You've seen the planets, what now? A guide to the night sky in the coming months part 1

The Summer of Planets for 2025 is wrapping up.  Mars is still an amazing sight in telescopes and it's the best time to see it for a couple of years. Jupiter is also quite dazzling at the moment as well. 

Over the last few months we've been delighted by the rush of new astronomers who've purchased telescopes from us to catch this rare planetary alignment. 

As we head into end of summer and towards the autumn months, you'll find a wide variety of deep-sky astro objects that can be viewed in telescopes of all sizes. 

At BINTEL we really, really love observing and photographing the Solar System planets and learning about them. The problem is that there are only a few of the with in the reach of amateur telescope gear compared to the thousands of deep-sky astro objects that are the Milky Way and beyond. 

In this article we'll look at some of the most spectacular things you'll be able to see - Nebulae

Rather than simply listing what's in the sky, we'll chat about some of astronomer's favourites in a few categories.

A nebula is a region in space that contains clouds of interstellar gas and dust. When they contract and collapse due to gravity, new stars can be formed. Our own Sun was formed when this happened about 4.6 billion years ago.  Once stars start shining through nuclear fusion, these clouds are spread further out space. It's a complicated process and astronomers study nebulae to better understand the life cycles of stars. 

There are number of different types of these gas and dust clouds and what we'll cover here are Emission Nebula.

These are nebulae shine because the gas in them is excited by the energy they absorb from nearby stars.  They don't reflect the light of stars, but rather emit their own light and at very specific wavelengths. Emission nebulae can be bright cover a large area of the sky. 

Orion's Sword or Handle of the Saucepan?

One of the most famous emission nebula in the sky is The Great Orion Nebula or M42*. 

This is visible with just your eyes alone as a small, misty patch in the handle of the saucepan in Orion for us folks in the Southern Hemisphere. (Of if you're in the Northern Hemisphere where everything is upside down, in the sword that hangs off the belt of Orion.)

It's easily found being part of a bright constellation. If you're using any of the Celestron StarSense Explorer telescopes, the included phone app will take you directly there. 

Where to find The Orion Nebula in the "handle of saucepan"

While M42 can be seen with your eyes, a pair of binoculars will show it as a small patch of what looks like cloud. Even a small telescope will reveal to the mist like clouds of gas that spread away a central brighter region.  These are not passing clouds as many first time viewers of M42 have thought. They're vast regions interstellar gas that cover up to 25 years across, or about six times the distance that Earth is to our nearest star. 

The M42 star forming region is also over 1,300 light years away from Earth. It's amazing to think of how much energy is being collected by the nebula that it lights up like a neon light so brightly that it can be seen by local inhabitants of a rocky planet that far away.

M42 covers roughly the same amount of sky as the Full Moon - about half a degree across. 

If you'd purchased larger telescope from BINTEL such as the saxon 8" Dobsonian,  you'll see the central star is actually several - a cluster called the Trapezium. 

Some far southern skies delights:

The largest and brightest nebula region in the night sky is not M42. The Carina Nebula  complex in the far southern sky and easily seen as a dense part of the Milky Way that runs near the Southern Cross and appears more than four times larger then M42. 

It's also called NGC 3372 and Caldwell 92

Close up view of the Carina Nebula region

The Carina Nebula was known the ancient cultures and "discovered" by Europeans in 1752.  It's located some 8,500 light years from Earth.

It appears to your eyes as a bright knot, embedded in the Milky Way and is part of the Milky Way in a region called the Carina–Sagittarius arm. Follow the Milky Way up from the Southern Cross Binoculars will show more detail and again, a delight in any telescope.  As it covers such as large area, it's best first explored with the low powered eyepieces. A bright star system in the nebula complex is Eta Carina (in fact sometime the nebula region is simply referred to as "Eta Carina") contains at least two stars orbiting each other that's more than a million times brighter than the Sun.

An obvious feature of the Carina Nebula is a dark region that seems to cut the nebula in half. This is not because of different section to the bright gas clouds, but rather due a region called a dark nebula that's in front of it as seen from Earth. This is also a cloud of gas and dust however there are no nearby stars to illuminate it and it blocks the light from distant stars and other nebulae.  Possibly the most famous dark nebula in the sky is the "Coalsack" which in the Southern Cross which blocks the light from the Milky Way in its lower section and appears as a black patch against the brilliance of the sky in that region. It's something you'll easily spot with your eyes along under dark skies. 

There are many features including star clusters around the Carina Nebula. An area you'll never get bored exploring with a telescope.

Do other galaxies have nebulae?

They certainly do! While we're observing this part of the sky the largest nearby galaxy, the Large Magellanic Cloud (LMC) was another bright object in the night sky well known for thousands of years by the locals that was again "discovered" Ferdinand Magellan in 1519 and only then became known to Western science. It used to be thought of as a satellite galaxy of the Milky Way but we know thinks it's actually a smaller galaxy that's swinging by the Milky Way. (You can read more about this in a BINTEL article here.)

The Milky Way is a spiral galaxy** with regions of star formation that are normally found through its arms. The LMC is an irregular galaxy without such a clearly defined structure. It contains denser regions with rapid star formation over large areas. One area is the Tarantula Nebula which sits in one corner of the LMC. This also called NGC 20270 and Caldwell 103.

Where the Tarantula Nebula in the LMC can be seen within the LMC at around 9.30pm on the 5th of March 2024 from Sydney. The LMC itself appears as a detached area of the Milky Way.

This nebula is definitely one that needs a telescope to view. The reason it has the name of the Tarantula Nebula is the arcs of illuminated gas resemble the leg of a large spider!

Again, this is an object that is well worth exploring in any telescope. 

An illustration of the LMC produced by Stellarium showing where the Tarantula is located near the top of the image.

This entire region is well worth exploring in binoculars as cover a significant patch of the sky . It's amazing what a fuzzy are of the sky can reveal with even modest optical gear. 

In the next of the series about deep-sky astro objects for beginners we'll cover star clusters. 

Cheers, 

Earl White

BINTEL 

6th February 2025

*Astronomers use various catalogues to get track of objects. Common ones include Messier or M numbers, New General Catalogue NGC and others. 

** The structure of the Milky Way is complex. It's a barred spiral and we're still learning about its shape and even how many major arms it has.