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Description
In early November, John Pane had a rare opportunity — four clear, smokeless, and moonless nights at his home in the northern suburbs of Pittsburgh, PA and time available to devote to imaging. In this talk, John will discuss how he capitalized on the opportunity to create these eight images. https://www.flickr.com/photos/johnpane/sets/72157720226864279/
In imaging so many targets, he necessarily limited the time spent on each one, and thus their resulting quality. This principle of trading the optimal for the "good enough" is also reflected in his choices of equipment and to image from his suburban driveway instead of a darker site. John will also discuss some aspects of his ever-evolving image processing workflow.
Slides for this event: https://drive.google.com/file/d/1-FEn74IdXl-hCCddzP8x-rgCXUl-DQY_/view
A
Hi
everybody
welcome
to
the
2021
december
sjaa
imaging
sig
meeting
and
we're
going
to
start
a
series
of
talks
on
believe
it
or
not,
astro
imaging
for
the
next
at
least
three
months,
and
this
month
we
have
a
guest,
an
imager
from
pittsburgh,
john
payne
who's,
going
to
tell
us
all
about
his
november
new
moon
project.
So
john.
B
Since
I
started,
then
I'll
talk
a
little
bit
about
the
constraints
in
my
ability
to
image,
and
you
know
why
I
only
get
out
on
somewhat
rare
occasions
by
many
standards
of
imagers
and
and
because
I
don't
get
out
very
much.
I
make
certain
choices
about
what
I
do
when
I
can
get
out
and
what
equipment
I
buy
and
talk
a
little
bit
about
that
and
then,
if
there's
time
at
the
end,
I'll
make
a
few
comments
about
processing.
B
So
how?
How
did
I
meet
hi?
He
I
I
was
having
some
problems
with
k.
Stars
echoes
indeed
this
this
setup
that
I
run
partly
on
my
laptop,
partly
on
a
raspberry
pi,
that's
attached
to
my
mouth,
and
I
asked
how
I
asked
hi
some
questions,
because
I
knew
that
he
had
been
doing
some
development
work
on
the
autofocus
module
and
he
was
very
gracious
in
responding
to
my
emails
and
there
were
many
of
them
and
he
offered
helpful
suggestions
and
we
went
back
and
forth.
B
I
think
28
different
messages
where
I
stuck
with
me
through
that
and
eventually
I
solved
my
problems
then
later
after
that
weekend,
I'm
going
to
be
talking
about.
I
reported
back
on
how
well
everything
worked
over
those
four
dark,
clear
nights
and
he
seemed
interested
that
I
actually
imaged
eight
targets
in
four
nights,
and
so
when
I
finished
processing,
all
of
them
all
eight
of
them,
which
took
a
few
weeks,
I
sent
him
the
results
and
he
replied
asking
me
to
come
here
and
suggested.
A
B
B
B
We
were
skunked
like
most
people
were
after
the
big
hype
about
that
comment,
and
you
know
it
was
disappointing
because
you
know
my
dad
was
excited
and
we
hoped
to
see
you
and
we
took
short
drives
to
different
places
where
we
could
see
the
horizon
and
different
things,
but
we
never
saw
anything
and
fortunately,
a
couple
years
later,
I
didn't
realize
it
was
two
years
but
comet
west
appeared.
This
is
not
my
image,
but
we
saw
that
comment
from
our
backyard.
My
dad
woke
us
up
the
little
us
kids.
B
I
was
about
13
at
the
time
and
it
was
amazing
it
was
cl
a
little
cloudy,
so
we
could
see
it
through
broken
clouds,
but
we
did
see
these
striations
and
it
was.
It
was
so
exciting.
But
my
dad
had
his
camera
out
and
he
said
to
me:
hold
the
button
down,
hold
the
shutter
button
down
for
a
while,
which
you
know
I
had
used
the
camera
in
the
daytime,
but
I
had
never
done
that.
B
I
didn't
really
know
what
I
was
doing,
but
I
stood
there
and
held
the
shutter
button
and
then,
a
few
weeks
later,
when
the
slides
came
back
from
being
developed,
I
was
totally
amazed
with
the
photograph
of
god.
It
did
have
clouds
in
it.
Like
I
said
I
wish
I
could
find
it.
I
I
can't
find
it
anymore,
but
you
know
I
was
just
impressed
with
that
and
that
thought
stuck
with
me
for
a
long
time.
B
I
didn't
do
any
other
astrophotography
until
comments
started
to
come
about
in
the
90s
first
comment:
yakitaki,
where
I
got
excited
and
decided
to
image
that
a
couple
of
nights
with
film
and
then
having
had
that
success.
Of
course,
the
next
year
comet
hell
bob
was
here
and
I
went
out
many
nights.
This
is
just
a
sampling
of
four
photographs
of
that
comment
that
I
took,
and
I
continued
to
you
know.
B
B
It
was
very
foggy
in
pittsburgh
that
night,
but
I
drove
in
the
fog
about
an
hour
and
a
half
up
into
the
mountains
and
got
above
the
the
fog
and
saw
hundreds
and
hundreds
of
meteors,
but
one
that
was
quite
bright.
This
one
I
happened
to
capture
and
what
you're
seeing
in
the
center
of
the
screen
is
a
composite
of
several
images
that
are
on
the
right
there.
B
Well,
the
first
two
that
are
on
the
right
that
showed
first,
the
flash
of
the
meteor,
and
then
these
trails
of
gases
or
dust
or
whatever
that
were
blowing
in
the
upper
atmosphere
and
those
persisted
for
a
long
time.
Even
after
a
change
of
film
I
had
I
ran
out
of
color
film
and
that
last
image
is
a
black
and
white
image
with
a
new
rule
of
film.
