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Moravian Instruments G3 SERIES, Руководство по эксплуатации

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diameter. Focusing, especially on fast telescopes, is critical for sharp 
images. Electrical focuser is a huge advantage, because it allows 
focusing without shaking the telescope by hand and with precision 
surpassing the manual focusing.

Keep on mind that the star images are affected not only by focusing, 
but also by seeing. Star images will be considerably bigger in the night 
of poor seeing, no matter how carefully you focus.

●

Master image calibration (dark frame subtraction and flat fielding) and 
carefully calibrate all images. Various artifacts (thermal noise, hot 
pixels, gradients, telescope/lens vignettation, dust particles on filters 
etc.) degrade the image and properly calibrated image always looks 
better. Take care to obtain dark frames and flat fields for all filters 
used, for all resolutions/binnings etc.

●

If the image is processed to be as aesthetic as possible, other 
processing than basic calibration can significantly improve its 
appearance. Nonlinear stretching (called “curves” in some image-
editing packages), special filters (hot/cold pixels removal, noise 
reduction etc.) and other processing (e.g. deconvolution) enhances the 
image.

Warning:

Never perform these enhancing filters on images intended for data 
reduction processing. It is always good idea to store original image 
and to enhance only its copy. Scientific information can be 
significantly degraded by various noise filters, deconvolution etc. If 
for instance the image of some galaxy contains newly discovered 
supernova, photometric reduction of the original image can be 
scientifically very important.

●

A common saying “there is a science in every astronomical picture” is 
especially true for CCD images. Examine your images carefully, blink 
them with older images of the same object or field. There is always a 
chance some new variable star, new asteroid, new nova or supernova 
appear in the image.

●

Be patient. Although many advertisements proclaim “capture images 
like these your first night out”, they probably mean your first 
successful night out. Nights can become cloudy or foggy, the full 

51

Содержание G3 SERIES

Страница 1: ...G3 and G4 CCD Operating Manual ...

Страница 2: ...authorized for and should not be used within Life Support Systems without the specific written consent of the Moravian Instruments Product warranty is limited to repair or replacement of defective components and does not cover injury or property or other consequential damages Copyright 2000 2012 Moravian Instruments Moravian Instruments Masarykova 1148 763 02 Zlín Czech Republic tel fax 420 577 10...

Страница 3: ...ve 2 inch threaded filter cells 19 LRGB filter set 19 Clear C filter 19 UBVRI filter set 20 Separate filters 20 Telescope adapters for G3 cameras 20 Telescope adapters for G4 cameras 22 Getting Started 24 Camera System Driver Installation 24 Windows 7 System Driver Installation 25 Windows XP and Windows Vista System Driver Installation 25 Windows 2000 System Driver Installation 26 SIPS Software In...

Страница 4: ...ast Image Stretching 40 Calibration 41 Color Images with monochrome camera and filters 43 Color images with color camera 46 Balancing colors 48 Some General Rules for Successful Imaging 50 Camera Maintenance 53 Desiccant exchange 53 Changing Filters 54 Changing the Whole Filter Wheel 56 Changing the Telescope Adapter 56 Power Supply Fuse 57 ...

Страница 5: ...or 50 50 mm square filters or 7 positions for 2 inch 50 mm diameter filters are available for G4 cameras Also G3 cameras can be equipped with external filter wheel but it is not possible to combine internal and external wheels on single camera G3 camera mus be made without internal filter wheel to be compatible with external filter wheels Please note the G3 and G4 CCD cameras are designed to work ...

Страница 6: ... mouse and to provide the camera a direct USB connection to the host PC The G3 and G4 cameras need an external power supply to operate It is not possible to run the camera from the power lines provided by the USB cable which is common for webcams or very simple imagers G3 and G4 CCD cameras integrate highly efficient CCD chip cooling shutter and possibly filter wheel so their power requirements si...

Страница 7: ...rge to neighboring pixels when image is over exposed to ensure linear response to light through the whole dynamic range FF CCD detectors used for astrophotography are equipped with ABG to eliminate disrupting blooming streaks within field of view Cameras with Full Frame non ABG detectors are suitable for scientific applications where linear response is necessary for photometric applications in ast...

