Caldwell-kataloget

ID: phot-14a-09-fullres Press Photo: 14-09

Angle of view: 27' × 27' (0.792" per pixel), north is up.

It is an almost-true colour composite based on images made with the multi-mode VIMOS instrument on the 8.2-m Melipal (Unit Telescope 3) of ESO's Very Large Telescope. Exposures were taken in three different wavebands which were associated to a given colour : R-band (centred around 652 nm; red), V (540 nm; green) and B (456 nm; blue). The images were taken on the night of December 9 to 10, 2004 in the presence of the President of the Republic of Chile, M. Ricardo Lagos. The observing conditions were very good (seeing well below 1 arcsec). The total exposure was 2.25 min in R, 3 min in V and 6 min in B. The scale is 0.205 arcsec/pix and the image covers a 7.7 x 6.6 arcmin2 region on the sky. All exposures were taken and pre-processed by ESO Paranal Science Operation astronomers. Additional image processing by Henri Boffin (ESO).

Credit: ESO

Coordinates
Position (RA):  	2 46 19.04
Position (Dec): 	-30° 16' 29.62"
Field of view:  	6.85 x 7.74 arcminutes
Orientation:    	North is 0.1° left of vertical

Colours & filters Band	Wavelength	Telescope
Optical B       	456 nm  	Very Large Telescope VIMOS
Optical V       	540 nm  	Very Large Telescope VIMOS
Optical R       	652 nm  	Very Large Telescope VIMOS

Iridescent Glory of Nearby Helix Nebula.

About the Object

• Object Name: Helix Nebula, NGC 7293
• Object Description: Planetary Nebula
• Position (J2000): R.A. 22h 29m 48.20s

Dec. -20° 49' 26.0"

• Constellation: Aquarius
• Distance: About 650 light-years (200 parsecs)
• Dimensions: The image is roughly 27 arcminutes (5.1 light-years or 1.6 parsecs) across.

About the Data

• Data Description: Hubble data have been superimposed onto ground-based data taken by Travis Rector (NRAO) at the 0.9 meter telescope located on Kitt Peak, Tucson, AZ (NOAO/AURA/NSF). The HST data are from proposal 9700. Processed images may be obtained from the Helix MAST web site. The Hubble Helix Team includes M. Meixner, H.E. Bond, G. Chapman (STScI), Y.-H. Chu (U. Illinois, Urbana-Champaign), P. Cox (Institut d'Astrophysique Spatiale, France), W. Crothers, L.M. Frattare, R.Gilliland (STScI), M. Guerrero R. Gruendl (U. Illinois, Urbana-Champaign), F. Hamilton, (STScI), R.Hook (STScI/ESO), P. Huggins (New York Univ.), I. Jordan, C.D. Keyes, A. Koekemoer (STScI), K.Kwitter (Williams College), Z.G. Levay, P.R. McCullough, M. Mutchler, K. Noll (STScI), C.R. O'Dell (Vanderbilt Univ.), N. Panagia, M. Reinhart, M. Robberto, K. Sahu, D. Soderblom, L. Stanghellini, C. Tyler, J. Valenti, A. Welty, R. Williams (STScI).
• Instrument: ACS/WFC Mosaic I Camera on KPNO 0.9m telescope
• Exposure Date(s): November 19, 2002 November 3, 2001
• Exposure Time: 4.5 hours 25 minutes
• Filters: F502N ([O III]), F658N (H alpha) k1009 (H alpha), k1014 ([O III])

Thirty minutes (6 x 300 seconds)

Aufnahme des Planetarischen Nebels NGC 40 mit einer Webcam an einem 14" SCT Autor: Klaus Hohmann

A perfect donut of a galaxy.

Data from the following proposal were used to create this image: PHANGS-HST: Linking Stars and Gas throughout the Scales of Star Formation

Red: WFC3/UVIS F814W Green: WFC3/UVIS F555W Blue : WFC3/UVIS F438W+F336W+F275W

The Tau Canis Majoris Cluster is an open cluster — a group of stars born from the same molecular cloud. This means that all of the cluster’s inhabitants share a common chemical composition and are loosely bound together by gravity. Having been born together, they make an ideal stellar laboratory to test theories of stellar evolution, the chain of events that leads from a star’s birth in a cool, dense cloud of gas through to its eventual death.

Though the stars in this image were all created at the same time, their various different masses mean they will lead very different lives. As Tau Canis Majoris is one of the most massive and short-lived types of star, it will burn through its nuclear fuel long before its smaller companions, which will keep on shining for billions of years.

