Site logo,


1036 Ganymed - minor planet
108P/Ciffreo (comet)
154P/Brewington (comet)
16 Psyche - minor planet
17P/Holmes (comet)
2017 Jupiter chart
24 Themis - minor planet
273P/Pons-Gambart (comet)
290P/Jager (comet)
3C 66A
433 Eros trail, 2012 Jan 5
4 Vesta - minor planet
50mm EF lenses, comparison
63P/Wild (comet)
78P/Gehrels (comet)
abbreviations, Java
Active Galactic Nucleus (AGN) 3C 66A
adapters for eyepieces
adapters for filters
adding images
aligning a Newtonian telescope
alpha Lyrae (Vega)
altazimuth telescope mount
Andromeda galaxies M31, M32 & M110 (25cm telescope)
Andromeda Galaxy (M31) - photograph on fixed tripod
angles - programming pitfalls
animation: geocentric or heliocentric
animation of Jupiter's satellites
aperture of lens
API download
application, downloading
application for examining EXIF metadata in image files
Aquila - nova 2009
asteroid 1036 Ganymed
asteroid 16 Psyche
asteroid 24 Themis
asteroid 433 Eros trail, 2012 Jan 5
asteroid 4 Vesta
asteroid position plotting
AstroGrid - setting up to work with GRIP
AstroGrid - use in star charts
astrophotographic process - my usual
astrophotographs - processing steps
astrophotography exposure settings
astrophotography - trails
astrophotography with compact camera
astrophotography with fish-eye lens
astro-process steps
atmospheric turbulence and satellite trail
averaging images
avoiding saturation of star images
B145 dark nebula
B168 dark nebula (and Cocoon Nebula)
B33 nebula - Horsehead
background colour neutralisation
background correction
bands, definition
Barlow lens for photography
Barnard's Loop
barn door tracker
batch menu
Bayer filter pattern
Beehive cluster, M44
Bennett, Comet C/1969 Y1
Berlin Holocaust Memorial and the Milky Way
Betelgeuse and snaking dark nebula
bias frames
big-endian data
bits per channel
Black Eye Galaxy, M64
blob detection
blob detection in Java code
blob menu
border terrier
bring GRIP window to front
bring image to front
Brougham Castle and the Milky Way
Brough Castle and the Plough
Bubble Nebula (NGC 7635) & M52 cluster
Butterfly nebula NGC2346 in Monoceros
byte code
C/2010 G2 Hill (comet)
C/2010 S1 (LINEAR) (comet)
C/2011 F1 (LINEAR) (comet)
C/2011 L4 (PanSTARRS)
C/2012 C2 (Bruenjes) (comet)
C/2012 F6 (Lemmon) (comet)
C/2012 S1 (ISON) (comet)
C/2013 R1 (Lovejoy) (comet)
C/2014 E2 (Jacques)
C/2014 E2 (Jacques) - fixed tripod
C/2014 Q3 (Borisov)
calculator - field of view
calculator - star trail length
California Nebula - NGC1499
camera field of view calculator
camera field of view in telescope
camera field of view table
camera file formats
camera live view
camera pixel size & telescope resolving power
camera settings in image files
camera techniques
Canon 50mm EF lenses, comparison
Cassiopeia, centre of
Cassiopeia constellation
Cassiopeia nebulae (H-alpha and OIII)
Cassiopeia with comet C/1024 E2 (Jacques)
Cepheus (constellation), Milky Way in
Cepheus - Cygnus Milky Way
channel mixing
channels, definition
Christmas Tree star cluster, NGC 2264
classes involved in ImFrame
classifying pixels in Java code
clicking image to magnify it
clouds, nacreous
Cocoon galaxy (NGC4490) in CVn, 2012 Feb 18
Cocoon Nebula, IC5146 (and B168)
Collinder 421 star cluster
colour balance
colour histograms
colour of street lighting
colour profiles
colour saturation
colour theory
Coma Berenices constellation
coma corrector
combination menu on table of images
combining astrophotographs
combining images
combining images
comet 103P/Hartley
comet 108P/Ciffreo
comet 154P/Brewington
comet 17P/Holmes
comet 273P/Pons-Gambart
comet 290P/Jager
Comet 63P/Wild
Comet 78P/Gehrels
Comet C/1969 Y1 (Bennett)
Comet C/2004 Q2 (Machholz)
Comet C/2009 P1 (Garradd)
