Embed Size (px)
Citation preview
CCD ImagingCCD Imaging
David RichardsDavid Richards2004-04-132004-04-13
All astronomical images taken All astronomical images taken by David Richards, 2001-2004by David Richards, 2001-2004
(Meade 8” LX200 SCT / SBIG ST-7E )(Meade 8” LX200 SCT / SBIG ST-7E )
CCD ImagingCCD Imaging IntroductionIntroduction
Example CCD TargetsExample CCD Targets Typical CCD Results compared to Eyepiece View Typical CCD Results compared to Eyepiece View
CCD Imaging BasicsCCD Imaging Basics Components of a raw CCD ImageComponents of a raw CCD Image Image Reduction and Processing (Light, Dark and Flat Frames)Image Reduction and Processing (Light, Dark and Flat Frames)
CCD CamerasCCD Cameras CCD Chips and CamerasCCD Chips and Cameras Considerations when choosing a CCD Camera Considerations when choosing a CCD Camera Colour ImagingColour Imaging Comparison with Eyepiece View and FilmComparison with Eyepiece View and Film
CCD Images CCD Images Moon, PlanetsMoon, Planets Asteroids, CometsAsteroids, Comets Stars, Clusters & NebulaStars, Clusters & Nebula Galaxies, SupernovaGalaxies, Supernova
Science with CCD CameraScience with CCD Camera AstrometryAstrometry PhotometryPhotometry
Example CCD TargetsExample CCD Targets
Planets and other Solar System Objects
Galaxies
Stars and Clusters
Nebulae
Typical CCD result compared with Typical CCD result compared with Eyepiece ViewEyepiece View
CCD (processed)
Eyepiece View
M51 (Ursa Major)15 x 1 min exposures
Simulated
Notebook Drawing, 1997
Longer Exposure – Greater Longer Exposure – Greater Magnitude ReachMagnitude Reach
Consecutive CCD images (star field in Milky Way in Cygnus)2003-08-05 5.2 x 7.6 arc mins (suburban site, Dorset, UK)The 10 sec exposure reaches to mag +12.0 whilst the 40 sec exposure reaches to +13.5
Deep Sky - Abell 744 Galaxy Deep Sky - Abell 744 Galaxy Cluster Cluster
CCD Image, 3 x 60 sec exposure (summed) The image records distant galaxies down to magnitude +17
0 0 0 0 0
0 1 5 1 0
0 7 67 3 0
0 2 8 1 0
0 0 0 0 0
CCD Imaging – The CCD Imaging – The BasicsBasics
RamHard Drive
Software
Computer
CCD Camera (CCD Chip, Circuit Board, Electronics, Shutter, Cooling Equipment, Housing)
CCD Chip
Computer Screen
0 0 0 0 0
0 1 5 1 0
0 7 67 3 0
0 2 8 1 0
0 0 0 0 0USB or Parallel Cable
Electronics
Light Sensitive Areaphotons recorded as electrons in ‘square light buckets’
Shutter
Attachment
Object
Photon
Telescope Focuser
CCD Imaging involves some CCD Imaging involves some workwork
Final Image
Single Raw Image
Single Raw Image
Raw CCD ImageRaw CCD Image
Let’s examine the components of this image
Light from Galaxies and Stars Light from Sky / Aberdeen
Cosmic Ray
Dark Current Read Out Noise
Defective Pixel(s)
DustShadows
Light Gradient
Vignetting
Noise Noise
Pixel to PixelVariation in Sensitivity
Noise Satellite Or Aircraft Trail
15 stacked frames (summed, no alignment)
Stacking increases S/NStacking increases S/NSingle Raw Image (realtime contrast) Single Raw Image (adjusted contrast)
15 stacked frames (aligned and summed) 15 stacked frames (aligned & median combined)
Cross-Section through a CCD Cross-Section through a CCD Image Image (1)(1)
CrossSection
Light from3 Objects
Simulated image of light reaching camera in earth orbit
Simulated image of light reaching camera at Sea Level
0
50
100
150
200
250
300
Dust Vignetting
Read Noise Thermal Noise Hot Pixels
Light Pollution Object
-50
0
50
