My first try at imaging M27.

Canon 350D attached to 10" Newtonian at prime focus (f/6.3), mounted on an EQ6 Pro. Stack of 15 images, 300s @ ISO 800

These two Messier objects lie quite close together, see previous image for a full frame view.

M97. The Owl planetary nebula is about 3.7 arcminutes across in our sky but is actually 0.91 light years in diameter. It lies about 2600 light years distant. The central star has shed its outer layers which glow either red (hydrogen) or green-blue (oxygen) lit by the intense UV light of the remnant white dwarf star in the centre. Eventually, the star will cool and the gas will expand until the nebula fades away. It estimated that the nebula is about 6000 years old based on its size and expansion rate. Our own Sun may eventually suffer a similar fate.

A gravitational effect has formed a constrained tube of gas near the star before it expands into a sphere. We are looking down at about 45 degrees to the axis of the tube, these effects produce an "owl face" from our perspective.

Barred spiral galaxy M108 is about 45 million light years away and is almost edge on from our perspective. It’s 8.7 x 2.2 arcminutes diameter in our sky. It lacks a prominent core or bulge but has numerous dark dust lanes. It’s possible to see

a small yellow core at its centre (yellow or red stars tend to be old and mature) brownish dust lanes, pink hydrogen alpha zones and two bright blue "stellar associations” of young intensely bright stars at this magnification.

A Type II supernovae was observed here in 1969.

Technical card on previous full frame image.

M101 is a face-on spiral galaxy in Ursa Major. It is a "grand design" spiral galaxy meaning that it has a prominent central bulge and well-defined spiral arms.

Dates of observation: 9, 18, 19, 23, 24, 31 May and 1-3 June 2025

Location: Washington D.C.

Equipment:

ASI 2600MM Pro (monochrome) camera

Chroma 36mm LRGB Filter Set

WO Fluorostar 91mm f/5.9 triplet APO refractor with Adjustable Field Flattener 68III

iOptron GEM28-EC mount

Data and exposure times:

Data was acquired as LRGB images with the following exposure times:

18.5 hours (317x210s subs) with Luminance filter (L).

4.7 hours (80x210s subs) with Red filter (R).

3.2 hours (54x210s subs) with Green filter (G).

4.8 hours (82x210s subs) with Blue filter (B).

Fully processed in PixInsight.

Preprocessing notes:

Created L, R, G and B "masters" by Calibration, Cosmetic Correction, Weighted Subframes, Star Alignment, and Integration.

Postprocessing notes:

a. For the L master: Applied Dynamic Background Extractor, BlurXT and NoiseXT. Lastly, applied a Histogram Transformation to generate a nonlinear image which was saved as a postprocessed L image.

b. "Built" a color image from the R, G and B masters and applied a DBE to it using the same DBE settings as used for the L master. Since a color image is involved, this necessitated the application of Background Neutralization and Color Calibration to the resulting image. Continued with an application of BlurXT, NoiseXT and a Histogram Transformation. Saved the nonlinear result as a postprocessed RGB image.

c. Applied an instance from the postprocessed L image to the postprocessed RGB image.

d. Applied StarXterminator to create starless (i.e. containing the target image) and stars-only images.

e. Processed the starless image, after applying a range selection mask to protect the background, using Local Histogram Equalization, Curves Transformation and Color Saturation. Removed the mask and used an expression in Pixel Math to combine the result from this step with the stars-only image from the previous step.

f. After protecting the target image with a range selection mask, applied a Morphological Transformation to reduce the size and presence of background stars followed by an application of a Histogram Transformation.

Messier 20 or M20 (also designated NGC 6514) is a nebula and star cluster in the constellation Sagittarius.

It was discovered by Charles Messier on June 5, 1764. Its name means 'divided into three lobes'.

M20 lies at an estimated distance of 5200 light years.

Scope: 8" Celestron telescope C8-SGT (XLT)

Mount: Vixen Sphinx SXW Equatorial Mount

Camera: Canon EOS 5D M II

Exposure: 61 seconds

ISO Speed: 2000

© Jeff D. Muth 2015

The Pleiades, also known as the Seven Sisters and Messier 45, are an open star cluster containing middle-aged, hot B-type stars in the north-west of the constellation Taurus. It is among the star clusters nearest to Earth, it is the nearest Messier object to Earth, and is the cluster most obvious to the naked eye in the night sky.

The cluster is dominated by hot blue and luminous stars that have formed within the last 100 million years. Reflection nebulae around the brightest stars were once thought to be left over material from the formation of the cluster, but are now considered likely to be an unrelated dust cloud in the interstellar medium through which the stars are currently passing.

Equipment:

Scope: Lacerta 72/432 F6 0.85x reduktorral (367mm F5.1)

Mount: Skywatcher EQ-5 Pro Synscan Goto

Guide scope: Orion 50mm mini

Guide camera: ZWO ASI120mm Mini

Main camera: ZWO ASI183MM-Pro cooled monochrome camera

Accessories:

ZWO ASIAIR Pro

ZWO EFW 8x1.25"

Lacerta Dew-heater 20cm

Lacerta Dew-heater 30cm

Programs:

PixInsight

Adobe Photoshop CC 2020

Details:

Camera temp: -15°C

Gain: 53

Astronomik L-3 UV-IR Block: 92x180s

Astronomik Deep-Sky R: 16x180s

Astronomik Deep-Sky G: 14x180s

Astronomik Deep-Sky B: 20x180s

This was taken with the Stone Edge Observatory 20 inch telescope near Sonoma California. This is a bicolor image with h-alpha and oiii data. There is a total exposure of 3hr57m in h-alpha and 1hr29m40s total in oiii. The exposure is probably a little overkill... but I had the time to do it.

Description: This image of spiral galaxy M33 (or NGC 598), the Triangulum Galaxy, was developed from 124x300s subs or about 10 hours of total exposure time. Of interest is the presence of the irregular-shaped nebula NGC 604, an HII region, in one of the spiral arms. Initially, I found it difficult to locate NGC 604, but once I did, I decided for future reference to identify it with a magnification inset as shown in the image.

Date / Location: 1-5 December 2022 / Washington D.C.