SBIG ST-4000XCM
15x15min
Imager Temp -20C
APM/TMB 130/780
Field Flattener

The MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile captured this richly colourful view of the bright star cluster NGC 3532. Some of the stars still shine with a hot bluish colour, but many of the more massive ones have become red giants and glow with a rich orange hue.

Credit:

ESO/G. Beccari

About the Object

Name:	NGC 3532
Type:	• Milky Way : Star : Grouping : Cluster : Open
        • X - Star Clusters
Distance:	1300 light years
Constellation:	Carina

Colours & filters Band Telescope

Optical B	 MPG/ESO 2.2-metre telescope WFI
Optical V	 MPG/ESO 2.2-metre telescope WFI
Optical H-alpha MPG/ESO 2.2-metre telescope WFI
Infrared I	 MPG/ESO 2.2-metre telescope WFI

The globular cluster Omega Centauri — with as many as ten million stars — is seen in all its splendour in this image captured with the WFI camera from ESO's La Silla Observatory. The image shows only the central part of the cluster — about the size of the full moon on the sky (half a degree). North is up, East is to the left. This colour image is a composite of B, V and I filtered images. Note that because WFI is equipped with a mosaic detector, there are two small gaps in the image which were filled with lower quality data from the Digitized Sky Survey.

Coordinates
Position (RA):	13 26 47.32
Position (Dec):	-47° 28' 46.86"
Field of view:	31.88 x 29.99 arcminutes
Orientation:	North is 0.0° right of vertical

Colours & filters Band	Wavelength	Telescope
Infrared B	451 nm	MPG/ESO 2.2-metre telescope WFI
Optical V	539 nm	MPG/ESO 2.2-metre telescope WFI

• Source: Primary
• Image Credit: NASA/JPL-Caltech
• Image produced by: M. Regan (STScI), and the SINGS Team

Colours & filters
Band Telescope
Optical B MPG/ESO 2.2-metre telescope WFI
Optical V MPG/ESO 2.2-metre telescope WFI

The Wide Field Camera 3 (WFC3), a new camera aboard NASA's Hubble Space Telescope, snapped this image of the planetary nebula, catalogued as NGC 6302, but more popularly called the Bug Nebula or the Butterfly Nebula. WFC3 was installed by NASA astronauts in May 2009, during the servicing mission to upgrade and repair the 19-year-old Hubble telescope.

NGC 6302 lies within our Milky Way galaxy, roughly 3,800 light-years away in the constellation Scorpius. The glowing gas is the star's outer layers, expelled over about 2,200 years. The "butterfly" stretches for more than two light-years, which is about half the distance from the Sun to the nearest star, Alpha Centauri.

The central star itself cannot be seen, because it is hidden within a doughnut-shaped ring of dust, which appears as a dark band pinching the nebula in the center. The thick dust belt constricts the star's outflow, creating the classic "bipolar" or hourglass shape displayed by some planetary nebulae.

The star's surface temperature is estimated to be about 400,000 degrees Fahrenheit, making it one of the hottest known stars in our galaxy. Spectroscopic observations made with ground-based telescopes show that the gas is roughly 36,000 degrees Fahrenheit, which is unusually hot compared to a typical planetary nebula.

The WFC3 image reveals a complex history of ejections from the star. The star first evolved into a huge red-giant star, with a diameter of about 1,000 times that of our Sun. It then lost its extended outer layers. Some of this gas was cast off from its equator at a relatively slow speed, perhaps as low as 20,000 miles an hour, creating the doughnut-shaped ring. Other gas was ejected perpendicular to the ring at higher speeds, producing the elongated "wings" of the butterfly-shaped structure. Later, as the central star heated up, a much faster stellar wind, a stream of charged particles traveling at more than 2 million miles an hour, plowed through the existing wing-shaped structure, further modifying its shape.

The image also shows numerous finger-like projections pointing back to the star, which may mark denser blobs in the outflow that have resisted the pressure from the stellar wind.

The nebula's reddish outer edges are largely due to light emitted by nitrogen, which marks the coolest gas visible in the picture. WFC3 is equipped with a wide variety of filters that isolate light emitted by various chemical elements, allowing astronomers to infer properties of the nebular gas, such as its temperature, density, and composition.

The white-colored regions are areas where light is emitted by sulfur. These are regions where fast-moving gas overtakes and collides with slow-moving gas that left the star at an earlier time, producing shock waves in the gas (the bright white edges on the sides facing the central star). The white blob with the crisp edge at upper right is an example of one of those shock waves.