100
150
200
250
Cross-Section through a Cross-Section through a CCD (2)CCD (2)
Light from3 Objects
(after dispersionthrough theatmosphere)
0
50
100
150
200
250
300
1
Object Threshold
-50
0
50
100
150
200
250
Cross-Section through a Cross-Section through a CCDCCD
Raw Image asrecorded
Sky brightnessSky brightness
0
50
100
150
200
250
300
Dust Vignetting
Read Noise Thermal Noise Hot Pixels
Light Pollution Object
-50
0
50
100
150
200
250
Cross-Section through a Cross-Section through a CCD (3)CCD (3)
Addition of Sky Glow /Light Pollution
Effect of Vignetting and Effect of Vignetting and Dust and Pixel-to-Pixel Dust and Pixel-to-Pixel Variation in SensitivityVariation in Sensitivity
Av. 40 x 0.5 sec flat frames (tee-shirt flats)
0
50
100
150
200
250
300
Dust Vignetting
Read Noise Thermal Noise Hot Pixels
Light Pollution Object
-50
0
50
100
150
200
250
Cross-Section through a Cross-Section through a CCD (4)CCD (4)
Vignetting atedge of frame
0
50
100
150
200
250
300
Dust Vignetting
Read Noise Thermal Noise Hot Pixels
Light Pollution Object
-50
0
50
100
150
200
250
Cross-Section through a Cross-Section through a CCD (5)CCD (5)
Absorption of light from duston lenses andCCD window/ chip
and
Variation inPixel to PixelSensitivity
Dark CurrentDark Current(electrons counted due to ‘heat’, even in the (electrons counted due to ‘heat’, even in the
absence of light)absence of light)
0
50
100
150
200
250
300
Dust Vignetting
Read Noise Thermal Noise Hot Pixels
Light Pollution Object
-50
0
50
100
150
200
250
Cross-Section through a Cross-Section through a CCD (6)CCD (6)
Addition of thermal electronsduring exposure(includes noise)
Dark Current vs TimeDark Current vs Time10 sec
60 sec
120 sec
300 sec
All Frames -25 deg Cand identical white-black range(Black = 0 ADU / White = 1000 ADU)
Dark Current vs Dark Current vs TemperatureTemperature
All Frames 60s exposureand identical white/black range(Black = 150 ADU, White = 300 ADU)
-5 deg C
-15 deg C
-25 deg C
Colder
Astronomical Cameras typically cool CCD chips to 30 deg C below ambient (using Peltier cooling)
Dark Current vs CameraDark Current vs CameraSimulated 60s exposuresshown with identical white/black ranges
Low Spec Camera -15 deg C
Mid Spec Camera -15 deg C
High Spec Camera -15 deg C
High SpecCameras
Cosmic RaysCosmic RaysDark Frame
Dark Frame Dark Frame
Light Frame
Read Out NoiseRead Out Noise(Bias Frame – a 0 sec exposure)(Bias Frame – a 0 sec exposure)
-15 deg C
0
50
100
150
200
250
300
Dust Vignetting
Read Noise Thermal Noise Hot Pixels
Light Pollution Object
-50
0
50
100
150
200
250
Cross-Section through a Cross-Section through a CCD (7)CCD (7)
Addition ofReadoutNoise (+/-)
0
50
100
150
200
250
300
1
Object Threshold
-50
0
50
100
150
200
250
Cross-Section through a Cross-Section through a CCD (9)CCD (9)
Raw Image asrecorded
0
50
100
150
200
250
300
1
Object Threshold
Cross-Section through a Cross-Section through a CCD (10)CCD (10)
-50
0
50
100
150
200
250
Raw Image with Black Thresholdapplied
Compare with light from 3 objects
-50
0
50
100
150
200
250
Object
Getting Good ImagesGetting Good ImagesA principal aim during imaging (and subsequent reduction) is to maximise the A principal aim during imaging (and subsequent reduction) is to maximise the Signal-To-Noise (S/N) in order to get the best image of the astronomical object.Signal-To-Noise (S/N) in order to get the best image of the astronomical object.
