Introduction For many years, Amateur Astronomers have enjoyed the challenge and excitement provided by the Messier list of deep-sky objects. The 110 or so objects in the Messier Catalog introduced the observer to the importance of careful observing and record keeping. Upon completion of this project, however, the amateur was left somewhat in a void. He or she wanted to further the quest for deep-sky objects, but outside of the vast New General Catalog, there was no organized program that would provide that next vital step upward. With this idea in mind, the formation of the Herschel 400 list began. The William Herschel Catalog of deep-sky objects could be found in the original New General Catalog by Johann Dreyer. The New General Catalog was a compilation of several deep-sky catalogs circa 1880; it contained almost 8,000 objects, 2,477 of these objects were observed by William Herschel. The Ancient City Astronomy Club (ACAC) members separated his objects, which used a rather unique classification system with eight sub-categories. These subcategories are:

Class I - Bright Nebulae; Class II - Faint Nebulae; Class III - Very Faint Nebulae; Class IV - Planetary Nebulae; Class V - Very Large Nebulae; Class VI - Very Compressed and Rich Clusters of Stars; Class VII - Compressed Clusters of Small and Large Stars; Class VIII - Coarsely Scattered Clusters of Stars.

It was soon discovered that a vast majority of Herschel's objects were in Class II and III and, with magnitudes fainter than thirteen, were beyond the reach of many amateur telescopes. The ACAC decided the proposed Herschel 400 List would consist of enough objects to present a distinct challenge, yet still be within range of amateurs who possessed only modest equipment and were affected by moderate light-pollution problems. 400 objects were set as the best number of objects.

For the purpose of these astrophoto albums, the Herschel 400 was divided into 4 sub-lists of 100 objects each. This album contains the fourth and last 100 objects - NGC 5557 through 7814. My astrophotography efforts began in 1975 but my ability to obtain acceptable images was hampered by the need for lots of equipment and materials to process film and make final prints and lack of time to adequately develop the skills required. That situation changed dramatically in 2004 when I purchased a Canon EOS 20D digital single lens reflex camera. Relatively quickly, the resulting images began to meet the quality standards I had set for myself and I began a concerted program of deep-sky astrophotography. Three books provided some of my inspiration:

Atlas of Deep-Sky Splendors, Hans Vehrenberg, 1971. The Messier Album, John H. Mallas and Evered Kreimer, 1978. The Cambridge Deep-Sky Album, Jack Newton and Philip Teece,

1983. Goals

Photograph all the Herschel 400 objects from my location in Prescott Valley, Arizona.

When possible display all the objects with identical image scale for size comparison

Show that quality images can be obtained with modest-sized high quality equipment

The Cameras

Canon EOS 20Da, 3504 x 2336 pixel CMOS, 8.2 Mpx Canon EOS 60Da, 5184 x 3456 pixel CMOS, 17.9 Mpx

The sizes of the imaging chips in the cameras are the identical APS format. As a result the 60Da has 1.48 times more pixels per inch than the 20Da. When images from the cameras are displayed at the same resolution on a computer screen, the images from the 60Da will be 1.48 times larger. When viewing the photographs obtained with the 60Da will exhibit higher image scale and resolution.

The Optical Systems

Canon EF 180mm f/3.5L Macro USM Canon EF 100-400mm f/4.5-5.6L IS USM set at 400mm f/5.6 Takahashi Sky 90 with 0.8X focal reducer/field flattener - 405mm f/4.5 Stellarvue SV80ST-25SV with SFFR80-25 field flattener - 480mm f/6

The Mounts

Vixen GPDX equatorial mount with SkySensor 2000 on JMI Wheeley Bars

Software Bisque Paramount MX equatorial mount on a permanent pier controlled by TheSkyX Pro and an Apple MacBook Pro laptop computer.

Focusing Initially focusing was done manually while observing a star through a Canon Angle Finder C at 2.5x magnification. The quality of focus was checked by examining a test image on the camera's LCD screen. Unfortunately image focus varied significantly, resulting in refocusing and second or even third images being acquired. Eventually a JMI Motofocus and a Bahtinov mask were added to the Sky 90 optical system. Focus was achieved by observing the Bahtinov diffraction pattern on the computer screen using Stack Labs' Nebulosity 3. This focusing method is vastly superior to the manual method and the need to repeat image acquisition was eliminated. A Bahtinov mask and Nebulosity 3 are also used with the Stellarvue SV80 to check focus with adjustments being made manually. Image Acquisition The basic image acquisition scheme was to obtain 5 dark-frames, then 30 light-frames and finally 5 more dark-frames, yielding an image set of 10 dark-frames and 30 light-frames for calibrating and stacking. Exposure duration of each frame was 1 minute at ISO 1600 (20Da) or ISO 3200

(60Da) with a 10-second delay between exposures and a 5-second delay from sequence initiation and the first exposure. No bias or flat frames were used. Images were saved as highest quality JPEG files on the cameras' memory cards. Image acquisition was controlled with a Canon Timer Remote Controller TC-80N3. Basic Image Processing The 30 light-frames were examined and any with bright satellite or airplane trails were discarded. DeepSkyStacker 3.3.2 was used to calibrate and stack the good frames (usually 27 to 30) from each image set. The final raw stacked image file was saved as a 32-bit TIFF file. Image enhancement and optimization was performed with Adobe Photoshop CS2. First the image file Mode was changed to 16-bit. While examining the upper right corner of the image, Levels was used to adjust the RGB black point such that R=G=B at a value of 10-15.