comet C/2010 G2 Hill
comet C/2010 S1 (LINEAR)
comet C/2011 F1 (LINEAR)
comet C/2011 L4 (PanSTARRS)
comet C/2012 C2 (Bruenjes)
comet C/2012 F6 (Lemmon)
comet C/2012 S1 (ISON)
comet C/2013 R1 (Lovejoy)
comet C/2014 E2 (Jacques)
comet C/2014 E2 (Jacques) - fixed tripod
Comet C/2014 Q3 (Borisov)
comet-like ghost image
comet position plotting
compare measurements of several images
Comparing Canon's two 50mm EF lenses
compression in image files
computer use in the dark
Cone Nebula, NGC 2264
configuration menu
constellation - Cassiopeia
constellation - Coma Berenices
constellation - Cygnus
constellation - Monoceros
constellation - Orion
constellation - Ursa Major
constellation - Virgo
contrast - changing manually
contrast - inverting
contrast - stretching automatically
converting an image between 8 and 16 bits per channel
converting an image to monochrome
convolutions menu
coordinate system for position measurements
Copernicus: geocentric or heliocentric
copying images
copying measurement shapes
correcting background
correcting coma
correcting defective pixels
correcting with dark frames
correcting with flat field images
Crab Nebula, M1
Crayford focusser
Crescent Nebula (NGC 6888)
Crescent Nebula (NGC6888)in H-alpha
cropping an image
curves - changing contrast manually
Cygnus (constellation), Milky Way in
Cygnus constellation
Cygnus in H-alpha light
Cygnus nebulae (H-alpha)
dark-adapted software
dark frames
dark frames
dark frames in the batch astro process
dark nebula around Betelgeuse
dark nebula B145
dark nebula B168 (and Cocoon Nebula)
defective pixels
defective pixels - detecting and saving the list
defective pixels - loading a list of
defective pixels - using
Delphinus (constellation)
Delphinus - nova in 2013
detect defective pixels
detecting blobs
detecting objects in images with Java
detector layout in cameras
digital camera file formats
digital negative file format
distance calibration
dividing by flat field images
DNG image format
DNG image format
documentation of SkyWatcher telescope
double cluster in Perseus
Double Cluster in Perseus & the Heart Nebula (IC1805)
download compiled application
download GRIP source code & API
download JRE
drive error analysis
drive errors reduced by stacking
dumbbell nebula M27
dwarf galaxy Leo II
Earthshine on the crescent Moon
eclipses of the moon
edit menu on table of images
electronic noise
enlarging an image
equatorial mounts: go to or not go to?
equatorial telescope mount
Eros (asteroid 433) trail, 2012 Jan 5
Eskimo planetary nebula (NGC 2392), 2012 Jan 5
estimating star magnitudes
estimating star magnitudes (photometry)
ET Cluster, NGC457
EV = Exposure Value = stop
EXIF metadata
EXIF metadata in image files, application for examining
exposing stars without saturation
exposure settings for astrophotography
exposure time
Exposure Value (EV) = stop
extending GRIP
extreme value filter
eyepiece adapters
farmhouse ruin in twilight
features of GRIP
field of view calculator
field of view table
file formats
file menu on main window
file menu on table of images
filter adapters
filter - mean
filter - median
filter - nearest extreme
filter pattern on sensor (Bayer)
filter - rank
filters, narrowband - why they work
filter - variance
find GRIP window and bring to front
find image and bring to front
finding a target with Hopper
fireball?, 2012 Jan 22
fish-eye lens astrophotography
fish-eye lenses
FITS image format
FITS image format
fixed tripod: comet C/2014 E2 (Jacques)
fixed tripod: Milky Way in Cygnus
fixed tripod: Milky Way in Scutum
fixed tripod - Orion
fixed tripod photography of Andromeda Galaxy (M31)
fixed tripod photography of Milky Way
Flame nebula (NGC 2024)
