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Light Pollution is Ruining Our Night Sky

|light pollution|6 Comments

Have you ever looked at a brightly lit building or street light in your neighborhood and thought it was excessive? You know, light shining in all directions or perhaps in your bedroom window, rather than only lighting up the intended area. That is light pollution

Light pollution is misdirected excess/obtrusive outdoor artificial light in a night environment. Too much light pollution washes out the night sky, interferes with astronomical research, disrupts ecosystems, wastes energy, and has adverse health effects.

Urban towns, cities, and suburbs are known for their excessive light. These light sources can be found by way of exterior/interior lighting, advertising, streetlights, parking lots, etc.

For non-stargazers, over-lighting or light pollution is likely a new concept and one they might not consider a problem. Even worse though, is the absence of a dark star-filled night sky is not even missed. 

Over-lighting has become a global problem in need of a paradigm shift. Before we can make positive change, we must understand the negative impacts of light pollution and strengthen our connection with the natural environment. 

light pollution example

Light pollution from a commercial greenhouse turns this Bortle Scale Class 3 location into an 8. 

Types of Light Pollution 

There are several different types of light pollution, including:

  • Glare: light reflecting off a surface making it difficult to see
  • Skyglow: light shining up into the atmosphere creating a yellow halo
  • Light trespass: light shining outside the intended area or where it is not needed
  • Clutter: bright, excessive groupings of light sources
  • Over-illumination:  the use of too much or excessive light

Sources of Light PollutionBenedek via iStockphoto. Let’s Talk Science 

Often when discussing the issue of light pollution, people discuss the matter of using lighting for safety reasons. While there has been no evidence from studies to suggest that lighting increases safety, the bigger issue is around selecting more efficient lighting to light up only the areas we need, when we need them. 

Neighborhood Lighting

Before and after neighborhood lighting change to direct light downward, where it is needed. IDA/Richard O’Brien

Light Pollution and the Night Sky

According to the International Dark-Sky Association (IDA), everyone had access to a starry night sky less than 100 years ago.

Now, there are millions of people living in urban cities that will never see the Milky Way from where they live or are stuck living under permanent sky-glow. 

For example, on August 14, 2003, nearly 50 million people across Ontario and Eastern United States experienced a massive blackout and were left without power for a few days.

During this time, even in the core of downtown Toronto (which has a population of 250,000), there were people seeing the Milky Way for the first time ever.

Before and after light pollution

Light pollution before and after from the suburbs of Toronto during the 2003 blackout. IDA/Photo by Todd Carlson

Light pollution alters our view of the sky and makes it difficult to see smaller or faint objects.

It washes out stars, constellations, galaxies, and nebulae, reducing the overall contrast between these objects and the darkness of the sky, impacting astronomical research and the hobby of astrophotography. 

Light Pollution and Astrophotography 

The night sky viewed from a light-polluted city will not compare to the detail of what can be seen from truly dark skies.

While large objects, like planets and prominent constellations, can be seen from the city, fainter objects or deep-sky objects will need to be captured under darker skies. 

Astrophotography from a light-polluted area has its challenges. A light pollution filter is often your first line of defense against a washed-out sky.

Light Pollution and the Bortle Scale

8 levels of light pollution. The Orion constellation captured from Bortle Scale Class 1-8 locations. Credit to: Josh Wilson/ Richie Mills/ James Markgraf/ Remco Kemperman/ Robin Lim/ Andrew Wryghte/ Carsten Groinig/ Abhiroop Bhattasali

Popular light pollution filters include the Optolong L-Pro and Astronomik CLS. The filters do their best to ignore the bandpasses of the visible associated with artificial light.

Some photographers insist that shooting without a filter is best. In this scenario, you’ll need to have a solid game plan for processing the image to reveal your deep-sky object from a bright sky.

Deep-sky astrophotography is arguably much easier to accomplish from a light-polluted location than wide-angle shots or nightscapes.

Capturing distant objects through a telescope has the advantage of isolating a very small patch of the bright sky, while a Milky Way panorama shows off nearly the entire sky.

separating a Galaxy or Nebula from a brown sky is easier than digging out each star and constellation of a nightscape photo. For this reason, I do not recommend capturing wide-angle photos of the night sky from a light-polluted location.

Bortle Scale 

Astrophotographers often use the Bortle Scale as a way to measure the brightness (or quality) of their night sky as it relates to light pollution. There are nine levels to the Bortle scale (Class 1-9) with Class 9 being the most extreme amount of light pollution. Five or under is required to see the Milky Way. 

How to find your Bortle Scale class

You can use the ‘Clear Outside’ mobile app for a rough indication of your current Bortle Scale rating. 

Light Pollution Map 

You can also access a light pollution map to determine your level of light pollution that will provide the Bortle Scale classification. This can come in handy if you are looking to travel to darker skies in order to capture a landscape photo of the Milky Way or a deep-sky object. 

light pollution map

A light pollution map displays the amount of light radiating from the largest city centers.

Impacts of Light Pollution 

As noted above, light pollution impacts the night sky and the hobby of astrophotography, but light pollution impacts more than astronomers/astrophotographers. 

Human Health

Life of Earth has always had natural sources of light by way of the sun and moon that produce a day-night cycle. This cycle, referred to as the circadian rhythm, acts as an internal clock that our bodies follow and is controlled by the light sources around us. 

Our bodies produce the hormone melatonin as a result of this cycle which is necessary for our overall health. Excess artificial light at night disrupts the cycle, suppressing melatonin production and negatively affecting human health. 