I
can't
remember
how
long
it
persisted.
It
was
a
long
time
and
this
this
image
actually
got
quite
a
bit
of
attention.
B
First,
nasa
asked
to
include
it
on
a
report.
They
were
doing
about
near
earth
objects
and,
and
then
several
media
throughout
the
world.
Magazines
and
newspapers
published
the
image
with
commentary,
and
it
also
is
was
put
into
museum
science
museum
exhibits
in
two
cities
in
america.
I
think
they're
both
there,
although
I
haven't
confirmed
that
recently
and
then
you
know
another
comment
in
2007-2008
by
then
I
had
a
dslr,
but
still
pretty
rudimentary.
B
I
think
I
had
a
a
simple
tracker
but
fairly
rudimentary
equipment.
At
the
time
I
caught,
I
photographed
comet
holmes
a
number
of
times
throughout
its
apparition.
It
had
a
sudden
brightening
and
you
know,
started
out
as
a
very
small
object
here.
You
can
see
on
the
25th
of
october,
there's
a
tiny
little
dot
there,
and
then
I
went
out
as
many
times
as
I
could.
B
B
Motion
so
this
was
essentially
part
of
its
retrograde
motion
during
this
time
when
it
had
done
this
outburst
and
the
first
images
through
january
30th
were
the
astronomy
picture
of
the
day.
The
only
time
I've
had
that
honor
back
in
2008
and
I
captured
a
few
more
images
after
they
published
that
a
pod.
B
B
The
scope
is
a
stellar
view,
130
millimeter
triplet,
and
this
is
the
needs
mount
with
the
auto
guider.
The
the
the
ota
on
the
left
is
that
star,
auto
guider
system
there's
actually
two
two
cameras
with
two
otas
one
wide
field
and
one
narrow
field,
and
it
uses
those
to
help
with
high
precision
pointing
as
well
as
guiding
and
a
few
other
features
of
the
thing,
and
that
picture
of
the
scope
was
taken.
When
I
still
had
a
dslr.
B
As
I
said,
I
now
have
a
a
dedicated
astro
cam
and
the
scope
is
on
a
dolly
to
move
it
in
and
out
of
my
garage.
It
stays
in
the
garage
almost
all
the
time,
but
when
I
want
to
image,
I
take
it
out
and
I
have
to
sort
of
jack
up
the
dolly,
so
the
wheels
are
off
the
ground
and
then
align
the
camera,
and
it's
a
bit
of
a
time-consuming
process
setting
up.
Because
of
that.
B
This
is
a
more
detailed
progression
of
equipment.
I'm
not
going
to
read
through
all
of
that,
but
the
important
things
or
the
things
that
I'm
using
now
are
all
equipment
that
I
purchased
in
2015
or
later
the
lx850
mounts
the
telescope
and
then
I
started
the
automation
with
the
raspberry
pi
a
couple
years
ago,
and
then
I
got
the
dedicated
camera.
B
B
They
don't
count
it.
If
it's
you
know,
there's
clouds
passing
over,
but
there's
still
a
lot
of
sun
in
the
sky
and
of
course,
when
you're
imaging
at
night
that
that
matters
we'll
say
59
nights
a
year.
This
might
not
be
exactly
right,
but
and
then,
if
you
think
well,
the
moon
interferes
for
three
quarters
of
those.
B
B
So
I
get
out
you
know,
probably
I
would
say
an
average
year
over.
The
past
couple
of
years
has
been
maybe
four
or
five-
maybe
six
nights
six
times
per
year,
sometimes
there's
a
couple
consecutive
nights
and
the
advantage
of
consecutive
nights
is.
If
I
know
it's
going
to
be
that
way,
I
leave
the
image
set
up
and
and
polar
aligned,
and
I
leave
the
rig
out
there
and
polar
aligned.
So
I
don't
have
less
set
up
time,
the
next
few
nights
and
that's
what
happened
in
early
november.
B
This
is
the
light
pollution
map
for
pittsburgh
that
cross
in
the
center
is
the
location.
This
is
pittsburgh
to
my
south
east
and
I'm
right
on
the
border
of
like
a
portal
5
portal,
6
area,
the
other
cities.
Here
we
have
detroit
up
here
in
the
upper
left-hand
corner,
diagonally
down
towards
pittsburgh
as
cleveland
and
then
off
to
the
left
is
columbus
at
the
top
of
the
screen
is
buffalo
new
york
and
at
the
far
right
bottom
is
washington
dc.
The
dark
sites
around
me
are
first.
B
B
B
So
my
strategy
is
that
I
try
to
maximize
imaging
productivity
when
I'm
out
there
imaging
and
that
gets
to
some
of
the
choices
I
make
about.
What
I
do,
and
you
know
first,
is
that
I
use
a
one
shot:
color
camera.
I
have
the
zwo
asi
6200
mc
one
shot
camera,
because
what
that
lets
me
do
is
you
know
capture
through
red,
green
and
blue
filter?
Simultaneously,
I
don't
have
to
do
them
serially,
and
you
know,
of
course,
there's
compromises
with
the
bayer
sensor,
but
you
know
part
of
the
spatial
resolution.
B
B
You
know,
of
course,
there's
less
of
sensitivity
for
the
l.
You
know
capturing
everything,
but
I
think
I
think
for
what
I
do
and
the
amount
of
time
I
have
to
be
out
there.
It's
a
good
compromise.
I
also
picked
the
camera.
It
was
just
a
fantastic
move.
Up
from
the
dslrs
that
I
was
using,
I
was
using
canon
cameras
which
were
good
but
the
yeah.
