looking up SSW at around 1am.
It’s a horrid mess of a picture. Yes, you can see the Milky Way, but that’s about it: out of focus, no other context, no colour, heavily streaked stars, noisy, boosted to hell in Photoshop. Funnily enough, for a while I was quite impressed, though I didn’t really solicit opinions. If you've never photographed a night sky before, you too may be impressed, but this is really not very good.
Round 2 – 8.5/10 for Composition, 3/10 for Execution
Five months later, Christmas 2016, I had another go. It's obviously a slightly different shot, but it was taken from the same patio as above. I tried to get the Milky Way and the Andromeda Galaxy visible in a recognizably local setting.
I used the same set-up as Round 1, but shorter exposure and lower ISO: 30s at f/2.8 and ISO 1600. I showed this picture around and received many compliments, it’s undoubtedly more interesting. Personally I like it, but only as a small image. Blown up, it’s unpleasantly grainy and the star-trailing is evident, especially top-left (click the picture and a full-size image will open, it'll be obvious). To make the Milky Way stand out, I had to really “stretch” the faint detail, exacerbating the noise.
Describing the scene: The bump towards the left with two bright lights is Mount Gabriel, atop which sits Europe’s western-most air traffic control radar domes. The brightness at far left is the town of Schull, and looking right from Mt Gabriel we have the bright glow of Ballydehob, Whiddy Island behind the hills (the floodlit white of a major oil terminal, Ireland's strategic oil reserve), then Bantry an extended yellow glare behind the hills and finally at the right edge (by now looking due North) and this side of the hills, the village of Church Cross.;
Looking up, above Mt Gabriel the bright smudge is the Andromeda Galaxy which, at 2.5 million light years away, is the most distant thing visible to the naked eye [see footnote]. Together with the Milky Way, it was chiefly what I wanted to catch in the photo, if possible. This is the “boring side” of the Milky Way which unfortunately is the only bit we get to see in the Northern Hemisphere winter. Even this, though, is evident to the naked eye from Ballylynchy. By the way, if you know your sky, you might also be able to spot the Triangulum Galaxy amongst all the noise. It's there.
Round 3a - 5/10 for composition, but much better execution: 8/10 I reckon
This is the same scene as before, but at a different time of year (September, rather than the New Year of the Andromeda picture). The dominating night-sky feature is now not Andromeda or the Milky Way, but Ursa Major (The Plough) whose "saucepan end" is nearly vertical, pointing up towards Polaris, i.e. approximately Due North. Exposure: 45 seconds 24mm f/1.4 ISO 1600 with an AstroTrac.
It's not as pleasing a picture as the Andromeda/Milky Way one, but it is much better executed. The graininess is gone and the sky has a liquid quality that's beautiful. Compositionally it's markedly inferior, way too much deep black foreground, not enough sky. But, the sky colour is correct: orangeish at the horizon (light pollution) and above the horizon a greenish glow that's 558nm Oxygen-emission "airglow", if our eyes were sensitive enough they'd notice it. And finally the "fading to black" of the lovely West Cork night sky and its amazing starscape.
In due course, hopefully around Christmas 2017, I'll re-take this with the Milky Way and Andromeda (and Triangulum) back in. Hopefully my latest equipment addition, a heavy-duty Ball Head (Sirui k-40x) for the top part of my AstroTrac set-up, will allow me more easily to point the camera at the scene I want with fewer contortions - the orientation of the earth's equatorial plane this far North means the whole tripod-top set-up must be angled over at 39 degrees!
Round 3b – Round 1 re-done using lessons learned
My first Milky Way picture, the “horrid mess”, also deserved a re-run, essentially a practise–run to learn lessons. Again I used my Canon EOS 6D, my new 24mm Samyang and the AstroTrac: 51 seconds, 24mm at f/1.4 and ISO 1600. I also post-processed it better. As a result there’s lots of colour and little noise.
The bright star almost centre-frame is Altair, flanked by its two neighbours Tarazed (on the right) and Alshain. Looking down and slightly right, across the Milky Way cloud lane, notice a pair of little gems: lighter patches in the orange: open clusters NGC6633 and Graff’s Cluster, aka Tweedledum and Tweedledee. Open a larger version by clicking on the image and take a closer look.
Summary of Lessons Learned and applied so far: Round 1 to Round 3
I received some good “press” for my Round 2 pic and was pleased but I realised that, although not bad for a pure novice second attempt, it was still not very good. I determined to re-take both these pictures, and to get them right. Specifically, I needed to improve and expand my equipment (slightly), my shooting and exposure technique (quite a lot), my subject knowledge (somewhat) and my post-processing (a lot).
My Canon EOS 6D is, apparently, a superb camera for this sort of work: full-frame sensor to make full use of wide-angle lenses; very low noise from “on-sensor noise suppression”, eliminating the need to take and subtract bias or dark frames (don’t ask).