Equipment:

Scope: WO Zenith Star 81mm f/6.9 with WO 6AIII Flattener/Focal Reducer x0.8

OSC Camera: ZWO ASI 2600 MC Pro at 100 Gain and 50 Offset

Mount: iOptron GEM28-EC

Guider: ZWO Off-Axis Guider

Guide Camera: ZWO ASI 174mm mini

Focuser: ZWO EAF

Light Pollution Filter: Chroma LoGlow Broadband

Processing Software: Pixinsight

Processing Steps:

Preprocessing: I preprocessed 124x300s subs (= 10.3 hours) in Pixinsight to get an integrated image using the following process steps: Image Calibration > Cosmetic Correction > Subframe Selector > Debayer > Select Reference Star and Star Align > Image Integration.

Linear Postprocessing: Rotation > Dynamic Crop > Dynamic Background Extractor (both subtraction to remove light pollution gradients and division for flat field corrections) > Background Neutralization > Color Calibration > Noise Xterminator.

Nonlinear Postprocessing and additional steps: Histogram Transformation > Local Histogram Equalization (2 cycles) > Curves Transformation (2 cycles) > SCNR Noise Reduction (2 cycles).

Taken with a TMB92L, Canon T3i DSLR, Orion SSAG autoguider and 50mm guidescope, and Celestron AVX mount. Consists of 30 180-second light frames and 18 180-second dark frames, all at ISO 800, as well as 15 flat and 30 bias frames. Captured with BackyardEOS, stacked in DeepSkyStacker, and processed in Photoshop.

Description: Going from bottom right to top left along a curve in this image of the Markarian's Chain in the Virgo Cluster are M84, M86, NGC 4438, NGC 4435, NGC 4461, NGC 4473 and NGC 4477. The magnification inset shows the "Markarian's Eyes" NGC 4438 and NGC 4435.

Date / Location: 13-14 April 2023 / Washington D.C.

Equipment:

Scope: WO Zenith Star 81mm f/6.9 with WO 6AIII Flattener/Focal Reducer x0.8

OSC Camera: ZWO ASI 2600 MC Pro at 100 Gain and 50 Offset

Mount: iOptron GEM28-EC

Guider: ZWO Off-Axis Guider

Guide Camera: ZWO ASI 174mm mini

Focuser: ZWO EAF

Light Pollution Filter: Chroma LoGlow Broadband

Processing Software: Pixinsight

Processing Steps:

Preprocessing: I preprocessed 37x300s subs (= 3.1 hours) in Pixinsight to get an integrated image using the following processes: Image Calibration > Cosmetic Correction > Subframe Selector > Debayer > Select Reference Star and Star Align > Image Integration.

Linear Postprocessing: Dynamic Background Extractor (both subtraction to remove light pollution gradients and division for flat field corrections) > Background Neutralization > Color Calibration > Noise Xterminator.

Nonlinear Postprocessing: Histogram Transformation > Local Histogram Equalization.

One of my fist short exposure learning/test Astro-images, photographed close to the city.

The Lagoon Nebula (M8, Messier 8 or NGC 6523) is a giant interstellar cloud in the constellation Sagittarius. The Lagoon Nebula is estimated to be between 4000 - 6000 light years from Earth in the Milky Way Galaxy, and is classified as an emission nebula.

Emission nebulae are glowing clouds of interstellar gas which have been excited by some nearby energy source, usually a very hot star. The red light seen in this picture is glowing hydrogen captured in the Hydrogen-Alpha (Hα) Infrared wavelength of light at 656nm.

Photographed rather close to the "light polluted" suburbs of the West Rand and North Rand of Johannesburg (Gauteng Province, South Africa). Light Pollution Map .

Astrometry info::

RA, Dec center: 271.058268626, -24.3623113276 degrees

Orientation: 0.715439826321 deg E of N

Pixel scale: 4.18683362403 arcsec/pixel

nova.astrometry.net/user_images/774837#annotated

Gear:

GSO 6" f/4 Imaging Newtonian Telescope (Astrograph).

Celestron Advanced VX Equatorial Mount.

Orion UltraBlock Narrowband Light Pollution Filter.

Canon 60Da DSLR (sensitive to IR light at 656.28 nm).

Processed in PixInsight.

Polar Aligned, but Unguided.

Stacked 20 sec. exposures (Lights/Subs).

Calibration Frames: Darks and Bias frames (no Flats).

Martin

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Also known as the Ring Nebula in the constellation Lyra. It is also a planetary nebula with a distance of 2300 +/-1500-700 light years. This exposure is three and a half hours total integration. Nearby (although much further away!) is a cross-linked barred spiral galaxy known as IC 1296. It sits at a rough distance of 235 million light years.

Captured using a 10-inch Meade LX200 Schmidt-Cassegrain telescope and a Nikon DSLR at the Loowit Imaging observatory in Shelton, Washington.

M37 is one of three Messier objects that is an open cluster in the constellation Auriga. It passes overhead from my latitude. This was a somewhat humid night, which I think accentuated the colors of stars in the cluster.

Stack of 19 45s exposures shot through a Celestron Edge HD 925 at f/2.3 with Hyperstar and an Atik 314L+ color CCD with Baader UHC LP filter. Preprocessing in Nebulosity, stacking and initial processing in PixInsight, final touches in PS CS 5.1.

The image center (J2000) is at

RA 5h 52m 22s

DEC +32° 32' 52"

This is an example of what you can get with a DSLR and some of the darkest skies on the planet. This is a stack of 19 10 s exposures with a Canon Rebel T1i. Dark frames were subtracted, and the resulting images were registered, stacked, and initially processed in PixInsight. Final processing was in PS CS 5.1.

This part of the sky was 50° to 60° above the horizon at this time, and there was no light pollution. The zodiacal light looked like a flashlilght beam going into the sky after sunset. Scorpius and Sagittarius are the constellations that fill this view, including a multitude of emission nebulae, younger open star clusters, and older globular clusters. The most prominent glow is from the bulk of stars in the direction of the center of our galaxy, the Milky Way. The features that stand out the most, in my opinion, are all the clouds of dark molecular material and dust that cut across the brighter background features. This is where stars are being born - in all of those little wisps and puffs of darkness. Many of those are tens of light years across, and they conceal the next generation of stars in our galaxy.

