The Sagittarius Triplet (Aleix Roig)

The Sagittarius Triplet

Link: https://astrocat.info/the-sagittarius-triplet/

Link to TIFF/FITS: https://astrocat.info/the-sagittarius-triplet/

Close to the Galactic Center of our Milky Way we can find an interesting trio of nebulae. Well known since the 17th century these nebulae are one of the most popular deep sky targets. Located some 4,100 light-years away from planet Earth, this trio is composed of the Lagoon nebula, Messier 8, the Trifid nebula, Messier 20, and NGC 6559.

Together with the three main nebulae we can distinguish some other faint nebulae such as IC 4684, IC 4685, IC 274 and IC 275. Some of those nebulae are emission ones while others reflect the light from the closer stars (that's the case of the blueish part of M20).

In the image we can also see two star clusters as follows.

Close to M8, at the bottom of the image, we can see NGC 6544, a globular cluster located at a distance of 9,500 light-years. This group of stars was firstly discovered by Willian Herschel back in 1784. It only covers a diameter of 1 arcminute. Within this globular cluster, in 1999 was discovered a millisecond pulsar in a binary system catalogued as PSR J1807-2459.

Another cluster of stars can be found in this field, close to M20, at the top of the image. This open cluster is catalogued as Messier 21, NGC 6531, and popularly known as the Webb's Cross. It's located some 3,900 light-years away from Earth and was discovered by Charles Messier back in 1764.

This image was acquired last Agust during my trip to Tivoli Astrofarm in Namibia. I captured a bit more than 2 hours of data using my monochrome camera, ASI2600MM on the small refractor FRA300.

The full image shown above covers an area of 4º28' x 2º58' at a resolution of 2.59"/pixel.

Image details:

L: 12x300" (1h)
RGB: 12x 60" each channel (36')
Ha: 6x300" (30')
[OIII]: 6x300" (30')
Calibrated with darks, flats. dark-flats.

Total exposure: 2h 36'

Moon at 6%Sky darkness: 22,05 mag/arcsec2
Image resolution: 2.59”/pixelFOV (full image): 4º28' x 2º58'

Equipment:

FRA300 + ASI2600MM + LRGB ZWO filters + ZWO EFW 7 pos + ZWO EAFZWO AM5 mountASI AIR PlusGuiding with ASI120MM and ZWO Mini Guide Scope

Aleix Roig, November 2022
Tivoli Astrofarm (Namibia).

Cloudy Nights

	Distinct awarded users	Total awarded images
Image of the day
Top picks
Top pick nominations

	Image of the day	Top pick	Top pick nominations	Total submitted
Deep sky
Solar system
Extremely wide field
Star trails
Northern lights
Noctilucent clouds
Landscape

	Image of the day	Top pick	Top pick nominations	Total submitted
Backyard
Traveller
Own remote observatory
Amateur hosting facility
Public amaeteur data
Professional, scientific grade data
Mix of multiple sources
Other
Unknown

Submitted The date and time when you submitted this image for IOTD/TP consideration.	...
Views by Submitters (available since September 19th, 2023) Every image is assigned to 50% of available Submitters. In the event that at least 80% of them don't view the image before its time in the IOTD/TP process expires, it's assigned to the other 50% of Submitters and the process begins anew.
Promotions by Submitters When 3 distinct Submitters promote the image, it moves on to the next stage of the process: evaluation for Top Pick status. This requirement, in addition to anonymization of images and distribution to only a subset of them, prevents biases and ensures that the best images are selected.
Promotions by Reviewers When 3 distinct Reviewers promote the image, it moves on to the next stage of the process: evaluation for IOTD status.
Early dismissal Staff members have a lot of images to inspect on a daily basis, and they can dismiss images if they believe they don't meet the requirements for IOTD/TP selection. If an image is dismissed 5 times, it's removed from the process. This streamlines the process and ensures that any bias present in promotions could be overruled by other staff members.

Status	Advanced success
Started	...
Astrometry.net job	6533177
PixInsight job	2IWSWE7U35O3JPM86B5FH6HWQ52KX1UW
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	18h05m28s.23
RA (top/left)	18h12m26s.39
RA (top/right)	17h54m11s.49
RA (bottom/right)	17h58m15s.10
RA (bottom/left)	18h16m51s.66

Dec (center)	-23°49′09″.6
Dec (top/left)	-21°40′39″.3
Dec (top/right)	-23°07′19″.1
Dec (bottom/right)	-25°56′23″.3
Dec (bottom/left)	-24°27′58″.10

Image Index:

Contribution Index (beta):