flat frames
flat frames, how to obtain
flat frames in the batch astro process
flipping an image horizontally or vertically
flowchart of full stakcing process
focus - effect of temperature
focussing with 2-hole telescope lid
galaxies M31, M32 & M110 in Andromeda (25cm telescope)
galaxies M77 et al in Cetus, 2012 Jan 16
galaxies M81 & M82
galaxies M84 & M86
galaxies M89 & M90
galaxies NGC4485 & 4490 in CVn, 2012 Feb 18
galaxy M101
galaxy M105
galaxy M106
galaxy M109 in Ursa Major, 2012 Feb 18
galaxy M33 (pinwheel)
galaxy M51 (whirlpool)
galaxy M82
galaxy M96
galaxy NGC 2403 in Camelopardalis
galaxy NGC4216 & neighbours
Galilean satellites of Jupiter - identification
Gamma Cygni & NGC6910
Gamma Cygni nebulosity, 2011 Oct 15
gamma explanation
Ganymed - minor planet 1036
Garnet Star (Mu Cephei)
Garradd, Comet C/2009 P1
Gaussian kernels
Gehrels, Comet 78P
Gemini and Orion - Milky Way
geocentric or heliocentric (animation)
geometry menu
ghost reflections inside lenses
globular cluster M13 in Hercules
globular cluster M15
globular cluster M3
globular cluster M53 in Coma Berenices
globular cluster M71
globular cluster M92 in Hercules
gnomonic projection
Go to or not go to? (equatorial mounts compared)
Great Orion Nebula, M42 (HDR), 2012 Jan 16
grey-scale images, definition
GRIP, downloading
GRIP's main menu
GRIP's object detection mechanism
GRIP's unusual features
GRIP API download
GRIP introduction & image formats
GRIP source code download
Gyulbudaghian's variable nebula
h & Per double cluster
H-alpha (etc) filters - why they work
H-alpha & unmodified DSLR - Cygnus (incl. Veil)
H-alpha & unmodified DSLR - NGC7000 & Pelican
H-alpha regions around Monoceros
H-alpha - Veil nebula
H-alpha view of Orion
HDR version of M42 (Orion), 2012 Jan 16
Heart and Soul nebulae, H-alpha
Heart Nebula (IC1805) & Double Cluster in Perseus
heliocentric or geocentric (animation)
help menu on main window
help menu on table of images
HEQ5 and HEQ5 Pro equatorial mounts compared
Hercules - M13 globular cluster
Hercules - M92 globular cluster
Hind's variable nebula (NGC1555)
hints & tips for SkyWatcher telescope
Hipparcos data file (hip_main.dat)
histogramming an area of an image
history view
holes in telescope lid
Holocaust Memorial Berlin and the Milky Way
Hopper - star finder software
Horsehead Nebula (B33)
hot pixels
hover and magnify
how to find & photograph the Andromeda Galaxy (M31)
HR Delphini (variable star)
Hubble's variable nebula (NGC 2261)
hydrogen clouds around Gamma Cygni
hydrogen clouds in Cassiopeia
hydrogen clouds in Cygnus
hydrogen in Orion
IC1318A/B/C nebulae near Gamma Cygni
IC 1396 nebula
IC1805, H-alpha
IC1805 (Heart Nebula) & Double Cluster in Perseus
IC434 nebula - Horsehead
IC5146, Cocoon Nebula
identifying the satellites of Jupiter
image file formats
image files, application for examining metadata in
image formats for GRIP
image help menu
image information
imageio package
image measurement and calibration
image menu
image metadata
image reading and writing
image representation in Java
images - combining
image segmentation in Java code
image sizes
images open - table
images - selecting
image structure
image types
image window menus
ImFrame and associated classes
ImFrame menus
internal lens reflections
interpolating a RAW image
interpolation between pixels
introduction to GRIP
inverting contrast in an image
ISO speed
JAR files
JAR files for AstroGrid
Java 7 language features
Java Advanced Imaging
Java course
Java image representation
Java introduction
Java is little-endian
JavaScript course
Java terms and abbreviations
javax.imageio package
JDK (Java Development Kit)
Jedburgh Abbey at night
JPEG image format