The
differences
in
readout
noise,
amp
glow
the
fact
that
it's
cooled
so
there's
a
lot
less
shot
noise
and
having
16
bits
and
high
quantum
efficiency.
B
You
know
one
downside
of
not
using
narrowband
filters
is
that
I
can't
really
separate
out
various
emission
lines,
and
so
a
lot
of
my
images
are
very
red
and
I
think
someday.
Maybe
I'm
going
to
get
bored
with
that,
you
know
using
false
colors
is
at
least
makes
the
interest
the
images
more
interesting,
rather
than
looking
at
red
all
the
time.
B
And
then,
how
high
asked
me
how
I
picked
these
targets
and
really
what
I
did
was?
I
saw
that
there
was
likely
to
be
a
few
days
opportunity,
and
you
know
last
minute
I
got
onto
this
site
telescopius
or
telescopius
or
whatever
it's
called,
and
I
basically
put
in
some
parameters
there
to
to
look
at.
You
know
what
the
possibilities
were,
and
basically
what
I
did
was.
B
Three
or
four
hours
per
our
object-
and
you
know
part
of
the
reasoning
about
three
and
four
hours
is
that
you
know.
If
I
doubled
that
time
and
used,
you
know
the
entire
night
or
you
know
used
all
the
time
that
they
are
above
30
degrees
to
image,
I
might
increase
the
signal
to
noise
ratio
by
a
factor
of
1.4.
So
the
payoff
of
doubling
you
know
is
a
trade-off
I'm
willing
to
make
in
in
favor
of
just
getting
twice
as
many
targets,
I'm
going
to
just
pause
for
a
second
in
case.
B
B
You
know
each
filter
is
probably
only
hitting
one
of
the
three
colors
or
making
it
through
only
one
of
the
three
colors
so
yeah.
I
think
I
lose
a
lot
of
efficiency
in
terms
of
the
time
out
there.
It
is
something
that
maybe
I
will
experiment
with.
If
I
really
get
bored
with
you
know
the
limited
color
palette
that
I
can
get
with
what
I
have
one
yeah
one
other
thing
I
like
about
rgb,
of
course,
is
that
it's
very
easy
to
get
natural
colors
of
stars
and
having
images
that
are
somewhat
realistic.
B
You
know
a
lot
of
times,
people
don't
know
much
about
astronomy.
Ask
me
if
that's
what
it
really
looks
like,
and
at
least
I
can
say
well
those
are
the
colors.
You
probably
can't
see
the
colors
with
your
naked
eye,
but
you
know
I'm
not
making
up
that.
It
looks
this
color
so
yeah.
I
I
do
like
that
sort
of
authenticity
of
rgb.
B
D
B
D
B
That's
true,
yes,
yeah
and
the
camera
was
expensive
too
yeah
and
it's
all
a
factor,
although
you
know
really,
I
I
really
you
know,
did
not
consider
seriously
a
mono
camera
coming
from
the
dslr
and
being
used
to
that
and
seeing
at
least
on
paper
what
I
thought
was
going
to
be
a
lot
of
improvement
in
switching
to
the
you
know
dedicated
astro
camera.
I
I
thought
that
would
be
my
first
move
and
then
you
know
I
can
later
you
know,
sell
this
equipment
and
get
something
different.
B
B
B
What
time
they
said,
how
high
they
got
it
when
they
were
at
the
meridian
and
then
those
arrows
were
just
me,
sort
of
figuring
out
how
to
sequence
them
so
that,
like
two
things
that
would
fit
together
well
in
in
in
one
night
and
essentially
that's
how
I
decided
you
know
what
to
do
the
first
night
and
then
I
picked
the
next
two
for
the
next
night
and
so
forth,
and
there's
more
scratch
on
the
back
side
of
this
little
piece
of
paper.
But
that's
that's
it.
B
A
B
No,
I
I
tried
to
get
some
naps,
but
I
usually
tried
to
be
awake
when
the
camera,
when
things
were
getting
dangerous
in
terms
of
the
camera,
possibly
colliding
with
the
tripod
legs
or
a
meridian
flip
supposed
to
happen.
I
did,
for
the
first
time,
have
successful
automated
meridian
flip
with
with
that
set
up
the
ecos
and
everything
during
that
weekend,
but
I
also
did
have
a
collision
with
the
with
the
tripod
that
weekend
and
you
know
other
weird
things
happened
that
I
didn't
anticipate
like
the
object.
B
A
B
B
B
Runs
of
various
pixel
text
inside
things
and
it
takes
hours
and
hours
and
hours
for
that
to
complete
it's
a
huge
amount
of
data.
I
try
to
keep
all
the
working
files
on
my
ssd,
but
I
have
to
kind
of
prune
things,
so
you
know
there's
all
these
intermediate
files
are
generated
and
if
I
know
that
I
am
not
going
to
need
those
intermediate
files,
I
have
to
like
clean
up.
B
B
Yes,
I've
been
taking
two
minute
exposures,
and
so,
if
I'm
imaging
for
four
hours,
I'm
starting
out
with,
like
you
know,
200
plus
images
wait
is
that
right,
30
times,
four,
no
120
or
so
120
150
is
a
common
number
that
I'm
starting
out
with
and
then
very
often
there's
clouds
coming
through
or
my
mouth
glitches.
And
you
know
the
stars,
are
you
know
the
stars
move?
So
I
discard
you
know.
B
Sometimes
I
can
keep
all
my
sub
frames,
but
you
know
sometimes
I
discard
a
substantial
number,
mainly
because
of
clouds,
and
so
you
know
that
that
narrows
it
down,
and
you
know
I
do
I'm
a
little
bit
selective.