NGC 6302 was imaged on July 27, 2009, with Hubble's Wide Field Camera 3 in ultraviolet and visible light. Filters that isolate emissions from oxygen, helium, hydrogen, nitrogen, and sulfur from the planetary nebula were used to create this composite image.

The filaments are dramatic markers of the feedback process through which energy is transferred from the central massive black hole to the surrounding gas. The filaments originate when cool gas is transported from the center of the galaxy by radio bubbles that rise in the hot interstellar gas.

At a distance of 230 million light-years, NGC 1275 is one of the closest giant elliptical galaxies and lies at the center of the Perseus cluster of galaxies.

The galaxy was photographed in July and August 2006 with the Advanced Camera for Surveys in three color filters.

Coordinates
Position (RA): 	3 19 48.39
Position (Dec):	41° 30' 41.00"
Field of view: 	3.86 x 2.99 arcminutes
Orientation:   	North is 8.5° left of vertical

Colours & filters Band	Wavelength	Telescope
Optical B	435 nm	Hubble Space Telescope ACS
Optical V	550 nm	Hubble Space Telescope ACS
Optical R	625 nm	Hubble Space Telescope ACS

In some ways, star clusters are like giant families with thousands of stellar siblings. These stars come from the same origins — a common cloud of gas and dust — and are bound to one another by gravity. Astronomers think that our Sun was born in a star cluster about 4.6 billion years ago that quickly dispersed.

By studying young star clusters, astronomers hope to learn more about how stars — including our Sun — are born. NGC 6231, located about 5,200 light years from Earth, is an ideal testbed for studying a stellar cluster at a critical stage of its evolution: not long after star formation has stopped.

The discovery of NGC 6231 is attributed to Giovanni Battista Hodierna, an Italian mathematician and priest who published observations of the cluster in 1654. Sky watchers today can find the star cluster to the southwest of the tail of the constellation Scorpius.

NASA's Chandra X-ray Observatory has been used to identify the young Sun-like stars in NGC 6231, which have, until recently, been hiding in plain sight. Young star clusters like NGC 6231 are found in the band of the Milky Way on the sky. As a result, interloping stars lying in front of or behind NGC 6231 greatly outnumber the stars in the cluster. These stars will generally be much older than those in NGC 6231, so members of the cluster can be identified by selecting signs of stellar youth.

Young stars stand out to Chandra because they have strong magnetic activity that heats their outer atmosphere to tens of millions of degrees Celsius and causes them to emit X-rays. Infrared measurements assist in verifying that an X-ray source is a young star and in inferring the star's properties.

This Chandra X-ray image of NGC 6231 shows a close-up of the inner region of the cluster. Chandra can detect a range of X-ray light, which has been split into three bands to create this image. Red, green, and blue represents the lower, medium, and high-energy X-rays. The brightest X-ray emission is white.

The Chandra data, combined with infrared data from the Visible and Infrared Survey Telescope for Astronomy (VISTA) Variables in the Vía Lactéa survey has provided the best census of young stars in NGC 6231 available. An infrared image from NASA’s Wide-field Infrared Survey explorer is shown on the left.

There are an estimated 5,700 to 7,500 young stars in NGC 6231 in the Chandra field of view, about twice the number of stars in the well-known Orion star cluster. The stars in NGC 6231 are slightly older (3.2 million years on average) than those in Orion (2.5 million years old). However, NGC 6231 is much larger in volume and therefore the number density of its stars, that is, their proximity to one another, is much lower, by a factor of about 30. These differences enable scientists to study the diversity of properties for star clusters during the first few million years of their life.

Chandra studies of this and other young star clusters, have allowed astronomers to build up a sample from which cluster evolution can be studied. These clusters come from dozens of star-forming regions, but NGC 6231 adds a crucial piece to this puzzle because it shows how a cluster looks after the end of star formation. A comparison of the ages, sizes and masses of clusters in this sample implies that NGC 6231 has expanded from a more compact initial state, but it has not expanded sufficiently fast for its stars to break free from the cluster’s gravitational pull. Astronomers are not sure what will happen next: will it remain held together by gravity? Or will its constituents one day disperse as our Sun’s ancestral cluster once did?

Nearby star-forming regions frequently contain multiple star clusters, most of which are individually less massive than NGC 6231. The simple structure of NGC 6231, along with its relatively high mass, suggests that NGC 6231 was built up by mergers of several star clusters early its lifetime, a process known as "hierarchical cluster assembly".