Light pollution also increases the risk of:

  • Sleep disorders
  • Diabetes
  • Weak immune system
  • Obesity
  • Depression
  • Certain cancers

Wildlife/Ecosystem Health

Much like humans depend on the day-night cycle for their health, ecological systems are dependent on this cycle for reproduction, nourishment, sleep, protection from predators, etc. 

There are several examples of these types of disruptions in nature affecting the existing ecological balance (migratory birds, turtle hatchlings, etc.). Declining insect populations as a result of light attraction can also negatively impact the balance of nature as all species depend on insects. 

Excessive artificial light:

  • Affects nocturnal wildlife who are active/hunt during the night
  • Changes predator/prey interactions
  • Alters species interactions
  • Confuses animal navigation
  • Affects plant/animal physiology
  • Draws in insects

According to research scientist Christopher Kyba, for nocturnal animals, “the introduction of artificial light probably represents the most drastic change human beings have made to their environment.”

Energy Consumption

Unnecessary use of resources is wasteful, which includes using too much light or lighting areas where it is not needed.

According to the IDA, it is estimated that at least 30 percent of outdoor lighting in the U.S. is wasted, mostly by lights that aren’t shielded. To put a dollar value on that, it adds up to $3.3 billion and releases 21 million tons of carbon dioxide per year.  

We can make better lighting choices to cut down on wasted energy and carbon emissions. This will save money, and ultimately allow everyone to enjoy the night sky. 

How to Reduce Light Pollution

Reducing light pollution involves reducing skyglow, glare, trespass, and clutter. 

There are several ways you and your community can take action against light pollution in order to minimize the risk to ecosystems, human health and protect the night sky. 

Start by assessing the light on your own property, and see if there are improvements you can make to your lighting. 

  • Look to reduce inefficient and/or unnecessary outdoor lighting
  • Reduce the intensity of your lighting and use minimum intensity
  • Adjust the orientation of your lighting making sure lighting is positioned downward, lighting only the area you need to light.
  • Consider installation timers on your lights or using motion sensors to use lights only when they are needed
  • Use soft or amber lighting over white light which contributes more to sky glow and health risks.
  • Use dark-sky-friendly lighting at your home. IDA works with specific retailers to establish IDA-certified lighting so you know it is light pollution friendly. 

Home Lighting

Non-Shielded versus shielded lighting to control light pollution. Lamps Plus.

In addition to adjusting your outdoor lighting, you might choose to become an advocate for light pollution.

You could do this by speaking with your friends and neighbors about the importance of reducing light pollution, engaging a greater community online through social media, setting up an outreach table at your local event, or advocating for a lighting ordinance in your town.

Check out the IDA and their resources to support any of these options. 

Compensating in Astrophotography

It is often said in the astrophotography world, “there is no substitute for dark skies”. This statement is very true, as you will always take better images from a location with an unspoiled sky.

In the past, I have traveled from 1-4 hours to enjoy a dark sky. The best time to enjoy a dark sky location is during the new moon phase, so you can fully appreciate the number of stars you will see in the sky.

The reality is, most of us spend the majority of our time under a light-polluted sky at home. To photograph the deep space objects in the sky, we must get creative with our approach, and/or utilize specific filters to get the job done. 

The Milky Way

The Milky Way photographed from a Bortle Scale Class 3 location.

Short Exposures / No Filter

One technique that you can try, is to shoot several short exposure images without the use of a light pollution filter. This method has the benefit of capturing the most natural-looking star colors, but will significantly reduce the exposure time of your individual images.

For example, I was able to capture the Trifid Nebula from my Bortle Scale Class 7 backyard sky without using a filter. The sub-exposures were limited to 2-minutes each, using ISO 1600 on my Canon EOS Ra camera.

The trick is to shoot enough sub-exposures to overcome the noise (through integration) and use multiple gradient removal techniques to separate the deep-sky object from the bright sky. You may be surprised to find high-quality data buried beneath a washed-out sky.

deep sky astrophotography

Optolong L-Pro Filter

There are many light pollution filters available for astrophotography from the city. The Optolong L-Pro is my number one choice when it comes to a broad-spectrum light pollution filter that captures natural-looking images. 

The biggest difference you will notice when using a filter is the contrast between the stars/nebulae/galaxy and the sky. A filter helps to separate the object from a bright night sky, at the expense of altering the natural colors of the area slightly.

You will need to make some careful color adjustments to the stars (and your subject) to restore a natural look.

Optolong L-Pro filter review

Before/After using a light pollution filter from the city (Optolong L-Pro Filter). 

Dark Sky Organizations 

There are organizations with the mission to protect the night from light pollution. The International Dark sky Association is the main recognized authority on light pollution and is the leading organization combating light pollution worldwide.

While celebrating dark, star-filled skies, they also advocate and educate about light pollution, provide resources for individuals/policymakers/industry, and promote responsible outdoor lighting.

AstroBackyard is an IDA member which means we pay a membership fee to support their preservation efforts to protect our dark skies. It’s a great way to support the dark skies we all crave as astrophotographers. 

Here in Canada, Ontario Parks and the Royal Astronomical Society of Canada (RASC) are working to protect and preserve our night skies in partnership with the IDA, and are designating locations (mostly Provincial Parks) as Dark Sky Preserves based on the following criteria: 

  • Control of local lighting
  • Outreach programs aimed at the general public and neighboring municipalities
  • Good nighttime lighting practices

There are many other local organizations that are also discussing the issue of light pollution and raising awareness in their communities. Feel free to drop the name of other organizations you know who are advocating for dark skies in the comments section. 

If you are an astrophotographer who appreciates dark skies, I would encourage you to look into/connect with an organization in your community or otherwise to see how you can make a difference and help protect our skies. 