The lens I used for Rounds 1 and 2, the Canon EF 24-70mm f/2.8L, is less ideal. True, it's an “L” lens (Canon’s pro line). But it’s a zoom, and zooms seriously distort stars. Also, it’s only f/2.8, which is barely fast enough. Even Canon’s and Nikon’s fast primes (non-zooms) are terrible for star distortion, and very expensive.
I got a Samyang/Rokinon 24mm f/1.4. Renowned for low distortion, it renders stars well and is only “quite” expensive. It’s manual-focus, but auto-focus doesn’t work on the night sky anyway. It will let in 4 times as much light as an f/2.8, so I could've achieved the same quality as the noisy Round 1 in only 7.5 seconds rather than 30, and without trailing. To eliminate the star-trails altogether, I got an AstroTrac, which is a beautiful mechanism that sits between two heads on a tripod. It rotates the camera to exactly counteract the movement of the stars around the sky as the Earth itself rotates.
Exposure and Shooting Technique
This is a huge subject, far too big to go into in detail here even if I understood it properly, which I don't yet (there's no end) so I'll simply suggest you visit the best-by-far and comprehensive description of the topic by Richard N Clark aka clarkvision.com . Armed with this new knowledge for Rounds 3a and 3b, 45-50 seconds (tracked) at f/1.4 and ISO 1600, produced nice results. Compare that to Round 2 for example, 30s at f/2.8 ISO 1600, which collected only 1/6-1/7th the amount of light.
The pair of image-extracts below from Round 2 and Round 3, of the same object, Mount Gabriel, demonstrates the difference that 6x the light makes:
Notice the right-hand image now suffers from “streaking ground” rather than “streaking stars”, because of the sky-tracking. Depending on how important you think that is, you can either ignore it, or take a separate untracked frame and do some image-editing to overlay the untracked - and therefore sharp - bottom portion. You may think that’s “cheating”, but it's not: more about this a bit later.
Focussing deserves a paragraph of its own. Auto-focus at night doesn’t work, and it’s a bit hit-or-miss even in daylight. Focus needs to be absolutely spot on for stars. Set the camera to high sensitivity such as ISO 6400, find a suitably bright star and set “Live View” to 10x magnification. Focus by hand until sharp. Richard Clark advises going even further and using a magnifying glass as well (don't forget to change the settings back after focussing!).
Furthermore: shoot RAW, use a remote shutter release, set mirror lock-up and 2 second shutter delay to minimize vibration; long-exposure noise reduction should be OFF (not necessary for modern sensors) and the top dial set to "B" for “Bulb” (otherwise you're limited to 30 seconds); I’ve saved all these settings in a “Custom Setting” on the camera’s top dial.
Most people, using a modern digital camera, press the button, and Hey Presto! there’s a jpeg.
But the camera is doing a lot of work between recording a raw data file from the sensor and producing a viewable image file. The camera is making many decisions in the conversion process, arbitrarily deciding tone, contrast, saturation, black point, sharpness etc etc. Night-sky images are extremely dependent on these settings, and control needs to be taken over them from the very start. For example, "light pollution" will need to be "subtracted" from the image in almost all cases and at the outset of processing.
Shooting RAW makes the (albeit large) raw data file the camera’s primary output, preserving every scrap of information (every photon). Downloading the files into a “developer program” such as Adobe Raw Converter, which comes with Photoshop, or Adobe DNG Converter, which is free, allows me to manipulate the settings for conversion into an initial viewable image, and once downloaded (“developed”) further processing can be done in the application of choice, which in these cases was Photoshop. Learning these settings is a continuing matter of practise, research and trial-and-error.
Meanwhile, for now, I hope this has been interesting and perhaps of some help to any aspiring night-scene photographers.
Note about how astronomy pictures are produced
I alluded above to the fact that many people regard making images from anything other than single-shot frames as "cheating". However every single picture you see from NASA or the Hubble Space Telescope will be a stack of sometimes hundreds of "sub-images" overlaid on top of each other and signal-processed to extremes to extract the very few photons that arrive to the camera-sensor from the dimmest of subjects [present company excluded ;-) ], and to minimize the noise. If there's a foreground involved, such as a Milky-Way nightscape, it will have been taken "untracked" and pasted over the top in something like Photoshop to allow both stars and ground to appear "unstreaked" in a 30-60++ second exposure. There's simply no other way to do it.
**Some will tell you that actually the Triangulum Galaxy (aka Messier 33) slightly further away than Andromeda (if a mere 200,000 light years further can be called “slight”!!!!), holds that accolade. Look up Bortle Scale, which is a popular way of categorizing how dark a site is, to see that it uses the “naked-eye-osity” of Triangulum as a darkness-diagnostic. But this has been challenged lately, and I for one would need truly exceptional conditions to barely observe Triangulum with the naked eye. If, using the Bortle Scale, one inserts Andromeda (M31) instead of Triangulum (M33), it makes much more sense, for my mid-50s-year-old eyes at least. back up*