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Here are some of the pictures I've taken with my 12-inch SCT, using a webcam or a Clear-, H-alpha-, or BVRI-filtered CCD camera. In all pictures, North is up and East is to the left (direct sky view) and all dates are UT. |
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(20 October 2009) This is a new 100-minute unfiltered exposure (20 x 5') of one of my favorite objects, a globular cluster known as the Intergalactic Wanderer, NGC 2419. It's so named because it is farther away from our Milky Way Galaxy than any other globular cluster. Note that the outer limits of the cluster are seen better here compared to a similar image from 10 Mar 2007 (10 minute exposure) and another from 30 Jan 2008 (5 minute exposure), below. This cluster is at a distance of 295,000 light-years in the constellation of Lynx. The original image scale is 1.14 arcsec per pixel. |
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(March-October 2009) This is a graph of the light curve of the eclipsing binary star, IP Pegasi. Photometry with the CCD camera shows the variable brightness (y-axis) plotted as a function of time (x-axis). This unusual binary star has an orbital period of only 228 minutes, and as the two stars revolve, matter falls from the companion star to the white dwarf primary star, creating a hot-spot and forming an "accretion disc," similar to spiral arms of a galaxy, around the white dwarf. The companion star also eclipses the white dwarf, creating the deep minimum in the light curve. There are more eclipsing variables here. |
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(23 March 2009) An unknown satellite tumbled through the field of view of this 50-second exposure around SW Cancri, an eclipsing binary. Mid- exposure (arrow) is at 01:08:38 UT, Mar 23. The 4-flash cycle in the image trail shows that, in the space of 50 seconds, the satellite has tumbled about 5½ times. At mid-exposure, the satellite's position is RA= 09:09:04.07 and Dec= +09:36:17.2, and alt=57.092 and az=148.934. It's moving west to east (right to left) at a rate of 9.89 arcsec per sec. The brightest flashes compare with the 15.1 magnitude star, ZN075:0900 (circled). more |
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(17 January 2009) This is a 210-minute exposure in total, made up from 14 fifteen-minute individual exposures taken under very poor conditions. NGC 3190 is a disturbed sprial galaxy about 60 million light years from Earth, in the direction of the constellation of Leo. It and it's companion, NGC 3187, have had a gravitational interaction over the eons, such that their spiral arms have been tidally distorted. These two are members of a larger group, Hickson 44, comprising at least six galaxies in total. The image scale in this image is 1.14 arcsec per pixel. |
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(1 November 2008) This 158-minute exposure of NGC 772 was composited from 19 500-second exposures. The image scale in this image is 1.14 arcsec per pixel. NGC 772 is about twice the size of the Milky Way Galaxy, located in the constellation of Aries at a distance of approximately 130 million light years. This galaxy is also known as #78 in Arp's Atlas of Peculiar Galaxies. A smaller companion elliptical galaxy, NGC 770 is seen to the southwest. In space, it's only a mere 160,000 light years from NGC 772. |
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(23 October 2008) M 77 is a compact spiral galaxy located in the constellation Cetus the Whale. Galaxies of the type of M77, with a small bright nucleus, are known as Seyfert galaxies. Seyfert galaxies have very energetic cores and many similarities to quasars. There is also a strong source of radio wave energy emitted from the core of this galaxy. M77, one of the brightest of the Seyfert galaxies, is located at a distance of 60 million light years. It's spiral arms span 120,000 light years. This image is a 145-minute exposure. The original image scale is 1.14 arcsec per pixel. |
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(20 October 2008) NGC 1232 is dominated by millions of bright stars and dark dust, in spiral arms rotating about the center. Open clusters containing bright blue stars are sprinkled along these spiral arms, with dark lanes of dense interstellar dust between. The spiral arms are easily traced. This image is a 35 minute exposure. NGC 1232 is 70 million light years away, in the direction of the constellation Eridanus. The original image scale is 1.14 arcsec per pixel. |
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(20 October 2008) NGC 628, also known as M 74, is an island universe with 100 billion stars. It's located 30 million light years away in the direction of the constellation of Pisces. The spiral arms are easily traced with clusters of bright young stars and gaseous nebulae. This image is a 25 minute exposure. The original image scale is 1.14 arcsec per pixel. |