Two papers describing recent studies of NGC 6231, both led by Michael Kuhn while at the Universidad de Valparaíso in Chile, have been published and are available online at https://arxiv.org/abs/1706.00017 and https://arxiv.org/abs/1710.01731.

Found some data for NGC 5694 today. This is the core of the globular cluster. I haven't bothered with globular clusters before but this one seems to have rarely been processed. The problem I have with globular clusters is that they all look the same to me. I know they cool things and we can learn a lot from them but at best they look like gems without the animated sparkle and at worst I once seriously thought one was a pile of salt on black velvet. Apparently they are very rewarding to view directly through a telescope. I wouldn't know. :(

I used the f170w data in the blue channel to represent ultraviolet. Hopefully I'm not mistaken that it's UV. All the information I could find on it indicated it was such. So anyway, some of the stars are very blue and that's why.

Red: hst_11975_40_wfpc2_f555w_pc_sci + hst_05902_01_wfpc2_f555w_pc_sci Green: hst_08095_11_wfpc2_f439w_pc_sci + hst_05902_01_wfpc2_f439w_pc_sci Blue: hst_05902_01_wfpc2_f336w_pc_sci + hst_11975_40_wfpc2_f300w_pc_sci + hst_11975_40_wfpc2_f170w_pc_sci

Globular clusters are vast, spherical clouds of old stars bound together by gravity. They are found circling the cores of galaxies, as satellites orbit the Earth. These star clumps contain very little dust and gas — it is thought that most of it has been either blown from the cluster by winds and explosions from the stars within, or stripped away by interstellar gas interacting with the cluster. Any remaining material coalesced to form stars billions of years ago.

These globular clusters spark a considerable amount of interest for astronomers — 47 Tucanae, otherwise known as NGC 104, is a huge, ancient globular cluster about 15 000 light-years away from us, and is known to contain many bizarre and interesting stars and systems.

Located in the southern constellation of Tucana (The Toucan), 47 Tucanae orbits our Milky Way. At about 120 light-years across it is so large that, despite its distance, it looks about as big as the full Moon. Hosting millions of stars, it is one of the brightest and most massive globular clusters known and is visible to the naked eye [1]. In amongst the swirling mass of stars at its heart lie many intriguing systems, including X-ray sources, variable stars, vampire stars, unexpectedly bright “normal” stars known as blue stragglers (eso1243), and tiny objects known as millisecond pulsars, small dead stars that rotate astonishingly quickly [2].

Red giants, stars that have exhausted the fuel in their cores and swollen in size, are scattered across this VISTA image and are easy to pick out, glowing a deep amber against the bright white-yellow background stars. The densely packed core is contrasted against the more sparse outer regions of the cluster, and in the background huge numbers of stars in the Small Magellanic Cloud are visible.

This image was taken using ESO’s VISTA (Visible and Infrared Survey Telescope for Astronomy) as part of the VMC survey of the region of the Magellanic Clouds, two of the closest known galaxies to us. 47 Tucanae, although much closer than the Clouds, by chance lies in the the foreground of the Small Magellanic Cloud (eso1008), and was snapped during the survey.

VISTA is the world’s largest telescope dedicated to mapping the sky. Located at ESO’s Paranal Observatory in Chile, this infrared telescope, with its large mirror, wide field of view and sensitive detectors, is revealing a new view of the southern sky. Using a combination of sharp infrared images — such as the VISTA image above — and visible-light observations allows astronomers to probe the contents and history of objects like 47 Tucanae in great detail. Notes

[1] There are over 150 globular clusters orbiting our galaxy. 47 Tucanae is the second most massive after Omega Centauri.

Caldwell 35, another of astronomer William Herschel’s discoveries, is a giant elliptical galaxy, the largest and brightest galaxy near the center of this Hubble image. It is accompanied by other members of the Coma cluster of galaxies, and is set against a backdrop of hundreds of even more distant galaxies. (One bright star on the right side of the image, and a dimmer star above it, belong to our own galaxy.)

Scientists believe Caldwell 35 is about two and a half times larger than the Milky Way. Hidden in the heart of this tranquil-seeming galaxy lies a supermassive black hole. With a mass 21 billion times greater than the Sun, it is the most colossal black hole ever discovered. (For comparison, the black hole at the center of our galaxy is thought to be 4 million times more massive than the Sun.)