JRE, downloading
Julian Date
Jupiter, Venus & the Moon, 2012 Mar 26
Jupiter's satellites - how to identify
Jupiter's satellites without a telescope
Jupiter chart 2017
Jupiter in Aries (observatory), 2011 Nov 6
kernel for (de-)convolution
landscapes with astronomical backgrounds
laser collimator
LED street lamps
length calibration
lens aperture
lens field of view table
lens reflections causing ghosts
Leo's tail
Leo II dwarf galaxy
Leo Triplet, galaxies M65, M66 & NGC3628
levels menu
light pollution
linear convolutions
little-endian data
live view on the camera
loading images from disc
Loop, Barnard's
Lowther Castle and star trails
lunar eclipses
lunar photography
Lyra - M57 planetary nebula
M100 galaxy in Coma Berenices
M101 & SN2011fe (supernova)
M101 spiral galaxy
M105 galaxy
M106 galaxy
M109 galaxy in Ursa Major, 2012 Feb 18
M110 Andromeda galaxy (25cm telescope)
M11 open cluster in Scutum
M13 globular cluster in Hercules
M15 globular cluster
M1 supernova remnant (the Crab Nebula)
M27 dumbbell nebula
M29 star cluster
M31 (Andromeda Galaxy) - photograph on fixed tripod
M31 Andromeda galaxy (25cm telescope)
M32 Andromeda galaxy (25cm telescope)
M33 pinwheel galaxy
M3 globular cluster
M42, the Orion nebula
M42 Orion nebula (HDR), 2012 Jan 16
M44, the Beehive cluster
M45, the Pleiades
M51 whirlpool galaxy
M52 cluster & NGC 7635 Bubble Nebula
M53 globular cluster in Coma Berenices
M57 planetary nebula in Lyra
M64 Black Eye Galaxy
M65 & M66 galaxies (in Leo Triplet)
M71 globular cluster
M76 planetary nebula in Perseus
M77 and other galaxies in Cetus, 2012 Jan 16
M78 & McNeil's variable nebula
M81 & M82 galaxies
M82 galaxy
M84 & M86 galaxies
M89 & M90 galaxies
M92 globular cluster in Hercules
M95, M96 galaxies + supernova SN2012aw
M96 galaxy
Machholz, Comet C/2004 Q2
magnified view around mouse
magnitude estimation
magnitudes, measuring (photometry)
main menu of GRIP
Maksutov-Cassegrain telescope
margins, RAW image
masks for detecting objects in images
McNeil's variable nebula
Meade ETX telescope
mean filter
measurement and calibration menu
measurements - comparing several images
measurements include metadata
measuring along a line in an image
measuring an area of an image
measuring a single point
measuring blobs
measuring objects in images with Java
measuring pinhole diameter
measuring position - coordinate system
measuring star magnitudes (photometry)
median filter
Melotte 111 (Coma Berenices)
memory required for images
menu - batch
menu - blob
menu - combining images
menu - convolutions
menu - geometry
menu - image
menu - image help
menu - levels
menu - measurement and calibration
menus - main
menus on image window
menus on table of images
metadata in image files, application for examining
metadata in measurements
meteors - Perseids
Milky Way
Milky Way between Cepheus and Cygnus
Milky way - fish-eye view
Milky Way in Cepheus
Milky Way in Cygnus
Milky Way in Scutum
Milky Way past Gemini and Orion
Milky Way - photograph on fixed tripod
minor planet 1036 Ganymed
minor planet 16 Psyche
minor planet 24 Themis
minor planet 433 Eros trail, 2012 Jan 5
minor planet 4 Vesta
minor planets
mixing channels
Monoceros constellation
Monoceros - H-alpha regions
monochrome images, definition
Moon, Jupiter & Venus, 2012 Mar 26
Moon, just past full
Moon - Earthshine
moon eclipses
Moon last quarter in daylight
moonlit observatory (trails)
moon photography
moons of Jupiter - identification
mosaic of part of Virgo cluster of galaxies
mounts for telescopes
moving measurement shapes
Mu Cephei (the Garnet Star)
multiplying images
my usual astrophotographic process
nacreous clouds
narrowband filters - why they work
navigating with Hopper
