©2023 Marsha Kirschbaum

©2022 Marsha Kirschbaum

IC 4592

Credit: Giuseppe Donatiello

IC 4592 (called the Blue Horsehead Nebula) is a reflection nebula in the Scorpius constellation.

Reflection nebulas are actually made up of very fine dust that normally appears dark but can look quite blue when reflecting the light of energetic nearby stars. In this case, the source of much of the reflected light is a star at the eye of the horse.

That star is part of Nu Scorpii, one of the brighter star systems toward the Scorpius. A second reflection nebula dubbed IC 4601 is visible surrounding two stars at the image center.

Its distance is about 400 light-years.

The blue area at the bottom is part of the Rho Ophiuchi cloud complex.

A two panel wide-field mosaic of the Blue Horsehead Nebula (IC 4592), a faint reflection nebula in the constellation Scorpius. The nebula is lit by the multiple Star System Nu Scorpii.

Gear:

William Optics Star 71mm f/4.9 Imaging APO Refractor Telescope.

QHY163M (Sensor cooled to -20°C).

Optolong L-Pro, R, G, B filters.

Technical Card:

Integration Time:

24 hours total (12 hours per panel).

L = 6 hours x 2 mosaic panels (Binning 1x1).

R = 2 hours x 2 mosaic panels (Binning 2x2).

G = 2 hours x 2 mosaic panels (Binning 2x2).

B = 2 hours x 2 mosaic panels (Binning 2x2).

Calibration frames:

Bias, Darks & Flats.

Image Acquisition:

Guiding in Open PHD.

Image acquisition in Sequence Generator Pro.

Plate Solving in Platesolve 2 via SGP Framing & Mosaic Wizard.

Processing:

Pre-Processing and Linear workflow in PixInsight,

and finished in Photoshop.

Astrometry Info:

Center RA, Dec: 244.286, -19.402

Center RA, hms: 16h 17m 08.686s

Center Dec, dms: -19° 24' 08.014"

Size: 4.46 x 2.97 deg.

Radius: 2.681 deg.

Pixel scale: 10 arcsec/pixel.

Orientation: Up is 186 degrees E of N.

View an Annotated Sky Chart of this image.

View this image in the WorldWideTelescope.

This image is part of the Legacy Series.

Photo usage and Copyright:

Medium-resolution photograph licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Terms (CC BY-NC-ND 4.0). For High-resolution Royalty Free (RF) licensing, contact me via my site: Contact.

Martin

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Acquisition details: Fujifilm X-T10, Samyang 135mm f/2.0 ED UMC @ f2.0, ISO 1600, 48 x 60 sec, tracking with iOptron SkyTracker Pro, stacking with DeepSkyStacker, editing with Astro Pixel Processor and GIMP, taken just before astronomic dawn on Apr. 20, 2020 from Bortle 2 skies. At my latitude, 47 deg. N, this region of the sky is at about 20 deg above the horizon at its highest.

IC 4592 is a reflection nebula located in the constellation of Scorpius at approximately 400 light years from Earth.

IC 4592 makes up part of the Rho Ophiuchi cloud complex that sits low in the horizon close to the Milky Way core.

Taken over 6 nights in March 2023 from two locations. Primarily 4 nights from my backyard in Gérgal, Spain and two nights from Gorafe Megalithic Park in Granada, Spain.

High and full resolution versions with imaging and equipment details are available on my Astrobin page at astrob.in/full/rgyuz8/0/

Thank you for looking!

Imaging summary:

Location: Gérgal and Gorafe, Spain

Scope: William Optics GT 81

Camera: ZWO ASI2600MC Pro

Mount: Sky-Watcher EQ6-R Pro

Filter: ZWO UV/IR Cut

169 x 300 seconds exposures

Total Integration: 14 hours

equipmnent: Sigma 28mmF1.4 DG HSM Art and Canon EOS 5Dmk2-sp2, modified by Seo-san on Takahashi EM-200FG-Temma 2Z-BL, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, Starlight Xpress Lodestar Autoguider, and PHD2 Guiding

exposure: 6 times x 15 minutes, 4 x 4 min, 8 x 1 minute at ISO 1,600 and f/3.5

site: 2,430m above sea level at lat. 24 39 52 South and long. 70 16 11 West near Cerro Armazones Chile

Atacama Desert just before Sunset July 2019

www.flickr.com/photos/hiroc/48588682472

The shape of Gegenschein looked not round but irregular.