If
I
have
a
lot
of
images
in
terms
of
you
know,
sort
of
weeding
out
some
of
the
less
less
strong
ones.
Maybe
if
they
have
a
larger
background
gradient
or
something.
D
A
A
D
A
D
B
B
B
Okay,
so
thank
you
for
the
questions
and
you
know
just
speak
up
if
you
have
another
one,
even
if
I
don't
pause
to
ask,
let's
see
here
so
why
two
minute
sub
frames.
I
I
mentioned
that
I
take
two
minutes.
The
way
I
selected
that
was
there's
a
few
excel
spreadsheets
around
one
of
them
is
called
the
ideal
exposure
calculator
there's
another
one
on
a
cloudy
night's
thread.
I'll
show
you
part
of
it
in
a
second.
B
A
B
Description
anyway,
these
calculators,
you,
you
input
a
lot
of
facts
about
your
camera
and
the
sky
conditions
where
you
are
imaging
and
the
filters
you're
using
and
so
forth,
and
it
calculates
an
exposure
that,
at
which
point,
the
the
light
pollution,
essentially
swamps
out
the
reed
noise
by
a
factor
of
10.,
and
so
essentially,
you
know
once
you've
subtracted
the
light
pollution
out
of
there.
Your
weed
noise
is
also
gone,
and
you
know
going
longer
than
that.
B
Wouldn't
improve
your
noise
that
much.
But
if
at
all,
I
don't
really
fully,
you
know
know
exactly
what
would
happen
if
you
went
longer,
but
it
would
saturate
star
cores
and
also
in
my
case,
because
my
mouth
is
imperfect.
It
would
increase
the
risk
of
losing
the
subframe
because
of
tracking
errors
or
passing
clouds,
and
so
I
picked
two
minutes
as
sort
of
like
an
ideal
exposure
time.
It's
also
by
the
way,
with
a
gain
of
100
on
this
camera.
B
This
will
give
you
a
range
of
exposure
choices
in
terms
of
time.
You
know
length
of
exposure
and
gain
news
and
so
forth,
and
let's
see
here,
I
think
I
have
yeah
here's
a
just
a
somebody
made
like
a
little
help
thing
where
you
you
enter
things
like
your
sky,
brightness,
your
telescope
and
camera
specs,
the
filter
you're
using
which
is
a
drop
down
menu
over
here
you,
you
say
what
filter
you
have
and
you
can
override
it
by
putting
in
bandwidth
if
necessary
and.
B
I'm
not
sure
exactly
what
the
transmission
efficiency
is.
That's
quantum
efficiency
plus
something
else,
and
then
this
is
that
swamp
factor
like
how
much
brighter
the
sky
is
going
to
be
versus
the
read
noise
and
and
then
how
long
your
total
integration
time
will
be
and
then,
based
on
that
it
gives
you
parameters
like
the
number
of
exposures,
the
gain
and
the
subframe
duration.
B
So
it's
a
handy
calculator
if
you
haven't
tried
it
yeah
this
one
that
I
have.
This
screenshot
from,
I
believe,
is
set
up
with
with
parameters
for
many
of
the
zwo
cameras
and
possibly
more
I'm
not
sure
exactly
how
extensive
it
is.
It's
been
a
while,
since
I
looked
at
whoops,
I
did
the
wrong
thing.
There.
A
Can
I
ask
you
a
question
about
that
sure
there
I
haven't
participated
in,
but
I've
noticed
a
conversation
on
the
indie
lib
forums.
Where
you
know
people
were
requesting
the
feature
of
a
calculator
like
this
for
k-stars
or
in
the
ecos.
I
should
say-
and
I
don't
know
I
mean
I
was
pretty
ambivalent
about
that
sort
of
thinking.
Well,
you
know
you
do
that
once
and
you
know
like
why
do
you
really
need
to
redo
this
calculation?
You
know
you
have
a
rough
idea
that
anyway,
that
was
my
point
of
view.
A
B
Right
come
on.
No
I'm
with
you
on
that.
I
I
think
that,
for
someone
like
me,
who's
imaging
from
the
same
place
with
the
same
equipment-
it's
yeah,
I
I
did
that
once
and
then
I
went
back
again
just
to
refine,
because
I,
like
learned
a
little
more
and
like
I
wanted
to
make
sure
I
entered
everything
correctly,
but
then
you
know
I
just
have
been
sticking
with
this
two
minute
thing:
I've
played
around
a
little
bit
with
you
know,
plus
or
minus.
B
You
know
within
those
sort
of
boundaries
that
they
suggest
as
the
output
from
these
calculators.
But
but
it's
true,
I
don't
use
it
a
lot.
It's
been,
probably
you
know
six
months
or
more
since
I
last
looked
at
the
calculator
until
tonight,
when
I
grabbed
this
screenshot
for
the
presentation,
any
any.
You
know.
D
I
was
gonna
chime
in
that
you
know
sharp
and,
and
you
know,
francesco
can
chime
in
he's
gonna
be
the
the
expert
I
think,
but
you
know,
sharpcap
has
a
feature
that
where
you
can
actually
characterize
your
your
camera.
So
if
you,
if
there
wasn't
one
of
these
spreadsheets
that
somebody
had
already
developed
for
your
model
of
camera,
then
you
could
use
that
to
take
some
simple
exposures
and
it's
supposed
to
then
do
some
of
this
kind
of
thing
for
you,
so
a
little
more
advanced
feature
set.
I
think.
A
Yeah,
I
mean,
I
think,
what
it's
gonna,
what
it
when
it
characterizes
that
it's
gonna
look
at
your
dark
current
and
who
knows,
maybe
it
will
look
at
you
know
the
sky
background
for
that
night
or
you
know
that
location.