nearest extreme filter
Nebulae around Gamma Cygni, 2011 Oct 15
nebulae in Cassiopeia
nebulae in Cygnus
nebulosity around Gamma Cygni (H-alpha)
negating an image
negative projection photography
neutralising background colour
new telescope - documentation
Newtonian telescope, 254mm
NGC 1023 - galaxy in Perseus
NGC1499 - California Nebula
NGC1555 Hind's variable nebula
NGC 2023 & 2024 nebulae - Zeta Orionis
NGC 2237 - Rosette Nebula
NGC 2244 - star cluster in Rosette Nebula
NGC 2261 Hubble's variable nebula
NGC 2264 - Christmas Tree cluster & Cone nebula
NGC2346 planetary nebula in Monoceros
NGC2371-2 planetary nebula in Gemini
NGC 2392 Eskimo planetary nebula, 2012 Jan 5
NGC 2403 galaxy in Camelopardalis
NGC281 - Pacman nebula in Cassiopeia
NGC3628 galaxy (in Leo Triplet)
NGC4216 & other galaxies
NGC4248 galaxy
NGC4258 galaxy (M106)
NGC4485 & 4490 galaxies in CVn, 2012 Feb 18
NGC4565 edge-on spiral galaxy
NGC457 - the ET Cluster
NGC 6765 planetary nebula in Lyra, 2012 Jan 5
NGC6888 (Crescent Nebula)in H-alpha
NGC 6888 - the Crescent Nebula
NGC6910 & Gamma Cygni
NGC 6910 star cluster near Gamma Cygni
NGC 6960 - veil nebula (W part)
NGC 6992 - veil nebula (E part)
NGC7000, North America Nebula
NGC7000 (N America) & Pelican in H-alpha light
NGC 7331 - galaxy in Pegasus
NGC 7635 Bubble Nebula & M52 cluster
NGC 869 & 884 - double cluster in Perseus
night scenes with castles etc
night sky photography - compact camera
night sky photography -trails
noise in images
noise in photographs
non-integral pixel coordinates
non-linear convolutions
non-linear curves (gamma)
North America & Pelican nebulae in H-alpha light
North America Nebula, NGC7000
nova Aql 2009
Nova Delphini 1967
Nova Delphini 2013
object detection in Java code
observatory by moonlight (trails)
observatory slit: Jupiter in Aries, 2011 Nov 6
OIII filter - Veil nebula
open cluster M11 in Scutum
open images - table
Oracle (Java providers)
orienteering maps
Orion and Gemini - Milky Way
Orion and his bow, single exposure
Orion constellation
Orion from fixed tripod
Orion in H-alpha light
Orion nebula, M42
Orion Nebula - Trapezium stars
Orion over Jedburgh Abbey
overlapping photos
Pacman Nebula (NGC281)
panoramic images
partial solar eclipse 2015 Mar 20
path of Jupiter in 2017
pattern for reading/writing pixels
Perseid meteors
Perseus double cluster, h &
Perseus Double Cluster & the Heart Nebula (IC1805)
Perseus - M76 planetary nebula
photographing stars without saturation
photographing the moon
photographing the night sky - compact camera
photographing the night sky - trails
photometry - measuring star magnitudes
pinhole measurement
pinhole photography
pinwheel galaxy M33
pixel, definition
pixel classification in Java code
pixel interpolation
pixel reading/writing pattern
pixels - defective
planetary nebula M27 (dumbbell)
planetary nebula M57 in Lyra
planetary nebula M76 in Perseus
planetary nebula NGC2346 in Monoceros
planetary nebula NGC2371-2 in Gemini
planetary nebula NGC 2392 (Eskimo), 2012 Jan 5
planetary nebula NGC 6765 in Lyra, 2012 Jan 5
planets, minor
Pleiades, M45
Pleiades and Comet Machholz
plotting positions of solar system objects
Plough in twilight - stacked different ways
position measurements - coordinate system
prime focus photography in Newtonian scope
printable scale for calibration
processing steps for astrophotographs
process - my astrophotographic
profiling along a line in an image
programming pitfalls - angles (geometry)
programming with GRIP
projection - gnomonic
PSD image format
PSD image format
Psyche - minor planet 16
PV Cephei (Gyulbudaghian's nebula)
random noise
rank filter
RAW image format
RAW image - processing into a 16-bit image