Techniques include :Techniques include :
Minimise noise from sky light by imaging from a dark site (if possible)Minimise noise from sky light by imaging from a dark site (if possible) Cool the CCD Chip as far as possible (temperature control important)Cool the CCD Chip as far as possible (temperature control important) Use longest exposure that telescope can track for without drifting, and Use longest exposure that telescope can track for without drifting, and
without over-saturating the chip.without over-saturating the chip. Using on camera pixel binning (may decrease resolution – but not if seeing Using on camera pixel binning (may decrease resolution – but not if seeing
limited)limited) Use camera with low read out noise / low dark currentUse camera with low read out noise / low dark current Reduce images to remove dark current, allow for the varying response of each Reduce images to remove dark current, allow for the varying response of each
CCD pixel and remove the impacts of vignettting and dust on CCD chips or CCD pixel and remove the impacts of vignettting and dust on CCD chips or telescope opticstelescope optics
Minimise read-out and dark noise (using Median of multiple Dark Frames)Minimise read-out and dark noise (using Median of multiple Dark Frames) Use average (or median) of multiple Flat FramesUse average (or median) of multiple Flat Frames Use stacking to ‘add’ light from target, whilst cancelling noise – thereby Use stacking to ‘add’ light from target, whilst cancelling noise – thereby
increasing the S/Nincreasing the S/N
Longer Exposure – Longer Exposure – Higher S/NHigher S/N
Reduction Steps (1)Reduction Steps (1)
0
50
100
150
200
250
300
1
Dark Reduced Signal
0
50
100
150
200
250
300
1
Object Threshold
-50
0
50
100
150
200
250
Removal of Dark Frame (an image with same exposure length but taken with closed shutter)
Done in order to reduce read-out & thermal noise
Dark FrameRaw Light Frame Dark Reduced Frame
- =
Reduction & Processing Reduction & Processing ExampleExample
Dark Frame (median of 9)
Raw Light Frame (60s) Reduced Light Frame
Final Image (15 frames stacked)
Reduction Steps (2)Reduction Steps (2)
0
50
100
150
200
250
300
1
Raw Flat
0
50
100
150
200
250
300
Dust Vignetting
Read Noise Thermal Noise Hot Pixels
Light Pollution Flat Light
-50
0
50
100
150
200
250
Creation of Flat Frame
Even Light Raw Flat Frame
Flat Frame (after dark subtraction)Raw Flat Frame
- =
Dark Frame (same exposure as flat frame)
-50
0
50
100
150
200
250
Flat Light
0
50
100
150
200
250
300
1
Raw Flat
-50
0
50
100
150
200
250
-50
0
50
100
150
200
250
Flat FrameFlat Frame
Av. 40 x 0.5 sec flat frames (tee-shirt flats)
Reduction Steps (3)Reduction Steps (3)
0.000
0.200
0.400
0.600
0.800
1.000
1.200
1.400
1.600
1.800
2.000
1
Normalised Flat
0
50
100
150
200
250
300
1
Raw Flat
0.000
0.200
0.400
0.600
0.800
1.000
1.200
1.400
