Sky & Telescope - March 2022 - 65

the class of object, its constellation, the telescope, and also
the camera and filters used to photograph it - any terms by
which you and others might want to search for it. All those
metadata carry through to gallery websites such as 500px,
Flickr, PhotoShelter, and SmugMug, though not to the popular
AstroBin, nor to Facebook or Instagram.
Next, use Adobe's program Lightroom Classic (included
with a Photoshop subscription) to add your pictures to its
catalog by pointing Lightroom at the main drive and folders
where you store your master photos, then importing them.
Once Lightroom knows about a folder, to add images in the
future just select Library > Synchronize Folder.
Can Photoshop
Do That?
The usual practice for deepsky
image processing is to
stack multiple exposures in
order to reduce noise. Many
photographers use a dedicated
program for the task. But
few realize that Photoshop
can stack, align, and mathematically
average photos,
a function present since at
least CS6 from 2012, though
only in the extended scientific
edition. Starting in 2013, it's
been included in all Creative
Cloud versions of Photoshop.
The longhand way to stack
images is to use Adobe
Bridge to browse to and
select the pictures, then
choose Tools > Photoshop >
Load Files into Photoshop
Layers. After they load into
Photoshop, select all the image
layers and choose Edit
> Auto Align Layers. Once
aligned, select all the layers
again and pack them into a
smart object with Layer >
Smart Objects > Convert to
Smart Object.
Then go to Layer > Smart
Objects > Stack Mode and
choose either Mean (for
the best noise reduction) or
Median (to eliminate satellite
trails). You can always
change the stack mode later.
Lightroom makes it easy to search tens of thousands of
files, or to create " smart collections " of photos automatically
grouped by metadata values or the keywords you chose. If you
don't wish to use Lightroom, then ACDSee or Exposure X7 are
good, low-cost alternatives.
By following these tips, you should be able to work smarter
and save time by using Photoshop (and Lightroom) more easily
and quickly to edit (and find!) your astronomical masterpieces.
¢ ALAN DYER is co-author with Terence Dickinson of the new
fourth edition of The Backyard Astronomer's Guide. For more
details, see BackyardAstronomy.com.
Adobe Bridge
< This will load selected
images into Photoshop
as layers
STARTING A STACK IN BRIDGE The process begins in Adobe Bridge, an often underappreciated
program included free with all versions of Photoshop. Bridge allows easy culling, labeling,
rating, and transfer of sets of images over to Photoshop, in this case into a layered file.
Adobe Photoshop
File > Scripts > Statistics automatically
stacks, aligns, and averages images
SCRIPTED SHORTCUT As an alternative, File > Scripts > Statistics will perform each stacking
step automatically, using already open files (as here) or files selected from the dialog box. Choose
Mean or Median. Then check the " Attempt to Automatically Align Source Images " box.
sk yand tele scope .o r g * MARCH 2022 65

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Sky & Telescope - March 2022

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