Black holes usually spark visions of stars and planets hurtling into the inky blackness of a tornado-like vortex, clutched in the unrelenting grip of unseen forces. While Caldwell 35’s black hole used to feed on material in its younger years, astronomers believe its galactic buffet has run out and it has stopped feeding. Not only are stars not being sucked in, brand new stars are actually forming and orbiting peacefully about the black hole.

This image was taken with Hubble's Advanced Camera for Surveys in visible and infrared light. With a magnitude of 11.5, Caldwell 35 is best seen using a large telescope under dark skies. As in the Hubble image, a number of fainter galaxies can be seen accompanying Caldwell 35 in the field of view. From the Northern Hemisphere, late spring is the ideal time to view the galaxy, which is located in the constellation Coma Berenices. From the Southern Hemisphere, look for it in the late autumn.

For more information about Hubble’s observations of Caldwell 35, see:

www.spacetelescope.org/images/heic1602a/

Credit: NASA & ESA

For Hubble's Caldwell catalog site and information on how to find these objects in the night sky, visit:

Another planetary nebula. Very similar to <a href="https://www.flickr.com/photos/geckzilla/9667741870">NGC 6826</a> but it's interesting to compare the subtle differences. Why are they so similar? Why are some parts not similar? Are they <a href="http://hubblesite.org/newscenter/archive/releases/2013/37" rel="nofollow">aligned for some reason</a>?

Processing notes: Most of the nebula was on three filters but the edges were cut off around the outer part of the fainter spheroid. Something like <a href="File:NGC_3242_-HST-_R658G656B502.png" rel="nofollow">this</a> but I used a different set for the WFPC2-PC squares. There's more than one way to process a nebula...

Red: hst_08773_13_wfpc2_f658n_pc_sci Green: hst_08773_13_wfpc2_f555w_pc_sci Blue: hst_08773_13_wfpc2_f502n_pc_sci

Extra bits around the edge that were missing from the PC: hst_10822_02_wfpc2_f547m_wf_sci

Lots of cosmic rays in this one I had to remove manually even after running my automatic noise removal over it. It's so difficult for a computer to tell the difference between cosmic rays and actual galaxy parts. The tattered blue bits emanating from the core I think are interesting, though they are a little difficult to see. <a href="http://www.geckzilla.com/apod/NGC5005.jpg" rel="nofollow">www.geckzilla.com/apod/NGC5005.jpg</a>

HST_9788_b8_ACS_WFC_F658N_sci

Angle of view: 4' × 4' (0.3" per pixel), north is up.

Picture Details:

   Optics             24-inch RC Optical Systems Telescope
   Camera           SBIG STL11000 CCD Camera
   Filters              Custom Scientific
   Dates               August 22nd - September 3rd 2008
   Location          Mount Lemmon SkyCenter
   Exposure          LRGB = 405:120:150:120 minutes
   Acquisition       TheSky (Software Bisque), Maxim DL/CCD (Cyanogen)
   Processing        CCDStack (CCDWare), Mira (MiraMetrics), Maxim DL (Cyanogen), Photoshop CS3 (Adobe)

Coordinates
Position (RA):	0 47 1.99
Position (Dec):	-20° 44' 45.83"
Field of view:	33.77 x 21.00 arcminutes
Orientation:	North is 90.0° right of vertical

Colours & filters
Band	Telescope
Optical B	MPG/ESO 2.2-metre telescope WFI
Optical V	MPG/ESO 2.2-metre telescope WFI
Optical H-alpha	MPG/ESO 2.2-metre telescope WFI
Optical R	MPG/ESO 2.2-metre telescope WFI

This seemingly starless dark patch is actually an opaque interstellar dust cloud that obscures the light of the background Milky Way stars. Dust grains in the cloud redden the starlight that reaches us by absorbing blue light preferentially, so that the red stars shimmering in the northern and darkest part of the Coalsack appear more crimson than they would in the absence of this dust.

The first European to see this remarkable object was probably the Spanish navigator and explorer Vincente Yanez Pinzon when he sailed to the South American coast in 1499. The Coalsack earned the nickname "Black Magellanic Cloud” in the 16th century, apparently rivalling the prominence of the Large and Small Magellanic Clouds, the two dwarf irregular galaxies that shine brightly in the skies of the Southern Hemisphere. The Incas tell that the god Ataguchu, in a fit of temper, kicked the Milky Way and a fragment flew off, forming the Small Magellanic Cloud where it landed on the sky, and leaving the black mark of the Coalsack behind. Beware of Inca gods in a bad mood!