Dark Sky Locations

As part of the work being done by the IDA, they also designate locations as part of the International Dark-Sky Places Program. These locations offer dark skies for those looking to escape light pollution with some facilities geared towards astronomers/astrophotographers. 

I have attended the Cherry Springs Star Party for several years, which is held at Cherry Spring State Park, an International Dark Sky location. 

For a full list of parks/locations that are part of the IDA Places Program, click here

International Dark-Sky Week

The International Dark-Sky Association also hosts International Dark-Sky Week during the month of April to help raise awareness about light pollution.

Keep an eye out for activities each year presented by the IDA.

Helpful Resources:

What is light pollution?

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Deep Sky Astrophotography in Light Pollution

|Nebulae|11 Comments

If you’ve been following AstroBackyard on YouTube, you’ll know that I regularly shoot DSLR astrophotography images under the heavily light polluted skies at home. My night sky is classified as Bortle Class 8 in terms of sky quality, a white zone on the light pollution map. This certainly makes things more difficult in terms of collecting data and image processing, but I welcome the challenge.

It’s true, there is no substitute for dark skies. But being able to set up a portable astrophotography kit in the backyard on a weeknight is pretty cool. I don’t have to pack up heavy gear into the car and worry about mobile battery power or internet access. I can open up the garage door and start capturing images through my telescope before it gets dark after work.

light pollution map

I live in the center of town, a red zone on the light pollution map

Don’t get me wrong, I adore traveling to dark sky locations, it just doesn’t happen as often as I’d like it to. For me, a typical night of deep-sky imaging happens during the week in between work, family time and lots of dog walking. A clear sky in the backyard is my idea of the perfect night, no matter which target I’m shooting.

I’ve been successfully capturing deep sky images from this light-polluted backyard for 3 years now. The best part about it is that I get to show others that live in the city that deep sky astrophotography is not only possible, but you can capture some truly incredible images. In this post, I’ll share my latest results from the backyard using a Canon EOS Rebel T3i DSLR camera and a small refractor telescope.

deep sky astrophotography

The Soul Nebula captured with a Canon DSLR and the equipment shown below

Light pollution is a major side-effect of urbanization, and is said to compromise your health and can disrupt ecosystems. To discover the amount of light pollution where you live, simply locate your house on this interactive light pollution map. The Bortle scale is a way of measuring the brightness of the night sky.

Photographing a Nebula from the City

After much deliberation, I have decided to dedicate an increasingly rare and precious clear night to the Soul Nebula in Cassiopeia. I’ve photographed IC 1848 before, so I’ll be combining the new images I take with the previous data to create my best image of this emission nebula yet. All of the data I’ve ever collected on this nebula was shot here in the backyard with a DSLR.

My secret weapon is to collect absolutely as much exposure time on my target as possible. Stacking several images together can increase the amount of signal collected while reducing noise by canceling out its random output. For more information about the concept of signal-to-noise ratio, Craig Stark explains it better than I ever could.

astrophotography telescope

My telescope with the Canon EOS Rebel T3i attached

Overcoming light-polluted skies

I’ve got lots of experience here, as the majority of my deep-sky astrophotography is done from home. In theory, a light pollution filter will let you shoot longer exposure times before being blown out on the histogram, but this comes at a price. The signal (light) is often weak, and the natural color emitted from the stars has been altered. For both of these trade-offs, capturing more integrated exposure time can be a huge help.

A popular and effective method of overcoming the light-polluted skies of an urban backyard is to use a monochrome camera equipped with narrowband filters (narrowband imaging). This has the power to aggressively ignore artificial light and isolate the light associated with specific gases in objects in space. But what about those shooting with a DSLR camera?

A color camera like a DSLR uses an internal Bayer matrix to create full-color images in a single shot. This convenience comes at the expense of a much weaker signal when compared to a monochrome CCD or CMOS camera. To offset this challenge, I like to use camera filters that help me isolate the light I want to collect.

camera filter

I use a clip-in light pollution with my Canon DSLR (Skytech CLS-CCD)

Shoot During New Moon

Although narrowband filters have allowed me to take photos during all moon phases, the new moon phase is a special time for amateur astrophotographers. The days surrounding the new moon phase mean that I can finally capture true color images of my subject with more natural colors.

Believe it or not, the bright glow of Earth’s natural satellite produces enough skyglow to really reduce contrast in your deep-sky images. Even a narrowband filter won’t help if your target is sitting too close to a bright full moon.

Light pollution filters such as the Astronomik CLS and IDAS LPS D-1 help to reduce moonglow, but for the absolute best data on a deep sky target, the new moon phase is best. If you’re planning on shooting unfiltered, this is definitely when you want to try it.

Shooting Without a Light Pollution Filter

It’s also worth noting, that for certain targets, an incredible image can be captured without using a filter at all. Don’t believe me? Have a look at this photo of the Andromeda Galaxy posted by Jon Rista on Astrobin. The image was created by stacking 174 x 150-second subs at a modest ISO 400 under light-polluted skies. Inspired? I was too.

I plan to capture the Pleiades from my backyard again soon using only the required UV/IR (luminance) filter with my modified DSLR. This target does not emit light that a narrowband filter can isolate, as it is a reflection nebula. Another target that would be a great test subject for this technique is M31, as seen in Jon’s image above.


I captured the Pleiades star cluster using a new light pollution filter, the Optolong L-Pro. This is a multi-bandpass filter the does a great job of preserving the natural star colors in my images from the city. Have a look at sample image comparing an unfiltered image and one using the Optolong L-Pro:

filter comparison

My full review of this broadband astrophotography filter includes an image of the Pleiades star cluster captured with a stock Canon 5D Mk II camera.

