Astrophotography allows us to capture the mesmerizing beauty of the night sky, but achieving sharp focus in low light conditions can be a challenge. Precise focus is crucial for capturing breathtaking images of celestial objects. In this article, we will explore some essential tips and techniques to help you achieve sharp focus in nighttime astrophotography.

Use Manual Focus

Switching to manual focus mode is crucial for astrophotography. Auto-focus systems struggle in low light conditions, often resulting in blurry images. Take control and adjust the focus manually using the focus ring on your lens. Find a bright star and use the magnification feature on your camera’s Live View to carefully fine-tune the focus until the star appears as a pinpoint of light.

Utilize Manual Focus Assist Tools

Some cameras offer manual focus assist tools. Features like focus peaking or digital zoom can significantly aid in achieving precise focus. Enable these tools in your camera’s settings and utilize them to ensure accurate focusing on the stars.

Utilize Infinity Focus

In astrophotography, many subjects are at an infinite distance from the camera. To ensure sharp focus, set your lens to infinity focus. Most lenses have an infinity symbol (∞) on the focus ring. Align this symbol with the marker or use trial and error to find the precise point of infinity focus. A piece of tape can help secure the focus ring in place.

Utilize Hyperfocal Distance

When shooting astrophotography (or landscapes and cityscapes) at night, utilizing the hyperfocal distance technique can be advantageous. By setting your lens to the hyperfocal distance, you can achieve maximum depth of field, ensuring sharp focus from the foreground to the background. Use a hyperfocal distance calculator or smartphone app to determine the ideal settings for your lens and aperture.

Take Test Shots

To confirm that you have achieved sharp focus, take test shots of the night sky and review them on your camera’s LCD screen. Zoom in to inspect the stars for sharpness and adjust the focus if necessary. It may take a few attempts to achieve the desired focus, so be patient and persistent.

Use a Bahtinov Mask

A Bahtinov mask is a helpful tool for achieving precise focus in astrophotography. It consists of a patterned mask placed over the front of the lens. When properly focused, the mask produces a distinct pattern of diffraction spikes around bright stars. Adjust the focus until the spikes are symmetrical and centered, indicating optimal focus.

Conclusion

Achieving sharp focus in nighttime astrophotography is essential for capturing stunning images of the night sky. By utilizing manual focus, infinity focus, test shots, manual focus assist tools and Bahtinov masks you can significantly improve the sharpness and clarity of your astrophotography. Experiment with different techniques, practice regularly, and be patient in your quest to master the art of focusing at night. With dedication and persistence, you’ll be able to capture breathtaking images of the cosmos that will leave viewers in awe! Here are some of my personal favorite photographs of the night sky if you want to have a look!

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Have you ever wanted to remove the stars in your astrophotography photos? Perhaps you want to focus on the details of your deep-sky object, or maybe you want to process the stars and the object separately to achieve a punchy image without blowing out the stars. Whatever your reason, there is a simple and free software called StarNet (formerly known as StarNet++) that can help you. In this tutorial, I’ll show you how to use StarNet to remove stars from your photos.

StarNet is a neural network-based software that removes stars from images in a single step. It works by analyzing your image and determining which pixels are stars and which are the background or the object. The star pixels are then replaced with an interpolation of the surrounding pixels, resulting in a starless image.

Download StarNet++

First download StarNet from its official website. The command line tool is available for Windows, Linux and Mac OS. The Mac OS version is relatively new and still experimental so you might find some bugs. The graphical user interface version is available only for Windows. Choose the one that matches your operating system and download it.

Extract StarNet++

Once you have downloaded StarNet, you will need to extract it. You will get a folder called StarNetv2CLI_Win. Inside this folder, you will find the starnet++.exe application file if you have downloaded the command line tool or starnetGUI.exe if you have downloaded the graphical user interface version.

Run StarNet++

All you need to do now is place your astrophotography image in the same folder where StarNet is stored. The image must be in .TIF format. Then, drag and drop your image file onto the appropriate application icon if you have downloaded the command line tool or use the browse button of the graphical user interface button to load your image. A black window will appear and StarNet will begin removing stars from your image.

Check Your Results

When StarNet finishes processing your image, it will create a new file with -Starless appended to its name. For example, if your original image was called DSF4902.tif, then your starless image will be called DSF4902-Starless.tif. You can open this file with any image viewer or editor and check your results.

You should see that all the stars have been removed from your image, leaving only the background. Depending on your image, you may see some artifacts in the starless image, but you can fix them later with some post-processing.

