Siril Download for Astrophotography – Instant Improvement

This Siril download is a must because successful astrophotography depends on astro software. on this page, I’ll explain why you should use this software for stacking and processing your astronomical images, together with other software such as Gimp, Nina, or Astrophotography Tool.

Downloading the latest version of Siril will help you with so many tasks that you’ll need to complete in order to produce a great astrophoto. This is one of my favourite programs, and in this post, I’ll explain why. I’m going to go into detail about what it can do and why you should get this free tool for astrophotography.

I have been using Siril for more than two years, and it is my go-to program, especially for image stacking and some astrophotography processing. I need to do this after collecting my valuable images. Please note that most of what follows is based on my personal experience, with the input of some others too. Don’t expect this information to be very technical, because I aim to guide you to try it for yourself and give this software a try.

I hope that my advice and experience can help you if you are looking for a reliable, quality stacking and processing program to make the most of the image data you have captured.

Now, enough, let’s get started!

Why do I need this program?

The list of things you can use Siril for includes:

• Image stacking
• Pre process image tasks (calibrating with biases, darks and flats)
• Post-processing tasks
• Noise reduction
• Colour calibration
• Background extraction (detailed information on how to use this can be found here)
• Colour channel separation

And much more!

Siril is constantly being updated and improved, and the latest version has many new features inside it. I haven’t yet been able to try all of them, but there are many tutorials you can follow on YouTube, including these I recommend:

Comparison to other astrophotography software

I have used most of the astrophotography software out there, both free and paid. I’d like to explain why I ended up choosing Siril and staying with this excellent software program.

So, how does it compare to other software I’ve tried?

Some of the apps I’ve used for astrophotography include:

• Deep Sky Stacker
• Sequator
• Astro Pixel Processor
• Startools
• Photoshop
• Gimp

This list is much shorter than the actual list of software I’ve tried in my years as an astrophotographer, but it should serve to show why I believe that Siril is a great choice and perhaps the best available tool for stacking image sequences and post-processing astrophotos.

I’ve carried out many tests myself and found Siril to produce very good and repeatable results. I tested it out against Sequator, which I used as my default stacking program for some time. I found that the results were much better than Sequator when stacking exactly the same data and then processing it in Photoshop.

This is why, about 2 years ago, I switched from Sequator, which I have found is better for stacking and aligning Milky Way panoramas and other types of landscape astrophotos. This is because Sequator can treat the foreground, background, and sky portions of images separately and freeze the part of the image that doesn’t move (the landscape). Sequator cannot really process your images.

Image-Stacking Software

Astrophotography involves an important process called image stacking. If you don’t know what this is let me quickly explain.

I have taken many photographs of distant and very faint deep sky objects. When I look at one frame its hard to see any details at all, just a faint blur is usually all you can see. So how to go from this to a great astro image?

The process we use to take incredible pictures of distant objects in space is called stacking. By taking many photos of the same object and stacking them together the image becomes more detailed and less noisy. The more images you take, the better.

The noise in astrophotography images can really spoil the picture and hides details and colour. Stacking is important because it reduces the noise by a factor equal to the square root of the number of images taken. So, take 4 images and you halve the noise, take 9 images and you’re left with a third of the original amount of noise. That’s a reduction of 66%

Noise reduction is not the only important benefit of stacking many astrophotography images. You also boost the signal you want from your target so SNR (Signal to Noise Ratio) increases drammatically. The result is a higher quality image.

I also discovered another source of noise that was ruining my images. I found out that using a technique called dithering removes this “walking” noise. This technique enables your stacking software to average out this noise. Now my images are much better.

Also, stacking creates an average overall image and removes things present in individual frames like plane or satellite trails that often appear in several of my images through the night. With Skynet satellites making this problem worse, we can really benefit from stacking software which automatically removes these artifacts but adds more valuable signal to the stack.

There is a rule in astrophotography that the more exposure time, the more detailed and less noisy our images will be. The best way to increase overall exposure time is to take multiple images of shorter exposure time and stack them rather than taking one long exposure. This is much more practical than taking one shot for hours.