Equipment: Sigma 35mmF1.4 Art, IDAS Clear Filter, and EOS R6-SP5, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 10 times x 600 seconds, 9 x 240 sec, and 10 x 60 seconds at ISO 1,600 and f/3.2

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

Equipment: Zeiss ApoSonnar 135mmF2, IDAS Clear Filter, and EOS R-SP4II, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 13 times x 600 seconds, 12 x 240 sec, and 10 x 60 seconds at ISO 1,600 and f/3.2

I put 60-second frame and 240-second frame on starless frame.

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

The shape of Gegenschein looked not round but irregular.

Equipment: Sigma 35mmF1.4 Art, IDAS Clear Filter, and EOS R6-SP5, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 10 times x 600 seconds, 9 x 240 sec, and 10 x 60 seconds at ISO 1,600 and f/3.2

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

Jupiter was in Scorpius then and bright in the left half on the frame. Zodiacal light was crossing obliquely near the center of the frame.

Here is a bit closer frame of the area, taken with 105mm lens.

www.flickr.com/photos/hiroc/48645404297

equipmnent: Sigma 40mmF1.4 DG HSM Art and Canon EOS 6D-sp4, modified by Seo-san on Takahashi EM-200FG-Temma 2Z-BL, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, Starlight Xpress Lodestar Autoguider, and PHD2 Guiding

exposure: 10 times x 15 minutes, 8 x 4 min, 4 x 1 minute at ISO 1,600 and f/4.0

site: 2,430m above sea level at lat. 24 39 52 South and long. 70 16 11 West near Cerro Armazones Chile

Equipment: Sigma 35mmF1.4 Art, IDAS NB12 Dual Narrowband Filter or Clear Filter, and EOS R6-SP5, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 7 times x 1,200 seconds, 8 x 240 sec, and 10 x 60 seconds at ISO 6,400 and f/3.2 with Dual Narrowband Filter and 10 times x 600 seconds, 9 x 240 sec, and 10 x 60 seconds at ISO 1,600 and f/3.2 with Clear Filter

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

Here’s my first experiment at a Milky Way nightscape photography which includes sufficient exposures and processing to highlight some deep space objects, such as Rho Ophiuchi (that colorful patch behind stars which “bleeds” dark nebula into the Milky Way), which normally don’t make an appearance in already-beautiful Milky Way landscape photography.

This was taken at Antelope Island State Park, Utah (Bortle 4), on April 19, 2021. The bright patch of light in the bottom left-hand section is the light pollution dome over Salt Lake City. The assorted red patches through the Milky Way and in surrounding areas are emission nebula (most prominent in the nebula Sh2-27, a red patch around the star Zeta Ophiuchi toward the top of the composition), which don’t typically show up in images captured by off-the-shelf cameras.

It may go without saying, but this sort of photography brings out detail far, far beyond what we can make out with our crumby eyeballs. Although everyone ought to experience, at least once, what the Milky Way looks like in the night sky under truly dark skies after our eyes have fully acclimated to the darkness. You know, in my rather biased opinion.

Technical Details

Multiple photographs were shot for the sky and the for the foreground. Photos were taken with an Olympus E-M1 Mk.III and the Olympus 7-14/2.8 Pro lens. Additional data was used for emission nebula (see below).

