First visit to this astronomy/astrophotography blog? Well, firstly a warm welcome to you and thanks for stopping by. After reading this post, if you want to find out more about me and this blog, why not visit my introductory page at https://undersouthwestskies.blogspot.com/2025/01/welcome-to-my-new-astronomyastrophotogr.html You can also browse other posts by using the search bar or the blog post list on the right hand side and I'd really like to hear from you via the comment boxes. Drop me a tip, an observation or a question. Take care and clear skies to you. Steve
Beginner tutorial – how to stack comet images in Deep Sky Stacker (my work flow)
Ever
wondered how to turn your series of faint comet frames into one crisp, detailed
image? In today’s post. I’ll walk you through my step-by-step work flow for
stacking comet images in Deep Sky Stacker DSS) – a free, powerful tool that’s
perfect for astrophotographers who want to capture the beauty of a comet
without those distracting star trails.
In summary,
the work flow order goes like this:
1.
Open
picture frames
2.
Then
for each image use the green comet image to select the comet’s nucleus – saving
the position for every frame
3.
Entering
the stacking settings, choosing a comet stacking mode (Comet only, stars only,
both)
4.
Starting
the process of stacking
So, let’s dive
straight into the more detailed work-flow.
Step
1: Register all images
First, let’s
get your light frames ready.
- Open Deep Sky Stacker and click
‘open picture files’
- Select all the comet frames you
want to stack
- (Select all the bias, flats and
dark frames you want to add in)
- Click ‘check all’ – and then
choose ‘Register checked pictures’
· In the pop-up window, make sure to: –
o check ‘register already registered
pictures’
o check ‘automatic detection of hot
pixels’
o DO NOT check ‘stack after registering’.
o Then click ‘OK’ to start the
registration process
This last step
makes sure DSS knows exactly how to align and handle your images before we move
on to the comet itself.
Step
2: Mark the comet’s nucleus in each image
Now for the
fun part — telling DSS where your comet is in each shot.
- Select the first image in your
list
- Click the green comet icon on
the right side of the screen
- hold down the Shift key
and click directly on the comet's nucleus to mark its position. A pink
circle should appear around it.
- Save the changes for that image.
You can click ‘save all’ so DSS keeps track of the comet position across
all selected frames OR
- Repeat this process for every light
frame
This step
can be a little repetitive, but it’s essential — it tells DSS how the comet
moves across your frames, allowing it to align the comet while still handling
the star background correctly.
Tip: If you’ve seen the tutorial “How
to Stack and Process Comet Images with Deep Sky Stacker,” it shows a great
visual example of this process. How to Stack and Process
Comet Images with Deep Sky Stacker
Step
3: Stack the images
With
everything marked, it is time to stack
your comet.
- Click ‘Stack checked pictures’.
- When dialogue box appears, choose
‘Stacking parameters’ appears
- go to the Comet tab
and choose your desired stacking mode.
- "Stars" (comet
trails)
- "Comet" (star trails)
or
- "Stars + Comet"
(both) – my go to choice
- Click OK to start the stacking
process.
- If another pop-up window appears
called ‘stacking steps’, keep the default settings and just click ‘OK’
again.
When DSS
finishes, save your stacked image as a TIFF file, ready to edit in your favourite
processing software — whether that’s Photoshop, Affinity Photo, PixInsight, or
any other astrophotography editor.
Want to
See It in Action?
If you
prefer to follow along visually, these videos do a fantastic job of
demonstrating how to select and use the comet stacking modes in DSS:
How
to STACK Comet in Deep Sky Stacker - Beginners Astrophotography Tutorial
How
to Stack Comet Images Without Star Trails in DeepSkyStacker
Final
Thoughts
Stacking
comet images in DSS might feel a bit technical at first, but once you’ve done
it a couple of times, it becomes second nature. The reward is absolutely worth
it — a clean, vibrant image that beautifully captures the motion and structure
of your comet, without losing the stars in the background.
Give it a
try with your next comet data set and watch your images transform! As
always, if you have a tip or an observation about my work-flow, then drop me a
comment so we can improve it for all and, it goes without saying, but I
will anyway – stay safe, have fun and clear skies to you all
Steve