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(04 August 2008) The brightest galaxy in Pegasus is this one: NGC7331 is a spiral at a distance of 49 million lightyears. This photo is a composite of ten 10-minute exposures using an SBIG ST7-XME CCD camera with a Schuler Clear filter. The images were registered, stacked, contrast modified and sharpened in MaxIm v5. Three other, much more distant galaxies can be seen in this photo. NGC 7337 is to the left and down, behind a star; NGC 7335 to the left and up; and NGC 7325 to the right. The original image scale is 1.14 arcsec per pixel. Compare to an August 2006 photo (below). |
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(17 July 2008) Messier 27 - the Dumbbell Nebula, is found in the constellation of Vulpecula, the fox. It is a planetary nebula. The distance is not well known. A commonly quoted value is 1200 light years. Most of the light from this nebula is emitted in the green part of the spectrum, at a wavelength of 5007 Angstroms. This image consists of 33 30-second images in each of three color bands, V, R and I, plus 33 additional unfiltered images at 30 seconds each. The original image scale is 1.14 arcsec per pixel. |
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(29 May 2008) NGC 5395 (left) and NGC 5394, in Canes Venatici, are an interacting pair of spiral galaxies at a distance of roughly 184 million light years. The larger galaxy is about 155,000 light years across. Ten 2-minute exposures were stacked and processed to improve contrast and detail. Another more distant galaxy, called PGC 211092, lies to the right of NGC 5394. Computer simulations of galaxy encounters are able to reproduce some of the main features of this colliding system. The original image scale is 1.14 arcsec per pixel. |
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(05 May 2008) 19 million light years away, M64, sometimes called the "Blackeye Nebula", appears here in a composite false-color image made from three 9-minute exposures, through I, R & V filters. These were stacked and processed to improve contrast and detail. M64 is a barred spiral (type Sb) located in the constellation of Coma Bernices and was first seen in 1779. M64 can be glimpsed in a good pair of binoculars. The conspicuous dark structure is a dust feature that obscures the light from the stars behind it. The original image scale is 1.27 arcsec per pixel. See also a 30 Apr 2007 image, below. |
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(03-10 Mar 2008) This new image of the barred-spiral galaxy, NGC 2903, is made from 57 individual 10-minute guided exposures through a clear filter. These were stacked and processed to improve contrast and reveal the wispy outer arms of this galaxy. NGC 2903 is a barred spiral (type Sb) located in the constellation of Leo, and is about 31 million light-years away. The original image scale is 1.27 arcsec per pixel. I'm still working on it! (See also 21 Mar 2007 and 09 Feb 2006, below) |
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(30 Jan 2008) This is a ten-exposure composite photograph of the globular cluster called the Intergalactic Wanderer, totaling 5 minutes. Compare this with a similar picture of the same object from 10 Mar 2007 (below). The definition and contrast in the image is better here because of the dynamic digital processing applied to the image. IGW is in the constellation of Lynx at a distance of 295,000 light-years, far outside the boundaries of our Milky Way Galaxy. The original image scale is 1.27 arcsec per pixel. |
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(21 Jan 2008) Here are two pictures of the asteroid 00169 Zelia. Each is a 30-second image - the first is taken about 5 minutes before the second. It's retrograding, and in this pair it has moved only about 2-1/2 pixels. According to Wikipedia, Zelia is a main-belt asteroid that was discovered by the brothers Paul Henry and Prosper Henry on September 28, 1876. It is named after a niece of the astronomer Camille Flammarion. Zelia has an orbital period of 3.62 years, a diameter of 34 km and a rotation period of 13.3 hours. The original image scale is 1.27 arcsec per pixel. |
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(03 Jan 2008) It's been a good year for comets. Here's a brief movie of Comet Tuttle/8P, a periodic comet that returns every 13.6 years. This animation was made on a very windy night with bad seeing from 16 individual sixty-second images taken over forty minutes. Near perihelion, it's speed through space right now is a minimum of 80,000 miles per hour, in a highly eccentric orbit that carries it out beyond the orbit of Saturn at its farthest point. |