Sky Photographs

45x45 seconds 9mm f/2.8 ISO 640

62x45 seconds 14mm f/2.8 ISO 640

Two series of sky photographs were taken. One focused on the Milky Way and the full field of view and featured the top of the mountain below for placement, and a second series zoomed in more narrowly focused on Rho Ophiuchi and fainter deep space objects appearing to the right of the Milky Way. Dark and bias frames were used; flat frames were not—I forgot my equipment to take flats frames in the dark of night—but should have been. Photos were stacked and initially processed, aligned, and cleaned up in PixInsight, stars separated, and then passed on to Adobe Photoshop.

Landscape Photographs

10x60 seconds 14mm f/6.3 ISO 200

These photographs were stacked and aligned in Adobe Photoshop (allows for bringing out more detail and better colors with less noise) and captured while the moon was still up for some natural light (sky photos captured while the moon was down).

Nebulosity

Some wide angle data of nebulous regions (red patches) was used from some other photographs I’ve captured was used to bring out the red/pinkish regions in the photo. My Olympus camera has not been modified to pick up more red-spectrum light, otherwise this data would have come through properly in the original exposures.

Adobe Photoshop

The final images of the sky and foreground were combined in Adobe Photoshop in position and scale true to the landscape and night sky and edited/blended with masks.

A Couple Thoughts

Next time, I’ll capture more data, and be fussed to capture flat frames. I’ll spend more time getting my mask separating sky from foreground right the first time. An astro-modified interchangeable lens camera would be nice to capture the emission nebulosity if I made a habit of this. In the future I’ll stick to very dark skies. It was unpleasant to process out deep sky detail, without flats, in an image which scaled from fairly dark skies to the intensely bright light pollution above Salt Lake City, although I’m glad I did this once as an homage to the city I live in.

Equipment: Zeiss ApoSonnar 135mmF2, IDAS NB12 Dual Narrowband Filter or Clear Filter, and EOS R-SP4II, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 11 times x 1,200 seconds, 12 x 240 sec, and 16 x 60 seconds at ISO 6,400 and f/3.2 at Dual Narrowband Filter and 13 times x 600 seconds, 12 x 240 sec, and 10 x 60 seconds at ISO 1,600 and f/3.2 with Clear Filter

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

This is the final version of the series.

Equipment: Zeiss ApoSonnar 135mmF2, IDAS NB12 Dual Narrowband Filter or Clear Filter, and EOS R-SP4II, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 11 times x 1,200 seconds, 12 x 240 sec, and 16 x 60 seconds at ISO 6,400 and f/3.2 at Dual Narrowband Filter and 13 times x 600 seconds, 12 x 240 sec, and 10 x 60 seconds at ISO 1,600 and f/3.2 with Clear Filter

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

Blue Horsehead Nebula - IC 4592

This is a rarely imaged nebula, located about 400 light years from us, visible in the constellation Scorpio. IC 4592 is a true reflection nebula, being formed of cosmic dust, the central part appearing blue due to the energy released by Jabbah, the star whose light makes this nebula visible. The popular name of this nebula, Blue Horsehead, is given by the more or less obvious resemblance to a horse's head and, as most astronomy enthusiasts know, this is not the only "horsehead" visible in the night sky. Practically every night of the year a "horsehead" nebula can be seen, regardless of whether it is "blue" or "dark". As an additional note, the above statement is valid for the latitude where I am (44 degrees North).

Equipment and settings:

Tracking - Skywatcher Star Adventure GTI

Camera - Nikon D610A

Photo lens - Rokinon 135 F2

98 x 60 sec - F2.8 iso 1600.

Stacking in Deep Sky Stacker.

Edit in Pixinsight.

Equipment: Zeiss ApoSonnar 135mmF2, IDAS Clear Filter, and EOS R-SP4II, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 18 times x 600 seconds, 12 x 240 sec, and 13 x 60 seconds at ISO 1,600 and f/3.2

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

Hi Folks,

I have just published a new imaging project on the website!

IC 4592 - The Blue Horsehead Nebula

This image is the result of 4.5 hours of LRGB integration with my Askar FRA400 Astrograph using a ZWO ASI1600MM-Pro camera and an IOptron CEM26 mount.

This was shot over 4 evenings of 6-29-22, 6-30-22, 6-31-22, and 7-03-22.