In this Hubble telescope image, the "parka" is really a disk of material embellished with a ring of comet-shaped objects, with their tails streaming away from the central, dying star. The Eskimo's "face" also contains some fascinating details. Although this bright central region resembles a ball of twine, it is, in reality, a bubble of material being blown into space by the central star's intense "wind" of high-speed material.

In this photo, one bubble lies in front of the other, obscuring part of the second lobe. Scientists believe that a ring of dense material around the star's equator, ejected during its red giant phase, created the nebula's shape. The bubbles are not smooth like balloons but have filaments of denser matter. Each bubble is about 1 light-year long and about half a light-year wide.

Scientists are still puzzled about the origin of the comet-shaped features in the "parka." One possible explanation is that these objects formed from a collision of slow-and fast-moving gases.

Picture Details:

   Optics            32-inch Schulman Telescope (RC Optical Systems)
   Camera            SBIG STX CCD Camera
   Filters           AstroDon Generation II
   Dates             March 3rd and 4th 2011
   Location          Mount Lemmon SkyCenter
   Exposure          LRGB = 170:70:70:70 minutes
   Acquisition       ACP Observatory Control Software (DC-3 Dreams),TheSky (Software Bisque), Maxim DL/CCD (Cyanogen)
   Processing        CCDStack (CCDWare), Photoshop CS3 (Adobe)
   Guest Astronomers:                   Walt Lickteig

Skywatcher 10" Quattro Newtonian, Skywatcher AZ-EQ6 GT mount, Skywatcher f4 aplanatic coma corrector, Skywatcher 9x50 finderscope, Lacerta MGEN-II Superguider Canon EOS100D camera, 8x10 min exposures, ISO 800, 15x10 min dark frames, processing made with DeepSkyStacker 3.3.4 and IrfanView 4.42

Globular clusters like Caldwell 42 are relics of the galaxy’s earliest years. Since they were born as the nascent galaxy was forming, these clusters provide a glimpse backward in time and provide a hint of what the Milky Way was like billions of years ago. Studying globular clusters allows scientists to learn more about how the first stars formed in our galaxy and the role the clusters played in the galaxy’s development. However, Caldwell 42 has a very elongated orbit around the center of our galaxy, which might hint toward an extragalactic origin. It seems that some globular clusters may have once been independent dwarf galaxies that were later absorbed by the Milky Way.

The cluster is nestled in the diminutive constellation Delphinus and is best viewed in the late summer in the Northern Hemisphere or late winter in the Southern Hemisphere. It was discovered in 1784 by British astronomer William Herschel — the discoverer of dozens of celestial objects in the Caldwell catalog. Caldwell 42 isn’t terribly bright to begin with compared to other star clusters, so at its distance of about 135,000 light-years from Earth it’s really not the most impressive sight to most amateur astronomers. In a moderate-sized telescope, the magnitude-10.5 cluster appears as a dim, circular smudge. It is difficult to pick out individual stars in the cluster, though large amateur telescopes may be able to resolve a few of the cluster’s most vibrant stellar members.

This image, taken by Hubble’s Advanced Camera for Surveys, includes light detected at both visible and infrared wavelengths. When viewed in visible wavelengths alone, Caldwell 42 appears dimmer. This is because intervening dust between us and Caldwell 42 scatters some of the cluster’s visible light but lets the infrared light pass through. Hubble’s multi-wavelength view transforms this otherwise faint smudge into a dazzling spectacle, while helping astronomers analyze the cluster’s stars and investigate Caldwell 42’s history.

For more information about Hubble’s observations of Caldwell 42, see:

www.spacetelescope.org/images/potw1137a/

Credit: ESA/Hubble & NASA

For Hubble's Caldwell catalog site and information on how to find these objects in the night sky, visit:

Imaging Telescope:
Explore Scientific 127mm ED Refractor (952 focal length)

Field Flattener:
HoTech 2" SCA Field Flattener

Mount:
Celestron CGX

Polar Alignment:
QHYCCD PoleMaster

Imaging Camera:
ZWO ASI1600MM-Cool

Lum=90x60s
Red=15x60s
Green=15x60s
Blue=15x60s
Total Time: 2.2 hours

Gain: 139, Offset: 21

Guide scope:
Orion ST80

Guide Camera:
Lodestar X2

Guide Software:
PHD2

Calibration Frames:
Darks: 50, Bias: 50, Flats: 50

Capture software:
Sequence Generator Pro (SGP)

Stacking software:
PixInsight

Post Processing:
PixInsight, PhotoShop