Taken with a TMB92L, Canon T3i DSLR, and Celestron CG-4 mount. Consists of 38 light and 29 dark frames, each a 35-second exposure at ISO 800, stacked in DeepSkyStacker and processed in Photoshop.

This Hubble Space Telescope image of M80 features observations in ultraviolet, visible, and infrared wavelengths of light. This data helped scientists learn more about the sequence of cosmic events that lead to the formation of various sub-populations of stars in globular clusters like this one.

Credit: NASA, ESA, and G. Piotto (Universita degli Studi di Padova); Image Processing: Gladys Kober

For more of Hubble's Messier Catalog, visit: www.nasa.gov/content/goddard/hubble-s-messier-catalog

The Merope Nebula (also known as Tempel's Nebula and NGC 1435) is a diffuse reflection nebula in the Pleiades star cluster, surrounding the 4th magnitude star Merope. It was discovered on October 19, 1859 by the German astronomer Wilhelm Tempel. The discovery was made using a 10.5cm refractor. John Herschel included it as 768 in his General Catalogue of Nebulae and Clusters of Stars but never observed it himself.

Equipment:

Scope: Lacerta 72/432 F6 0.85x reduktorral (367mm F5.1)

Mount: Skywatcher EQ-5 Pro Synscan Goto

Guide scope: Orion 50mm mini

Guide camera: ZWO ASI120mm Mini

Main camera: ZWO ASI183MM-Pro cooled monochrome camera

Accessories:

ZWO ASIAIR Pro

ZWO EFW 8x1.25"

Lacerta Dew-heater 20cm

Lacerta Dew-heater 30cm

Programs:

PixInsight

Adobe Photoshop CC 2020

Details:

Camera temp: -15°C

Gain: 53

Astronomik L-3 UV-IR Block: 92x180s

Astronomik Deep-Sky R: 16x180s

Astronomik Deep-Sky G: 14x180s

Astronomik Deep-Sky B: 20x180s

Messier 39 / M39 / NGC 7092

Barnard 363 / B 363 / LDN 1007

M39 is an open cluster about 1,000 light-years away. This young cluster, estimated to be 280 million years old, appears as a sparse group of blue stars in front of the rich Milky Way star field that runs through the constellation of Cygnus. Dark nebula structures (interstellar clouds made of gas and dust) are scattered across the field. Barnard 363 is the dark nebula towards the upper right.

Just 1 year earlier, I attempted this target with a 250mm lens on a cheap tracking mount: flic.kr/p/2cbMn7b

Total integration: 5 hours 14 minutes (314 minutes)

11/25/19: 82 x 120 seconds ISO400

11/28/19: 75 x 120 seconds ISO400

Location: Charlottesville, VA

SQM: 19.22 mag/arcsec^2 (Bortle 6)

Camera: Canon T3i (stock/unmodified)

Average camera temperature: 84 F (29 C)

Telescope: Explore Scientific ED80 f/6.0 Apochromatic Refractor (with ES field flattener)

Mount: Orion Sirius EQ-G

Guide scope: Svbony 50mm f/4.0 Guide Scope

Guide camera: Orion StarShoot AutoGuider

Software: N.I.N.A. with ASTAP (slewing and plate solving), PHD2 (guiding), Magic Lantern (image capture)

Pre-processed with PixInsight, processed with PixInsight and Paint.NET

Taken with a TMB92L, Canon T3i DSLR, Orion SSAG autoguider and 50mm guidescope, and Celestron AVX mount. Consists of 35 120-second light frames and 35 120-second dark frames, all at ISO 800, as well as 20 flat and 50 bias frames. Captured with BackyardEOS, stacked in DeepSkyStacker, and processed in Photoshop.

Equipment:

Scope: Lacerta 72/432 F6 0.85x reduktorral (367mm F5.1)

Mount: Skywatcher EQ-5 Pro Synscan Goto

Guide scope: Orion 50mm mini

Guide camera: ZWO ASI120mm Mini

Main camera: ZWO ASI183MM-Pro cooled monochrome camera

Accessories:

ZWO ASIAIR Pro

ZWO EFW 8x1.25"

Lacerta Dew-heater 20cm

Lacerta Dew-heater 30cm

Programs:

PixInsight

Adobe Photoshop CC 2020

Details:

Camera temp: -15°C

Gain: 111

Astronomik 6nm Ha:

18x300s

10x30s

10x60s

Two spiral galaxies from the Messier catalogue lying in Coma Berenices. Imaged over 2 nights which is a rarity for me in cloudy Northern Ireland.

Messier 88 lies top right and is a classic spiral galaxy. It measures 6.9 x 3.7 arcminutes. A supernova was detected there in 1999.

Messier 91 lies bottom left, it is a barred spiral galaxy and is classified as "anaemic" - see below! It measures 5.4 x 4.3 arcminutes.

Both galaxies lie in the Virgo galactic cluster which comprises many thousands of galaxies moving at speed under the influence of local gravity. Eventually, they will all collide at the local centre of gravity.

Tenuous hot gases and dust lie inbetween the galaxies forming a hot intracluster medium. As the galaxies race through the resistance of the medium, ram pressure stripping shears their own gas away and leaves them increasingly incapable of forming young new blue stars.

Messier 91 shows this effect more than M88 - it is pale and yellowish for a spiral galaxy - hence anaemic!

Some interesting small galaxies are seen in the field including on the mid right border, a small irregular spiral galaxy - IC 3476 which appears disrupted - probably by approaching too close to a larger galaxy in the past.

Technical Card:

900/120mm f/7.5 Equinox ED doublet refractor.

Skywatcher x 0.85 FR with 2 inch IDAS LPS P3 filter

MoonLite electronic focuser

Astro-modified Canon 80D at ISO400; 26 x 10 minute subs

QHY PoleMaster for polar alignment.

NEQ6 pro mount with Rowan belt drives -2 star align.

Camera control with Backyard EOS

Post processed in PixInsight 1.8.8

60 Flats EL panel: 1/40s @ ISO400

Master Dark from Dark Library, 50 x ISO and Temp. matched.

