NGC 6888 on August 16, 2004

NGC 6888 on August 16, 2004. Prime focus (f/8.0). Total integration time 565×8.53 sec = 80 min. This is the famous Crescent Nebula, also number 27 in the Caldwell list. The bright star in the lower right, HD192163, is a Wolf-Rayet star. It blew off its outer atmosphere, revealing a hot stellar core whose intense radiation drives a massive stellar wind. The shock front resulting from this high-speed material plowing into the previously blown-off (and slower moving) outer atmosphere causes the glow we now see as the nebula. The whole nebula (about half is shown here) measures about 25×16 light years, and it is about 4700 ly distant.

NGC 7331 on August 6, 2004

NGC 7331 on August 6, 2004. Prime focus (f/8.0). Total integration time 210×8.53 sec = 30 min. The main target in this image is a spiral galaxy of Hubble class Sb. Its integrated magnitude is approximately 10, and it is roughly 14 Mpc distant.

M27 on August 6, 2004

M27 on August 6, 2004. Prime focus (f/8.0). Total integration time 285×8.53 sec = 40.5 min. Bright sky with fast-moving low clouds moving in. This is a planetary nebula commonly referred to as the "Dumbbell" nebula — a name first given by John Herschel. Its integrated magnitude is 7.6, and it is approximately 1100 ly distant.

IC 3568 on July 20, 2004

IC 3568 on July 20, 2004. 2× barlow, minus violet filter. I should have used the 4× powermate. Very bright sky with clouds moving in (could only see Arcturus and Vega!) This is a planetary nebula commonly referred to as the "Baby Eskimo" nebula. Its integrated magnitude is 11.6, while the central star is 13.4. IC 3568 is approximately 6800 ly distant.

M51 on June 1 and 12, 2004

M51 on two nights, June 1 and 12, 2004. Prime focus, IR blocking filter. This is a classic, grand design Sc spiral galaxy. It is interacting gravitationally with the small galaxy (NGC 5195) just to M51's north.

Transit of Venus on June 8, 2004

The following images were taken with my 6-inch refractor from the roof of USNO's main building, when such things were still allowed. Like many places along the East Coast, we were greeted at dawn with thick fog, and all optical surfaces immediately acquired a thick coating of dew. After a panic search of the observatory, someone located a small electric heat gun made for such things which cleared off the dew.

Spaceweather.com has a gallery of ToV photos that is worth a browse.

10 seconds before third contact

third contact

M53 on June 7, 2004

M53 on June 7, 2004. Prime focus, IR blocking filter. This is another large globular cluster. It is very far away, about 60,000 light years, and about 220 light years across—a large cluster.

M3 and NGC 4631 on June 3, 2004

M3 on June 3, 2004. Prime focus, IR blocking filter. This is one of the most-studied of globular clusters, containing the largest number of RR Lyrae stars of any known cluster. It is roughly 10 kpc distant and was formed about 11 Gyr ago.

NGC 4631. Prime focus, IR blocking filter. This is an edge-on spiral that has been distorted due to interaction with the nearby elliptical, NGC 4627.

AR0618 on May 23, 2004

M13 on May 22, 2004

M13 on May 22, 2004. Prime focus, IR blocking filter. This is a large globular cluster. It is approximately 26,000 light years distant — on the far side of our galaxy and way above the galactic plane.

About my solar images…

Over time I've acquired my solar images with a cannibalized inexpensive webcam (the guts of a Philips Vesta 675), cooled with two small CPU fans, and a video camera. The cameras are attached to an inexpensive 150 mm f/8.0 achromatic refractor (one of the recent Chinese imports). The CCD in the Vesta series of webcams is a 659×494 5.6 micron square-pixel Sony color CCD. The onboard electronics resamples to produce 640×480 8-bit RGB output. The video camera CCD has 768×494 pixels, 8.4×9.8 microns.

Most of the early imaging here was done both at prime focus and with a good-quality, 3-element barlow. (Some of the oldest images were obtained with eyepiece projection.) Just in front of the camera I have an 82 Angstrom FWHM filter centered on 5200 Angstroms. This completely removes the chromatic aberration from the inexpensive doublet objective lens. Most recently, I replaced the barlow with a Televue 4x Powermate stacked with a Televue 2x "Big Barlow". These are 2-inch diameter components, so I had to cobble together a 1.25-to-2 inch adapter so I could keep using the 1.25-inch Herschel wedge. Later I obtained a 2-inch Herschel wedge from APM Telescopes in Germany.

A brief description and photos of my solar imaging setup and other hardware can be found here.

Nyquist sampling for this telescope and CCD occurs around f/24 or so. Prime focus imaging is therefore undersampled and benefits from the stacking of several frames. Flat fields, suitably normalized, were divided into all frames (thus removing most of the dust speck shadows) before any kind of processing was done. Orientations indicated are approximate. The Earth images are to scale.

Recently, special attention was paid to scattered light. I coated the insides of the refractor tube and extension tubes with the coarse, non-skid material from 3M that is used on cement steps. (It has an excellent adhesive backing.) I painted everything with Krylon ultra-flat black, including the non-skid material. Until recently, I've been using a full-aperture filter made of the excellent Baader solar filter material (both visual and photographic densities). I now use a Herschel wedge, thus dispensing with the Baader filter. The images are noticeably sharper with the wedge, and much brighter, thus allowing larger magnifications. As you'll see below, I can now easily record granulation and penumbral structures, despite the shortcomings of the inexpensive, 8-bit webcam, and the not-so-inexpensive StellaCam II video camera.

AR0606 on May 14, 2004

M82, M64, NGC 4111, IC 3568 on May 12, 2004

M82, M64, NGC 4111, and IC 3568 on May 12, 2004
(Inaugural images from the StellaCam II)

New video camera and NB filter

New video camera acquired and used for images from here on up. I now have an Astrovid StellaCam II, which is essentially a Watec 120N video camera. The CCD has 768×494 pixels, 8.4×9.8 microns. I'm using a frame grabber from ImperX to transfer the images from the camera to a laptop hard drive. Pixels are squared off in software to 8.4×8.4 microns for the images shown here. I'm also now using a narrower, 30 Å FWHM, filter centered on 514.5 Å.

AR10380 and AR10377 on June 6, 2003