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(17 Nov 2007) This is the same picture of the Orion Nebula complex as the one immediately below. The nine images have been correctly calibrated and more carefully mosaicked using MaxIm. The seams between the images have all but disappeared, and the contrast across the whole image has been adjusted to bring out details in both the low-light regions and the bright regions. |
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(17 Nov 2007) In this picture of the Orion Nebula complex, I've made a first attempt at making a mosaic from individual images. Here there are nine images of 45 seconds each, and they were taken one after the other. Balancing the grey tones was not too satisfactory because the images are not properly calibrated. The whole field of view is 43' x 28', almost three times the size of an individual image. A picture of the full moon would fit in this space. All images were taken at an original image scale of 1.27 arcsec per pixel. |
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(17 Nov 2007) This picture of a magnificent edge-on spiral galaxy is a composite of 9 sixty-second exposures, stacked and processed to bring out some of the fine detail. To do justice to this object requires much longer exposure times. NGC 891 is at a distance of about 27 million light years, in the direction of the constellation of Andromeda. The original image scale is 1.27 arcsec per pixel. (see also 02 Sep 2007, below) |
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(17 Nov 2007) This picture of Comet Holmes shows a more pronounce tail stretching from the comet's head downward and slightly to the right. The image is a composite of several images totaling 170 seconds. When this picture was taken Comet Holmes was almost 250 million kilometers from the Earth, and 380 million kilometers from the Sun. Compare this image to the ones below, taken at the same image scale. |
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(29 Oct 2007) This picture of Comet Holmes is a mosaic of two images, showing how the comet has changed its position in the sky relative to the background stars. The first (left) was taken at 03:35 UT 28 Oct. The second (right) was taken at 05:13 UT 29 Oct. In the intervening 26 hours, as the comet was moving away from the Sun, the coma expanded by about 25%. The image below shows the motion of the comet in the space of 40 minutes on the 28th of October. |
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(28 Oct 2007) Here's an animation of Comet Holmes. Twenty exposures of 30 seconds duration each were stretched using DDP, aligned and animated in MaxIm. The brightness variations are probably not real, because the background and stars brightnesses were only crudely balanced. The twenty frames started at 03:30 UT represent about 40 minutes of elapsed time. The comet is at a distance of about 245 million kilometers from the Earth, which makes the halo seen here about 350,000 km across. The original image scale is 1.27 arcsec per pixel. |
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(06 Oct 2007) Stephan's Quintet is a visual grouping of five galaxies. The five of them, in an arc stretching above the center of this image across to the left, are at a distance of 280 million light years and are colliding or gravitationally interacting. Another (arrow; largest in the image) is 39 million light years away and only appears superimposed near the more distant, interacting galaxies. This image was made from ten 10-minute exposures, stacked, sharpened and contrast adjusted a bit. Stephan's Quintet is located in the constellation of Pegasus. The original image scale is 1.27 arcsec per pixel. |
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(29 Sep 2007) IC 1340 is part of the larger diffuse nebula called the Veil Nebula. A remnant of a 5-10 thousand-year-old supernova explosion, located in the direction of Cygnus at a distance of 2,600 light years, the Veil is six times the diameter of the full Moon. IC 1340 is a very small part of the whole Veil. Forty-seven 1-minute exposure were aligned and stacked, then sharpened and contrast stretched with DDP. The original image scale is 1.27 arcsec per pixel. |
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(18 Sep 2007) This stellar nursery, in the constellation of Cepheus, is located just over 2700 light-years from Earth. Called the "Elephant Trunk Nebula," the whole region, of which this is less than a hundreth part, spans an area in the sky six times the size of the moon. The "trunk" seen here is about 10 light-years long. The area includes hot, ionized hydrogen regions (bright curved edges) behind dark lanes of denser hydrogen gas, and reflection nebulae near the brightest stars. 164 unfiltered images were processed and stacked, for a total exposure of 2h 16m. The original image scale is 1.27 arcsec per pixel. |