Master Bias from Library, 03/2021

Camera sensor temperature (external battery): 12-14c

Local parameters:

Temp: 7.0 - 9.2c

Humidity: 55.4%

Pressure: 1010 hPa

Light Pollution and Weather:

SQM (L) at end of session night 1 (0110 hrs UT) =20.33 mag/arcsec2. Clear both nights throughout - no subs lost due to weather.

Astrometry:

Center (RA): 12h 33m 40.785s

Center (Dec): +14° 24' 26.77"

Size: 1d 01m 58.9s x 50m 35.3s

Image scale: 0.977 arcsec/pixel

Focal distance: 792.08mm

Pixel Size 3.75 microm

Polar Alignment:

QHY Polemaster alignment -

Error measured by PHD2= 2 arc minute.

RA drift + 2.07 arcsec/min

Dec drift + 0.52 arcsec/min

Guiding:

PHD2 guiding with ZWO ASI290mm/PrimaLuce Lab 240/60mm guide scope. Every 3rd shot dithered.

RA RMS error 1.3 arcsec.

Dec RMS error 0.84 arcsec.

Personal Notes:

Compared with my last session with this setup - I was pleased to see that the IDAS P3 LPS filter was much better than the D2 filter - subs showed less background light pollution and the horrible star haloes have gone!

The trailed stars produced by differential flexure in my guidescope have also disappeared - just tightened all the guidescope connections.

M50 (NGC 2323) is an open star cluster that lies at the eastern edge of the Winter Hexagon. The view here has north roughly at the top.

Shot with a Celestron Edge HD 925 at f/2.3 with Hyperstar and a mono Atik 414-EX camera with LRGB filters from Optolong.

Stacking info:

L channel - 95 20 s exposures

R channel - 31 60 s exposures

G channel - 27 60 s exposures

B channel - 29 60 s exposures

Preprocessing in Nebulosity; registration, stacking, channel combination and initial processing in PixInsight; final touches in Photoshop

Captured with a Nikon D5500 and a 10-inch Meade LX200 'Classic' f/6.3 wide-field telescope.

EXIF data is removed via stacking processes in Autostakkert!2 for planetary imaging and in Deep Sky Stacker for deep sky imaging.

24x30s R

30x30s G

29x30s B

Imaging telescopes or lenses: Explore Scientific 127 ED APO Carbon

Mounts: SkyWatcher EQ6-R Pro

Guiding telescopes or lenses: Artesky Ultraguide 70mm

Guiding cameras: Orion Starshoot Autoguider Orion Starshoot

Focal reducers: Explore Scientific 0.7 Reducer/Flattener

Software: PixInsight · N.I.N.A · PHD2

Filters: ZWO LRGB 1.25" Filters

Accessory: Pegasus Astro Pocket Powerbox Advance · Pegasus Astro Focus Cube2 · ZWO EFW 1,25"

Visible right next to the stinger of the scorpion in the constellation Scorpius, Messier 7 is an easy naked-eye target for stargazers in southern latitudes. The second-century astronomer Claudius Ptolemy first recorded this open star cluster in 130 AD, earning it the nickname Ptolemy's Cluster.

Open star clusters contain stars formed from the same initial cloud of gas and dust and are typically irregular in shape. Over time, as open clusters revolve around a galaxy, gravitational disruptions from other cosmic objects can disperse the stars. Ptolemy’s Cluster is one of more than a thousand open clusters in the Milky Way and contains about 80 stars. Residing about 980 light-years from Earth, M7 likely formed about 220 million years ago.

Astronomer Charles Messier added the cluster to his catalog in May 1764. M7 is the southernmost Messier object, making it challenging to see for those in northern latitudes. It is located close to Messier 6, the Butterfly Cluster, and both can be spotted without binoculars or small spotting telescopes. Both M7 and M6 are best viewed from the northern hemisphere around 10 p.m. in July, when the Scorpio constellation is highest in the sky.

Credit: NASA, ESA, D. Bennett (University of Maryland), and K. Sahu (STScI); Image Processing: Gladys Kober

For more of Hubble's Messier Catalog, visit: www.nasa.gov/content/goddard/hubble-s-messier-catalog

Taken with a Sigma AF 70-300mm f/4-5.6 APO DG at 200mm and f/6.3, Canon T3i DSLR, and Celestron Advanced VX mount. Consists of 100 light and 43 dark frames, each a 60-second exposure at ISO 3200. Captured with BackyardEOS, stacked in DeepSkyStacker, and processed in Photoshop.

Even the great observer Charles Messier had trouble seeing this globular cluster when building his Catalog of Nebulae and Star Clusters. It was originally spotted in 1752 by a French astronomer in what is now South Africa, but it took until 1778 for Messier to catalog it.

This is because, while Messier 55 is large and reasonably bright, it is lacking a dense core and many of its stars are quite faint, making it hard to observe in non-optimal conditions.

For northern observers M55 sits low in the sky, so the view is hampered by a thicker layer of atmosphere, as well as water vapor and light pollution. This hindered Messier’s view from his Paris observatory. When he cataloged it, Messier noted that “its light is even and does not appear to contain any star.”

Though this image shows just a portion of M55, the cluster as a whole appears spherical because the stars’ intense gravitational attraction pulls them together. Hubble’s clear view above Earth’s atmosphere resolves individual stars in this cluster. Ground-based telescopes can also resolve individual stars in M55, but fewer stars are visible.

Even in skies with low light pollution, viewed through binoculars, the cluster will only appear as a round hazy patch. Small telescopes can begin to resolve individual stars in M55, while larger aperture telescopes will pick out low magnitude stars easily. The star cluster is found in the southern part of the constellation Sagittarius and is easiest to spot in August.

The globular cluster is about 20,000 light-years away and has a diameter of about 100 light-years. It contains an estimated 100,000 stars with 55 variable stars whose brightness changes.