1.600
1.800
2.000
1
Normalised Flat
0
50
100
150
200
250
300
1
Dark Reduced Signal
-50
0
50
100
150
200
250
Dark Reduced Frame
Normalised FlatFlat
/
/
-50
0
50
100
150
200
250
-50
0
50
100
150
200
250
Normalised Flat
AverageFlat Field Value
=
0
50
100
150
200
250
300
1
Light
-50
0
50
100
150
200
250
Final Image
Final ProcessingFinal Processing
0
50
100
150
200
250
300
1
Light
0
50
100
150
200
250
300
1
Light Threshold
0
50
100
150
200
250
300
1
Light
-50
0
50
100
150
200
250
Final Image (with Black Threshold Set)Final Reduced Image
-50
0
50
100
150
200
250
Wavelet (assumed shape of atmospheric
dispersion)
-50
0
50
100
150
200
250
Final Reduced Image
0
50
100
150
200
250
300
1
Deconvolved Light Threshold
Processed (Deconvolved) Image
Deconvolved with
=
The challenge of recording very faint The challenge of recording very faint objectsobjects
Attempt at imaging 2004 DW (a mag +19 Kuiper Belt Object). Star field in Hydra with the predicted position of Kuiper object
marked by green circle. 2 x 5 min exposure (summed)Faintest visible objects are mag +17.7
Reduction/Stacking Example Reduction/Stacking Example IC 434 (Horsehead Nebula)IC 434 (Horsehead Nebula)
60s Raw
60s Reduced (dark subtract)
11 aligned frames summed
Final Image
Reduction/Stacking Reduction/Stacking Example Example NGC 2903NGC 2903
60s Raw
60s Reduced (dark subtract)
Average 10 x 60s
CCD CamerasCCD CamerasSBIG (USA)e.g ST-7e, $1995 (US) Starlight Express (UK)
e.g HX-916 (Mono) £1395
WebCameg Philip ToUCam Pro II, £75
HX7-C (Colour) £995
Low Light Videoe.g. Watec 120N, £579 e.g. Astrovid,
$ 995 (US)
Apogee (USA)
Example range of CCD Example range of CCD CamerasCameras Cookbook CCD CamerasCookbook CCD Cameras
TC-211 (Mono)TC-211 (Mono) 13.8 x 16um,13.8 x 16um, 192 x 164 px, 2.6 x 2.6mm192 x 164 px, 2.6 x 2.6mm £50-100 £50-100
Electronic EyepiecesElectronic Eyepieces Meade Electronic EyepieceMeade Electronic Eyepiece TV/VCR/Camcorder connectionTV/VCR/Camcorder connection £90£90
WebCam Based CamerasWebCam Based Cameras
Philips ToUCam ProPhilips ToUCam Pro , Video, Video 5.6 x 5.6um,5.6 x 5.6um, 640 x 480 px, 4.6 x 4.0mm640 x 480 px, 4.6 x 4.0mm £75£75
Digital CamerasDigital CamerasVariousVarious £200 - £400£200 - £400
Long Exposure Video CCD CamerasLong Exposure Video CCD CamerasMinitronMinitron £299£299Watec 120NWatec 120N 8.6 x 8.6 um, 752 x 582 px, 6.5 x 5.0 mm, 0.00002 lx , 0.15 kg8.6 x 8.6 um, 752 x 582 px, 6.5 x 5.0 mm, 0.00002 lx , 0.15 kg £579£579
Smaller CCD CamerasSmaller CCD CamerasStarlight Express MX5 (Mono) Starlight Express MX5 (Mono) 9.8 x 12.6um, 500 x 290 px, 4.9 x 3.6mm, 9.8 x 12.6um, 500 x 290 px, 4.9 x 3.6mm, £495£495Starlight Express MX5C (Colour) Starlight Express MX5C (Colour) £620£620