I
I
think,
that's
what
they're
doing
right
they're
measuring
those
two
things
that
he's
hand
inputting.
B
D
Yeah,
I
seem
to
remember
when
you
know
I
recently
switched
from
asi
1600
to
asi
294
and
there's
some
sort
of
special
things
with
that
camera
that
happen
around
a
certain
gain
level
and
stuff.
So
there
was
there
was
some
amount
of
and-
and
I
used
this
type
of
spreadsheet,
if
not
the
the
same
one,
but
for
that
camera.
But
there
was
some
amount
of
stuff
where
you
had
to
kind
of
enter
your.
I
guess
you
entered
there,
the
camera
gain
of
100,
but
you
had
to
make
some
choices.
You
know.
E
A
A
B
Yes,
I
I
think
that
you
know
hopefully
like
I
said
I
haven't
looked
at
it
recently,
but
I
think
that
when
they
say
that
they've,
like
characterized
the
cameras
that
would
include
that
sort
of
change
in
the
in
the
way
it
performs
when
you
get
to
certain
game
levels,
the
camera.
I
have
does
the
same
thing
right
at
game
100
and
that's
why
I
use
that
it.
It
reduces
the
read
noise
at
some
cost
to
dynamic
range.
E
In
general,
with
the
cmos
cameras
now,
the
the
result,
noise
is
so
low
that
it's
no
longer
really
a
problem
to
swamp,
to
expose
long
enough
to
use
one
period
noise.
The
main
concern
is
the
one
that
john
was
also
mentioning
that
you
don't
want
to
go
too
far
in
the
in
making
the
exposure
longer.
Otherwise,
you
saturate
your
stars.
B
E
B
B
F
F
So
I
always
like
ignore
that
and
just
settle
up
at
like
something
which
will
give
me
right
enough
exposures
which
my
computer
can
handle
like
which
effectively
I
end
up
with
like
one
and
a
half
minutes
two
minutes
and
what
my
mount
can
do,
which
is
like
a
atlas
pro,
because
if
I
do
three
minutes,
I
lose
half
my
subs
because
something
happens
to
that.
Mount.
B
B
The
first
is
that
text
insight
recently
added
the
ability,
when
you're
debary
debayering
the
images
to,
rather
than
create
a
color
image,
to
create
separate
rgmb
images,
and
I
actually
was
talking
with
juan
the
developer
of
pixinside
about
this,
because
I
was
getting
differential,
atmospheric
dispersion
in
my
rb
and
g
channel,
so
that
I
was
having
trouble
keeping
the
colors
aligned.
It
was
not
an
optics
problem,
it
was
atmospheric
dispersion
and
this
enabled
me
to
essentially
eliminate
that
problem.
B
But
now
you
know,
for
the
most
part
I
mean
like
when
you
look
at
my
images.
Really
close
you'll
probably
find
the
color
aberrations
of
various
kinds,
but
it
helped
a
lot.
Let's
say
with
with
that
atmospheric
dispersion
problem,
and
basically
what
you
do
is
you
align
each
of
those
color
images
to
to
one?
B
I
I
align
the
the
red
and
the
blue
to
the
green
allowing
for
distortion
and
what
happens
then
is
that
the
those
three
channels
are
right
on
top
of
each
other,
but
then
what
that
means
is
it's
also
tripling
the
number
of
subframes
I'm
dealing
with
I'm
not
dealing
with
one
color
subframe
for
every
subframe
that
I
shot.
I'm
now
dealing
with
three
mono
subframes
for
each
subframe
I
shot
and
so
there's
a
lot
more
files
being
handled.
B
B
What
this
thing
does
is
it
uses
photometric
techniques
to
figure
out
how
bright
the
gradients
are
in
front
of
stars?
It's
essentially,
I
think,
if
I'm
understanding
correctly,
what
it
does
it
it's
using
known
information
about
the
brightness
of
stars
and
then
any
excess
is
caused
by
atmospheric
things,
and
so,
if
that's
varying
across
the
frame,
that's
an
indication
of
a
gradient
and
what
this
software
does.
Is.
It
essentially
tries
to
match
all
of
your
subframes
to
have
the
same
gradient
as
a
master.
B
So
you
pick
your
your
best
subframe,
which
might
be
the
one
right
at
the
meridian
or
as
close
to
the
meridian
as
you
can
get
and
and
then
all
the
other
ones
are
matched
to
that
through
this
process.
So
then,
when
you
get
to
the
point
where
you're
doing
background
removal,
you
should
have
a
simpler
gradient
to
deal
with,
maybe
less
severe,
but
also
less
complex.
B
B
B
So,
anyway,
you
know
it
seems
to
help.
But
you
know
it
is
a
very
computational
expensive
thing
and
you
know
I
think
that
some
people
have
done
some
some
measures
related
to
like
signal
signal
to
noise
ratios
or
something
that
the
demonstrate
quantitatively.
That
is
better,
but
I
haven't
fully
comprehended
all
of
that
information.
B
Let's
see
so,
the
next
thing
that
I
have
been
really
careful
about
lately
is
background
extraction
and
yeah.
The
the
problem
is
that,
first
of
all
now
that
I
have
my
images
as
three
separate
colors,
I
do
the
background
extraction
separately
on
each
each
color.
I
don't
do
it
when
I
have
a
color
image,
and
you
know
one
of
the
things
about
background
extraction
is
to
make
sure
that
you're
not
getting
any
signal,
and
so
usually
I'm
using
a
brightness
limit.