Process Your Images

Now that you have removed the stars from your image, you can process it as you wish. Open both images in Photoshop with the starless image at the top. Next change its blend mode to Difference and press Ctrl + Alt + Shift + e to create a stamp of the visible layers. This will create a layer which contains only the stars.

Next, you can enhance the details of your starless image, adjust the colors and contrast, reduce noise and artifacts, etc. You can also process your stars only image separately if you want to add some saturation and vibrance or adjust the temperature for example.

Add the Stars Back

If you want to add your stars back to your final image, make sure the stars only image is at the top and change its blend mode from Normal to Screen. You can also adjust its opacity if you want to make the stars less prominent. You can even apply a star reduction technique.

Final Words

And that’s it! You have successfully removed and added back the stars to your astrophotography image using StarNet++. This technique works great for wide angle astrophotography images like landscape images with the Milky Way! I hope you found this blog post helpful and informative. If you have any questions or comments, feel free to leave them in the comments below.

And if you are interested, here is a collection of my favorite Milky Way photos!

Clear Skies!

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Most astrophotographers undoubtedly enjoy capturing the center of our Milky Way galaxy. Since the core season of the Milky Way begins in March, I thought I’d provide some tips and tricks to help you improve your milky way photography. So, let’s get started!

1. Find dark skies

The first step in capturing an excellent photo of the Milky Way is to seek for the darkest sky possible. Without a dark sky, no matter what gear you have, filters you employ, or post processing you do, you won’t get very far. As a result, utilise a website like https://www.lightpollutionmap.info/ to discover a local spot that isn’t excessively light polluted. But don’t forget to think about which way you’ll be facing. Make sure there are no towns or cities towards where you’re photographing.

2. Scout in the daytime

Trying to come up with an interesting composition late at night is not only difficult, but also dangerous. Make use of the daylight to scout the area for an unique subject or composition. Also, keep an eye out for potential hazards such as a hole in the ground or a cliff edge. This way, you’ll be prepared for the night, knowing exactly what your composition will be and what to avoid. During the day, take a couple photographs with your camera or even your smartphone to ensure that your composition works.

3. Plan your shot

Nowadays you can even plan your shot even before getting at the location. Search Google for photographs of the location and use Google Maps Street View to take a look around. You can also use an app like Photo Pills to see where the Milky Way is, when the Milky Way Core is visible, and other information.

4. Use a fast lens

A fast lens is required to catch as many details of the Milky Way as possible. At the very least, I recommend f2.8, but if you can find a lens that opens up to f1.8 or f1.4, that’ll be much better. The more light you gather, the less noise there will be in the photograph, the brighter the milky way will be, and the more detail there will be. A wider aperture allows you to use a lower ISO, resulting in less noise.

5. Use a star tracker

The rotation of the earth limits the exposure time. This means that, in order to eliminate star trails, there is an upper limit on your exposure time based on your lens and camera. Because it moves with the earth, a star tracker allows you to get around this restriction. As a result, while your stars are round and pinpoint, you can easily acquire 1 or 2 minute exposures. You can also keep your ISO low, resulting in a lower-noise image. You’ll eventually get more information, the milky way will be brighter, and the image quality will be so much better!

6. Stack your photos

No matter whether you have a star tracker or not you can use a technique called photo stacking in order to get rid of the noise in your astrophotos. You take multiple photos of the same scene without moving your camera which you later blend together using a software. Because noise is distributed randomly throughout the image, these software average pixels and remove noise as a result. I like using Sequator which is a free software for Windows. If you are a Mac user, try Starry Landscape Stacker. However, it is not free. Experiment to find out how many photos you will need to stack in order to create a great final image.

I hope you find those tips and tricks useful! You can also check my How to photograph the milky way for beginners tutorial and my How to stack Milky Way photos using Sequator!

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Milky way photos are really impressive for sure. However capturing photos of the night sky pushes the sensors of modern DSLRs and mirrorless cameras to their limits. If you want more details I have also written a tutorial on how to photograph the milky way. In a few words photographing a brilliant milky way photo with beautiful colors and pinpoint stars requires a shutter speed of a few seconds, depending on your camera and lens, which means you will have to use a high ISO. Usually something like 1600 or 3200. And this introduces noise in your image. One way to get a noise free image is to use a star tracker. This equipment will allow you to shoot longer exposures with low ISO keeping noise low as well. For those of us who do not own a start tracker though there is Sequator. Sequator is only available for Windows. If you are using Mac OS you can try one of the alternatives such as Starry Landscape Stacker.