‘‘Standard’ Size CCD CamerasStandard’ Size CCD CamerasStarlight Express MX716 (Mono) Starlight Express MX716 (Mono) 8.6 x 8.3um, 8.6 x 8.3um, 752 x 580 px, 6.47 x 4.83mm, 0.2kg, 752 x 580 px, 6.47 x 4.83mm, 0.2kg, £895£895SBIG ST-7XME, SBIG ST-7XME, 9 x 9 um, 9 x 9 um, 765 x 510 px, 6.9 x 4.9 mm, 0.9 kg, 765 x 510 px, 6.9 x 4.9 mm, 0.9 kg, $1995 (US)$1995 (US)
Large Format CCD CamerasLarge Format CCD Cameras Starlight Express HX916 (Mono) Starlight Express HX916 (Mono) 6.7 x 6.7um, 1300 x 1030 px, 8.71 x 6.9mm, 0.25 kg, 6.7 x 6.7um, 1300 x 1030 px, 8.71 x 6.9mm, 0.25 kg, £1345£1345SBIG ST-9XSBIG ST-9X 20 x 20um,20 x 20um, 512 x 512 px512 x 512 px , 10.2 x 10.2 mm, 10.2 x 10.2 mm $3195 (US)$3195 (US)SBIG ST-8XME, SBIG ST-8XME, 9 x 9 um, 9 x 9 um, 1530 x 1020 px, 13.8 x 9.2 mm, 0.9 kg, 1530 x 1020 px, 13.8 x 9.2 mm, 0.9 kg, $5995 (US)$5995 (US)
Very Large Format CCD CamerasVery Large Format CCD CamerasStarlight Express SXV-M25 (Col) Starlight Express SXV-M25 (Col) 7.8 x 7.8um, 3000 x 2000 px, 23.4 x 15.6mm, 7.8 x 7.8um, 3000 x 2000 px, 23.4 x 15.6mm, Spring 2004Spring 2004SBIG STL-11000CMSBIG STL-11000CM9 x 9 um, 9 x 9 um, 4008 x 2745 px, 36 x 24.7mm (26 sec download)4008 x 2745 px, 36 x 24.7mm (26 sec download) $8995 (US)$8995 (US)
Considerations when choosing a Considerations when choosing a CCD CameraCCD Camera
Chip Size / Pixel Size / Number of Pixels / Pixel ShapeChip Size / Pixel Size / Number of Pixels / Pixel Shape Match with Telescope Focal LengthMatch with Telescope Focal Length Sensitivity of CCD Sensitivity of CCD Dark Current / Read NoiseDark Current / Read Noise Cooling / Temperature Regulation / ShutterCooling / Temperature Regulation / Shutter Digitisation (12 bit/ 16 bit)Digitisation (12 bit/ 16 bit) Linearity of CCD / Capacity of a pixelLinearity of CCD / Capacity of a pixel Anti-Blooming (ABG vs NABG)Anti-Blooming (ABG vs NABG) CCD Quality / Defective PixelsCCD Quality / Defective Pixels Camera Weight / SizeCamera Weight / Size Binning / Windowing CapabilitiesBinning / Windowing Capabilities Download Speed, USB / Parallel Download Speed, USB / Parallel Self Guiding CapabilitiesSelf Guiding Capabilities Single Shot Colour / Filter Wheel attachment Single Shot Colour / Filter Wheel attachment SoftwareSoftware CostCost Reliability / SupportReliability / Support
Example Spectral Response Example Spectral Response CurvesCurves
CCD Chip Sizes Compared CCD Chip Sizes Compared with 35mm Filmwith 35mm Film
35mm film
KAF0400ST7
KAF1600ST8
SLR
Camera
New Large Format Cameras
TC211
Matching CCD and Matching CCD and Telescope (1)Telescope (1)
Calculating Image Scale (arc secs per pixel)Calculating Image Scale (arc secs per pixel)
Image Scale = 206 x pixel size (in um) Image Scale = 206 x pixel size (in um) --------------------- --------------------- focal_length (in mm) focal_length (in mm)