Nowadays I try to get 10-15 hours of total exposure time and I find it best to break that into 5 or 6 minute subs. When targets have very bright cores, or if it is windy, I tend to lower the exposure time and stack more frames.

Software is required to align and stack together many photos that we take of an astronomy target such as a nebula or a galaxy. Often, calibration frames, for example, dark frames, are added to the program, which uses them to extract some of the noise from the images and produce a cleaner-looking stack. You can stack without calibration frames by selecting only your light images or light frames to be stacked and ignoring the calibration tab in the program.

So, to summarize image stacking software is extremely important if you want top quality astrophotography images.

What is the Best Image Stacking Software?

The answer I give will only be my opinion, but I have tried most of the popular programs out there, especially the free ones. Of course, there are expensive options such as Pixinsight and so on, but why pay when there is good free software available?

I would say these are some of the best programs I’ve tried for stacking astrophotography:

• Deep Sky Stacker – very popular and does the job with some processing capability. Can also stack groups of images from separate nights. I find it a bit clunky and confusing to get the hang of.
• Sequator – I used this very early on when I first started astrophotography and liked the simplicity of the software. Very easy to use. Good results I thought until I did a direct comparison with Siril. I decided to use Sequator for widefield and Milky Way shots, perhaps comets too. I believe that there are better programs for deep sky objects. It’s a good program which allows you to align the stars in your images and freeze the background. very handy!
• Siril has been my first choice and I believe it is the best stacking software I have found. It is also free! It has powerful post processing components as well as the stacking. You must try it!

Deep Sky Stacker is very popular and is used by so many astrophotographers for image stacking. I tried it for a while but found more difficult to use than other software. I had problems with DSS’ registration method, and several times my raw images didn’t stack properly because of an insufficient number of detectable stars. Perhaps this had more to do with my lack of experience then and the fact that I had more stars trailing then than now.

As I have become more experienced and now use better equipment, I have improved the quality of my images and stars. However, this caused me to move away from Deep Sky Stacker. Maybe you’ll have more luck with DSS than I did!

Post-processing tools

Siril has many image-processing tools, and they work well. I’ve found, for example, that doing background extraction to remove the light pollution gradient in my image before going to Photoshop is better than trying to remove the gradient in Photoshop. This is what I used to do, and I found it took longer, and the result was worse than the quick and easy-to-use background extraction tool in this program.

You may be tempted to go for tools like Startools (free trial), Astro Pixel Processor (30-day free trial), or Gimp (free open source). I’ve tried all of these, and for me, the Astro Pixel Processor was good but used a lot of resources on my computer. I suffered many crashes! The same was true for the Startools software. I did only have 4 GB of RAM on my laptop, and then I decided to upgrade it to 16 GB, which removed these problems completely.

Startools works for many, but I just couldn’t get it to do what I wanted and found it difficult to use. Again, I tried this in my early days to discover how to do image processing, so the program may be better if you have some experience. This is my opinion based on my own experience. Please note that Startools is not a stacking program but focuses on image processing.

Even so, Siril was always easy to use and did not crash even the first time I tried it. I do suggest, though, that if you are going to use your laptop for astrophotography, you should consider upgrading or buying a more powerful computer with at least 16 GB of RAM. Certainly, upgrading my laptop to an SSD drive and from 4 to 16GB of RAM made a huge improvement in running time, especially when stacking many images, and made the use of Photoshop for image processing possible.

Features

There are so many different features of this free software in addition to image stacking that we cannot talk about them all here. I include the following in my current workflow:

1. Auto Stretch. You can stretch your image with one click to view it without making any changes to it unless you press apply. I do not stretch here; I leave that until I work in Photoshop. The choice is yours, though.
2. Photometric colour calibration. I love this feature because all you need to do is enter the details of your astronomical target (the best is to use its Messier number or NGC number). In many cases, with the more commonly known targets such as Orion’s Nebula or the Crab Nebula, you can type in the name and it will find the object in its database. It is then just a matter of clicking apply and the photometric colour calibration sets the correct colours for you in seconds.
3. Background Extraction. This is part automatic and part manual. It’s also very quick and easy. I’ve found this is better than manually removing the gradient in Photoshop or even using paid plugins like Gradient Xterminator or other similar tools. I always use this tool prior to my final processing in Photoshop.
4. Remove the green noise. This is an excellent one-click function that takes out a bit more noise. It works in the green channel. It does help a little. I leave my noise reduction until my processing steps in Photoshop. However, I have only looked very quickly at the different noise-reduction tools that Siril has on offer. Perhaps I will return to using these again another time. Furthermore, as always in this game, try things out and experiment for yourself. We all have different preferences, different equipment, and different circumstances under which we image and process.
5. I then save my image in .tiff file format and go to Photoshop to do the final processing to get my images to the stage that I want them to be at. This is the truly fun and creative part!

OK, so this is what I have discovered from using this software. I hope that this has helped you decide what you need to do and whether this program might be the best choice for you.

Latest update: The download file has been updated a number of times, and the latest version has added new processing tools, which are very good and easy to use. I have only tried a few of them, so I cannot claim to be an expert. I will experiment with these and make further updates here when I have tried all of them.

How to Download

This is quite straightforward. Go to this page and follow the instructions:

Download Siril Here¹ 

Compatibility with different operating systems

As with all software, you need to be sure that your computer has the processing power to handle the program and that your operating system is compatible with it.

The software is compatible with:

• Linux
• Windows
• Mac

Visit the website² for more information, such as FAQs, Tutorials, and more.

How to Use Siril for Astrophotography

Rather than go through each step here, I encourage you to check out the tutorials at Siril.org, on Youtube, and so on. There is a lot of information out there. Here is a start for you with some of the videos that helped me out when I first started using this program:

Siril a Free Alternative to Pixinsight by Cuiv the Lazy Geek (2021, a bit old but still good!)

Tutorials ³: various tutorials that cover most of the things you will need.

From Raw to Finished: A Siril v1.0.6 Tutorial for Beginner Astrophotographers by Deep Space Astro⁴ (Early 2023)

My Videos

I’ve published a number of videos showing how I use this software, so take a look at these:

In the above video I show how much difference stacking multiple images makes to your astrophotography and how I use Siril in my workflow.

Here is a five-minute tutorial from my Astroimagery Youtube Channel:

That should get you started and well on your way to mastering this nifty little program!

Other notable tutorials are by AstroBackyard (updated in 2021), Dylan O’Donnell, and others. I included these two because I have watched their videos since starting this hobby. Dylan is particularly hilarious, whereas Trevor Jones of Astrobackyard is knowledgeable and well-respected but a bit serious. Well, this is science!

Tips for getting the best results

Here are some lesser-known tips for those who are a bit more advanced and for those who want to go much deeper into this wonderful astro software.

• Use scripts to automate your processing steps there are several scripts that can help you process your images quickly and easily. You can also create your own scripts or modify the existing ones to suit your needs.
• Use the astrometry tool to identify objects in your image and get more information about them. Siril can interact with online astrometry services to plate-solve your image and display the coordinates, orientation, and field of view of your image. You can also use this tool to align your images with a reference image or catalogue.
• There is a deconvolution tool that you can try out. It will sharpen up your image and bring out the details if you do it right. Different algorithms can be applied, such as Richardson-Lucy, Van Cittert, or Maximum Entropy. Play around with it to see what you can do with it.
• You can apply different histogram stretches to change your image in subtle ways. You can also use this tool to balance colours or apply a colour mask. This is truly limitless!

I hope I’ve encouraged you to try this software for yourself. Go see what you can do with it, and I hope it takes your astrophotography to the next level. I know how much it has improved mine!

All of the stacking software mentioned allows you to remove noise in your images and improve the SNR.

References

1. Siril, 2024. Downloads. [online] Available at: https://siril.org/download/.

2. Siril, 2024. Available at: https://siril.org.

3. Siril, 2024. Tutorials. [online] Available at: https://siril.org/tutorials.

4. Siril, 2024. No title. [online] Available at: https://www.youtube.com/watch?v=HYVKuS7jenU.