Front Yard CCD Front Yard CCD AstrophotographAstrophotograph

yyJanuary 11, 2007January 11, 2007

My Recommendations for My Recommendations for startingstarting

Learn!Learn! Purchase/read “The New CCD Astronomy” by Purchase/read “The New CCD Astronomy” by

Ron WodaskiRon Wodaski Purchase/read “Photoshop for Purchase/read “Photoshop for

Astrophotographers” by Jerry LodrigussAstrophotographers” by Jerry Lodriguss SBIG users groupSBIG users group Websites: Websites:

http://www.rc-astro.com/http://www.rc-astro.com/ (Russell Croman) (Russell Croman) http://www.robgendlerastropics.com/http://www.robgendlerastropics.com/ (Robert (Robert

Gendler)Gendler) http://www.mistisoftware.com/astronomy/http://www.mistisoftware.com/astronomy/ (Jim Misti) (Jim Misti)

Club expert/mentor (John Boudreau)Club expert/mentor (John Boudreau) Webcam and planets/moonWebcam and planets/moon

What can I do?What can I do? Start: Photographs of the moon and Start: Photographs of the moon and

planetsplanets WebcamWebcam RegistaxRegistax Good scopeGood scope Moderate tracking abilityModerate tracking ability Works from light polluted areas (bright Works from light polluted areas (bright

objects)objects) Good results with minimal investment Good results with minimal investment

obtained from stacking hundreds of obtained from stacking hundreds of imagesimages

What can I do?What can I do? Deep-sky objects from Andover Deep-sky objects from Andover

Light pollution effects photograph quality Light pollution effects photograph quality (increased sky background noise )(increased sky background noise )

Long exposure times >5 hours/objectLong exposure times >5 hours/object Practical implications of seeing conditions Practical implications of seeing conditions Good to high level quality equipment Good to high level quality equipment

produce better quality photos produce better quality photos (expense/investment)(expense/investment)

Produce good quality photographsProduce good quality photographs Digital Development Processing algorithms Digital Development Processing algorithms

(DDP) and photo-processing “workflows” (DDP) and photo-processing “workflows” can correct many problems can correct many problems

Deep Sky CCD – Mount Deep Sky CCD – Mount SelectionSelection

Spend 60% of Spend 60% of money on Mountmoney on Mount Periodic error Periodic error

correction (PEC)correction (PEC) 30 sec exposure less 30 sec exposure less

importantimportant 30 min exposure 30 min exposure

requires good PEC requires good PEC and tracking (auto and tracking (auto guiding)guiding)

Telescope focal length Telescope focal length significant factorsignificant factor

Accurate auto-Accurate auto-guidingguiding

Worm-gear designWorm-gear design Motor designMotor design

Deep Sky-Mount Deep Sky-Mount SuggestionsSuggestions

I use Astro-Physics 900 GTOI use Astro-Physics 900 GTO Mounts others have usedMounts others have used

Losmandy (G11 and Titan)Losmandy (G11 and Titan) TakahashiTakahashi ParamountParamount Mountain InstrumentsMountain Instruments Meade (RX400, LX200)Meade (RX400, LX200) Celestron (CGE)Celestron (CGE)

Learn characteristics of Learn characteristics of your mount-Auto-guidingyour mount-Auto-guiding

BalanceBalance “ “Slight” east Slight” east

weightingweighting Appropriate selection Appropriate selection

of weights to center of weights to center moment armsmoment arms

Adjust worm gear / Adjust worm gear / meshmesh

Software or mount Software or mount firmware PEC firmware PEC correctioncorrection

Deep Sky CCD – Telescope Focal Length Deep Sky CCD – Telescope Focal Length (ref: “The New CCD Astronomy”)(ref: “The New CCD Astronomy”)

LengtLengthh

SeeingSeeing ApertApertureure

TargetTargetss

FlexibiliFlexibilityty

400-400-800800

RarelyRarely 3-6”3-6” Big Big targetstargets

Good-add Good-add BarlowBarlow

800-800-15001500

A A consideratconsiderat

ionion

5-10”5-10” More More targetstargets

Good if Good if focal focal

reducers reducers availableavailable

1500-1500-20002000

Always Always mattersmatters

8-16”8-16” Many Many more more

targetstargets

Good if Good if focal focal

reducers reducers availableavailable

Deep Sky – Telescope Deep Sky – Telescope SelectionSelection

Better optical quality provides sharp correct Better optical quality provides sharp correct color round starscolor round stars