e.g for SBIG ST-7 and 8” f/10 SCT e.g for SBIG ST-7 and 8” f/10 SCT Pixel Size = 9 umPixel Size = 9 umFocal length = 25.4 x 8 x 10 = 2032 mmFocal length = 25.4 x 8 x 10 = 2032 mmImage Scale at 1x1 binning = 206 x 9 / 2032 Image Scale at 1x1 binning = 206 x 9 / 2032 = 0.9 arc sec/pixel= 0.9 arc sec/pixelImage Scale at 2x2 binning = 206 x 18/2032 Image Scale at 2x2 binning = 206 x 18/2032 = 1.8 arc sec /pixel= 1.8 arc sec /pixel
Typical seeing is 2-4 arc sec, so 2x2 binning (1.8 arc sec/pixel) is about right Typical seeing is 2-4 arc sec, so 2x2 binning (1.8 arc sec/pixel) is about right (At 2x2, sensitivity is better and downloads are much faster, but images are only 382 x (At 2x2, sensitivity is better and downloads are much faster, but images are only 382 x 255)255)
1x1 binning only really of benefit when imaging planets when there is benefit in 1x1 binning only really of benefit when imaging planets when there is benefit in sampling at <1 arc sec, and there is opportunity to benefit from brief moments of sampling at <1 arc sec, and there is opportunity to benefit from brief moments of exceptional seeingexceptional seeing
With Focal Reducer (63%) 1x1 binning = 1.3 arc sec/pixel, 2x2 binning = 2.5 arc With Focal Reducer (63%) 1x1 binning = 1.3 arc sec/pixel, 2x2 binning = 2.5 arc sec/pixelsec/pixel
General rule : chose CCD (or choose Telescope) that gives around 2 arc sec General rule : chose CCD (or choose Telescope) that gives around 2 arc sec /pixel/pixel
Matching CCD and Matching CCD and Telescope (2)Telescope (2)
Calculating Field Of ViewCalculating Field Of View
Field (Horizontal) in arc mins Field (Horizontal) in arc mins = Image Scale x No. pixels (horizontal) / 60= Image Scale x No. pixels (horizontal) / 60Field (Vertical) in arc mins) Field (Vertical) in arc mins) = Image Scale x No. pixels (vertical) / 60= Image Scale x No. pixels (vertical) / 60
e.g for SBIG ST-7 and 8” f/10 SCT e.g for SBIG ST-7 and 8” f/10 SCT Pixel Size = 9 um, Pixel Size = 9 um, Focal length = 25.4 x 8 x 10 = 2032 mmFocal length = 25.4 x 8 x 10 = 2032 mmImage Scale at 1x1 binning = 206 x 9 / 2032 Image Scale at 1x1 binning = 206 x 9 / 2032 = 0.9 arc sec/pixel (765 x = 0.9 arc sec/pixel (765 x
510)510)
Field (Horizontal) Field (Horizontal) = 0.9 x 765/60 = 11.4 arc min = 0.9 x 765/60 = 11.4 arc min Field (Vertical) Field (Vertical) = 0.9 x 510/60 = 7.7 arc min= 0.9 x 510/60 = 7.7 arc min
With focal reducer (63%) Image Scale at 2x2 = 2.5 arc sec/pixel (382 x 255)With focal reducer (63%) Image Scale at 2x2 = 2.5 arc sec/pixel (382 x 255)Field (Horizontal) Field (Horizontal) = 2.5 x 382/60 = 15.9 arc min = 2.5 x 382/60 = 15.9 arc min Field (Vertical) Field (Vertical) = 2.5 x 255/60 = 10.6 arc min= 2.5 x 255/60 = 10.6 arc min
General rule : Dependant of proposed Targets chose a Camera with a General rule : Dependant of proposed Targets chose a Camera with a larger dimension CCD to gives a larger FOV (price will be a limitation).larger dimension CCD to gives a larger FOV (price will be a limitation).
