What Is High Resolution

Learn Photo Editing

Learn Photo Editing

Get Instant Access

The term high resolution has changed over the last 10 years. Generally it means working at image scales where seeing dominates the ability to resolve fine detail in an image. It can range from 1.0 arcsecond/pixel image scales under 3 arc-second seeing conditions to 0.5 arcsecond per pixel for 1.5 arcsecond or better conditions. I have been imaging with CCDs since 1995, starting with the construction and operation of a highly modified Cookbook 245 CCD camera. At that time it was stated that 2 arcsecond/pixel was the optimum image scale for deep-sky imaging under average seeing conditions.

By the late 1990s, images taken by Rob Gendler and Bill McLaughlin demonstrated noticeable resolution improvements by working at 1 arcsecond/pixel or

Figure 8.2. Galaxy NGC4244. LRGB image of 80:50:50:70 minutes total exposures, respectively (5-minute individual exposures) using a non-IR-blocked luminance image and Custom Scientific RGB filters. Image calibration and color combination using MAXIM DL (RC Console for Sigma Combine and pixel cleanup within Maxim DL), image registration using Registar, Ron Wodaski's gradient removal, AIP for Lucy Richardson deconvolution on the luminance, luminance layering in Photoshop for final color and star shaping processing. Equipment: RCOS 20-inch f/8 RC and Finger Lakes IMG6303E CCD camera with all images acquired in 2 x 2 bin mode for an image scale of .92 arcsecond/pixel in 2.3 arcsecond seeing and magnitude 4.9 suburban/rural skies.

Figure 8.2. Galaxy NGC4244. LRGB image of 80:50:50:70 minutes total exposures, respectively (5-minute individual exposures) using a non-IR-blocked luminance image and Custom Scientific RGB filters. Image calibration and color combination using MAXIM DL (RC Console for Sigma Combine and pixel cleanup within Maxim DL), image registration using Registar, Ron Wodaski's gradient removal, AIP for Lucy Richardson deconvolution on the luminance, luminance layering in Photoshop for final color and star shaping processing. Equipment: RCOS 20-inch f/8 RC and Finger Lakes IMG6303E CCD camera with all images acquired in 2 x 2 bin mode for an image scale of .92 arcsecond/pixel in 2.3 arcsecond seeing and magnitude 4.9 suburban/rural skies.

less image scales. This coincided with the availability of smaller pixel CCD arrays, such as the Kodak KAF1600 and KAF0400 with their 9u pixels followed by the KAF3200 with its 7.4^ pixels. The tradeoff was longer exposure times but the results proved that significant resolution improvement could be obtained. At the same time, new image-processing techniques, especially in the area of deconvolution, allowed the extraction of high-resolution information that was hidden by the seeing blur in the image frames.

These developments resulted in deep-sky color images taken by amateurs that revealed previously unrecorded detail and color information. Currently the challenge for advanced imagers is finding reference images for comparison of color balance or that some new feature in the image is actually real. For example, in early 2004, I imaged M106, a very large galaxy with faint outer arms, using my 20-inch RCOS scope and Finger Lakes IMG6303E CCD camera (Figure 8.3). I took a long H-alpha exposure to best capture some of the discrete HII regions in the arms and followed it with a conventional clear luminance series and RGB color set. During the final color combination steps I spotted two noticeably red colored

streaks originating from the core of the galaxy. I checked a number of other personal imager Web sites and couldn't find any record of them. With further research, I found a weak monochrome image on a professional observatory Web site that confirmed the feature. Sure enough they were galactic jets, something unexpected in M106, and finding them was a first for an amateur.

Was this article helpful?

0 0
Learn Photoshop Now

Learn Photoshop Now

This first volume will guide you through the basics of Photoshop. Well start at the beginning and slowly be working our way through to the more advanced stuff but dont worry its all aimed at the total newbie.

Get My Free Ebook


Post a comment