Recommend match telescope with CCD Recommend match telescope with CCD camera (ref: camera (ref: http://www.sbig.com/sbwhtmls/online.htm)http://www.sbig.com/sbwhtmls/online.htm)

Telescope Field of ViewTelescope Field of View CCD chip sizeCCD chip size CCD chip pixel sizeCCD chip pixel size

Flat field neededFlat field needed Adapter for telescope (field flattener)Adapter for telescope (field flattener) Optical design with flat field (modified Petzval)Optical design with flat field (modified Petzval) Astro-Physics sells adapter for SBIG cameras that fits in Astro-Physics sells adapter for SBIG cameras that fits in

front of camera (front of camera (http://www.astro-physics.com/http://www.astro-physics.com/ - -CCD CCD Telecompressor (CCDT67))Telecompressor (CCDT67))

My Deep Sky Telescope My Deep Sky Telescope SelectionSelection

Takahashi FSQ 106 NTakahashi FSQ 106 N APO fluorite refractorAPO fluorite refractor Modified Petzval - 88mm Modified Petzval - 88mm

circle flat field imagecircle flat field image 4” focuser4” focuser 36036000 camera angle camera angle

adjusteradjuster Aperture 106mmAperture 106mm Focal length 530mmFocal length 530mm Compatible with large Compatible with large

CCD chips currently on CCD chips currently on marketmarket

Modified Petzval DesignModified Petzval Design

Deep Sky-CCD Camera Deep Sky-CCD Camera SelectionSelection

Anti-Blooming Gate (ABG)Anti-Blooming Gate (ABG) Easier to useEasier to use Less sensitiveLess sensitive

Non-Anti-Blooming Gate Non-Anti-Blooming Gate (NABG)(NABG) More sensitiveMore sensitive Careful planning of exposure time Careful planning of exposure time

needed (experience)needed (experience) Minor blooming can be fixedMinor blooming can be fixed

SoftwareSoftware Photo Processing takes more timePhoto Processing takes more time

Camera DesignsCamera Designs One-shot color cameraOne-shot color camera

Filters located on chip – no filter wheelFilters located on chip – no filter wheel Easy to use –good example is planets via Easy to use –good example is planets via

webcamwebcam Less flexibleLess flexible

Black and white with filter wheelBlack and white with filter wheel Flexible – can use many different types of Flexible – can use many different types of

filtersfilters More complex to photo-process to color imageMore complex to photo-process to color image Better control over quality and composition of Better control over quality and composition of

color imagecolor image

Match Camera, Telescope Match Camera, Telescope and Mountand Mount

Telescope focal length (ref: Telescope focal length (ref: http://www.sbig.com/sbwhtmls/online.hthttp://www.sbig.com/sbwhtmls/online.htm)m)

Ability of mount to track and guide Ability of mount to track and guide effectivelyeffectively Compensate for longer exposure times Compensate for longer exposure times

needed for ABG needed for ABG NABG better if short exposure times are NABG better if short exposure times are

needed to match mount capabilityneeded to match mount capability Light pollution-NABG offers advantageLight pollution-NABG offers advantage

Auto-guiding optionsAuto-guiding options

Separate CCD and Separate CCD and scope for guidingscope for guiding

Camera with built-in Camera with built-in guide chip (Santa guide chip (Santa Barbara Instrument Barbara Instrument Group, Inc (SBIG))Group, Inc (SBIG))