Alternatively select a low focal ratio telescope (eg f/4) or use a focal Alternatively select a low focal ratio telescope (eg f/4) or use a focal reducerreducer
CCD Cameras – with ordinary CCD Cameras – with ordinary Camera LensCamera Lens
CCD Cameras can also CCD Cameras can also be used piggy-backed be used piggy-backed to a Telescope and to a Telescope and fitted with ordinary fitted with ordinary camera lenses. This camera lenses. This can provide wider can provide wider fields of viewfields of view
Important to use Good Important to use Good Quality LensesQuality Lenses
ST7e with 200mm ST7e with 200mm lenslens
Long Exposures / Long Exposures / Guiding (1)Guiding (1)
Unless a scope is perfectly polar aligned and has perfect Unless a scope is perfectly polar aligned and has perfect tracking, stars will trail on long exposures (at focal length of tracking, stars will trail on long exposures (at focal length of 2000mm this might be observed after only 2 mins exposure)2000mm this might be observed after only 2 mins exposure)
Two main solutions to the problemTwo main solutions to the problem- Take short (60 sec) exposures, then align & stack- Take short (60 sec) exposures, then align & stack- Guide the telescope during the exposure- Guide the telescope during the exposure
Simulated unguided image
of M5112 min exposure
Long Exposures / Long Exposures / Guiding (2)Guiding (2) CCD manufactures have developed several alternative guiding CCD manufactures have developed several alternative guiding
solutions :solutions :
Track and Accumulate (SBIG)Track and Accumulate (SBIG)
Separate CCD Camera (e.g Meade)Separate CCD Camera (e.g Meade)
Self Guided (SBIG)Self Guided (SBIG)
Star2000 (Starlight Express)Star2000 (Starlight Express)
Main Camera
Guide Camera
Telescope
Main CCD
Guide CCD
Camera
ExposeExpose ExposeGuide Guide
Off-AxisFinder
Interline CCD Image FrameGuide Frames
Colour Imaging (1)– Single-Shot Colour Imaging (1)– Single-Shot CamerasCameras
Colour Imaging (2)– Using Colour Imaging (2)– Using FiltersFilters
SBIG CFW-8A
Red, Blue, Green, Clear Filters
Option to take and image in other filter bands
e.g UBRVI for photometry
Colour Filter WheelColour Filter Wheel
Colour Imaging – with Colour Imaging – with FiltersFilters
Red (Av. 3x10s) Green (Av. 3x10s) Blue (Av. 3x20s)
Luminance (Av. 6x10s) Colour Image (LRGB)
M42(Orion)
CCD Imaging compared with CCD Imaging compared with Eyepiece ViewingEyepiece Viewing
+ve +ve Can ‘see’ fainter objects (i.e. can ‘see’ objects impossible to see with the Can ‘see’ fainter objects (i.e. can ‘see’ objects impossible to see with the
naked eye)naked eye) Much easier to record and share what has been ‘seen’ Much easier to record and share what has been ‘seen’ Can generally ‘see’ more detail in objects (particularly nebula)Can generally ‘see’ more detail in objects (particularly nebula) Can find and locate objects more quickly (with appropriate software)Can find and locate objects more quickly (with appropriate software) Can even view from the leisure of indoors (with remote connection)Can even view from the leisure of indoors (with remote connection) Can playback /animate motion of slowly moving objects (eg Pluto)Can playback /animate motion of slowly moving objects (eg Pluto) Can acquire the colour of faint objects (ones which look grey to naked eye)Can acquire the colour of faint objects (ones which look grey to naked eye) Can undertake more accurate (certainly easier) astrometry and Can undertake more accurate (certainly easier) astrometry and
photometryphotometry
-ve -ve Some objects more impressive with naked eyeSome objects more impressive with naked eye
(eg red/blue double star , Jupiter + moons)(eg red/blue double star , Jupiter + moons) Loose some of that ‘3D’ effect & feelings of awe Loose some of that ‘3D’ effect & feelings of awe Difficulty of claiming one actually Difficulty of claiming one actually sawsaw / / observedobserved the object the object Realtime CCD images are often very noisyRealtime CCD images are often very noisy
Typical realtime CCD image Typical realtime CCD image compared with compared with Eyepiece View Eyepiece View
CCD (raw image on screen)
Eyepiece View
M51 (Ursa Major)1 min exposure
CCD – Comparisons with CCD – Comparisons with FilmFilm
+ve +ve CCD Images immediately available (no waiting on CCD Images immediately available (no waiting on
film lab)film lab) Digital (no need to scan in order to process Digital (no need to scan in order to process
further),further),Easier manipulation - ability to stackEasier manipulation - ability to stack
Light record is linear (no recripicty)Light record is linear (no recripicty) With suitable software the image can be used to With suitable software the image can be used to
automatically locate telescope position or to guide automatically locate telescope position or to guide the telescope.the telescope.