B
That's
trying
to
you
know
make
sure
that
I'm
capturing
only
background,
but
if
I
have
three
different
colors
with
diff
that
have
not
yet
been
color
corrected,
then
this
might
be
a
good
upper
bound
for
the
background
for
one
color
but
not
another,
and
so
that
I
think,
was
causing
some
problems.
So
now,
because
I'm
doing
this
separate,
rgb
channel
thing
coming
flowing
all
the
way
from.
B
All
the
way
from
when
I
debayered
by
the
time
I
integrate
the
images,
I
still
have
three
separate
color
three
separate
monochrome
images
representing
the
colors,
and
so
I
can
do
the
background
extraction
separately.
But
I
don't
let
whether
I
use
automatic
or
dynamic
background
extraction.
I
do
not
let
it
do
the
subtraction
itself.
B
What
I
do
is
I
try
to
minimize
the
amount
of
subtraction,
I'm
doing
just
enough
to
normalize
the
image.
So
if
it's
claiming
that
the
background
is
ranges
from
0.05
to
0.1
across
the
the
background
image
that
is
created,
I
subtract
the
minimum
from
the
whole
image
and
only
subtract
whatever's
left
from
my
image.
So
essentially
I'm
leaving
a
constant
pedestal.
You
might
call
it
there
rather
than
subtracting
the
background,
all
the
way
to
zero
from
what
it
thought.
B
So
anyway,
that
seems
to
have
helped.
You
know
I
used
to
have
a
lot
of
problems
with
background,
causing
background
extraction,
leaving
behind
gradients
or
revealing
noise
in
the
image
that
you
know,
I
I
wasn't
satisfied
with
and
somehow
this
seems
to
help
with
that
is
really
trying
to
be
to
limit
how
much
is
subtracted
when
I'm
doing
the
background
extraction.
A
B
B
B
But
again
I
was
confronted
with
the
same
problem
that
my
rg
and
b
levels
are
not
the
same,
and
so
when
I
was
setting
an
upper
limit
on
what
the
you
know,
what
to
consider
background
that
might
only
be
truly
applicable
to
one
of
the
three
channels,
and
so
essentially
what
I
do
is
a
similar
process
to
tr.
Essentially
what
I
do
is
I
figure
out
through
inspection
throughout
the
image,
a
minimum
value
in
each
channel,
and
then
I
subtract.
B
I
I
again
do
this
sort
of
residualization,
where
whatever
the
min
like,
if
my
blue
has
the
smallest
minimum
value,
then
I
don't
subtract
anything
from
blue.
I
just
subtract
from
red
and
green
enough
to
make
it
match
the
blue,
and
so
I
get
a
neutral
background
again
subtracting
the
minimum
amount
that
I
need
to
do
that,
and
I
think
you
know
I
don't
know
how
big
of
an
error
it
is
to
to
subtract
more
in
background
neutralization,
but
that
is
applied
after
the
color
calibration.
B
E
Have
you
considered
the
fitting
the
the
rg
and
b
masters
to
each
other
before
doing,
combination
and
pcc
in
this
way,
but
essentially
a
background?
Naturalization
wouldn't
introduce
any
color
shift
and
it's
very
similar
to
what
you're
doing,
because,
instead
of
doing
comparing
the
the
gradient
to
the
minimum
value,
it
essentially
compares
it
with
the
median
or
average
value.
B
Yeah
good
idea,
no,
I
I
haven't
thought
of
that.
You
know
I'm
not
coming
from
you
know
I
I'm
new
at
having
separate
rgb
channels
so
like
that
idea,
you
know
sort
of
hasn't
been
part
of
my
work
throw
in
the
flow
in
the
past,
so
I
definitely
think
about
doing
that.
Is
that
also
something
that
like
so?
If
I'm
doing
that
prior
to
rgb
combined,
would
you
then
recommend
doing
the
background
extraction
after
they've
been
combined
since
they've
been
fit
to
each
other?
Well,.
E
B
E
E
B
B
E
I
had
a
question
about
this:
eight
images
that
you
are
showing
there
quite
a
few
of
them
that
are
right
in
this
mac
middle
of
the
milky
way
and
the
stars
are
really
well
controlled.
Are
you
using
something
like
star
net
plus
plus
or
star
exterminator,
to
separate
stars
and
nebulae
and
process
them
separately.
E
B
I
think
it's
the
crescent
nebula
image.
I
actually
ran
that
multiple
times,
because
the
background
nebulosity
was
very
hard
to
see,
and
I
think
that
in
some
ways
it's
starting
to
look
excessive
from
my
aesthetic
point
of
view,
but
I
ran
it
at
least
twice
maybe
three
times,
because
I
really
wanted
to
be
able
to
see
some
of
that
background
that
we
lost
to
the
event
and
it's
very
weak.
B
B
A
E
Let's
see
well,
I
I'd
just
like
to
comment
that
hi
and
glenn
you
and
bruce
you
might
remember
when,
when
john
was
talking
about
his
efforts
in
predicting
when
the
the
targets
would
become
visible
across
the
meridian,
I
was
picturing
in
my
head.
Our
experience
when
we
rented
that
house
near
pinnacles
that
you
guys
were
all
you
know
doing
automation
from
inside
the
range,
and
I
had
to
go
out
there
each
time
to
tend
to
things
like
meridian
flipping,
switching
targets.
B
B
B
B
B
To
be
honest,
it
was
so
it
was
a
second
image
that
I
was
capturing
and
I
wasn't
sure
how
hard
it
was
going
to
be.
You
know
it
has
a
pretty
low
surface
brightness,
so
I
I
wasn't
sure
how
much
I
needed,
and
so
I
was.