When I want to stack Milky Way photos I usually capture a dozen of photos with my camera. Once you have your photos ready you can import them into Sequator. It supports both RAW and jpeg/tiff files. Keep in mind that Sequator doesn’t support the Prophoto RGB format. The colors of your photo will look strange if it is in this format. I usually export my photos from Lightroom in TIFF format, Adobe RGB as Color Space and 16bits as Bit Depth.

This is the user interface of the software.

So click on the Star Images and load your images. Sequator will automatically choose one of them as the base image. This is the image that Sequator will use to stack the photos onto. Sequator will automatically chooses the middle image for you. You can change it to the one you prefer by clicking on the “Base image”.

In this tutorial I will use 5 photos taken with my Fujifilm X-T20, the Samyang 12mm at f/2.8, ISO 1600, 15 seconds.

Afterwards you might add noise images which are also known as dark frames. You create those images by taking photos just after you have finished taking your star photos, but with the lens cap on. These images are used to remove the noise produced by the sensor heat from your final image. 5 to 10 images are enough, although I don’t usually get into this process.

Now double click on Output and navigate to where you want to save your star trails final image. A 16 bit tiff file will be produced at the end which includes enough color information to further process it if you wish. Processing Milky Way photos is a tutorial on its own though!

In composition we will choose Align Stars in order Sequator to align our images based on the stars. At this points you must also check the Freeze ground checkbox along with selective. This way both sky and ground will be stacked and as a result you will get a sharp and overall clean image.

Next you have to define the sky part of your photos. Click on the “Sky Region”. Usually I choose the irregular mask and I paint on the sky. To remove an area you painted just use the right mouse button. Using the scroll wheel you can increase and decrease the brush size.

• Auto brightness will adjust the brightness levels in your image in case you have accumulated a too long exposure. I usually turn it off.
• High dynamic range isn’t something I use. Usually it is better to leave it off.
• Remove dynamic noises will try to remove hot pixels. If you have used Noise images you can leave this off.
• Reduce light pollution tries to reduce the effects of city lights. You can play with it and see if it improves your image if you have such a case. Usually I leave it off.
• Reduce distortion effects will help in case your star images have significant displacement because of the lens or projection distortion.
• Enhance starlight will increase the brightness of your stars. I prefer doing this myself in post.
• Merge pixels tries to create a cleaner image but since it reduces the image size I also leave it off.
• Color space lets you choose between sRGB, RGB and Linear. Just leave it to sRGB since this is the most common color space used all over the internet.

Once you are ready click on Start. Sequator will start processing your images and after a while, depending on the number of your images and your computer’s cpu, it will show you the final result!

Here you can see how much cleaner and noise free the final image is by using just 5 photos. Stacking images can take your astrophotography to the next level!

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I always found fascinating the milky way and the night sky since I was a little kid. When I got my first DSLR camera I started experimenting with astrophotography by photographing the milky way and star trails. In this tutorial I will share with you some information to help beginners get started and photograph the milky way.

Basic gear

A camera with manual exposure control of aperture, shutter speed and ISO. And manual focus as well. Of course a full frame camera would be better since it handles better noise in high ISO. But an APSC sensor will also do the job. It doesn’t really matter whether it is a DSLR or a mirrorless camera.

A wide angle and fast lens. A wide lens means you can get a bigger part of the milky way in your frame as well as part of the foreground to achieve a good composition. Something like 14mm for full frame or 10mm for APSC will be ok. Also a fast lens will allow you to capture more light and keep ISO lower in order to avoid noise. Something like f/1.4 and f/2.8 would be ideal.

A sturdy tripod. Since you will have to take exposures of many seconds you have to be sure that your camera will stay still. Even the slightest movement will ruin your photo.

Good to have gear

A headlamp with white and red light so that you can find your way in the dark and not ruin your night vision. Moreover you can use it to light paint the scene!

A remote release cable to avoid camera shake and take consequent shots. Use this to trigger your shutter. Alternatively you can always set a timer of 2 seconds so that the camera will stabilize before taking the shot.

Dark skies, light pollution and the moon

First of all in order to photograph the milky way you must find dark sky. This means getting away from big cities to avoid light pollution. A light pollution map will help to find such a location. Of course there are such applications for Android and iOS as well. Moreover since you need the darkest sky possible you should schedule your photo shooting around new moon.

Focusing at night

Probably the biggest problem when I first started taking pictures of the milky way was focusing. There are a couple of different ways to focus correctly at night. First set your aperture to the widest possible (or the one you have chosen to shoot with).

If there is a light source far away you can use this to auto focus on it and afterwards change your lens to manual focus and keep it like this the whole night. Press your shutter up to half so that your camera auto focuses and without leaving it change your lens to manual focus. There should be a button for this on it. Now you can leave the shutter button and your lens will keep this focus. Just remember to change it back to auto focus when you finish.