Don’t guideDon’t guide WebcamWebcam Short exposures (30 Short exposures (30

sec) and stack 50 – sec) and stack 50 – 200 images200 images

Improve signal to Improve signal to noise noise

My Camera Selection SBIG My Camera Selection SBIG ST-2000XM (ref: SBIG ST-2000XM (ref: SBIG

website)website)CCD

CCD Kodak KAI-2001M + TI TC-237

Pixel Array 1600 x 1200 pixels CCD Size 11.8 x 8.9 mm

Total Pixels 2 million Pixel Size 7.4 x 7.4 microns square

Full Well Capacity ~45,000 e- unbinned ~90,000 e- binned

Dark Current 2.5e-/pixel/sec at 0 deg. C. Antiblooming Standard

Readout Specifications

Shutter Electromechanical Exposure 0.001 to 3600 seconds

Correlated Double Sampling Yes A/D Converter 16 bits

A/D Gain 0.18e-/ADU unbinned Read Noise 13.5e- rms

Binning Modes 1 x 1, 2 x 2, 3 x 3 Pixel Digitization Rate ~ 425kps Full Frame Download ~ 4.5 seconds

My Camera Selection SBIG My Camera Selection SBIG ST-2000XM (ref: SBIG ST-2000XM (ref: SBIG

website)website)

My Camera Selection SBIG My Camera Selection SBIG ST-2000XMST-2000XM

My Camera Selection SBIG ST-My Camera Selection SBIG ST-2000XM2000XM

Photo Session-Focus Photo Session-Focus

Maxim DL Maxim DL SoftwareSoftware View of star size View of star size

and number of and number of small faint starssmall faint stars

Optimize for Optimize for maximum intensity maximum intensity for star (signal)for star (signal)

Optimize for Full Optimize for Full Width at Half Width at Half Maximum (FWHM)Maximum (FWHM)

Focus Zen-Maxim DLFocus Zen-Maxim DL Gross focus with imaging chip at 2 binGross focus with imaging chip at 2 bin Fine focus small selected area of CCD at Fine focus small selected area of CCD at

full resolution 1binfull resolution 1bin Set exposure time at >2 sec so that Set exposure time at >2 sec so that

changes in seeing are not major factorchanges in seeing are not major factor Watch temperatureWatch temperature

FSQ in focus range is 35 micronsFSQ in focus range is 35 microns Temperature change >2Temperature change >200F causes stars to F causes stars to

bloat and loss in signalbloat and loss in signal Focus-aid: Plan to purchase Robo-FocusFocus-aid: Plan to purchase Robo-Focus

Photo Session – ObjectPhoto Session – Object Study objectStudy object

Size (mosaic will need to be planned)Size (mosaic will need to be planned) ColorColor BrightnessBrightness

Globular cluster uniformGlobular cluster uniform Galaxy Bright core faint outer regionGalaxy Bright core faint outer region Nebula have strong narrow band emissionsNebula have strong narrow band emissions

Filter selectionFilter selection Luminance for white light detail (L)Luminance for white light detail (L) Red, Blue, Green (RGB) for colorRed, Blue, Green (RGB) for color Halpha (656.26 nm) narrow band filter for red nebulaHalpha (656.26 nm) narrow band filter for red nebula Narrow band filter compositesNarrow band filter composites

Match filters to object and combine (LRGB, Match filters to object and combine (LRGB, RRGB, HalphaGB, LHalphaRGB)RRGB, HalphaGB, LHalphaRGB)

Photo Session – Frame Photo Session – Frame and Lockand Lock

Locate objectLocate object Roughly frame object on image chipRoughly frame object on image chip Find suitable guide-star (>25000 Find suitable guide-star (>25000

ADU for filter transmitting lowest ADU for filter transmitting lowest signal – Halpha)signal – Halpha)

Finalize object framingFinalize object framing Lock on guide starLock on guide star Auto-guideAuto-guide

Photo Session-CCD Camera Photo Session-CCD Camera Correction FramesCorrection Frames

Dark Frames. Dark Frames. Correct for dark Correct for dark current that current that increases as a increases as a function of time and function of time and temperature temperature (Thermal signal)(Thermal signal)

Bias Frames. Bias Bias Frames. Bias that occurs when that occurs when pixel is read by pixel is read by camera (Zero light camera (Zero light exposure)exposure)

Photo Session – Flat Field Photo Session – Flat Field Correction for OpticsCorrection for Optics

Taking Flat Field FramesTaking Flat Field Frames