This target was challenging for me for a few reasons.

It is located pretty low in my southern sky, ranging between 22 - 25 degrees of elevation - which means that I have to look through a lot of atmosphere in order to see it.

It also falls within the narrowest gap that I have between my two treelines! As a result, I could only capture about an hour each night before it was again hidden in the trees.

This is a large and faint object. It is so large that I could only fit part of it into the field of view of my 400mm astrograph. It is so faint that it really demands longer integration times - since that was not possible for me, given my location and circumstance, I had to do the best I could with the data that I had.

I really like this target - I love the shape and the colors and the fact that the bright star Nu Scorpii provides a nice blue eye for the horse just adds to the aesthetics!

I was surprised by how little data I was able to find about this target. I'd like to learn more about it so I will have to dig a bit deeper.

The story of the image and complete processing walk-through can be seen on my website at:

cosgrovescosmos.com/projects/ic4592

Thanks for looking, and let me know if you have any questions!

Pat

There were beautiful flowlines of dust and gas in the area. I like every chip of them. There was a dark part near the left lower corner, which was unclear in the dense star field.

Equipment: Zeiss ApoSonnar 135mmF2, IDAS Clear Filter, and EOS R-SP4II, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 13 times x 600 seconds, 12 x 240 sec, and 10 x 60 seconds at ISO 1,600 and f/3.2

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

IC 4592

Credit: Giuseppe Donatiello

IC 4592 (called the Blue Horsehead Nebula) is a reflection nebula in the Scorpius constellation.

Reflection nebulas are actually made up of very fine dust that normally appears dark but can look quite blue when reflecting the light of energetic nearby stars. In this case, the source of much of the reflected light is a star at the eye of the horse.

That star is part of Nu Scorpii, one of the brighter star systems toward the Scorpius. A second reflection nebula dubbed IC 4601 is visible surrounding two stars at the image center.

Its distance is about 400 light-years.

The blue area at the bottom is part of the Rho Ophiuchi cloud complex.

This is the final version of the series. I could enjoy all process of astroimaging.

Equipment: Zeiss ApoSonnar 135mmF2, IDAS NB12 Dual Narrowband Filter or Clear Filter, and EOS R-SP4II, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 9 times x 1,200 seconds, 13 x 240 sec, and 14 x 60 seconds at ISO 6,400 and f/3.2 with Dual Narrowband Filter and 18 times x 600 seconds, 12 x 240 sec, and 13 x 60 seconds at ISO 1,600 and f/3.2 with Clear Filter

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

Equipment: Zeiss ApoSonnar 135mmF2, IDAS NB12 Dual Narrowband Filter, and EOS R-SP4II, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 9 times x 1,200 seconds, 13 x 240 sec, and 14 x 60 seconds at ISO 6,400 and f/3.2

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

Equipment: Sigma 35mmF1.4 Art, IDAS NB12 Dual Narrowband Filter, and EOS R6-SP5, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 7 times x 1,200 seconds, 8 x 240 sec, and 10 x 60 seconds at ISO 6,400 and f/3.2

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

The Veil Nebula is a cloud of heated and ionized gas and dust in the constellation Cygnus. It constitutes the visible portions of the Cygnus Loop, a supernova remnant, many portions of which have acquired their own individual names and catalogue identifiers. The source supernova was a star 20 times more massive than the Sun which exploded between 10,000 and 20,000 years ago. At the time of the explosion, the supernova would have appeared brighter than Venus in the sky, and visible in the daytime. The remnants have since expanded to cover an area of the sky roughly 3 degrees in diameter (about 6 times the diameter, and 36 times the area, of the full Moon). In modern usage, the names Veil Nebula, Cirrus Nebula, and Filamentary Nebula generally refer to all the visible structure of the remnant, or even to the entire loop itself. The structure is so large that several NGC numbers were assigned to various arcs of the nebula. There are three main visual components: the Western Veil (also known as Caldwell 34), consisting of NGC 6960 (the "Witch's Broom", Lacework Nebula, "Filamentary Nebula") near the foreground star 52 Cygni; the Eastern Veil (also known as Caldwell 33), whose brightest area is NGC 6992, trailing off farther south into NGC 6995 (together with NGC 6992 also known as "Network Nebula") and IC 1340; Pickering's Triangle (or Pickering's Triangular Wisp), brightest at the north central edge of the loop, but visible in photographs continuing toward the central area of the loop. This wide-field image of the entire Veil Nebula was captured over 4 hours using a Samyang 135mm lens at f/2.0 on a ZWO ASI2600MC cooled astro camera and an Antlia ALP-T Dual Band 5nm Ha&OIII Highspeed filter.