Optolong L-Pro Filter Review – An Urban Broadband Astrophotography Filter

An Astrophotography Filter for the City

In the following video, you’ll see me describe the challenges of photographing deep-sky objects in space from a light-polluted area. The Optolong L-eNhance filter is an excellent choice to consider when shooting nebula targets that include areas of H-alpha and Oxygen III.

The image in this video was not shot using a DSLR camera, instead, a dedicated astronomy camera. However, a dual bandpass filter like the Optolong L-eNhance is a great choice for DSLR camera owners as well. This filter was designed especially for one-shot-color cameras. 



Selecting a Target

I no longer go into my astrophotography projects blind. In the early days, I would set up my telescope and astrophotography gear and think to myself “what will I shoot tonight?”. As carefree and exciting as those nights were, they also included a lot of wasted clear sky time looking at a computer screen while the night passed me by.

These days, I prefer to take a much more organized approach to deep-sky astrophotography as my time is limited, and clear nights are rare. I find it best to double down on deep-sky targets that not only compliment my equipment but maximize exposure time and increase the chances of “completing” a final image.

astrophotography book

I often refer to my “The 100 Best Astrophotography Targets” book for inspiration (On Amazon)

Be sure to check out my list of 14 Best Astrophotography Books for many more great choices. 

My decision-making process involves answering the following questions:

  • Have I photographed this target before?
  • Is the target in the early, mid or late position for the season?
  • Is it a good fit for the focal length of my telescope?
  • Does this object require narrowband data to properly showcase?
  • Will it turn out well in color using a DSLR camera?

As an example of a target’s position relating to the season – you wouldn’t want to start a new astrophotography project on a DSO that is on its way out and fading deeper and deeper into the Western twilight each night. Right now, Orion (winter target) is in the early season stages, while objects like the Crescent Nebula (Summer target) are on their way out.

It’s beneficial to select a deep sky target that will get as high from the horizon as possible. This will, of course, vary by your location but aim to collect light on subjects that are in their optimal position for the time of year. Your backyard window of the sky and potential obstructions in your yard will also factor into your selection.

deep sky imaging setup

My deep-sky imaging setup in the backyard

Despite having several previous iterations of IC 1848 on my hard drive, The Soul Nebula checked off the most boxes and won the battle for option selection. It currently sits in an opportunistic area of the night sky to collect a serious amount of exposure time this month.

This will be a great opportunity to improve my broadband color data collected on the Soul Nebula to improve upon my image from last year.

Why I’m using a DSLR

With a number of dedicated astronomy cameras and cooled CMOS cameras in my possession, why would I opt for using an old DSLR camera instead of an impressive astronomy camera like the QHY128C? (I’m working on it)

For starters, I wanted to produce another example image using the Zenithstar 73 APO with a DSLR. In my last video I shared images of the heart Nebula and Butterfly Nebula in narrowband Ha – but this time I’ll collect images in good old full color. My results on the Soul Nebula should give you a good idea of what to expect with a crop sensor DSLR camera like my Canon T3i or similar models.

A telescope like the Zenithstar 73 is a logical telescope choice for deep sky beginners just entering the hobby, and many of those people will be using a DSLR. It’s easy to get carried away in my posts and videos and skip over the basic information beginners are looking for, so I’ll try my best to scale back when the situation calls for it.

connecting a DSLR to a telescope

My DSLR attached to the Flat 73 Field Flattener and Zenithstar 73 Telescope

Camera Settings for a Washed Out Sky

From my bright sky here in the city, I’ll use 3-minute exposures at ISO 800 to capture the Soul Nebula. This is a rather conservative approach, which may have you wondering why I’m not shooting longer subs. A typical DSLR light frame under moderately light polluted skies would normally be 5 minutes at ISO 1600, but it’s a hot a humid night, and those settings would absolutely cook my sensor.

In these conditions, there is little value in collecting images longer than 3-minutes. As the noise increases significantly, the signal sees very little improvement. You are much better off capturing several shorter images over time. (My camera sensor hit 32°!) Even at 180-seconds, I am capturing A LOT of skyglow that will have to be dealt with in post-processing.

Camera Settings in the City

  • Mode: Manual
  • Format: RAW
  • ISO: 800
  • White Balance: Auto
  • Exposure: 180-seconds (3 minutes)

*Note without using a light pollution filter, this exposure time would be cut in half.

light frames

Previewing my 3-minute light frames in Adobe Bridge before stacking

Focal Ratio is Important

The Zenithstar 73 APO is fast. It’s fixed f-ratio of F/5.9 can collect light faster than most of the refractor telescopes I’ve used in the past (Including my Explore Scientific 102). This gives my images a much-needed boost in signal for each short 180-second sub. A lower focal ratio allows more photons to hit your camera sensor in a single exposure, which makes a big difference in terms of SNR.

Naturally, the aggressiveness of the filter (in this case a SkyTech CLS CCD) in front of the camera sensor changes how much signal I can record in a single exposure.

White Balance

I’ll leave the cameras white balance set to auto, as I see no benefits in adjusting this setting at this stage. Because I am shooting the images in RAW format, I can manually adjust the white balance to whichever temperature I want in post-processing. With that being said, there have been some interesting discussions on the topic of the benefits of using a custom white-balance for astrophotography in heavy light pollution.

Capture Software

The images are being captured using APT (Astro Photography Tool) on my new laptop computer. Autoguiding through PHD2 guiding and the Altair GPCAM + 50mm guide scope means that each image contains sharp stars each and every time. If you’re looking for an affordable autoguiding package to upgrade your kit, have a look at the Starfield autoguiding package offered from Ontario Telescope.

The images are dithered between each frame to further reduce noise – which can easily be switched on within the gear tab of APT. To learn more about the process of data acquisition including the use of support files (dark frames, flat frames), please visit the get started page.

