Sky & Telescope - June 2024 - 66

SUPERNOVA REMNANT IN CASSIOPEIA: MARCEL DRECHSLER / YANN SAINTY / BRAY FALLS /
NICOLAS MARTINO / RICHARD GALLI; BETA GRUIS: MARCEL DRECHSLER
Nebulae Hunters
BIG SUPERNOVA REMNANT California amateur Bray Falls, along
with Marcel Drechsler, discovered this supernova remnant while examining
an image that Falls recorded over a year and a half earlier. The object,
now known as G107.5-5.2, lies in Cassiopeia and spans some 3°.
ber of the French group, Xavier Strottner, contacted him. The
two quickly joined forces and combined their efforts to become
more efficient in their searches. To date, the pair have chalked
up no less than 350 scientifically relevant discoveries, with
many of their PNe confirmed by independent spectroscopic
observations and included in the HASH database.
A Good Strategy
The search for previously undiscovered celestial objects can be
an emotional roller coaster. The brain lurches from moments
of ecstasy, because you spot an interesting object in survey
images, to deep dejection when after days of research your
object turns out to be already cataloged.
Although many amateurs hunt for new finds on their own
images, others focus their attention on the massive archive of
pre-existing survey images available online.
This search for cosmic treasure often consists of examining
field after field on a survey website, such as the Digitized
Sky Survey, which contains all of the Palomar Observatory
Sky Survey I and II plates. When you notice a fuzzy spot or
non-stellar object, note its approximate coordinates and
begin searching for known objects around its location in the
large and small databases. Compared to computers and artificial
intelligence, the human brain is still the most effective
tool for identifying these subtle patterns.
A few primary resources are the SIMBAD Astronomical
Database (simbad.cds.unistra.fr/simbad) and the HASH
database (hashpn.space). SIMBAD is a continually updated
66 JUNE 2024 * SKY & TELESCOPE
HIDDEN IN THE GLARE Some discoveries are found in surprising
locations. This strange ultraviolet shell surrounds the star Beta (β) Gruis
and evaded detection until recently because of light scatter due to the
brightness of its magnitude-1.7 progenitor.
database that provides information on known objects and is
searchable by identifier or coordinates. It also contains links
to the VizieR database.
Don't discount surveys focused on wavelengths beyond
the visible spectrum, either. Often objects discovered at
radio wavelengths have an optical component, too. Still,
hydrogen-alpha surveys tend to bear the most fruit. Based
on Drechsler's experience, only one out of every 100 of his
potential finds turns out to be new.
If a thorough search of online databases at your suspected
find's location comes up empty, you should enlist
the help of a fellow hunter or imager who can confirm the
discovery. It's only when the candidate object clears this
hurdle that you should attempt the next, most important
step: submitting your object for publication. The first port of
call for previously undiscovered PNe is with Pascal Le Dû at
planetarynebulae.net. He's responsible for the registration of
PN candidates that are transferred to the HASH database.
For every discovery of a new PN, a detailed report is sent
to Le Dû. It should include the object's coordinates, at least
two independent photographic references, a description of its
characteristics, and a brief scientific analysis. For example,
is the object most prominent in O III or Hα? What are its
angular dimensions?
If you intend on performing a search with your own equipment
or do follow-up observations of a potential find yourself,
the most effective tools for the task are a sensitive digital
camera equipped with a set of narrowband filters. Such filters
http://www.planetarynebulae.net http://simbad.cds.unistra.fr/simbad
Sky & Telescope - June 2024

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