-ve -ve Smaller image area FOV (typically only ~ 20% that Smaller image area FOV (typically only ~ 20% that
of 35mm film)of 35mm film)
Comparisons of CCD Images with Comparisons of CCD Images with Film and Eyepiece ObservationsFilm and Eyepiece Observations
CCDFilmRecording of naked eye observation
Presentations
Own records
World Wide Web
Astronomical Records
Use and Sharing of CCD Use and Sharing of CCD ImagesImages
CCD Images (2001-2004)CCD Images (2001-2004)
MoonMoon
Moon – Apollo 17 Moon – Apollo 17 Landing SiteLanding Site
PlanetsPlanetsVenus 2004 Mars 2003 Jupiter 2003 Saturn 2001
Uranus 2002 Neptune 2002 Pluto 2003
Jupiter / Saturn / Uranus Jupiter / Saturn / Uranus MoonsMoons
Six of Saturn's moons appear in this CCD Image (2 sec exposure)
Asteroids (Minor Asteroids (Minor Planets)Planets)
Animated Sequence of 10 CCD Images of Minor Planet Kleopatra (216)
The animation records 58 arc sec motion of the minor planet over a period of 1 hr 56 min (= 30 arc sec/hour).
Near Earth AsteroidNear Earth Asteroid
CometsComets
Comet C/2000 WM1 (LINEAR)2001-Nov
(passing through star field in Aries)
C/2002 T7 (Linear)2004-Feb
(passing through star field in Pegasus)
Clusters in Gemini (CCD Mosaic)Clusters in Gemini (CCD Mosaic)
M35
NGC 2158
M45 Pleiades (CCD M45 Pleiades (CCD Mosaic)Mosaic)
Double Cluster In Perseus Double Cluster In Perseus (7 x 6 CCD Mosaic, 20s exposures)(7 x 6 CCD Mosaic, 20s exposures)
Globular ClusterGlobular Cluster
M15 (Pegasus), 6 x 10s
Extra-Solar Planets ?Extra-Solar Planets ?
HD 209458 (Pegasus) has a transiting Jupiter mass short period extrasolar planet.(HD 209458-b). Every 3.5 days, the planet produces a dimming of the star of 1.7 % that lasts for about 3 hours. The dimming has been detected by Castellano and Laughlin using almost identical equipment to me (ie 8" telescope and ST-7E CCD camera), which presents me the opportunity to also have a go at trying to detect a extra-solar planet lying at a distance of 1.45 x 1015 km (153 light years) from Earth..
NebulaNebulaM57 Ring Nebula (Lyra) M16 Eagle Nebula (Serpens Caput)
M27 Dumbbell Nebula (Vulpecula)
NGC 2261 - Hubble's Variable Nebula (Monoceros)
GalaxiesGalaxies
NGC 2903 Spiral Galaxy
NGC 7331(Pegasus)
M64 Black-eye Galaxy(Coma Berenices)
M100 (Coma Berenices)
NGC 4567 / 4568(Virgo)
NGC 2903 (Leo)
M105 (Leo)
Galaxy ClusterGalaxy ClusterNGC 7320 Galaxy Cluster (Stephan's Quintet, Andromeda)
The 5 main galaxies range frommagnitude +13.6 to + 14.8
Faintest galaxy in image is +16.6
2002-10-02 21:44 to 21:51h UTCCD Image, 2 x 2 min exposure (2x2 binning)11.4 x 7.6 arc min (#28003 & 28005)
Supernova / Supernova Supernova / Supernova RemnantsRemnants
SN 2001ib, 2001-Dec M1, Crab Nebula
Colour Imaging - 2004Colour Imaging - 2004NGC 2392 Planetary Nebula (Eskimo or Clown Face Cluster)
Saturn Jupiter
M42 Orion
NGC 2903 Spiral Galaxy, Leo
NGC 1857, Auriga
More Recent ImagesMore Recent Images
NGC 3628 Spiral Galaxy, Leo
M63 Spiral Galaxy (Sunflower Galaxy)
M65 M65 AreaArea
Out-takes (1)Out-takes (1)
Out-takes (2)Out-takes (2)