RAW images - Bayer filter pattern with stars
RAW margins
reading images from disc
reasons for stacking multiple frames
recombining channels
red computer display
reducing an image
reflecting an image horizontally or vertically
reflections inside lenses
region of interest (ROI) detection in Java code
resolving power of telescope & camera pixels
RGB filter pattern
Rievaulx Abbey and the Milky Way
Rosette Nebula
rotating an image
RR Tauri and its variable nebula
ruined farmhouse in Weardale, twilight
S/N ratios
satellites of Jupiter - how to identify
satellite trail with atmospheric turbulence
saturation and star photos
saving images
saving images to disc
scale for calibration
scaling an image
scenery at night
Scutum (constellation), Milky Way in
Scutum - M11 open cluster
segmenting images in Java code
selecting images
Sesame service - use in star charts
Seven Sisters (M45, the Pleiades)
shapes for measuring
show GRIP window in front
show image in front
signal-to-noise ratios
single point measurements
sizes of images
SkyWatcher telescope documentation
slide show controls
SN2011fe supernova in M101
sodium lamps
solar eclipse 2015 Mar 20
source code for GRIP
spectrum of street lighting
spiral galaxy M101
splitting the channels of an image
squaring the circle
stacking multiple frames - why?
stacking photos different ways - the Plough
stacking process, flowchart
star chart, using AstroGrid, Sesame, Hipparcos and Tycho
star detection
star detection in Java code
star hopping using Hopper
star magnitude estimation
star photography - compact camera
star photography - trails
stars in RAW images - Bayer filter pattern
star trail length calculator
star trails
star trails (moonlit observatory)
star trails and castles
Stephan's quintet (of galaxies)
stop = Exposure Value (EV)
street lighting
stretching image contrast automatically
subtracting dark frames
subtracting images
Sudoku helper
Sun and sunspots
Sun Microsystems
sunspots, 2011 Oct 15
sunspots, 2011 Oct 16
sunspots, 2011 Oct 17
sunspots, 2011 Sep 8
sunspots (compare 4 days), 2011 Oct 18
supernova remnant M1
Supernova SN2011fe in M101
supernova SN2012aw in M95
SVG scale for calibration
table of open images
target finding with Hopper
telescope - 254mm Newtonian
telescope aiming with Hopper
telescope - camera piggy-back
telescope documentation
telescope field of view with camera
telescope mounts - equatorial & altazimuth
telescope resolving power & camera pixels
temperature affecting focus
terms, Java
Themis - minor planet 24
thermal noise
thermal noise in images
Theta Orionis - the Trapezium
thresholding images in Java code
TIFF image format
TIFF image format
TIFF - little- vs big-endian
trails of stars
Trapezium stars in the Orion nebula
troubleshooting GRIP
T Tauri and Hind's variable nebula
twinkling - Vega at 1/2000s
Tycho data file (tyc_main.dat)
Ursa Major constellation
V1722 Aql
V900 Mon variable nebula
variable nebula, RR Tauri
variable nebula (Gyulbudaghian's)
variable nebula (McNeil's)
variable nebula (NGC1555, Hind's)
variable nebula NGC 2261 (Hubble's)
variable nebula V900 Mon
variable star magnitude estimation
variance filter
Vega at 1/2000s (twinkling)
veil nebula
Veil Nebula in H-alpha & OIII
Venus, Jupiter & the Moon, 2012 Mar 26
Vesta - minor planet 4
view history
Virgo cluster of galaxies
Virgo cluster of galaxies - mosaic
Virgo constellation
Warkworth Castle and star trails
warping astrophotographs to match
Weardale farmhouse ruin in twilight
whirlpool galaxy M51
whole-sky astrophotography
why stack multiple frames?
Wild, Comet 63P
writing images to disc
XSLT generating these pages
Zeta Orionis (Flame and Horsehead Nebulae)
zooming images