Emission nebulae got brighter and bigger thanks to the application of the dual narrowband filter, though reflection nebulae got fainter and smaller.

Gegenschein looked not round but irregular on the frame taken with clear filter, but the irregular parts of Gegenschein looked reddish a bit on this frame taken with dual narrowband filter. It means that the irregular parts were not Gegenschein but faint integrated flux nebulae containing hydrogen-alpha light from stars nearby.

Equipment: Sigma 35mmF1.4 Art, IDAS NB12 Dual Narrowband Filter, and EOS R6-SP5, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 7 times x 1,200 seconds, 8 x 240 sec, and 10 x 60 seconds at ISO 6,400 and f/3.2

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

Equipment: Zeiss ApoSonnar 135mmF2, IDAS Clear Filter, and EOS R-SP4II, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 18 times x 600 seconds, 12 x 240 sec, and 13 x 60 seconds at ISO 1,600 and f/3.2

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

Equipment: Sigma 35mmF1.4 Art, IDAS NB12 Clear Filter, and EOS R6-SP5, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 12 times x 600 seconds, 10 x 240 sec, and 9 x 60 seconds at ISO 1,600 and f/3.2 with Clear Filter

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

Equipment: Zeiss ApoSonnar 135mmF2, IDAS NB12 Dual Narrowband Filter or Clear Filter, and EOS R-SP4II, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 9 times x 1,200 seconds, 13 x 240 sec, and 14 x 60 seconds at ISO 6,400 and f/3.2 with Dual Narrowband Filter and 18 times x 600 seconds, 12 x 240 sec, and 13 x 60 seconds at ISO 1,600 and f/3.2 with Clear Filter

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

IC 4592 is a beautiful reflection nebula in the constellation Scorpius. It is very close to the brighter, larger, and more colorful Rho Ophiuchi molecular cloud complex. This object is best photographed in the summer and is a good challenge for advanced astrophotographers. One of the most beautiful aspects of the Blue Horsehead Nebula is a second, much smaller nebula that lies near the ear of the horse. IC 4601, which you can see on the left, is another blue reflection nebula that is illuminated by two binary blue giant stars.

The shape of Gegenschein looked not round but irregular.

Equipment: Sigma 35mmF1.4 Art, IDAS Clear Filter, and EOS R6-SP5, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 10 times x 600 seconds, 9 x 240 sec, and 10 x 60 seconds at ISO 1,600 and f/3.2

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

Equipment: Zeiss ApoSonnar 135mmF2, IDAS NB12 Dual Narrowband Filter, and EOS R-SP4II, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 11 times x 1,200 seconds, 12 x 240 sec, and 16 x 60 seconds at ISO 6,400 and f/3.2

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

Equipment: Zeiss ApoSonnar 135mmF2, IDAS NB12 Dual Narrowband Filter, and EOS R-SP4II, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 9 times x 1,200 seconds, 13 x 240 sec, and 14 x 60 seconds at ISO 6,400 and f/3.2

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

Equipment: Zeiss ApoSonnar 135mmF2, IDAS NB12 Dual Narrowband Filter, and EOS R-SP4II, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 11 times x 1,200 seconds, 12 x 240 sec, and 16 x 60 seconds at ISO 6,400 and f/3.2

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

Equipment: Zeiss ApoSonnar 135mmF2, IDAS NB12 Dual Narrowband Filter, and EOS R-SP4II, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 11 times x 1,200 seconds, 12 x 240 sec, and 16 x 60 seconds at ISO 6,400 and f/3.2

I put 60-second frame and 240-second frame on starless frame.