Credit: NASA, ESA, A. Sarajedini (Florida Atlantic University), and M. Libralato (STScI, ESA, JWST); Image Processing: Gladys Kober

For more of Hubble's Messier Catalog, visit: www.nasa.gov/content/goddard/hubble-s-messier-catalog

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I have a fondness for this cluster related to teaching astronomy labs. Our college has a set of 8" Dobsonians that we give our students a chance to use. At first, I will aim the scope so they get used to the view throught the scope compared to the view through the Telrad. I then hunt down some bright deep sky objects for them to view and sketch. Typically, there are eight scopes and 24-30 students, so they have to wait as I get around to each group. Some students decide to explore on their own, which makes me really happy. Usually, they aim the scope at random areas of the sky, but every so often they come across something. This particular autumn evening, while we were looking at objects in Cassiopeia, some students decided to go exploring while they waited for me to find a new object. We had looked at a few star clusters at this point, so they called me over.

"We think we found a star cluster!" they said.

I checked, and indeed they had! Looking through the Telrad, I could see we were on one side of the W of Cassiopeia. I showed them on Stellarium where we were looking and identified it as M103.

Is this a particularly spectacular cluster? Probably not, but I love that I now have this story attached to it. When you get to use a telescope, go exploring. Who knows what you might come across? Sure, chances are very high that it has already been discovered and cataloged, but *YOU* haven't seen it before. Enjoy that sense of personal discovery.

This is a stack of 32 30 s exposures with the Nikon D5100 at ISO 1600 while it was mounted at the back of my Celestron Edge HD 925. You can see that the guiding is a bit off. I took this on the night of 2021-11-10. The effective focal length was 2210 mm. Preprocessing, registration, stacking, and most processing was done in PixInsight. Final processing in Photoshop.

LATEST VERSION: flic.kr/p/2qbsjKf

Messier 7 / M7 / NGC 6475 / The Ptolemy Cluster

NGC 6453

M7 is a bright, loose open cluster in the constellation of Scorpius. It is about 980 light-years away and it is estimated to be 200 million years old. From our perspective, M7 lies in front of the Galactic Center (the center of the Milky Way). As a result, the dense starfield behind this cluster is the richest of all Messier objects and one of the richest in the entire night sky.

NGC 6453 is a globular cluster about 38,000 light-years away. It is heavily obscured by interstellar dust since it lies behind the Galactic Center. The cluster appears as a golden clump between M7 and the left edge of the frame.

2 years ago, my first attempted deep-sky image featured M7: flic.kr/p/2a8e8s2

1 year ago, this was my much-improved result: flic.kr/p/2hc2S3M

Total integration: 16 hours 37.5 minutes (997.5 minutes)

06/22/19: 307 x 30 seconds ISO800

08/17/19: 62 x 60 seconds ISO200

08/19/19: 168 x 60 seconds ISO200

06/25/20: 90 x 120 seconds ISO200

06/28/20: 55 x 120 seconds ISO200

06/29/20: 94 x 120 seconds ISO200

07/14/20: 68 x 120 seconds ISO200

Location: Coral Springs, FL

SQM: 18.18 mag/arcsec^2 (Bortle 8/9)

Camera: Canon T3i (stock/unmodified)

Average camera temperature: 104 F (40 C)

Telescope: Explore Scientific ED80 f/6.0 Apochromatic Refractor (with ES field flattener)

Mount: Orion Sirius EQ-G

Guide scope: Svbony 50mm f/4.0 Guide Scope

Guide camera: Orion StarShoot AutoGuider

Software: N.I.N.A. with PlateSolve2 and PHD2

Processed with PixInsight and Paint.NET

This Hubble Space Telescope image of M14 includes observations taken in ultraviolet, visible, and near-infrared wavelengths of light. Astronomers used this data to better understand the formation and chemical makeup of different populations of stars that reside within this cluster.

Credit: NASA, ESA, and F. D'Antona (INAF, Osservatorio Astronomico di Roma); Image Processing: Gladys Kober

For more of Hubble's Messier Catalog, visit: www.nasa.gov/content/goddard/hubble-s-messier-catalog

I read an article in Sky and Telescope online today by Bob King with the above title. I’d recently imaged Messier 3 and wondered if I could use the diagrams in the article to find the star near the globular cluster’s core.

I went back to my linear image and performed a very gentle stretch so as not to obscure the core stars and altered the orientation to match the diagrams. As this is an image of just the core of the cluster, it’s rather small.

The star marked in the image above was the first variable star located in a globular cluster. It’s magnitude varies between 11.8 and 13.2 over a period of 15.3 days. That longer period classifies it as a W Virginis type star or a Type II Cepheid. Most of the variables in M3 are RR Lyrae type with shorter periods.

The star pulsates regularly as an outer layer contracts slightly then heats up and traps energy radiating from the core. The star then dims slightly until rising pressure pushes the layer back out. And repeat... ...every 15.3 days.

It fuses Helium at its core with Hydrogen burning occurring in an outer shell. Variations in the pressure and temperature of the shell cause the pulsations.

The relationship between the luminosity and period of stars like this can be used as a “standard candle” to work out the distance to stars.

The stars light curve was first described by EE Barnard in 1906 and hence it is known as Barnard’s variable.

After this exercise, I can spot V154 in my main image of M3, it is somewhat brighter and whiter than most of the stars in the cluster.

Not certain but I think it is likely to be a F class star so hotter and bluer than most stars in a Globular cluster.

Exif:

Mount: Skywatcher EQ-5 Pro GoTO

Scope: Lacerta 72/432 w/ 0,85 reducer

Camera: Pentax K-1 (unmodified)

Guider: Orion 50mm and Zwo 120mm mini with ASIAIR

Exposures:

22x600s, ISO800

28x300s, ISO800

Calibrated with dark and bias.

I shake my head every time I look at this image. What an amazing view of the stars in the Milky Way! Photographed from the edge of Lake Burley Griffin, less than 500m from our apartment, in the middle of Canberra.

The photograph shows a portion of the Milky Way, centered on the constellation of Sagittarius, but with the constellation of Scorpius on the left edge of the image. The twin bright stars of Shaula and Lesath forming the tip of the scorpions tail can be seen in the lower left corner. Messier Object 6 (The Butterfly Cluster) is the bright cluster of stars close to the center bottom edge of the image. Messier Object 7 (Ptolemy's Cluster) is the bright collection of stars just left of the center of the image. Messier Object 8 (The Lagoon Nebula) is the bright feature on the center of the right edge.

