Venutianxspring

These three bright nebulae are often featured on telescopic tours of the constellation Sagittarius and the crowded starfields of the central Milky Way. In fact, 18th century cosmic tourist Charles Messier cataloged two of them; M8, the large nebula below and right of center, and colorful M20 near the top of the frame. The third emission region includes NGC 6559, left of M8 and separated from the larger nebula by a dark dust lane. All three are stellar nurseries about five thousand light-years or so distant. Over a hundred light-years across the expansive M8 is also known as the Lagoon Nebula. M20's popular moniker is the Trifid. Glowing hydrogen gas creates the dominant red color of the emission nebulae. But for striking contrast, blue hues in the Trifid are due to dust reflected starlight. The broad interstellarscape spans almost 4 degrees or 8 full moons on the sky.

Why would the sky glow like a giant repeating rainbow? Airglow. The air glows all of the time, but it is usually hard to see. A disturbance however -- like an approaching storm -- may cause noticeable rippling in the Earth's atmosphere. These gravity waves are oscillations in air analogous to those created when a rock is thrown in calm water. The long-duration exposure nearly along the vertical walls of airglow likely made the undulating structure particularly visible. OK, but where do the colors originate? The deep red glow likely originates from OH molecules about 87-kilometers high, excited by ultraviolet light from the Sun. The orange and green airglow is likely caused by sodium and oxygen atoms slightly higher up. The featured image was captured during a climb up Mount Pico in the Azores of Portugal. Ground lights originate from the island of Faial in the Atlantic Ocean. A spectacular sky is visible through this banded airglow, with the central band of our Milky Way Galaxy running up the image center, and M31, the Andromeda Galaxy, visible near the top left.

The remarkably blue comet C/2016 R2 PanSTARRS cruised through the solar system in 2018 and was captured juxtaposed against the stars of the Hyades cluster scattered through this mosaic spanning over 5 degrees on the sky toward the constellation Taurus.

Credit to Rogelio Bernal Andreo

The Rosette Nebula and other star forming regions are often shown in astronomical images with a predominately red hue, in part because the dominant emission in the nebula is from hydrogen atoms. Hydrogen's strongest optical emission line, known as H-alpha, is in the red region of the spectrum, but the beauty of an emission nebula need not be appreciated in red light alone. Other atoms in the nebula are also excited by energetic starlight and produce narrow emission lines as well. In this gorgeous view of the Rosette Nebula, narrowband images are combined to show emission from sulfur atoms in red, hydrogen in blue, and oxygen in green. Check this link to see the Rosette Nebula in a hydrogen predominant image for the red hue.

I'm going to kick off a monthly series highlighting some of the astronomical events that will be easily visible each month. Please feel free to make suggestions of anything that I missed, or if you have a particular celestial object that is visible now that you think is worth checking out, please let it below.

This month is host to a number of celestial events. A quick reference guide to help locate objects in the night sky, as well as a list of objects easily seen with the naked eye, binoculars, and telescope, can be found at SkyMaps.com. For an interactive map of the night sky, I recommend an app such as Stellarium, SkyMaps, though there are others that are also very good.

A few of this months events are:

Friday, July 7: Venus will appear at it's brightest for this cycle. Venus can be found after dusk in the lower western sky and will appear as a bright star.

Tuesday, July 11: Crescent Moon near Jupiter.

After the waning crescent moon clears the treetops in the east during the wee hours of Tuesday morning, July 11, it will be joined by the extremely bright planet Jupiter shining to its lower left (or celestial east).

Thursday, July 13: Crescent Moon near the Pleiades.

The eastern sky for several hours before dawn on Thursday, July 13 will host a pretty sight and photo opportunity when the slim crescent of the waning moon shines just 2 finger widths below (or celestial south of) the bright blue-white stars of the Pleiades Star Cluster. This will be a nice naked eye pairing with darker skies allowing for more of the seven sisters to be visible (how many can you see?)

Monday, July 17: New Moon.

These are the best times for observing the night sky, as the skies will be darkest during new moons.

Thursday, July 20: Earthshine Moon near Mars.

The crescent moon will shine several finger-widths to the upper right of the small, reddish dot of Mars. Look for the Earthshine moon, where sunlight reflected off of the Earth and back to the moon and slightly brightening the dark portion of the moon.

Sunday, July 30: Southern Delta-Aquariids meteors peak.

The annual Southern Delta-Aquariids meteor shower lasts from July 18 to August 21 in 2023. It will peak on Sunday afternoon, July 30 in the Americas, but it is quite active for a week surrounding the peak night. Expect 15-20 meteors per hour at peak.

Tuesday, August 1: Supermoon. This will be the second supermoon of 2023.

All summer: The Milky Way is visible from dark sky locations. This is the perfect time of the year to take a crack at photographing the milky way. Here is a link to getting started with your phone, or with a DSLR

Photo Credit

I can't believe how quickly this group is growing, it's only been a little over 2 weeks since this community was created so we could share awe-inspiring photos of the cosmos and we are already well over one thousand subscribers.

To continue to attract new people so that this community will really take off, we need to continue to have user engagement. So, if there are any ideas that you would like to see implemented here, or new ideas for the community, please let me know. Perhaps you would like to see more general space discussions, instead of solely sharing of images (there are not many space communities, so that could be a possibility)? Or maybe you hate the name and want to see it changed to something different from it's Reddit counterpart and have a great suggestion?

Don't be afraid to share your suggestions, I want this community to be active and reflect what the user's want it to be.

The Trifid Nebula is easily found with a small telescope in the Sagittarius constellation. It is around 5,000 light-years away and is one of the most strikingly colorful nebula in the Messier catalog. The Sagittarius constellation is very nebula dense and is a great region for beginner astronomer's and astrophotagraphers alike.

This is a large complex of stellar clouds found in the Cygnus constellation. This has always been one of my favorite cloud complex's in the night sky. The nebula towards the top is the Crescent Nebula, which is lit by a massive Wolf-Rayet star. A similar type star illuminates the faint blue loop towards the center. The Tulip nebula is the bright flaming nebula to the right and is illuminated by a massive Type-O star.

This image was taken by Team ARO and shows the brilliant emission nebula so aptly named the Flame Nebula. It is a predominantly hydrogen emission nebula found in the Orion Molecular Cloud Complex and is excited by the star Alnitak.

This open cluster of stars lies near outskirts of the small Magellanic Cloud, some 200K lightyears away. This relatively young cluster (~5 millions years) of stars is surrounded by the natal gases and material that remains of the stellar nursery that formed these stars.

As a bonus, an assortment of galaxies can be seen in the background.

It's amazing the similarities that can be found on our neighbor planet. This could easily be mistaken for an overcast day somewhere in Nevada. This photo was taken by Curiosity rover on March 19 2021 and is a tiled mosaic of 21 images.