Prosiectau Ffiseg ar gyfer myfyrwyr bl.3 a bl.4

Disgrifiad prosiect

Detection of Very Faint Comets or Asteroids in Time Sequence Astrophotography

(supervisor: Tony Cook)

Nature of project: software, data analysis

Available to students on full-time physics degree schemes or joint students.

Project description and methodology

The longer exposure we take of the night sky, the fainter stars we can see. However if an object, such as a faint asteroid or comet, is moving during the expoure, it will leave a trail, or if it is really faint, the background noise will swamp the signal and it won't be detected at all as its signal will be motion blurred. So the proposal here is to have a regular sequence of many shorter exposure images, of a region of the night sky, and to test out various velocities and directions, for a hypothetical moving object. This would utilize a Velocity versus Azimuth plot to look for the strongest local maximum - a kind of Hough Transform. You would do this for every point (pixel) in the background star field to find the strongest candidate for a faint moving asteroid or comet. To increase the chances of detection, it would be wise to work with difference images i.e. subtracting a mean or median of all the star field images from each individual image.

N.B. This project can be done entirely from home in case of another COVID-19 lockdown. You just need a laptop or PC.

A successful project will develop beyond the above in one/some of the following directions:
Work with/coordinate amateur astronomers to take deep sky field images for you at regular intervals - many of them do this anyway when looking for supernovae. Generate some synthetic asteroid motions and add these to some model star fields so as to investigate noise issues and confidence of detection in terms of astronomical magnitude.

To use solar corona images from the SOHO mission to detect comets swinging by the Sun.

When considering where to take your project, please bear in mind the time available. It is preferable to do fewer things well than to try many and not get conclusive results on any of them. However, sometimes it is useful to have a couple of strands of investigation in parallel to work on in case delays occur.

Additional scope or challenge if taken as a Year-4 project: Attempt a Fourier Transform, or Wavelet analysis, of any time series detected passages of asteroids/comets in order to see if the rotation rate shows up, and to what certainty can it be measured? To demonstrate the technique, using either a DSLR camera or a robotic telescope to detect space junk/satellites and to measure rotation rates. As a backup archive data can be provided.

Please speak to Tony Cook if you consider doing this project.

Initial literature for students:

  1. Duda, R.O. and Hart, P.E., Communications of Association for Computing Machinery, 15(1): 11-15, 1972
  2. Newberry, M., Publications of the Astronomical Society of the Pacific, 103: 122-130, 1991
  3. Arbour, R.W., Journal of the British Astronomical Association, 96(1): 12-16, 1985.
  4. Kraaikamp, E., Sky and Telescope, 2016 Sep, 68-72, 2016.

Novelty, degree of difficulty and amount of assistance required

Must know how to program and access pixel digital number (DN) values in images. Should be able to program in languages such as Python, C/C++, Java etc and know where to look for basic routines to load, access and save images. Will probably need to normalize each image photometrically to each other to compensate for changes in atmospheric transparency. Your supervisor will help you with making contact with amateur astronomers who would be able to take the images for you, and give some tips on programming.

Project milestones and deliverables (including timescale)

milestoneto be completed by
Idenitify some faint calibration asteroids that could be imaged from the UK, or elsewhere, during the coming monthsend of November
Contact amateur astronomers and request time sequence images or 4th year possibly time on SLOOHChristmas
Complete software developmentend of February
Finish analysismid-March