Light Pollution Filter for Canon DSLR’s

For broadband spectrum targets like galaxies (and many reflection nebulae), a light pollution filter is less effective. However, for an emission nebula like the Soul Nebula, isolating the light emitted in the H-Alpha and OIII wavelengths can make a big difference.

Longtime followers of the blog will remember the SkyTech CLS-CCD filter I reviewed last year. Time and time again, this filter has impressed me with its ability to produce impressive color images using my DSLR camera in heavy light pollution.

Light pollution filter for Canon

The SkyTech CLS-CCD clip-in light pollution filter for modified DSLR cameras

This filter has been my go-to choice when it comes to capturing true-color broadband images from home. It does a great job of creating contrast between my target and a washed out city sky. The only downside is that it also alters the color balance of my image and paints the surrounding stars with a red cast.

Later this month, I’ll be testing out an Optolong L-Pro filter with my DSLR camera, which is said to be “a true 5 bandpass filter”. This multi-bandpass filter is less aggressive than the CLS-CCD and should help with my color balance issues. My hope is that this filter is a much needed middle ground between shooting with the CLS-CCD filter and unfiltered. I expect my exposures to be shorter using this filter here in the city.

Optolong L Pro FIlter

The Optolong L Pro Filter is 5 Bandpass Light Pollution Suppression Filter

For Stock Canon DSLR cameras

Owners of stock (non-modified) DSLRs will want to get a standard CLS (city light suppression) filter such as the Astronomik CLS clip-in filter without the unnecessary UV/IR cut filter. If you’re unfamiliar with what it means to modify a DSLR for astrophotography, have a look at this page where I cover this aspect of astrophotography cameras and more.

The Soul Nebula in Cassiopeia

With an apparent size of 150′ × 75′, the Soul Nebula is a fantastic deep sky astrophotography target for a DSLR camera and compact wide-field refractor telescope. It also rises above the roof of my house just as nightfall sets in, which is perfect timing in terms of maximizing my imaging time.

It’s a beautiful emission nebula with several embedded open star clusters. It emits a strong amount of light in the hydrogen-alpha wavelength, which makes adding images captured through a Ha filter beneficial.

star map of the Soul Nebula

Where to find the Soul Nebula

If you’ve been following my backyard activity via the email newsletter, you’ll know that I’ve been using another exquisite compact refractor. This time, it’s the William Optics Zenithstar 73 APO, and my resulting image should give you a good idea of what you can expect from this affordable doublet from an urban sky.

My Telescope

The William Optics Zenithstar 73 APO is a compact F/5.9 doublet apochromatic refractor with an impressive entourage of accessories to get you up and running. The Flat 73 1:1 field flattener is an essential upgrade if you plan on imaging with a full frame camera.

This telescope has a focal length of 430mm, which creates an extremely wide field of view. This means that it is well suited for large nebula targets like the Soul Nebula or Heart Nebula in Cassiopeia, but less effective on smaller targets such as galaxies.

The package I have includes a guide scope rings and a matching 50mm guide scope with gold accents. Using the M48 Canon adapter, I thread my Canon T3i to the Flat 73 for incredible wide-field exposures of my target of choice. Owners of DSLR cameras looking for an easy entry point into deep sky astrophotography should look no further than the Zenithstar 73 APO.

DSLR camera and telescope

The William Optics Zenithstar 73 APO is available at Ontario Telescope

It’s incredibly compact and manageable to use. If you’ve ever fought with balancing a large reflector telescope on a mount, you’ll really appreciate a compact telescope like the Z73. There is less stress on the mount, meaning can effortlessly track your target, even if the overall payload balance isn’t perfect.

One of my favorite features is a simple yet ingenious design touch. They’ve built a Bahtinov focus mask into the lens cap.

Focusing the image with the Z73

The diffraction spikes focus mask is a convenient feature you’ll find in all-new William Optics refractors. To focus with my DSLR, I simply find a bright star in the live view screen with the focus mask attached. Because the material is made from optical acrylic rather than metal, this mask provides 92% light transmission.

DSLR camera sensors are not as sensitive as most dedicated astronomy cameras. So the added light transmission from this mask really comes in handy when focusing your star using the rather dim 10X live view mode.  You’re presented with nice long diffraction spikes to really nail down your optimal focus position.

focus bahtinov mask

The built-in Star Diffraction Spikes Bahtinov Mask on the Z73

You’ll need a telescope mount that’s capable of handling a refractor telescope, but its small size means that beginner level astrophotography mounts such as the Orion Sirius EQ-G, Celestron AVX or Sky-Watcher HEQ5 will perform well with it.

My Telescope Mount

The Sky-Watcher HEQ5 SynScan pro has been called in for duty to capture guided 3-minute subs on the soul. It’s more than capable of accurately tracking this gorgeous nebula with the 5.5-lb Zenithstar 73 APO attached. I purchased this mount from a Canadian astronomy classified website several years ago, and it’s been working flawlessly ever since.

It allows me to set up quickly and easily Polar Align the mount within minutes. I still use the SynScan hand controller to star align the mount and slew to my target, although most prefer to advance to using the EQMOD software to control this mount from their PC.

tracking telescope mount

My Sky-Watcher HEQ5 SynScan Pro Telescope Mount

Speaking of Sky-Watcher, I am not done with the Esprit 100 ED just yet, not even close. With the departure of the iOptron CEM60 mount a few weeks ago, I had to find a solution to carry my heavier telescopes.

I am excited to announce the arrival of a brand new Sky-Watcher EQ6-R GoTo Mount as of this week. The built-in illuminated finder scope, SynScan hand controller, and snow-white finish will all feel very familiar – except there’s no rust on the counterweight!