I
really
wanted
to
get
this
this
one,
so
I
imaged
it
longer
than
the
others,
and
I
think
probably
what
happened
was.
I
did
m33
while
I
was
waiting
for
this
to
get
positioned
in
the
sky,
where
I
could
shoot
it
for
the
rest
of
the
night.
B
B
B
B
B
B
Now
this
one,
I
put
seder
right
in
the
middle
of
the
image
where
I
tried
to,
and
I
figured
okay
if
there's
a
reflection,
it's
going
to
be
right
there
on
top
of
seder,
and
I
won't
have
to
deal
with
it,
but
it
was
off
by
a
little
bit.
So
the
the
the
reflection
was
off
to
the
side
a
little
bit
and
I
ended
up
having
to
mess
around
with
that
as
well.
B
And
then
I
think
this
is
the
last
in
the
series
the
witch
head
again.
I
wanted
something
diverse,
something
different
that
wasn't
read
to
balance
out
the
other
stuff
that
I
was
doing
and
wanted
to
see
how
much
I
could
get
out
of
the
object
that
I
thought
was
pretty
dim.
Maybe
I'm
wrong
about
that,
but
my
sort
of,
and
you
know
sort
of
base
assumption
was.
It
is
a
fairly
dim
nebula.
So
I
was
pretty
happy
with
how
that
turned
out.
B
A
B
B
B
I
think
so,
and
I
haven't
really
figured
out
what
the
two
reflective
surfaces
are.
So
I
have
very
little
there
because
so
it's
a
apochromatic
reflector,
so
there's
a
flattener
reducer,
and
I
noticed
that
that
is
a
curved
surface.
So
maybe
that's
involved,
but
the
only
other
glass
is
whatever
is
right
on
the
sensor
and
then
there's
a
cover
on
the
camera.
That
is
a
far
infrared
hot
mirror.
You
know
it
lets
through
the
the
nearer
infrared
so.
B
D
B
D
B
Right
and
it
you
know
it
is
like
symmetrical,
you
know,
sort
of
you
know
reflective
across
the
center
of
the
image,
and
so
you
know
that's
why
I
was
hoping
that
I
wouldn't
get
anything
if
I
entered
seder,
but
I
must
not
have
centered
it
very
well
and
that's
why
it
it
didn't
work
there,
but
you
know
here.
You
can
clearly
see
that
you
know
halfway
between
the
star
and
the
and
the
then
that
reflection
is,
is
the
absolute
center
of
the
image,
or
at
least
you
know
very
close.
D
Well,
my
so
again,
there's
others
that
might
be
more
expert
than
I
on
this,
but
when
I've
seen
things
that
are
because
of
not
great
anti-reflective
coatings
or
something
then
they're
they're,
more
halo
around
stars
and
by
calculating
their
their
size
and
and
your
sensor
parameters,
you
can
determine
how
far
away
it
is
and
verify.
You
know
what
surface
what
glass
surface
it
is,
but
this
is
seems
like
it
has
to
be
super
far
away
by
that
measure.
A
B
B
C
D
Yeah
and
this
this
other
presenter
and
hi,
you
can
remind
me
who
it
was,
but
you
know
it's
a.
He
had
a
a
paint
that
you
have
to
airbrush
on
multiple
layers
and
everything,
and
it's
like
incredibly
black
but
but
yeah
in
terms
of
a
easily
applied
commercial
product.
What
bruce
is
suggesting
is
a
good
way
to
go,
but
yeah,
I
don't
know
bruce
that
that
their
their
focuser
draw
tubes
and
stuff
would
be
coated
with
that
as
well.
It
might
just
be
anodized
aluminum,
which
is
going
to
be
the
case.
B
B
B
You
know
isaac,
who
is
their
customer
service.
Rep,
now
has
been
working
with
me
a
little
bit
and
suggesting
that
the
focuser
might
be
causing
other
pro
that
intro.
You
know
that
obstruction
by
the
focuser
might
be
causing
other
problems
as
well.
So
you
know,
maybe
eventually
I
will
do
that.
I
think
that
the
those
are
hard
to
get
right
now.
The
focusers.
E
C
E
D
E
E
E
D
C
C
Oh
yeah,
I'm
sorry.
Yes,
they
had
a.
They
had
a
problem
with
coatings
on
the
152s
on
one
run
of
the
152
telescopes
and
the
coding
shop
that
they
sent
the
objectives
out
to
didn't,
get
the
edges
perfect
and
it
was
causing
a
diffraction
spike,
a
single
diffraction
spike
in
in
bright
stars,
and
they
unfortunately
could
not
fix
that.
They
needed
to
get
brand
new
objectives
and
that
took
a
while.
It
took
about
a
year
that
replaced.
D
B
F
Can
I
ask
a
beginner
question,
so
I
have
a
asi
1600
train
john,
so
I
was
thinking
of
upgrading
to
like
that
gw
2600,
which
is
the
aps-c
format
or
possibly
6200.
So
how
do
you
decide
if
you're
imaging
train
with
the
current
focuser
and
stuff
will
match
with
your
camera
sensor
size?
Is
there
a
way
to
calculate
that
or
because,
when
I
did
1600
right,
si
1600
never
calculated
it?
I
just
got
everything
and
it
fitted
my
refractor
and
it
just
worked.
F
D
C
D
Well
it
it
they
should,
they
should
tell
you
if
it's
not
published,
you
should
be
still
be
able
to
ask
them.
You
know
what
is
the?
What
is
the
image
circle
at
the
focal
plane?
And
so
you
can?
