Sections in this page
The Royal Astronomical Society (RAS) will be 200 years old in 2020. In celebration there are to be projects to reach out and encourage newcomers into astronomy. More details of the planning are given on the RAS 200 page, where some preliminary ideas for projects are outlined (as of 2014 August).
I have my own suggestion, as follows.
Quite ordinary digital cameras are ideal tools for getting people interested in astronomy.
Probably most people in Britain now own some form of digital camera, even if it is just part of their phone. Sadly most of them also live in urban areas where artificial light reflected by dust in the atmosphere prevents them from appreciating the night sky. Consequently they do not realise that their cameras can be used to take amazing pictures of the night sky, without requiring much other hardware.
It is very satisfying to take such pictures for yourself rather than only seeing them in various media.
Having taken your own photographs naturally leads to wondering about various aspects of them, not only about the astronomical content but also about such things as technical aspects of photography, optics, atmospherics, the nature of digital images, and the physiology of the eye. Some of the questions that might be pursued are listed below, under the heading Things to think about and explore.
Trying to improve your own photos also leads you into aspects of the experimental methods used in science.
To start getting results it is certainly not necessary to have a telescope. It is not even necessary to have a motorised mount to follow the stars, nor any kind of guiding system. Quite dramatic photos can be taken using a fixed camera, ideally on a simple tripod. And I do not mean photos showing star trails, though they can also be instructive and dramatic.
What you do need is
- to drive away from urban lights, as far as possible;
- to put the camera on something to hold it fixed, perhaps a tripod;
- to download some free software for combining multiple exposures (stacking); and
- to follow some simple guidelines, but then try varying them to get better results.
So this project would mainly be aimed at owners of suitable cameras, to assist and encourage them to get out and be amazed at what they can photograph in a dark night sky. Advice could also be given on cameras to buy, and on how to go on from here with equatorial mounts and then telescopes. Meetings would provide the guidelines to show people how to start. Such meetings would generally be at venues where the real photography can be done. There are now many designated dark sky sites around Britain which may have the right facilities.
On present trends the cameras of 2020 should be even better for the job: more sensitive and yet with less noise and lower cost.
Perhaps a consumer camera maker could be interested in sponsoring the project. They may like to offer suitable cameras at a special discount for participants. My favourite would be Canon because I know from experience that both their compact cameras and their DSLRs work well. Unusually among camera makers they have also produced some cameras tailored to astrophotographical needs.
Hopefully taking some photos of the night sky will prompt some of the following questions, and many more. It is by pursuing the answers that we are likely to become more fascinated in the subject.
- Why are some stars brighter than others? (More than 1 reason.)
- Why do the stars seem to form patterns (constellations)? Why are constellations still useful despite the fact that we have moved on from mythological explanations?
- Your photos may easily show more stars than can be seen by the naked eye - why is that? And in an area bounded by certain stars (perhaps a constellation outline) how many more stars are shown by your photo than you could see by eye?
- Your photos may show that some stars have different colours. Why should that be? And why can we not see that by eye?
- The number of stars seen or photographed depends on the amount of light pollution at your site. How might we quantify that? (Eg, the Bortle scale.)
- If your camera allows you to control aperture, sensitivity (ISO) and exposure time manually (which is highly desirable for this kind of photography) what are the effects of changing the settings of each of those 3 things?
- How can we focus the camera in the dark?
- How can we avoid vibrating the camera by touching the shutter button. (Hint: just about all cameras have a self-timer.)
- If we take too long an exposure the stars trail. Why is that?
- What combination of manual camera settings would be best for minimising star trails? How is the answer affected by lens type (wide / telephoto) or zoom level (on a compact camera)?
- If we examine images closely we can see that stars occupy more than single pixels. Apart from the trailing effect, what else might cause this? (Bear in mind that all stars are so far away that no amateur equipment can show any disc: they are truly point sources of light.)
- On a moonless night away from urban lights, especially in autumn, the Milky Way is a prominent feature of the sky. What do your photos reveal about the nature of the Milky Way? (Not just the white areas but also the apparent clouds, which can easily be photographed, see example below, but cannot be seen with the naked eye.)
- What is the nature of a digital image when stored in a file on disc? Why does it comprise 3 colour components?
- What are the advantages of storing images in RAW format rather than JPEG? (Assuming your camera has the option.)
- Why are photos taken with a high ISO setting so full of noise (graininess)?
- How does stacking multiple exposures help, particularly when the camera is on a fixed tripod?
NB: Those used NO telescope, NO motorised mount, NO guiding. You really can start with just a camera plus some FREE stacking software. Although these examples were taken with a DSLR that is not necessary either: much cheaper cameras will work (I plan to demonstrate that soon too).
Note also that the techniques involved here are quite different from those used for planetary photography and are in many ways simpler for beginners.
But still on a fixed tripod! Experimental, as explained if you follow the link.