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(02 Sep 2007) This fine spiral galaxy is seen edge-on in a 45 minute unfiltered exposure made from 30 90-second individual unfiltered frames, stacked and digitally processed. NGC 891, located in the constellation of Andromeda, is a typical spiral galaxy having bright stars, gas and obscuring dust in a thin disk. Seen edge-on, the dark band through the middle is a zone of dust absorbing the light from the integrated starlight behind it. The distance is estimated to be just over 27 million light years from us. The original image scale is 1.27 arcsec per pixel. |
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(28 Aug 2007) Here is a b/w image of Messier 16 - the Eagle Nebula. The image is the result of stacking 20 two-minute exposures taken through a 9 nm H-alpha filter. M 16 is a great cloud of interstellar gas at a distance of 7,000 light years toward the constellation of Serpens. The massive, hot young stars in the cluster formed out of this cloud not much more than 5-1/2 million years ago. The original image scale is 1.27 arcsec per pixel. Compare this with a similar picture taken through an R filter a year ago (below). |
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(12 Aug 2007) This image of Messier 17 is made from thirty 30-second unfiltered exposures, aligned and stacked, along with R, V and B images of 450 seconds each. Located in the constellation of Sagittarius, M-17 (the Omega Nebula) is at a distance of about 5,000 light-years. |
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(1 Aug 2007) Here are two sixty-second exposures of Pluto taken 38 minutes apart, merged into one animation. At 14th magnitude, Pluto moved 1.5 arcsecond to the west in the time between the exposures. At the distance of Pluto (5,800 million km.), this amounts to over 11,000 km. The next image below is another animation showing Pluto's movement of 4,000,000+ kilometers over a period of eleven days. |
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(12 Aug 2007) This animation is of two pairs of images of Pluto taken eleven days apart, the first pair on August 1 (UT), the other on August 12 (UT). All images were sixty second unfiltered exposures. Because of the mosaicking process, Pluto appears fainter in the later exposure (right), although is has actually not dimmed appreciably in the intervening time. Pluto moved from RA 17h 45m 40s, Dec -16d 29m 39s on August 1st to RA 17h 44m 57s, Dec -16d 32m 22s on August 12th. The earlier exposure (same as above) is on the left. Can you see where Pluto moved to? |
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(10 Jun 2007) This animation (6 MB .gif) shows the variable star DQ Herculis, in the very center of the frame, in action. There are 100 exposures of 60 seconds each in this series, taken over a period of 2h 57m. During the deep eclipse in the middle of the sequence, DQ Her briefly disappears (fainter than 17th magnitude). In addition to being an eclipsing binary system with a period of 4h 37m, DQ Her is also a cataclysmic variable with much shorter, rapid variability (not seen in this movie). The observations here cover about two-thirds of the eclipse cycle. |
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(25 May 2007) Fifteen unfiltered, guided exposures of nine minutes each were stacked using MaxIm to produce this image. M-51 is off-centered to permit offset guiding on a particular field star. The image was further processed using digital development, and the brightness was adjusted to reveal the wispy gas surrounding this galaxy. The far distant irregular galaxy IC 4278 is left of center, below the triangle of nearby stars. The original scale is 1.27 arcsec per pixel. Compare this with the inset from the Sloan Digital Sky Survey. |
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(09 May 2007) Having created a decent animation of the RR Lyrae stars in M3, I went after them in M13. I took 204 60-second unfiltered exposures in a row, with an occasional refocus. When I looked at the images sequentially with MaxIm's animation tool, I didn't see anything varying (!?!). So, instead, I aligned and stacked the images, creating a single image equivalent to 3h 24m exposure. The seeing was remarkably constant throughout. The stack was processed with the DDP tool. The original scale is 1.27 arcsec/pixel. Compare this with a year earlier image of M13 below (25 April 2006). |
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(22 Apr 2007) I was inspired by a recent APOD (15 April) to make this movie of M3. There are 45 200-second unfiltered exposures in a row, with an occasional refocus. Three consecutive images are combined to make 15 frames in all. The movie plays for 3 seconds and covers just over 3 hours of real time. If you study this as it runs, you can see many RR Lyrae variable stars brightening and dimming. It's not atmospheric scintillation! At 1.27 arcsec/pixel, better would be a larger scale of 1.0 or 0.7 arcsec/pixel. M3 is 33,900 light years distant and contains ~500,000 stars. |
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