Using Curves, the low intensity nebulosity was enhanced while not 'blowing out' bright zones or causing the black background to lighten significantly by setting Curves set points approximately as shown in the figure above.

Any resulting vignetting in background sky intensity was 'neutralized' using techniques similar to those described in "Fixing Vignetting in Astrophotos", Sean Walker, Sky & Telescope, September 2001 and the book Photoshop Astronomy by R. Scott Ireland. Finally a modest Unsharp Mask (amount: 100%, radius: 1.0 pixel, threshold: 3 levels) was applied. The image scale of the three optical systems was determined using Adobe Photoshop CS2 and Voyager 4 Dynamic Sky Simulator. Then the image scale of the images from the Canon EF 100-400mm optical systems were up-sampled to match that of the Takahashi Sky 90 optical system for images obtained with the Canon 20Da. Images obtained with the Canon 60Da are displayed with image scale unchanged at 1.48 times that of the 20Da. Images were then appropriately cropped and combined to make the album pages with all the objects at the same image scale for direct comparison. Final Thoughts The images in the album were acquired over a period of 5.5 years with continuous improvement in equipment, techniques and skills. I am well aware that a number of images could be significantly improved and better photographs will be acquired in the future. In addition, a number of the planetary nebula are essentially 'stellar' in appearance and require significantly greater focal length and image scale yielded by larger OTAs to show detail. But 'perfection' can often be the enemy of 'finishing' so those better images await the future editions of this album.

Herschel 400 (NGC 5557 - 7814)

pn: planetary nebula sg: spiral galaxy ig: irregular galaxy bn: bright nebula eg: elliptical galaxy oc: open cluster sr: supernova remnant gc: globular cluster

NGC Type Mag RA Dec Optics Camera 5557 eg 11.6 14h 16.4m 36º 43' SV80 60Da 5566 sg 10.4 14h 17.8m 04º 11' SV80 60Da 5576 eg 11.7 14h 18.5m 03º 30' SV80 60Da 5631 sg 11.4 14h 25.1m 56º 48' SV80 60Da 5634 gc 10.4 14h 27.0m -05º 45' SV80 60Da 5676 sg 11.2 14h 31.0m 49º 41' SV80 60Da 5689 sg 11.4 14h 33.7m 48º 57' SV80 60Da 5694 gc 11.0 14h 36.7m -26º 19' Sky 90 60Da 5746 sg 10.1 14h 42.3m 02º 10' Sky 90 20Da 5846 eg 10.5 15h 04.0m 01º 48' SV80 60Da 5866 eg 10.8 15h 05.1m 55º 57' Sky 90 20Da 5897 gc 11.0 15h 14.5m -20º 50' Sky 90 60Da 5907 sg 11.3 15h 14.6m 56º 31' Sky 90 20Da 5982 eg 10.9 15h 37.6m 59º 32' SV80 60Da 6118 sg 11.5 16h 19.3m -02º 11' SV80 60Da 6144 gc 10.5 16h 24.2m -25º 56' Sky 90 20Da 6171 gc 9.2 16h 29.7m -12º 57' Sky 90 20Da 6207 sg 11.3 16h 41.3m 36º 56' Canon 400 20Da 6217 sg 11.5 16h 34.8m 78º 18' SV80 60Da 6229 gc 8.7 16h 45.6m 47º 37' Sky 90 60Da 6235 gc 10.4 16h 50.4m -22º 05' SV80 60Da 6284 gc 10.5 17h 01.5m -24º 41' SV80 60Da 6287 gc 9.9 17h 02.1m -22º 38' SV80 60Da 6293 gc 9.5 17h 07.1m -26º 30' SV80 60Da 6304 gc 9.8 17h 11.4m -29º 24' SV80 60Da 6316 gc 10.0 17h 13.4m -28º 05' SV80 60Da 6342 gc 10.0 17h 18.2m -19º 32' Sky 90 20Da 6355 gc 10.5 17h 20.1m -26º 19' SV80 60Da 6356 gc 9.5 17h 20.7m -17º 46' SV80 60Da 6369 pn 9.9 17h 26.3m -23º 44' Sky 90 20Da 6401 gc 11.0 17h 35.6m -23º 53' SV80 60Da 6426 gc 11.5 17h 42.4m 03º 12' SV80 60Da 6440 gc 10.4 17h 45.9m -20º 21' Sky 90 20Da 6445 pn 11.0 17h 46.3m -20º 00' Sky 90 20Da