I’ll have much more information to share about this soon.

Conclusion and Results

Mother nature doesn’t care what the calendar says, because Tuesday night’s imaging session was a nearly record-setting 31 degrees in Southern Ontario. Unfortunately, this increased the amount of noise in my images of the Soul Nebula (Sensor at 32°), but luckily my total integration time helped to improve the SNR.

Shooting with an uncooled DSLR is not ideal on hot nights like this – but nights like this are numbered, and soon I’ll be complaining about numb fingers, not camera noise.

The following image combines my latest data with images of the same target collected last year. All of the images were captured using a modified Canon EOS Rebel T3i camera and SkyTech CLS-CCD filter from the backyard.  The only difference in acquisition details between 2017 and 2018 was the use of a Meade 70mm Quadruplet Astrograph in 2017.

Narrowband Hydrogen-alpha data was added as a luminance layer to this image using the HaRGB method in Adobe Photoshop. This is a powerful way to boost the signal in an emission nebula captured under heavily light-polluted skies. For these images, an Astronomik 12nm ha clip-in ha filter was placed inside of the camera.

The Soul Nebula

IC 1348 – The Soul Nebula captured from Bortle Class 8 Skies with a DSLR Camera

The images captured this week on the Soul Nebula using the Z73 totaled 3 hours and 15 minutes (65 frames). As expected, the final still contained a fair amount of noise, even with the aid of dark frames and over 3 hours of exposure time. Doubling my integration time would certainly help.

The images were registered and stacked in DeepSkyStacker, with the final image processing done in Adobe Photoshop. The Astronomy Tools Action set contains many useful one-click actions that I regularly use on images like this taken from the backyard. (You can find a list of the software I use to process my images on the resources page)

Darker skies have a clear advantage when it comes to capturing deep sky astrophotography images. But with enough exposure time and the right image processing strategy, you can capture breathtaking images from your own backyard – no matter how light-polluted it may be.

Equipment Mentioned in this Post

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Astrophotography in the City

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Saturday Night Under the Stars

Astrophotography in the City

Last weekend I posted a new video to my YouTube channel titled DSLR Astrophotography – A Night in the Backyard with my Camera. It is now Early-April, and we are in what amateur astrophotographers call “Galaxy Season”, as we transition from the Winter Constellations like Orion and Taurus, to the Summer Milky Way objects.  In between, there are some fantastic deep-sky objects to observe in the Spring Constellations Leo, Coma Berenices, and Bootes.

The forecast called for clear skies on that crisp, cold Saturday night in Southern Ontario, and I was ready to image some deep-sky objects with my camera and telescope.  After a late dinner, it was a race against the clock to photograph my first subject of the evening, the Waxing Crescent Moon. If you want to jump straight to the video, you can find it at the bottom of this post.

Live-View DSLR Through a Telescope

Using the Canon 70D’s live view screen for telescope observing

Crescent Moon Astrophotography


I barely had time to get the beautiful Waxing Crescent moon into my telescope’s eyepiece before it became obscured by the surrounding trees in my neighborhood!  I shot a live-view video of the moon (with Earthshine visible) with my Canon EOS 70D DSLR through the telescope.  This may be of interest to anyone wondering what the view is like through an 80mm refractor telescope.  You need an adapter to attach the camera to the telescope, which you can buy online here.

After I focused the Moon and experimented with different ISO settings and exposure lengths, I snapped a couple of shots before moving on with the rest of my night.  You can have a look at the equipment I use for astrophotography here.


Earthshine Moon

The sky from my backyard

Next, I wanted to provide some examples of the dark-sky quality from my backyard.  Living in the central part of town has its advantages, but dark skies are not one of them!  I experience heavy light pollution from all directions.  This makes using a light-pollution filter on my camera necessary for long exposures.  Currently, I use the IDAS LPS clip-in filter on my Canon Rebel Xsi DSLR.  This allows me to capture exposures of up to 5 minutes from my backyard.


Astrophotography in the City

The night sky from my backyard on April 9, 2016


The Big Dipper Asterism

Looking towards the Big Dipper in Ursa Major

Deep-Sky Target: Edge-On Spiral Galaxy in Coma Berenices

NGC 4565 – The Needle Galaxy

Once the moon had set, I promptly prepared my deep-sky astrophotography rig for a night’s worth of photons on my photography subject.  I settled on NGC 4565 – The Needle Galaxy because of it’s size, magnitude, and current location in our night sky.  The Needle Galaxy is an edge-on spiral galaxy that resides about 30-50 million lights years from Earth.  This handsome galaxy is the current photo in my 2016 RASC Observer’s Calendar hanging in my office at work, perhaps that is what gave me the idea!

Astrophotography in the City - Needle Galaxy from my backyard

NGC 4565 – The Needle Galaxy

Photographed on: April 9/10, 2016

Total Exposure Time: 54 Minutes (18 x 3 Min. Subs @ ISO 1600)
Mount: Sky-Watcher HEQ-5 Pro
Camera: Canon 450D (modified)
Telescope: Explore Scientific ED80 Triplet Apo

Guided with PHD Guiding
Stacked in Deep Sky Stacker
Processed in Adobe Photoshop CC

This interesting NGC object shows up rather small in my 80mm telescope, as many galaxies do.  A larger telescope with a focal length of 1000mm or more would be a better choice for this DSO.  I also had a bit of a challenging evening out the background colour of this image.  Flat frames would have made this issue much easier to deal with in post-processing.  With just under an hour of exposure time, it is safe to say that I will need to add more time to this image to bring out the colour and detail.