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

Equipment: Sigma 35mmF1.4 Art, IDAS NB12 Clear Filter, and EOS R6-SP5, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 12 times x 600 seconds, 10 x 240 sec, and 9 x 60 seconds at ISO 1,600 and f/3.2 with Clear Filter

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

I like this framing of summer southern milkyway.

Stars got trailed near the right upper corner due to differential atmospheric refraction near the horizon during the later part of the imaging sessions.

equipment: Sigma 40mmF1.4 Art and EOS 6D-SP4, modified by Seo-san on ZWO AM5 equatorial mount on the genuine tripod with counter weight 4.8kg, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, ZWO ASI 120MM-mini, and PHD2 Guiding

exposure: 8 times x 900 seconds, 3 x 240 sec, 4 x 60 seconds at ISO 1,600 and f/3.2

site: 2,434m above sea level at lat. 24 39 52 south and long. 70 16 11 west near Cerro Armazones in Sierra Vicuña Mackenna in Coast Range of Chile

Ambient temperature was around 10 degrees Celsius or 34 degrees Fahrenheit. Wind was mild. Sky was dark, and SQML reached 21.83 at the night.

Yellow laser beams were in the frame from Paranal Observatory.

equipmnent: Sigma 105mmF1.4 DG HSM Art and Canon EOS 6D-sp4, modified by Seo-san on Takahashi EM-200FG-Temma 2Z-BL, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, Starlight Xpress Lodestar Autoguider, and PHD2 Guiding

exposure: 7 times x 15 minutes, 4 x 4 min, and 4 x 1 minute at ISO 1,600 and f/3.2

site: 2,430m above sea level at lat. 24 39 52 South and long. 70 16 11 West near Cerro Armazones Chile

Equipment: Zeiss ApoSonnar 135mmF2, IDAS Clear Filter, and EOS R-SP4II, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 18 times x 600 seconds, 12 x 240 sec, and 13 x 60 seconds at ISO 1,600 and f/3.2

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

I intended to optimize the frame at the center part, and the result got somehow orthodox or rather old fashioned frame.

"Supergiant Atmosphere of Antares Revealed by Radio Telescopes"

public.nrao.edu/news/supergiant-atmosphere-of-antares-rev...

Equipment: Zeiss ApoSonnar 135mmF2, IDAS Clear Filter, and EOS R-SP4II, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 13 times x 600 seconds, 12 x 240 sec, and 10 x 60 seconds at ISO 1,600 and f/3.2

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

Equipment: Sigma 35mmF1.4 Art, IDAS NB12 Dual Narrowband Filter, and EOS R6-SP5, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 7 times x 1,200 seconds, 8 x 240 sec, and 10 x 60 seconds at ISO 6,400 and f/3.2

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

Equipment: Sigma 35mmF1.4 Art, IDAS NB12 Dual Narrowband Filter, and EOS R6-SP5, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 11 times x 1,200 seconds,8 x 240 sec, and 17 x 60 seconds at ISO 6,400 and f/3.2

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

This is the final version of the series.

Equipment: Sigma 35mmF1.4 Art, IDAS NB12 Dual Narrowband Filter or Clear Filter, and EOS R6-SP5, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 7 times x 1,200 seconds, 8 x 240 sec, and 10 x 60 seconds at ISO 6,400 and f/3.2 with Dual Narrowband Filter and 10 times x 600 seconds, 9 x 240 sec, and 10 x 60 seconds at ISO 1,600 and f/3.2 with Clear Filter

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

There encroached satellites, aircrafts, and laser beams from Paranal observatory nearby, and I have excluded data containing them.

