What is guiding
Guiding
is
the
process
of
keeping
an
object
being
imaged
dead
centre
in
the
telescope
to
allow
for
long
exposures.
The
guidescope
and
guide
camera
are
fixed
to
your
telescope
and
the
guide
camera
is
connected
to
your
mount
and
some
software
on
your
laptop
or
remote
PC
dependant
on
how
you’re
connected.
The
guide
camera
is
fixed
on
to
a
star
and
the
software
analyses
the
feed
and
sends
minute
“push”
signals
to
your
mount
to
keep
this
star
centred
on
the
screen.
Because
the
star
is
(closely)
moving
at
the
same
rate
as
the
object
that
you’re
imaging
through
your
telescope,
by
keeping
the
star
centred
in
the
guide
camera,
the
object
being
imaged
through
the
telescope is kept centred. This means that you can take as long an exposure as your equipment will allow.
What you will need
1)
A guide camera
2)
A guidescope
3)
A laptop, mini PC, Raspberry Pi, ASIair or similar
4)
Guiding software, PHD2 is free and easy to use but a Google search will offer up other options.
You will notice two ports on the camera above. One connects the camera to the mount and this is called the ST4
port. The other connects to the USB port to talk to the guiding software on your laptop/miniPC/Raspberry pi etc...
The way it works is like this
1)
Connect your camera to the mount and laptop
2)
Start the guiding software and initialise the camera
3)
Select a star
4)
The software will now do some calibration by moving the star in the East, West, North and South directions
5)
Once the calibration has completed you will now be guiding on the selected star and good to go
6)
The camera sends consecutive short exposures to the guiding software, usually around 3 seconds
7)
The guiding software analyses each image received from the guide camera and notices any movement of the
star
8)
The software sends a signal to the mount via the camera and tells it to move in the correct direction to
counteract the movement of the star, thus keeping the star (and your DSO target) bang in the centre
Congratulations, you’re now guiding!!!
If
you
connect
your
equipment
to
either
a
mini
PC
/
Raspberry
Pi
/
ASIair
or
something
similar
then
you
can
lose
the
camera
to
mount
cable
and
utilise
a
setting
called
“Pulse
Guiding”.
This
setting
can
only
be
used
if
your
mount
is
connected
directly
to
one
of
the
above
devices.
It
sends
the
correction
“pulse”
directly
to
the
mount
instead
of
via the camera and this can help with cable control.
In
order
to
obtain
the
lengthy
exposures
needed
for
imaging
deep
sky
objects
(DSO)
then
you
will
need
to
add
a
process
(and
more
equipment)
to
your
setup.
Paired
up
with
an
equatorial
mount
a
guide
camera
and
guidescope
will enable your setup to greatly extend your exposure times to capture those all important photons.
When
imaging
a
DSO
you
need
to
let
as
much
light
fall
on
to
the
sensor
as
your
setup
will
allow.
The
longer
you
can
allow
the
light
to
hit
the
sensor,
the
more
light
data
builds
up
in
the
image
file.
You
then
take
a
series
of
these
long exposures that you will then stack to bring out even more detail.
The
problem
that
all
mounts
have
(no
matter
how
accurate
their
motors
are)
are
the
humans
that
operate
them.
We
already
Polar
align
our
mounts
to
enable
us
to
counteract
the
spin
of
the
Earth
which
in
turn
means
that
we
can
track
an
object
in
a
single
axis,
right
ascension
(RA).
This
is
ok
for
visual
observing
or
shorter
exposure
lengths,
and
in
general
a
very
well
polar
aligned
mount
can
give
between
1
and
a
half
to
2
minute
unguided
exposures
before
you
start
to
see
trailing
on
the
stars.
This
is
fine
when
imaging
bright
objects
like
the
impressive
Orion
Nebula
but
when
imaging
faint
targets
then
you
need
to
extend
your
exposure
times
considerably.
And
if
you
decide
to
dabble
in
narrowband
imaging
then
you
could
be
needing
some
seriously
long
exposures
dependant
on
the camera being used, the only way to achieve this is to implement guiding in to your setup.
Guiding
Guide/Planetary Camera
Guidescope
Camera & Guidescope Setup