AstroBackyard on Youtube

I am completely blown away with the response to my YouTube Channel has received.  Thank you to everyone who has subscribed, I look forward to many new astrophotography videos in the future!

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M33 Galaxy – The Triangulum Galaxy

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M33 Galaxy

M33 – The Triangulum Galaxy

The Triangulum Galaxy

The M33 Galaxy is the third-largest galaxy in the local-group of galaxies, behind the Milky Way and Andromeda.  Its large size from our vantage point makes my wide-field astrophotography 80mm telescope a great choice for imaging this target. Despite it’s size, the Triangulum Galaxy appears much dimmer than M31 – The Andromeda galaxy.  If you are new to astrophotography, chances are that the Triangulum Galaxy is one of the first few galaxy names you have learned.

M33 Galaxy Photo Details:

Telescope: Explore Scientific ED80 with WO Flat III 0.8x FR/FF
Mount: Skywatcher HEQ5 Pro Synscan
Guiding: Meade DSI Pro II and PHD Guiding
Guide Scope: Orion Mini 50mm
Camera: Canon EOS 450D (Modified)
ISO: 800
Total Exposure: 7 Hours (84 x 300 seconds)
Processing Software: Deep Sky Stacker, Photoshop CC
Support Files: 20 darks, 20 flats, 20 bias

Target Acquired – Messier 33

I have managed to image the M33 Galaxy from my backyard for multiple nights over the course of nearly a week. I can’t remember the last time we have had such a long stretch of clear night skies in the Niagara region. Mind you, these clear nights occurred during weekdays, and I have to be up early for work (and to walk the dog) early each morning. Needless to say, I haven’t been getting much sleep lately.  Luckily my astrophotography equipment can be set up and ready for imaging in about 30 minutes. This includes polar alignment, calibration, focus and guiding.  

M33 Galaxy - Astrophotography

My Telescope pointed at the M33 Galaxy

But first, the Elephant’s Trunk

My first imaging session was on the night of September 16th. Smack-dab in the middle of the work week. I didn’t originally intend to shoot the M33 galaxy that night, I started with IC 1396. The Elephant’s Trunk nebula is a concentration of interstellar gas and dust within IC 1396, located in the constellation Cepheus. You can view the results of this project below.

This area of the night sky is in a perfect spot for imaging at this time of year from my location, almost directly overhead. I captured 38 frames on this DSO on Wednesday night. The subs were 4 minutes each using ISO 800 on my aging modified Canon Xsi.

IC 1396 – Elephant’s Trunk Nebula

Elephant's Trunk Nebula

IC 1396 – Elephant’s Trunk Nebula – A tad noisy!

IC 1396 – Astrophotography Image Details

Telescope: Explore Scientific ED80 with WO Flat III 0.8x FR/FF
Mount: Skywatcher HEQ5 Pro Synscan
Guiding: Meade DSI Pro II and PHD Guiding
Guide Scope: Orion Mini 50mm
Camera: Canon EOS 450D (Modified)
ISO: 800
Total Exposure: 2 Hours, 24 Minutes (36 x 240 seconds)
Processing Software: Deep Sky Stacker, Photoshop CC
Support Files: 15 dark frames

The Elephant’s Trunk nebula can be seen in the top center-right of the photo above. It is a dark patch with a bright, sinuous rim. The rim is the surface of a dense cloud that is being illuminated and ionized by a very bright, massive star. Faint objects like this are difficult to image from light-polluted skies in the city. I found myself battling with horrible gradients and noise when processing this image. I will likely add more time to the Elephant’s Trunk Nebula during the weeks that surround the new moon in October. Another 4 hours should help me pull out more detail with less noise.

Canon 450D attached to my telescope

Canon Xsi 450D for astrophotography – attached to my telescope with the William Optics 0.8 FF

On to the M33 Galaxy…

After achieving a steady graph in PHD guiding, and a tight-focus on my reference star (Alderamin) I set BackyardEOS to take 50 frames, and I headed to bed.  I set my alarm for 2:00am, and managed to stumble back out to the patio to check on my results.  The Elephant’s trunk nebula was too far west, and my telescope would soon by aiming directly at my garage!  Because the sky was still crisp and clear, I figured I would add some time a second object for the night.  I imaged the M33 Galaxy back in 2012, but that was before I self-modded my 450D for astrophotography.  The Triangulum Galaxy contains some beautiful pink nebulosity within it that I knew I could now capture.

The following 2 nights of the week were also clear, and I took full advantage. This time, I shelved my plans for the Elephant’s trunk, and focused all of my efforts on Messier 33. I captured an impressive 49 subs the following night at 5 minutes each, and then I added another 17 light frames the night after that!

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M33 Galaxy

M33 – The Triangulum Galaxy

My total number of frames on this object was now over 100! That’s a lot of imaging in one week. All that was left now was to stack and process all of the data acquired. I set Deep sky stacker to use “the best 90% of frames” to register and stack, which resulted in a final stack of 84 images total, or exactly 7 hours. I even had success with my creation of flat and bias frames. I shot the bias frames through the telescope with the lens cap on, at the fastest shutter speed my camera allows (1/4000 of a second). The flat frames were created by shooting through the telescope, pointed at the early morning blue sky. These were shot with the camera in Av mode. I shot separate bias and flat frames for each night, except the first. Only dark frames were used for that imaging session.

Processing a photo with 7 hours worth of data is quite enjoyable.  There is less noise, and more detail than I am used to.  As with all of my astrophotography images, I am sure I will re-process my photo of Messier 33 several times until I feel like I have done the galaxy justice. Everyone has their own taste, and at the end of the day, you have to be happy with it.