Here is a frame of the area taken with dual narrow band filter in 2024: www.flickr.com/photos/hiroc/53775405400

The small yellowish reflection nebula near the left upper corner looked interesting. It is named as GN 16.38.7 and resembles The bright Antares Nebula in the shape.

equipment: Sigma 105mmF1.4 Art and EOS 6D-SP4, modified by Seo-san on ZWO AM5 equatorial mount on the genuine tripod with counter weight 4.8kg, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, ZWO ASI 120MM-mini, and PHD2 Guiding

exposure: 4 times x 900 seconds, 2 x 240 sec, 6 x 60 seconds at ISO 1,600 and f/3.2

site: 2,434m above sea level at lat. 24 39 52 south and long. 70 16 11 west near Cerro Armazones in Sierra Vicuña Mackenna in Coast Range of Chile

Ambient temperature was around 10 degrees Celsius or 34 degrees Fahrenheit. Wind was mild. Sky was dark, and SQML reached 21.83 at the night.

We can see wider extent of hydrogen-alpha emissions with narrow band filter, though the colorful area turned less colored.

Equipment: Sigma 105mmF1.4 DG HSM Art, IDAS NB12 Dual Narrow Band Filter, and EOS R6-SP5, modified by Seo San on ZWO AM5 Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 120MM-mini, and PHD2 Guiding

Exposure: 4 times x 60 seconds, 3 x 240 sec, and 2 times x 1,080 seconds at ISO 6,400 and f/3.2

site: 2,430m above sea level at lat. 24 38 55 South and long. 70 16 52 West near Cerro Armazones Chile

SQML was 21.55 at the night. Ambient temperature was around 6 degrees Celsius or 43 degrees Fahrenheit.

Equipment: Sigma 35mmF1.4 Art, IDAS NB12 Clear Filter, and EOS R6-SP5, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 12 times x 600 seconds, 10 x 240 sec, and 9 x 60 seconds at ISO 1,600 and f/3.2 with Clear Filter

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

Equipment: Sigma 35mmF1.4 Art, IDAS NB12 Dual Narrowband Filter, and EOS R6-SP5, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 11 times x 1,200 seconds,8 x 240 sec, and 17 x 60 seconds at ISO 6,400 and f/3.2

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

equipmnent: Sigma 40mmF1.4 DG HSM Art and Canon EOS 6D-sp4, modified by Seo-san on Takahashi EM-200FG-Temma 2Z-BL, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, Starlight Xpress Lodestar Autoguider, and PHD2 Guiding

exposure: 9 times x 15 minutes, 5 x 4 min, 5 x 1 minute at ISO 1,600 and f/4.0

site: 2,430m above sea level at lat. 24 39 52 South and long. 70 16 11 West near Cerro Armazones Chile

Equipment: Zeiss ApoSonnar 135mmF2, IDAS NB12 Dual Narrowband Filter, and EOS R-SP4II, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 9 times x 1,200 seconds, 13 x 240 sec, and 14 x 60 seconds at ISO 6,400 and f/3.2

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.

Emission nebulae got brighter and bigger thanks to the application of the dual narrowband filter, though reflection nebulae got fainter and smaller.

Gegenschein looked not round but irregular on the frame taken with clear filter, but the irregular parts of Gegenschein looked reddish a bit on this frame taken with dual narrowband filter. It means that the irregular parts were not Gegenschein but faint integrated flux nebulae containing hydrogen-alpha light from stars nearby.

Equipment: Sigma 35mmF1.4 Art, IDAS NB12 Dual Narrowband Filter, and EOS R6-SP5, modified by Seo San on ZWO AM5n Equatorial Mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, ZWO ASI 174MM-mini, and PHD2 Guiding

Exposure: 7 times x 1,200 seconds, 8 x 240 sec, and 10 x 60 seconds at ISO 6,400 and f/3.2

site: 2,560m above sea level at lat. 24 23 21 South and long. 70 12 01 West near the peak of Cerro Ventarrones Chile

Ambient temperature was 11 degrees Celsius or 52 degrees Fahrenheit. Wind was mild, and guide error RMS was 0.73". Sky was dark, and SQML was 21.77 at the night.