If your lens has a focusing distance ring you can usually set it to infinity and afterwards take it back a little to have everything in focus. Another way is to find a bright star in the sky and use this to manually focus using your live view screen.

Alternatively if you have a mirrorless camera that shows you the focus distance you can use this to manually focus to infinity. Of course if you have a foreground element pretty close to you you might need to focus stack in order to have everything in focus.

No matter which method you choose I suggest to switch to live view mode and zoom in on your screen. Check your stars so that they are as sharp as possible by playing with the focus ring of your lens.

Camera Settings

First set your lens to its widest possible apperture, let’s say f/2, or 1 stop up, f/2.8, since it will usually be a little sharper there. Remember you have to get as much light as possible.

Next switch your camera to manual mode and set ISO to the highest one in which you get reasonable noise. For APSC sensors this would be something like 1600 or 3200. For full frame cameras you can go with 3200 or 6400 for start.

Next you will have to find the shutter speed. Since earth and the stars are constantly moving if you set your shutter speed too high you will end up with star trails and a blurry milky way. You can follow the 500 rule. To determine the optimal exposure time, take 500 and divide it by the effective focal length of the lens

exposure time = 500/(crop-factor × focal length)

A full frame camera has a crop factor of 1 while an APSC camera has a crop factor of 1.5. For example if you are shooting with a 20mm lens on a full frame camera, you divide 500 by 20, which yields 25 seconds. That’s the longest shutter speed you should use before star trails start to appear. But since this rule seems fails to work correctly with modern cameras you might have to make your shutter speed even shorter. I advise to use this star trails calculator which uses the NPF rule which is most suitable for modern cameras. You can always test and see what satisfies you.

Finally you have to shoot RAW in order to post process your photographs and get the most details and color out of them. This way you can also change the white balance afterwards to something that looks pleasing to you. I leave my white balance to auto always and I change it at post.

Composition

Shooting the milky way on its own can look great at the beginning at least. However it’s always a good idea to find a wonderful location to incorporate with the milky way. A strong foreground element always helps. Try to tell a story with your photo.

Extra tip

I use a mobile application called Photo Pills to help me with my milky way shots. It can show you the position of the milky way, how much visible will it be, when it’s galactic center will appear and also calculate the shutter speed to avoid moving stars. It’s available for both Android and iOS.

And some last words. Go out and shoot! Experiment and learn your gear! You don’t need the latest and most expensive camera and lens to start.

Feel free to ask any questions or share your milky way shots with me! And clear skies!

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I have always been intrigued by the night sky. A thing that I loved while spending my summers away from the city was that I could see the stars and the milky way. Till now, whenever I have the opportunity, I enjoy going out at night to view the milky way. By bringing my camera together I can also photograph the stars and see the milky way in a way I couldn’t image. Here I am at a little village in Chalkidiki, called Loutra Agias Paraskevis. The milky way and its galactic core shine above Pelion.

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Although a thunderstorm ruined my initial plan to photograph the Perseids meteor shower I didn’t give up. I packed up my things but didn’t return home. Instead I headed towards the opposite direction where the sky was clear in order to try and photograph the Perseids. I managed to get one more shooting star along with the milky way core in one of my favorite locations in Chalkidiki. I was planning to shoot the milky way here for a long time now but there is a bar there whose lights never allowed me to do so. Well this summer was a bit different. All the night bars were closing early so I finally got the shot I wanted with a shooting star as a bonus! Oh, the two bright stars are Jupiter and Saturn heading towards their great conjunction. The 2020 ‘Great Conjunction’ of Saturn and Jupiter is the closest these planets will appear in the sky since 1623!

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Sithonia is becoming my favourite summer destination in Chalkidiki, Greece. Find an amazing view, leave your camera shooting and relax watching the stars in the night sky. And in the next morning choose one of the many amazing beaches to go for a swim! For this photo I shot around 100 images and combined them with a blue hour photo.

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This shipwreck is located in Epanomi next to Thessaloniki, Greece. It sank around 1970 and it has been there ever since. The shipwreck is very close to the beach and you can even swim close to it and do some snorkeling. This summer night was perfect for shooting the milky way and the stars. Oh, and there were no mosquitoes!

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This old fisherman’s boat is somewhere in Kalochori, next to Thessaloniki, Greece. Our plan was to spend some hours under the summer night sky shooting star trails and the milky way. However we were “attacked” by hundreds if not thousands of mosquitoes! Instead we spent the time in our car letting our cameras do the shooting.

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