Observation Log - June 19, 2001

Observation Log - June 19, 2001 - Tinton Falls, NJ

[Tonight was a little warm, with temps in the 60's. I had the Kendrick on low power from the beginning, but still got a little dew just before dawn. The setup on the 12" LX200 was: Crayford, f6.3 reducer, 1.25" vis back, and the MX516. Took bias and flat frames during morning twilight -GW]

This is NGC5987, a galaxy in Draco, magnitude 11.7, dimensions 4'.2 x 1'.3, surface brightness is 12.9 mag/sq arcmin, and the distance is 140 million light years. This image was made from seventy 1-minute exposures (70 minutes total integration time) taken between 11:04 and 12:32 a.m. the morning of June 19, 2001. The images were calibrated using MaxIm, aligned and composited, and a Digital Development filter (FFT, low-pass, mild) was applied. The resulting image was finished with a contrast enhancement.

Here is M12, a globular cluster in Ophiuchus, magnitude 6.6, diameter 14', distance is 19,000 light years, width is 80 light years. This image was made from ten 1- minute exposures taken between 12:51 and 1:09 a.m. the morning of June 19, 2001. The images were calibrated using MaxIm, aligned and composited, and a Digital Development filter (Kernel, low-pass, more) was applied. The resulting image was finished with a contrast enhancement. Here is another version with much more contrast stretch, which shows much fainter stars at the edge of the cluster.

Here is a little exploration of MaxIm capabilities, inspired by a question from Mike Lindner. I started with the raw image created above of M12, and altered the histogram specification. Here are all of the resulting images, with no adjustment except histogram specification:

Raw M12, medium contrast stretch.
Uniform histogram.
Exponential histogram.
Lognormal histogram.
Gaussian histogram.
Rayleigh histogram.
Straight-line histogram.

Next up is NGC6240, a galaxy in Ophiuchus, magnitude 12.9, dimensions 2'.1 x 1'.0, surface brightness is 15.1 mag/sq arcmin. This image was made from 1-minute exposures for a 41- minute total integration time, with all images taken between 1:13 and 2:18 a.m. the morning of June 19, 2001. The images were calibrated using MaxIm, aligned and composited, and a Digital Development filter (Kernel, low-pass, more) was applied. The resulting image was finished with a contrast stretch.

This is NGC6539, a globular cluster in Serpens, magnitude 8.9, diameter is 7', distance is 7,500 light years. This image was made from 1-minute exposures for a 28- minute total integration time, with all images taken between 2:33 and 3:10 a.m. the morning of June 19, 2001. The images were calibrated using MaxIm, aligned and composited, and a Digital Development filter (FFT, low-pass, mild) was applied. The resulting image was finished with a contrast stretch.

The final image of the night is NGC6781, (PK41-2.1) a planetary nebula in Aquila, magnitude 11.4, diameter is 1'.8, distance is 2,600 light years. The central star in this planetary is magnitude 16.8. This image was made from 1-minute exposures for an 18-minute total integration time, with images taken between 3:59 and 4:18 a.m. the morning of June 19, 2001. The images were calibrated using MaxIm, aligned and composited, and a Digital Development filter (Kernel, low-pass) was applied. The resulting image was finished with a contrast stretch. Here is another version which was resampled to twice the image scale.