This question came up in Quora today and I answered it.

Which entry level DSLR should I buy for getting good quality images of the night sky?

You want a camera that can expose dark scenes for long enough – in other words that it can expose for long shutter speeds. The Nikon D3300 for example can expose for a maximum of 30 seconds.

That might seem like a long time, but if you stop the aperture down in order to get good depth of field, then you are going to need long exposure times.

This is all with the camera on a tripod of course.

You could increase the ISO (which makes the camera sensor more sensitive to light) in order to cut down exposure times – but that carries a penalty which is that images are noisier.

And for night photos where there is already a lot of ‘dark’ you are going to see that noise more than for a daylight shot – so stick to low ISO.

jerusalem-church-of-the-holy-sepulchre
The current version of Photoshop is better at rescuing photos than were the older versions. At least I think it is – it might be my memory playing tricks on me.

This is the interior of the Church Of The Holy Sepulchre in Jerusalem, a building I enjoy exploring. It is the paradigm of what big architecture can be – organic, mysterious, grand but not pompous, and never-ending – stretching on and on in rooms and antechambers deep into the bowels of the Earth.

But the light from the sun spilling down into the building blinded the sensor on my camera and created an ugly patch of white nothingness.

I tried to rescue it and this time it’s a bit better than previous attempts.

And apropos thoughts about buildings, I was walking back home yesterday admiring the construction progress on the new school, when one thought led to another. I was thinking about the clean line of the building that had emerged when the scaffolding was removed.

That led me to think of the construction and the steel framework. And that brought to mind the conspiracy theories about the Twin Towers and how bits of metal found at the site were in some people’s opinion only capable of being formed in a thermite explosion.

That led me to think of the scarcity of comparable evidence, because it cannot be very often that aeroplanes of that size hit skyscrapers.

And then suddenly, the reality of what the hijackers had done – to ram two planes into the Twin Towers – struck me. I knew in that moment that I had not properly taken that fact into my head until then. It was as though until that moment I had taken the facts in like a dream or in another, unconnected universe.

All this despite the fact that I went up the Twin Towers in the summer before 9/11 and in about December of that year I went to the spot where the towers had stood. I read the messages pinned outside the church. I bought film in a drugstore and I had coffee in a coffee shop near the site.

I had even seen the events unfold on my monitor at work on 9/11, and I remember that I had thought at first that it was a play or a setup – like Orson Welles’ ‘War Of The Worlds’ on the radio in the USA in 1938 that was broadcast as a simulated news bulletin of an alien invasion.

Yet, despite all that, it had taken me thirteen years for the reality to hit me – the reality of what those hijackers did. It hit me how powerful it was, the way they had grabbed events by the tail and spun them to the direction they wanted to go. They found a weak spot and they pressed. Bastards, yes – but I was just thinking in that moment of the magnitude of what they did.

That led me to think of other, personal events that I could only access in a meaningful way years after the events.

The mysteries of the chambers and antechambers of the mind, eh?