M87
Arp 152, Virgo A, NGC 4486
38’ x 25’ | 0.8”/px | 3000 × 2000 px
Virgo
RA 12h 30m Dec +12° 22’ | -7°
Messier 87 (M87), also known as Virgo A or NGC 4486, is a supergiant elliptical galaxy located in the constellation Virgo. It is one of the most massive galaxies in the local universe and is notable for its prominent jet of energetic plasma that originates from its core and extends at least 5,000 light-years. M87 is approximately 53.5 million light-years away from Earth and is one of the most luminous radio sources in the sky. The galaxy is home to a supermassive black hole at its center, which has a mass estimated to be about 6.5 billion times that of the Sun. In 2019, the Event Horizon Telescope collaboration released the first-ever image of a black hole, which was the supermassive black hole at the heart of M87. This groundbreaking achievement provided direct visual evidence of the existence of black holes and offered insights into their properties. M87 is also known for its large population of globular clusters, with estimates suggesting it may have as many as 12,000, compared to the 150-200 found in the Milky Way. These globular clusters are dense collections of stars that orbit the galaxy and are thought to be among the oldest stellar systems in the universe. As a member of the Virgo Cluster, M87 plays a significant role in the dynamics and evolution of the cluster. Its strong gravitational influence affects the motion and distribution of other galaxies within the cluster.
source: Mistral
Data Acquisition
Data was collected over 3 nights, during early April 2025 using a 130mm refractor telescope with full-frame camera from the backyard in The Netherlands. Data was collected using standrad LRGB filters. A total of about 18 hours of data was combined to create the final image. Both M87 and M89 were captured in the same image and were cropped out as separate images during processing.
Location Backyard Observatory in Groningen, The Netherlands (53°N 6°E)
| Sessions | Moon% | Moon° | Hum% | SQM | T°C | Frames | Exposure |
|---|---|---|---|---|---|---|---|
| 20250402 | 30 | 107 | 70 | 19.5 | 8 | 114 | 6h 50m |
| 20250403 | 37 | 94 | 70 | 19.6 | 8 | 100 | 6h 36m |
| 20250404 | 46 | 80 | 80 | 19.3 | 6 | 88 | 5h 12m |
| Total | 302 | 18h 38m |
| Frames | Bin | Gain | Exp.(s) | Frames | Exposure |
|---|---|---|---|---|---|
| Lum | 1 | 0 | 180 | 196 | 9h 48m |
| Red | 1 | 0 | 300 | 40 | 3h 20m |
| Green | 1 | 0 | 300 | 32 | 2h 40m |
| Blue | 1 | 0 | 300 | 34 | 2h 50m |
| Total | 302 | 18h 38m |
Equipment
Telescope
Mount
Camera
Filters
Guiding
Accessoires
Software
Takahashi TOA-130, FL67 flattener, Pegasus Astro Motor Focus kit v2
10Micron GM1000HPS, EuroEMC S130 pier
ZWO ASI6200MM Pro, cooled to -15 ºC
Antlia 2” unmounted LRGB V-Pro, ZWO EFW 7-position
Unguided
Fitlet3, Pegasus Ultimate Powerbox v2, DeepSkyDad Flatpanel FT1 (30cm), Pegasus Uranus
Linux Mint, KStars/Ekos, INDI Library, Mountwizzard4, PixInsight 1.9.3
Processing
All processing was done in Pixsinsight unless stated otherwise. Default features were enhanced using scripts and tools from RC-Astro, SetiAstro, GraXpert, CosmicPhotons and others. Images were calibrated using 50 Darks, 50 Flats, and 50 Flat-Darks, registered and integrated using WeightedBatchPreProcessing (WBPP). The processing workflow diagram below outlines the steps taken to create the final image.
The luminance stack had some artefacts in the background that had not been corrected fully by the flats. To remove them, stars were temporarily removed and background was cleaned up using the CloneStamp tool. Then the stars were put back in again. After the processing was complete, I learned about the use of synthetic flats, which would have been an ideal method to apply here, but we will leave that for some other time.
Key to processing this image is to look for the plasma-jet that is ejected from the heart of the galaxy. With normal stretching, this jet is easily lost in its background. A number of different stretching methods were tried, but best results were obtained using the new Bill Blanshan scriplet Simple Stretch. Scriplets are little scripts embedded in a new script released by Cosmic Photons, called PixelMath UI. The fine control over the stretching process in combination with real-time preview feedback allowed for a quick and easy stretch that made the jet stand out from the rest of the galaxy. Later in the process, another scriplet was used (Wavelet sharpening) to increase sharpening. With this tool, the jet could be even further isolated from its surroundings. For the RGB stretch, a combination of ArcSinhStretch and GHS in Colour mode was used. I’ve found this the best way to keep colours intense and natural during the stretching phase. Often after the stretch not much additional saturation, if any, is necessary.
The rest of the processing followed a standard processing workflow.
Processing workflow (click to enlarge)
This image has been published on Astrobin.