You
know
you
want
your
your
sensor
to
be
inside
of
of
that,
and
then
you
know,
if
that's
bigger
than
your,
then
your
focus
or
draw
tube
right.
D
So
you
can,
you
know
it's
it's
kind
of
a
sweet
spot
for
for
narrow
band,
filter
prices
and
as
soon
as
you
start
going
up
in
sensor
size,
then
you
know
you
have
to
buy
bigger.
You
know
you
probably
for
aps-c.
You
probably
have
to
have
two
inch
filters
and
then
from
I
don't
even
know
from
there
right
what
the
diagonal
of
a
full-frame.
E
And
also
vignetting
is
only
part
of
the
story.
The
other
problem
is
having
that
field,
the
sufficient
flat
for
imaging
if
you
are
using
a
refractor,
not
having
a
secondary
collar
around
the
edges.
Now,
if
you're
using
a
mono
camera,
it's
you
can
get
away
with
it,
because
you're
focus
for
every
filter,
but
with
an
osc.
You
have
to
get
a
compromise.
F
B
But,
as
I
started
to
mention
earlier,
I
I
first
changed
the
the
tubes,
the
extension
tubes
between
the
flattener
and
my
camera
to
a
wider
diameter
which
helped
a
bit
with
vignetting,
but
it
didn't
really
solve
the
problems
until
we
figured
out
that
it
was
the
focus
or
draw
two
causing
some
problems.
So
you
know
if
I
had
known
that
the
scope
wasn't
really
designed
for
full
frame.
A
A
Not
vignetted,
and
you
can
deal
with
that
with
flats
right,
so
that
vignetting
by
itself
is
not
a
problem.
It's
like
where,
okay,
where
it's
crapped,
you
know
like.
So
it's
vignetted,
you
know
infinitely
and
you
know,
like
the
image
circle,
doesn't
match
the
sensor.
Okay,
that
that
has
it,
but
that
doesn't
mean
you
throw
away
the
image.
A
A
B
Isaac
is
suggesting
you
know,
even
though
the
vignetting
in
my
images
is
completely
solved
by
flat.
You
know
flat
correction
yeah,
there's
these
other
artifacts,
which
are
smaller
and
harder
to
see.
But
if
that's
what
it
is,
he
calls
it
vignetting,
maybe
there's
a
different
name,
because
it's
really
an
obstruction,
but
you
know
it
is
sort
of
the
same
thing.
So
you
know
that
that
I
think,
is
the
bigger
issue,
unless
all
of
that
is
also
outside
the
same
area
that
you
would
otherwise
crop.
B
But
in
my
case
it's
not,
you
know
it's
in
the
image.
I
I
don't
need.
The
crop
is
for
the
reduced
signal
that
we
usually
think
of
as
vignetting
or
the
dimming
around
the
edges
that
we
usually
think
of
as
vignetting.
These
are
other
artifacts
that
can
be
labeled,
vignetting
artifacts
that
are
not.
You
know
that
would
force
you
to
crop,
even
if
you
want
to
get
rid
of
them,
may
force
you
to
crop,
even
if
it's
not
completely
black
in
the
corners.
C
B
F
Yeah
yeah,
another
thing
which
I
struggle
with
is
right
is
the
with
the
asi
1600,
which
francisco
also
uses
like
I've,
learned
to
live
with
it
now,
but
it
it's
12
bit
and
it
saturates,
star,
saturates,
super
easily.
If
you
expose
it
too
long
and
they
all
become
white,
you
lose
color
really
fast
and
there
are
techniques
to
separately,
shoot,
rgb
stars
and
then
they
merge
them
back.
But
it
seems
like
this
camera
helps
you
with
keeping,
as
you
mentioned,
not
saturate
the
stars.
F
D
A
In
four
minutes
or
75
and
two
minutes,
okay,
I
mean
you're
going
to
saturate
a
few
stars,
but
yeah
I
mean,
of
course,
if
you
shoot
your
own
attack
or
something
yeah
yeah.
If
you
assuming
that
you're
talking
about
not
not
super
bright
stars,
I
think
you
should
be
able
to
get
away
with
75.
Is
you
know
these
gain
numbers
are
odd
right.
What
you
really
want
to
talk
about
is
like
how
many
photons
per
adu,
or
something
like
that,
so
139
that
you
were
using
is
one
to
one
yeah,
it's
the
pixel.
A
A
D
And
if
you're,
if
you're
doing
narrow
band
and
you're
you're
shooting
a
mission
nebula,
maybe
you
don't
care
so
much
about
the
star.
Colors
right
and
you're
you're
would
rather
spread
the
dynamic
range
of
the
you
know
right
side
of
the
histogram
across
a
wider.
You
know
wider
number
of
adu
so
yeah,
but
that
that
the
200
with
the
asi
1600
I
mean
that's,
really
a.
B
B
F
B
And
it's
it's
actually
getting
on
the
sensor
for
them,
so
I
would
recommend,
before
you
buy,
that
camera
that
you
at
least
read
through
that
thread.
Zwo
is
finally
responding
on
that
thread
about
what
they're
doing
for
the
people
and
the
guarantees
they're
offering
to
people.
But
you
know
don't
get
that
camera
without
being
aware
of
that
possibility
and
they
also
claiming
that,
after
a
certain
manufacture
date,
the
problem
is
solved.
B
F
F
B
Yeah,
I
think
it's
the
pat
it's
for
conducting
between
conducting
the
heat
from
the
back
of
the
chip
or
the
front
whatever
side
of
the
chip,
it
is
to
the
tech
cooler,
it's
something
to
improve
the
conductivity,
the
heat
transfer
between
those
two.
That
is
the
path
that,
I
think,
is
the
suspect.
One.