NGC Type Mag RA Dec Optics Camera 6451 oc 8.5 17h 47.4m -30º 11' SV80 60Da 6543 pn 8.8 17h 58.8m 66º 38' Sky 90 20Da 6514 oc 6.9 17h 58.9m -23º 02' SV80 60Da 6517 gc 10.5 17h 59.1m -08º 57' Sky 90 20Da 6520 oc 8.1 18h 00.3m -27º 54' SV80 60Da 6522 gc 9.5 18h 00.4m -30º 02' SV80 60Da 6528 gc 10.5 18h 01.6m -30º 04' SV80 60Da 6540 oc 11.0 18h 03.1m -27º 50' Sky 90 20Da 6544 gc 10.0 18h 04.3m -25º 01' Canon 400 20Da 6553 gc 10.0 18h 06.3m -25º 56' SV80 60Da 6568 oc 8.5 18h 10.1m -21º 36' SV80 60Da 6569 gc 10.4 18h 10.4m -31º 50' SV80 60Da 6583 oc 11.5 18h 12.8m -22º 09' SV80 60Da 6624 gc 9.5 18h 20.5m -30º 23' Sky 90 60Da 6629 pn 10.6 18h 22.7m -23º 14' SV80 60Da 6633 oc 5.5 18h 25.1m 06º 32' Sky 90 20Da 6638 gc 10.2 18h 27.9m -25º 32' Sky 90 20Da 6642 gc 10.5 18h 28.8m -23º 31' SV80 60Da 6645 oc 8.5 18h 29.8m -16º 56' SV80 60Da 6664 oc 8.9 18h 34.0m -08º 16' SV80 60Da 6712 gc 10.0 18h 50.3m -08º 47' Sky 90 20Da 6755 oc 9.0 19h 05.3m 04º 09' SV80 60Da 6756 oc 10.7 19h 06.2m 04º 35' SV80 60Da 6781 pn 11.0 19h 16.0m 06º 26' Sky 90 20Da 6802 oc 11.0 19h 28.4m 20º 10' Sky 90 20Da 6818 pn 10.0 19h 41.1m -14º 17' Sky 90 20Da 6823 oc 9.8 19h 41.1m 23º 12' SV80 60Da 6826 pn 8.8 19h 43.4m 50º 24' Sky 90 20Da 6830 oc 9.0 19h 48.9m 22º 58' SV80 60Da 6834 oc 10.3 19h 50.2m 29º 17' SV80 60Da 6866 oc 9.0 20h 02.1m 43º 51' Sky 90 20Da 6882 oc 5.5 20h 09.6m 26º 24' SV80 60Da 6885 oc 9.1 20h 09.9m 26º 20' SV80 60Da 6905 pn 12.0 20h 20.2m 19º 57' SV80 60Da 6910 oc 7.5 20h 21.3m 40º 37' SV80 60Da 6934 gc 10.0 20h 31.7m 07º 14' Sky 90 20Da 6939 oc 10.0 20h 30.4m 60º 28' Sky 90 20Da 6940 oc 6.5 20h 32.5m 28º 08' Sky 90 20Da 6946 sg 10.5 20h 33.9m 59º 58' Sky 90 20Da

NGC Type Mag RA Dec Optics Camera 7000 bn 20h 57.0m 44º 08' Canon 180 20Da 7006 gc 10.3 20h 59.1m 16º 00' Sky 90 20Da 7008 pn 13.5 20h 59.1m 54º 21' Sky 90 20Da 7009 pn 8.4 21h 01.4m -11º 34' Sky 90 20Da 7044 oc 11.3 21h 11.1m 42º 17' SV80 60Da 7062 oc 11.6 21h 21.5m 46º 10' SV80 60Da 7086 oc 9.4 21h 29.8m 51º 22' SV80 60Da 7128 oc 11.2 21h 42.4m 53º 29' SV80 60Da 7142 oc 10.4 21h 44.7m 65º 34' Sky 90 20Da 7160 oc 6.6 21h 52.3m 62º 22' SV80 60Da 7209 oc 7.6 22h 03.2m 46º 15' Sky 90 20Da 7217 sg 11.0 22h 05.6m 31º 07' SV80 60Da 7243 oc 7.6 22h 13.2m 49º 38' Sky 90 20Da 7296 oc 9.4 22h 26.2m -52º 02' SV80 60Da 7331 sg 9.7 22h 34.8m 34º 10' Sky 90 20Da 7380 oc 8.8 22h 44.9m 57º 49' Sky 90 20Da 7448 sg 11.2 22h 57.6m 15º 43' SV80 60Da 7479 sg 11.6 23h 02.4m 12º 03' Sky 90 20Da 7510 oc 8.8 23h 09.2m 60º 18' SV80 60Da 7606 sg 11.5 23h 16.5m -08º 46' SV80 60Da 7662 pn 9.0 23h 23.5m 42º 14' Sky 90 20Da 7686 oc 8.0 23h 27.8m 48º 51' SV80 60Da 7723 sg 11.1 23h 36.4m -13º 14' SV80 60Da 7727 sg 10.7 23h 37.3m -12º 34' SV80 60Da 7789 oc 9.6 23h 54.5m 56º 26' Sky 90 20Da 7790 oc 7.1 23h 54.5m 60º 56' SV80 60Da 7814 Sg 10.6 00h 03.2m 16º 09' SV80 60Da