The Messier Objects are a list of over 100 objects that were catalogued by Charles Messier, an 18th and 19th century French astronomer. It is fascinating that he created the list in 1771, not to study them, but to help him to ignore these bright features in his quest to find new comets.

earthsky.org/brightest-stars/scorpion-stinger-stars-also-...

en.m.wikipedia.org/wiki/Charles_Messier

en.m.wikipedia.org/wiki/Messier_object

www.messier-objects.com/messier-6-butterfly-cluster/

www.messier-objects.com/messier-7-ptolemys-cluster/

www.messier-objects.com/messier-8-lagoon-nebula/

[ The rules of thumb for the maximum exposure time (for full frame sensor cameras with 36.0 x 24.0 mm sensor size) such that the stars appear as points of light rather than short star trails are variously known as the "500 Rule" or the "600 Rule". The rules "state" that this maximum exposure time in seconds is 500 or 600 divided by the focal length of the lens. When the crop factor of the CRV-50c sensor is taken into account (sensor size 43.8 x 32.9 mm), the effective full frame sensor equivalent focal length of the 150mm f/4.0 lens used for this photograph is of the order of 120 mm. The maximum exposure time is thus 4 to 5 seconds. I shot this using an exposure time of 6 seconds, an ISO of 3200, and an aperture of f/4. The stars show up as quite distinct trails, suggesting to me that the "old" rules of thumb might need to be updated to take into account the resolution of sensors such as the 50MP one used in the CFV-50c digital back. I might have to create a "250 Rule". ]

Barton, Australian Capital Territory, Australia.

Photography notes ...

The photograph was taken using the following hardware configuration ...

- Hasselblad 500C/M body (1994).

- Hasselblad CFV-50c Digital Back for Hasselblad V mount camera.

- Hasselblad Focusing Screen for the CFV-50c digital back, with focussing prism and crop markings.

- Hasselblad 45 Degree Viewfinder PME-45 42297 (2001).

- Carl Zeiss lens - Sonnar 150mm f4 CFi T* - Nr 8912760 - Hasselblad - Prontor shutter (2003).

- FotodioX B60 Lens Hood for Select Hasselblad Telephoto CF Lenses.

(Year of manufacture indicated in braces where known.)

I acquired the photograph (8272 x 6200 pixels) with an ISO of 3200, exposure time of 6 seconds, and aperture of f/4.

Post-processing ...

Finder - Removed the CF card from the camera digital back and placed it in a Lexar 25-in-1 USB card reader. Then used Finder on my MacBook Air to download the raw image file (3FR extension) from the card.

Lightroom - Imported the 3FR image. Used the Map module to add the location details to the EXIF header. Then applied various adjustments in the Develop module, the essence of which is as follows ...

- White Balance (Temperature and Tint).

- Tone (Exposure, Contrast - Increased, Highlights and Shadows - Increased, Whites - Increased, Blacks - Decreased).

- Presence (Clarity - Increased, Vibrance - Increased, Saturation - Decreased).

- [HSL adjustments as required for selective color adjustments.]

- [Sharpening and Noise Reduction - Default values.]

- [Lens Corrections as required.]

- Dehaze - Increased.

- [Graduated and Radial filters as required for local adjustments.]

I then exported the image as a JPG file with 8272 x 6200 pixels from the Library module.

Stack of 29 25 s ISO2000 unguided frames taken with a Nikon D5100 on a Celestron Edge HD 925 at 2150 mm focal length.

I like this version better than what I got with the monochrome CCD and filter wheel set.

- I'm in South Bohemia away from major cities and we had a cloudless night so I was really happy to be able to see the Milky way with my own eyes. Here is a test shot of the sky where the Milky way is seen across the sky from the treetops. I can see one other nebulous object here below our own galaxy, I don't know which Messier object that is so please comment if you recognise it.

Update: I'm now quite sure that nebulous object is in fact the Andromeda galaxy.

Harlow Shapley remarked that about 1/3 of the globular clusters in our sky lie in the direction of Sagittarius. M28 (NGC 6626) is one of those many clusters.

Shot with LRGB filters from my backyard in Long Beach, CA.

L: 32 10 s exposures

R: 64 20 s exposures

G: 66 20 s exposures

B: 74 20 s exposures

All taken with an Atik 414-EX mono camera on a Celestron Edge HD 925 at a focal length of 530 mm using HyperStar. LRGB filters are from Optolong and changed with the Starizona filter slider system.

Pre-processing in Nebulosity; registration, stacking, channel combination, and processing in PixInsight; final touches in Photoshop.

M93 (NGC 2447) is an open cluster in Puppis. It's one of the more southerly Messier objects, so there's a shorter window for when I can shoot it from my location in Long Beach. These were taken on 2023-02-15 -- a rare clear night this winter.

I used a Celestron Edge HD 925 with Hyperstar at focal length 535 mm and an Atik 414-EX monochrome camera with Optolong CCD LRGB filters to get the following exposures:

L: 181 10 s exposures

R: 41 30 s exposures

G: 50 30 s exposures

B: 81 30 s exposures

Images were preprocessed in Nebulosity, then stacks were created in PixInsight. Channel combination and initial processing were in PixInsight, with final touches in Photoshop.

Messier 67 is less famous than the Beehive cluster (Messier 44) in Cancer but is quite appealing. Estimated age is about 5 billion years old, so very old for an open cluster but spectroscopic analysis of all the stars confirms this. Mostly main sequence stars, some red giants and a few blue stragglers. there are about 500 members in the cluster.

I’ve had a few issues with my 480mm scope recently in terms of guiding and some of the mechanical aspects of the mount. This is a test image of 50 x 5 minutes to play around with some guiding parameters and assess the quality of the stars.

The stars are a bit square suggesting some differential flexure or field rotation between main scope and guide scope. I’ll make sure everything is tightened up and properly aligned then try again.

Technical Card

480/80mm f/6 Altair Starwave triplet refractor.

Altair Planostar 1.0 x FF with 2 inch IDAS P3 LPS filter

ZWO ASI2600MC; 50 x 300 second subs, Gain 100, Offset 25, Temp = -15c.