BackyardEOS 3.1

I finally purchased a copy of BackyardEOS 3.1 Classic Edition. My trial period has ended, and I am very happy with the software. The focus and framing tab, dithering control, and file organization features are my favourite, and make me wish I had upgraded to this software a lot sooner. I always had a hard time getting accurate focus using the live-view function of my DSLR. The focusing function built-in to BackyardEOS allow you to view a digital readout of the star size in real-time as you focus your telescope. The lower number you see on-screen, the better your focus! The filename for each sub lists the ISO, object name, exposure time, date and even the temperature! This is extremely handy when stacking a large number of frames from multiple nights.


Screenshot of the BackyardEOS 3.1 Software

I would love to hear what you think of my results for this galaxy image.  You can also follow me on twitter to see more of the “behind-the-scenes” stuff from the backyard. As always, if you have any questions about the equipment I used, or my processing techniques, please leave a comment below.  Thank you so much for visiting my website.

Backyard Astrophotography

Another night under the stars in the backyard

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Sadr Star – Intersection of the Northern Cross

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Photographing the Sadr Star in Cygnus

If you follow me on Twitter, you may have noticed that I was poking around in the middle of the constellation Cygnus last weekend, specifically centered on to the extremely bright Sadr star. I really wanted to post a really snazzy wide field photo of this region on this blog, but I was unhappy with my results.

I set my mount and telescope up for imaging in the South, at the far edge of my backyard. This spot was a poor location for shooting straight up overhead at the constellation Cygnus for me, as I ran into trees by 1:30 am. The result, only 1 hour of total exposure on a hot night. Even the stacked final image including 15 dark frames was noisy after stretching! 

I was already sad about the trees, but after seeing my noisy photo, I was Sadr. (anyone?) Clearly, I need more time on it.

The night was not a complete waste. Aside from the mosquito bites and the ever constant worry from my neighbors “what is he doing out there!?”, I was able to snap this neat little photo of the Summer Triangle. The stars that make up this giant asterism are Altair, Vega, and Deneb. For this shot, I used my Canon 70D and 17-40mm lens, riding on the Sky-Watcher mount.  15 – 40-second shots were stacked together for the final image.

The Summer Triangle

The Summer Triangle


Tonight’s the Night – Gamma Cygni

Location of the Sadr Star

With the almost first-quarter moon setting tonight around midnight, and clear, cool skies in the forecast for the Niagara region, it looks like I am set for round 2 tonight. Tomorrow night looks clear as well, will this be the weekend of the Sadr Star? That might be the nerdiest thing I have ever said.  That’s not true.

Tonight, I will position the mount for an all-night-long session in Cygnus. My plan is to frame Gamma Cygni directly in the center. From the other images of this area, it looks like I should pick up a lot of nebulosity throughout the frame.

My 30-day trial of Backyard EOS is still in effect, so I am happy to use it’s handy imaging features for another free night before shelling out the $50 US for the full version. A fair price for this impressive software. See the star map to the left for an idea of where I will be shooting tonight. If all goes well, my next post will be a portrait of the intersection of the Northern Cross.


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Astrophotography from a Light Polluted Backyard

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Backyard Astrophotography

Summer would not be complete without spending a night enjoying the dazzling beauty that is the constellation Sagittarius. The “teapot” asterism just clears my fence to the south of my backyard in central St. Catharines. From my latitude, August is my last chance to image the many star clusters and nebulae that populate this area.

Last night, I set out to gather as much light on the Lagoon Nebula and the Trifid Nebula as possible before they dipped below the trees. With the nights being so short at this time of year, it is important to have your astrophotography equipment setup process down-pat.

As soon as Polaris is faintly visible in the North, I begin my calibration and alignment process on my trusty Sky-Watcher HEQ5 mount.

The summer triangle in the night sky

In the photo above, you can see the Summer Triangle asterism as seen from my backyard. This photo was processed extensively to reduce the light pollution present from my city backyard. When shooting through the glow of a bright city, it if often best to shoot your deep sky targets when they are directly overhead to avoid the light dome. 

The Light Pollution Effect

I should mention, that the third-quarter moon rose at midnight last night. (I ended my imaging session at 11:30pm) Enhanced detail and better contrast would be easier to pull out of this image if my imaging session took place closer to the new moon.

Light pollution is also a major factor where I live. My backyard lies within the border of a red/white zone for light pollution (Bortle Class 8). Surprisingly enough, however, I can still just barely pick out the Milky Way with my naked eye.

To compensate for this unfortunate reality, I use an IDAS Light Pollution Filter to help block out the unwanted light from the street lights and porch lights that surround me.

Wide Field Deep-Sky Image

The Trifid and Lagoon Nebula in the constellation Sagittarius

With my brief window of opportunity, I was able to take (14) 210 second exposures at ISO 800 with my modified Canon Rebel Xsi. Once stacked, the total exposure length equaled a whopping 49 minutes!

Despite the challenges mentioned above, I think I was able to produce an acceptable image of this summertime deep-sky treat. My 80mm telescope offers the perfect opportunity to capture both nebulae in the same field of view.  This will likely be the last photo taken in this rich and starry area of the Milky Way until next year, when it rises again in the Spring.

M8 and M20 Wide Field Image

M8 and M20 in Sagittarius

Telescope: Explore Scientific ED80 with WO Flat III 0.8x FR/FF
Mount: Sky-Watcher HEQ5 Pro Synscan
Guiding: Meade DSI Pro II and PHD Guiding
Guide Scope: Orion Mini 50mm
Camera: Canon EOS 450D (Modified)
ISO: 800
Total Exposure: 49 minutes (14 x 210 seconds)
Image Processing Software: DeepSkyStacker, Adobe Photoshop CC
Support Files: 9 dark frames

Backyard astrophotography setup

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