Apparatus and methods for time-lapse astrophotography

1. A method for operating an image-capture device to capture a time-lapse image sequence, the method comprising:

capturing a first plurality of photographs with the image capture device, wherein capturing each photograph of the first plurality of photographs comprises:

opening a shutter of the image-capture device;

while the shutter of the image-capture device is open, moving the image-capture device to reduce movement of a celestial object or celestial coordinate within a field of view of the image-capture device; closing the shutter of the image-capture device; and

while the shutter of the image-capture device is closed, moving the image-capture device to a subsequent orientation for capturing a next photograph;

wherein the subsequent orientation is the same for each photograph of the first plurality of photographs; and wherein moving the image-capture device to reduce movement of the celestial object or celestial coordinate within the field of view of the image-capture device comprises moving the image-capture device to keep the celestial object or coordinate substantially stationary within the field of view of the image-capture device; and wherein moving the image-capture device to reduce movement of the celestial object or celestial coordinate within the field of view of the image-capture device comprises changing an orientation of an optical axis of the image-capture device to track relative movement between the earth and the celestial object or celestial coordinate.

2. A method according to claim 1 wherein moving the image-capture device to reduce movement of the celestial object or celestial coordinate within the field of view of the image-capture device comprises changing an orientation of an optical axis of the image-capture device to track relative movement between the earth and the celestial sphere.

3. A method according to claim 1 wherein moving the image-capture device to reduce movement of the celestial object or celestial coordinate within the field of view of the image-capture device comprises changing an orientation of an optical axis of the image-capture device to auto-track the celestial object or celestial coordinate.

4. A method according to claim 1 comprising moving the image-capture device to an initial orientation prior to capturing a first one of the first plurality of photographs and wherein, for each photograph of the first plurality of photographs, moving the image-capture device to the subsequent orientation comprises moving the image-capture device to the initial orientation.

5. A method according to claim 1 comprising capturing a short-exposure photograph, wherein the short-exposure photograph has a shorter exposure period than an exposure period of at least one photograph of the first plurality of photographs.

6. A method according to claim 5 comprising holding the image-capture device stationary while capturing the short-exposure photograph.

7. A method according to claim 5 comprising selecting the exposure period of the short exposure photograph based on a reading of a light meter.

8. A method according to claim 5 comprising combining the short-exposure photograph with at least one photograph of the first plurality of photographs to thereby provide at least one composite photograph.

9. A method according to claim 8 wherein combining the short-exposure photograph with the at least one photograph of the first plurality of photographs comprises combining an image of a terrestrial object from the short-exposure photograph with an image of a celestial object from the at least one photograph of the first plurality of photographs.

10. A method according to claim 1 comprising capturing a second plurality of photographs corresponding to the first plurality of photographs using the image-capture device, wherein:

each photograph of the second plurality of photographs is captured by the image-capture device immediately before or after its corresponding photograph of the first plurality of photographs;

each photograph of the second plurality of photographs has an exposure period that is shorter than the exposure period of its corresponding photograph of the first plurality of photographs.

11. A method according to claim 10 comprising combining each photograph of the second plurality of photographs with its corresponding photograph of the first plurality of photographs to provide a third plurality of composite photographs.

12. A method according to claim 1 wherein capturing each photograph of the first plurality of photographs comprises waiting for a conclusion of an image-acquisition period prior to capturing a subsequent one of the first plurality of photographs.

13. A method according to claim 12 wherein the wait period is at least five seconds.

14. A computer program product comprising a non-transitory medium carrying a set of machine-readable instructions which, when executed by a processor of a mount for an image-capture device, cause the mount and an image-capture device supported by the mount to execute the method of claim 1 .

15. A mount for an image-capture device comprising a processor configured to cause the mount and an image-capture device supported by the mount to perform the method of claim 1 .

16. A method for operating an image-capture device to capture a time-lapse image sequence, the method comprising:

providing a motorized mount that is controllably moveable, the motorized mount supporting the image-capture device;

moving the mount to orient the image-capture device at an initial orientation;

repeating, for each of a plurality of photographs that make up the time-lapse image sequence:

opening a shutter of the image-capture device and, while the shutter is open during an exposure period, moving the mount and the image-capture device supported by the mount to compensate for the earth's rotation; closing the shutter of the image-capture device at the end of the exposure period; and

while the shutter of the image-capture device is closed, moving the mount to orient the image-capture device at the initial orientation prior to a next photograph;

wherein moving the mount and the image-capture device supported by the mount to compensate for the earth's rotation comprises moving the image-capture device to keep a celestial object or coordinate substantially stationary within the field of view of the image-capture device; and wherein moving the image-capture device to reduce movement of the celestial object or celestial coordinate within the field of view of the image-capture device comprises changing an orientation of an optical axis of the image-capture device to track relative movement between the earth and the celestial object or celestial coordinate.

17. A method according to claim 1 , wherein moving the image-capture device comprises moving a mount, to which the image-capture device is mounted, on a plurality of movement axes, to thereby move the image-capture device.