EQ6 pro mount with Rowan belt drives. EQMOD control. Primalucelab Sesto Senso electronic focuser.

Session control; SharpCap 4.0 on laptop with WiFi link to IPad.

Automated plate solving GOTO.

Automated FWHM multistar focusing every 16 frames. +/- 500 steps at 2s and 578 gain.

20 dark frames

50 flat frames (electroluminescent panel, 1500ms exposure @ 0 gain).

Post processed in PixInsight 1.8.9.

Light Pollution and Weather:

SQM (L) 19.90 at 11pm - first quarter Moon.

Session clear throughout.

Polar Alignment:

Error measured by PHD2= 0.3 arc minute.

RA drift + 1.75 arcsec/min

Dec drift - 0.09 arcsec/min

Guiding:

PHD2 guiding with ZWO ASI290mm/Altair Starwave 206/50mm guider. Every 4th sub dithered.

RA RMS error 0.8 arcsec

Dec RMS error 0.65 arcsec

Astrometry:

Resolution: 1.610 arcsec/px

Rotation: -97.267 deg

Observation start time: 2023-02-26 20:01:51 UTC

Observation end time: 2023-02-27 00:54:44 UTC

Focal distance: 481.58 mm

Pixel size: 3.76 um

Field of view: 2d 47' 42.0" x 1d 52' 5.2"

Image center: RA: 8 51 06.628 Dec: +11 50 16.80

Took the new 12-inch Meade LX200 out for a nice drive in the cosmos over the last few nights and put it through its paces.

The mount is still in need of some work but this scope is amazing!

This image of M19 includes Hubble observations taken in ultraviolet, visible, and near-infrared wavelengths of light. A small gap in Hubble data (horizontal line at center right) is instead filled in with observations from the ground-based Victor M. Blanco 4-meter Telescope. The Hubble proposal associated with this image sought to investigate M19’s formation and the ratios of different populations of stars within the cluster.

Credit: NASA, ESA, and C. Johnson (STScI); Image Processing: Gladys Kober

For more of Hubble's Messier Catalog, visit: www.nasa.gov/content/goddard/hubble-s-messier-catalog

Equipment:

Scope: Lacerta 72/432 F6 0.85x reduktorral (367mm F5.1)

Mount: Skywatcher EQ-5 Pro Synscan Goto

Guiding: OAG

Guide camera: ZWO ASI120mm Mini

Main camera: ZWO ASI183MM-Pro cooled monochrome camera

Accessories:

ZWO ASIAIR Pro

ZWO EFW 8x1.25"

ZWO EAF

ZWO OAG

ZWO 1.25 Helical focuser

Lacerta Dew-heater 30cm

Programs:

PixInsight

Adobe Photoshop CC 2020

Details:

Camera temp: -15°C

Gain: 53, 111

Astronomik 6nm Ha: 155x300s

Astronomik L-3 UV-IR Block: 132x180s

Astronomik Deep-Sky R: 20x180s

Astronomik Deep-Sky G: 20x180s

Astronomik Deep-Sky B: 20x180s

Bortle Scale: 4

Location: Isaszeg, Hungary

Acquisition date(s):

2021.02.28., 2021.03.02., 2021.03.06., 2021.03.07., 2021.03.08.,

A planetary nebula nicknamed the Dumbbell Nebula in the constellation Vulpecula at a distance of 1,360 light years. It has a diameter of 2 light years across and is easily visible in binoculars and a fantastic sight in a telescope at moderate magnification. 4 hour total exposure time on this one.

Captured using a 10-inch Meade LX200 Schmidt-Cassegrain telescope and a Nikon DSLR at the Loowit Imaging observatory in Shelton, Washington.

Dates: 23-24, 26-28 April 2025

Location: Washington D.C.

Equipment:

ASI 2600MM Pro (monochrome) camera

Chroma 36mm LRGB Filter Set

WO Fluorostar 91mm f/5.9 triplet APO refractor with Adjustable Field Flattener 68III

iOptron GEM28-EC mount

Data and exposure times:

Data was acquired as LRGB images with the following exposure times:

14.11 hours (242x210s subs) with Luminance filter (L).

3.50 hours (60x210s subs) with Red filter (R).

3.56 hours (61x210s subs) with Green filter (G).

3.44 hours (59x210s subs) with Blue filter (B).

Atmospheric conditions:

The shown image was developed from data acquired in a Bortle Class 8 area (i.e. in an environment experiencing a degree of light pollution typical of a city) where the sky quality during observation was such that both transparency (i.e. the level of atmospheric clarity) and seeing (i.e. the level of atmospheric turbulence) varied from average to below average.

Processed in PixInsight.

Preprocessing notes:

Created LRGB "masters" by Calibration, Cosmetic Correction, Weighted Subframes, Star Alignment, and Integration.

Postprocessing notes:

a. Dynamic Cropping of LRGB masters each to the same dimensions having a 3:2 aspect ratio.

b. Applied a Screen Transfer Function to view the resulting images.

c. For the L master: Applied a Dynamic Background Extractor and saved the settings to be used later when applying a DBE on the RGB masters.

d. Applied BlurXT and NoiseXT.

e. Applied a Histogram Transformation. This step generated a nonlinear image which was saved as a postprocessed L image.

f. "Built" a color image from the R, G and B masters by using LRGB Combination and applied a DBE to the color image using the same DBE settings as used for the L master.

g. Since a color image is involved, this necessitated the application of Background Neutralization and Color Calibration to the result from step f above.

h. Applied BlurXT, NoiseXT and a Histogram Transformation. Saved the nonlinear result as a postprocessed RGB image.

i. Used LRGB Combination to "apply" an instance from the postprocessed L image to the postprocessed RGB image.

j. Applied StarXterminator to create starless (i.e. containing the target image - in this case M51) and stars-only images.

k. Processed the starless image, after applying a range selection mask to protect the background area, using Local Histogram Equalization, Curves Transformation and Color Saturation. Curves Transformation was used only to boost the saturation whereas Color Saturation was used to enhance specific color hues.

l. Applied SCNR (Subtractive Chromatic Noise Reduction). Removed mask and used an expression in Pixel Math to combine the result from step k above with the stars-only image from step j.

m. As a final step, after protecting the target image with a Star Mask, applied a (star reduction) Morphological Transformation to the result from step l above.

