Telescope Reviews: Technical Notes: Imaging Super-Massive Black Holes

Recently the Hubble telescope produced the first closeup images of the SuperMassive Black Hole (or "Trou Noir Massif Superbe" for some of our Canadian neighbors) at the center of the Milky Way Galaxy (fig. 1). What few people realize, however, is that this type of imaging is not beyond the reach of the technically astute amateur astronomer. Having had extensive experience with this type of imaging, I decided it would be a good time to share my expertise with those on this forum who might have an interest in pursuing this admittedly complex subject.

There are several unique aspects involved with the imaging of SuperMassive Black holes which are definitely worth enumerating:

1. Exposure times can be remarkably brief. Unlike imaging DSO's which require lengthy exposures, it has been my experience that longer exposure times have little affect on the final photographic result. Compare Fig 2 with an exposure of 8h 33m with the one on Fig3. which was taken at 1/2000th of a second. I think most people will agree that the shorter exposure time did not result in an image which displayed any less detail.

2. There is very little difference in the appearance of super-massive black holes even in galaxies of very different configurations. Compare Fig. 4 which shows the Black hole at the center of an impressive spiral (M51) with the one in Fig 5 of a galaxy that we see side-on (M104).

3. A vast array of different telescopes and imaging devices can be used. Another surprising comparison here is shown in Fig. 6 which covers PRECISELY the same region as the Hubble imaged in Fig 1. Amazingly, this image was taken through a Coronado PST in the middle of the day with an exposure of only 1/30th of a second. Again, few could argue that the PST image dropped any of the detail displayed in the Hubble image. The HA filter on the PST has the advantage that it filters out the Hawking radiation from the Black hole that might otherwise hide some important structural details.

4. Viewing conditions have little effect on the results. Another perhaps unexpected result is shown in Fig.7 taken by the author during a heavy thunderstorm (see photo), and once again - no loss of detail in Fig 7. over Fig. 1.

There will no doubt be the usual dissenters on this forum who will claim that there are huge and obvious differences in Figs. 1-7 displayed here, and that images of super-massive black holes can only be properly accomplished using APO Refactors with apertures of 4 meters or more, but such instruments pose somewhat of a challenge for the average amateur who needs to carry their telescope to different observing sites.

Personally, I have always found these images of super-massive black holes to be compelling, and it must surely be more than a coincidence that the Berkley, CA Art Museum has on display what can only be described as a vision of inexplicable prescience in the painting: Abstract Painting No. 3 (fig. 8).

CESD, Astronomaire extraordinaire

Edited by Grizz (04/01/05 07:07 AM)