The Constellation Lyra
and the Lyra Ring Nebula, M57

Figure 1.  Looking east in the Spring the brightest star is Vega, in the constellation Lyra, shown connected by lines. The image is 26x39 degrees, with north to the upper-left. More stars are present in this image than can be seen by the unaided eye.  This picture was taken from a site in the mountains nearby, a mere 2200 feet higher than Santa Barbara, yet the sky was so much darker (being above the "boundary layer") that more stars can be seen.  The resolution of the original image is much better than this web page version, as shown by the "detail" image below. [Minolta 35-mm camera strapped to a Meade ETX125EC for tracking and occasional manual guiding adjustments, 50mm f/1.7 lens, Kodak Elite Chrome ISO 400 pushed to 800, 4.2-minute exposure.]

Figure 2.  Zooming in by a factor of 4 reveals detail of just the Lyra portion of the previous image (rotated so that north is at the top).  Along the southern-most leg of Lyra is a pair of lines indicating the location of the Ring Nebula, M57.  The faintest stars are magnitude 9.5, but M57 is visible even though it's magnitude is 9.7 - due to its unusual color.  The image is 11 degrees on each side, north up. The "full-width at half-maximum" for stars that are not overexposed is 160 "arc (2.7 'arc), which is pretty good for a 50mm focal length, f/1.7 lens.  (The original image still has slightly better resolution than this web page version.  Below each bright star is a dark ghost, caused by my film scanner's detector recovery from brief saturation after sampling a transparent portion of the slide film.)

Figure 2.  Zoom factor of 2.2, showing the Ring Nebula as a "green dot."  The faintest stars visible in this image are magnitude 13.7.  [2001.04.24, Nikon F3 camera, 400 mm f/5.6 lens, attached to Meade LX200 10-inch telescope for tracking and guiding adjustments, 11-minute exposure, Fujicolor Superia 400 film]

Figure 3.  Zoom factor of 2.4, showing that the Ring Nebula is more like a "donut" than a "dot" - but it certainly is green!  The faintest stars visible in this image are magnitude 14.1.  [2001.04.24, Nikon F3 camera, 400 mm f/5.6 lens, attached to Meade LX200 10-inch telescope for tracking and guiding adjustments, average of two 5.3-minute exposures, Fujicolor Superia 400 film]

Figure 4.  Zoom factor 1.6.  Color image made at the prime focus of a Celestron 14-inch (f/1.86). FOV is 70x45 'arc. [Celestron CGE 1400 SCT, HyperStar, SBIG CFW-8 and ST-8XE CCD, f/1.86, LRGB, 10-second exposures,1 for L, 3 for R and G and 6 for B; 2003.07.20, Hereford, AZ]

Celestron 11-inch, 25-min total exposure, AO-7 autoguide, FOV = 25 x 17 'arc. 2008.11.02

Figure 5.  A zoom factor of 3.3.  FOV is 23x15 'arc, showing a central star at the center of the ring.  Star images have a width of ~3 "arc. [Celestron CGE 1400 SCT, JMI focuser, f/7 focal reducer, SBIG CFW-8 and ST-8XE CCD, f/5.4, LRGB, 60-second exposures, 2 for R, one for G and 4 for B; 2003.08.20, Hereford, AZ]

Figure 8.  Zoom factor of 4.  Two versions of the same image (a small crop of a much larger image).  The left panel shows the ring unsaturated, revealing a delicate wisp structure.  Imagine that the ring consists of a short circular tube that is tilted to the right (actually, tilted toward the 4:00 o'clock angle), and the left and right sides are broader and fainter because at these locations the tilt spreads out the emitting region.  The right panel is a processed version that saturates the ring but reveals two faint extensions of nebulosity.  The extensions are to the northeast (upper-left) and southwest (lower-right) of the bright ring.  The faintest stars in the right panel image are magnitude 19.2.  The double star north of the ring has a separation of 5 "arc. The 14th magnitude central star causes the surrounding gas shell to glow consisting largely of 501 nm green light emitted by twice-ionized oxygen atoms.  [2003.05.17Z, average of 45 5-second exposures with SBIG ST-8XE CCD at cassegrain focus, with 2x focal reducer, Celestron 14-inch CGE Schmidt-Cassegrain, f/6.6].

To see what a regular digital camera can do when applied to an astrophotography task, click here.

For more zoom sequences of the sky, click on AstroPhotos (try the Whirlpool Galaxy).


This site opened:  June 25, 2000.  Last Update:  2008.11.02