I decided to continue this awesome galaxy, and try some new process on it. I think it is way better than the older images I was uploaded. It is near 7 hour of integration time with 5 min subs.

M: Skywatcher EQ-5 Pro GoTO

S: Lacerta 72/432 F6

R: Skywatcher 0,85x

C: Pentax K-1

G: Orion 50mm mini

GC: ZWO ASI 120mm Mini

Exposures:

Light: 79x300s, ISO800

Dark: 30, ISO800

Dark flat: 200, ISO800

Flat: 15, ISO800

Just as spring (in the Northern Hemisphere) is the best time for galaxies, summer is the best time for nebulae and star clusters. Two of the most famous nebulae are the Lagoon Nebula (at bottom, also known as M 8 or NGC 6523) and the Trifid Nebula (at the top right, aka M 20 or NGC 6514). You get glowing ionized hydrogen (pink). You get dust that is scattering starlight (blue). You get lanes of cold, dense dust that blocks the light of stars behind it. And if you have cold, dense dust, you get star formation. Some of the hottest, most massive stars visible to the naked eye are in these nebulae.

There is something else interesting about how they are aligned with our view from the solar system. The plane of the ecliptic cuts right between them. This means that, as the Earth travels around the Sun, the Sun appears to pass almost through the middle of this picture. It does so one day after the southernmost solstice. See, I didn't want to say "winter solstice" because of the whole Northern vs. Southern Hemisphere thing again. And, if you wait about 13,000 years, this passage will take place around the northernmost solstice due to Earth's cycle of precession.

Either way, enjoy the view!

Over a course of 4 separate nights in the summers of 2017 and 2018, I took 10 separate tiles to make this mosaic. All subframes are 2 minute exposures with a Celestron Edge HD 9.25" at f/2.3 with HyperStar and an Atik 314L+ color CCD camera. Preprocessing in Nebulosity; mosaic assembly and processing in PixInsight; final touches in PS CS 5.1.

The image center (J2000) is at:

RA 18h 4m 5s

DEC -23° 36' 13"

The image spans 1° 32' by 2° 5'.

I think I stopped the aperture down a bit too much on this one, causing the diffraction spikes around the Pleiades's brightest stars. Next time, I'll try f/5.6 or f/6.3.

Taken with a Sigma AF 70-300mm f/4-5.6 APO DG at 133mm and f/8, Canon T3i DSLR, and Celestron Advanced VX mount. Consists of 34 light and 30 dark frames, each a 90-second exposure at ISO 1600, and 21 flat frames. Captured with BackyardEOS, stacked in DeepSkyStacker, and processed in Photoshop.

Taken from Savannah Skies Observatory using a Canon EOS Ra and 400 mm lens.

LINK

Other images from this series:

1. M8 and M20: www.flickr.com/photos/jbrimacombe/51050919231/

2. M16: www.flickr.com/photos/jbrimacombe/51050319198/

3. NGC 6188: www.flickr.com/photos/jbrimacombe/51051043096/

4. M78: www.flickr.com/photos/jbrimacombe/51050317763/

5. Rho Ophiuchus: www.flickr.com/photos/jbrimacombe/51051288802/

6. Tarantula Nebula: www.flickr.com/photos/jbrimacombe/51051288607/

7. Vela SNR: www.flickr.com/photos/jbrimacombe/51050478748/

Taken with a TMB92L, Canon T3i DSLR, and Celestron CG-4 mount. Consists of 34 light and 20 dark frames, each a 45-second exposure at ISO 800, stacked in DeepSkyStacker and processed in Photoshop.

HaLRGB, ES 127 ED, ASI1600mm Pro

Full capture details at www.astrobin.com/seible/

Scope: WO Zenith Star 81mm f/6.9 with WO 6AIII Flattener/Focal Reducer x0.8

OSC Camera: ZWO ASI 2600 MC Pro at 100 Gain

Mount: iOptron GEM28-EC

Guide Scope: ZWO ASI 30mm f/4

Guide Camera: ZWO ASI 120mm-mini

Light Pollution Filter: ZWO Duo-Band Light Pollution Filter

Date: 24-25, 29-30 April and 2, 4-5 May 2022

Location: Washington D.C.

Exposure: 261x300s subs (= 21.75 hours)

Software: Pixinsight

Processing Steps:

Preprocessing: FITS data > Image Calibration > Cosmetic Correction > Subframe Selector > Debayer > Select Reference Star and Star Align > Image Integration.

Linear Postprocessing: Integrated image > Dynamic Crop > Dynamic Background Extractor (subtraction to remove light pollution gradients and division for flat field corrections) > Background Neutralization > Color Calibration > Blur Xterminator > Noise Xterminator.

Nonlinear Postprocessing: Histogram Transformation > Star Xterminator to decompose into Starless and Stars Only images.

Starless image > Histogram Transformation > Noise Xterminator > Local Histogram Equalization.

Apply a First Curves Transformation to boost the blue signal from the galaxy's arms. Apply an RGB Split. After adjusting the weights for the individual RGB components (noting that the R serves as both the L channel and the red channel when using an OSC camera), apply LRGB Combination to get a blue boosted image.

Apply a Second Curves Transformation to boost the red signal from the galaxy's core. Apply an RGB Split. After adjusting the weights for the individual RGB components (noting that the R serves as both the L channel and the red channel when using an OSC camera), apply LRGB Combination to get a red boosted image.

Use Pixel Math to combine 0.4 x red boosted image + 0.6 x blue boosted image to get a Composite image. These weights were determined by experimentation to produce an optimum balance.

Use Pixel Math again to combine 0.6 x Composite image + 0.4 x an HDR Multiscale Transform-modified Composite image to get a New Composite image.

New Composite > Curves Transformation using color masks > Histogram Transformation > Local Histogram Equalization > Final Starless image.

Use Pixel Math to rejoin the Final Starless image with the Stars Only image to get a rejoined image.

Rejoined image > Topaz Labs > DeNoise AI > Gigapixel AI.

Use Pixel Math to combine 25% x Rejoined image + 75% x AI image = Final Result.