Страница 8: ...tectors This mechanism is also known as electronic shuttering because it allows very short exposures and also digitization of the image without mechanically shielding of the detector from incoming light Also G3 cameras with IT CCDs are equipped with mechanical shutter because electronic shutter does not allow dark frame exposures necessary for proper image calibration etc The price for electronic ...

Страница 9: ...36 3 24 2 mm ABG No No Yes Yes Color mask No No No Yes G4 camera models Model G4 9000 G4 16000 CCD chip KAF 09000 KAF 16803 Resolution 3056 3056 4096 4096 Pixel size 12 12 µm 9 9 µm CCD area 36 8 36 8 mm 36 9 36 9 mm ABG Yes Yes Color mask No No Cameras with C suffix contains CCD detector covered with so called Bayer mask Color filters of three basic colors red green blue cover all pixels so every...

Страница 10: ... pixel which of course limits resolution of color image Imaging using color detectors is described in the Color images chapter CCD Chip Quantum efficiency sensitivity of CCD detectors used in G3 and G4 cameras depends on the particular camera model Inherent dark current of these detectors is quite low compared to other CCD detectors suitable for scientific applications which results into very good...

Страница 11: ...s Pixel size 24 24 µm Imaging area 24 6 24 6 mm Full well capacity Approx 220 000 e Output node capacity Approx 650 000 e Dark current 17 e s pixel at 0 C Dark signal doubling 5 5 C Model G3 11000 G3 11000 uses 11 MPx CCD Kodak KAI 11002 Class 1 or 2 Resolution 4032 2688 pixels Pixel size 9 9 µm Imaging area 36 3 24 2 mm Full well capacity Approx 60 000 e Dark current 12 e s pixel at 0 C Dark sign...

Страница 12: ...ark signal doubling 6 3 C Camera Electronics 16 bit A D converter with correlated double sampling ensures high dynamic range and CCD chip limited readout noise Fast USB interface ensures image download time within seconds Maximum length of single USB cable is 5 m This length can be extended to 10 m by using single USB hub or active USB extender cable Up to 5 hubs or active extenders can be used in...

Страница 13: ... the CCD chip used in particular camera model Model G3 6300 Gain 1 5 e ADU 1 l binning 2 3 e ADU other binnings System read noise 12 e LN read 15 e Standard read Full frame download 9 8 s LN read 8 1 s Standard read Model G3 1000 Gain 3 e ADU 1 l binning 5 e ADU other binnings System read noise 12 e LN read 15 e Standard read Full frame download 2 0 s LN read 1 7 s Standard read Model G3 11000 Gai...

Страница 14: ... KAF 6303 can be read with 11 e RMS Download times are valid for USB 2 0 host and may vary depending on host PC G4 16000 cameras use the same gain for unbinned and binned reading when used with system driver version 2 3 and higher When older driver is used stated gain 1 6 e ADU is used for 1 l binning only while all other binning use 2 7 e ADU Gain setting was unified to utilize the full A D conve...

Страница 15: ...cooling Thermoelectric Peltier modules TEC modules Two stages Maximal T 45 C below ambient Regulated T 40 C below ambient 75 cooling Regulation precision 0 1 C Hot side cooling Forced air cooling two fans Optional heat exchanger for liquid coolant Maximum temperature difference between CCD and ambient air may exceed 45 C when the cooling runs at 100 power However temperature cannot be regulated in...

Страница 16: ...ontrol tool in the SIPS This feature is important especially if you power the camera from batteries Warning The power connector on the camera head uses center plus pin Although all modern power supplies use this configuration always make sure the polarity is correct if you use own power source Mechanical Specifications Compact and robust camera head measures only 154 154 74 mm approx 6 6 3 inches ...

Страница 17: ...G3 with wheel 1 5 G3 without wheel G4 Package Contents G3 and G4 CCD cameras are supplied in the foam filled hard carrying case containing Camera body with a user chosen telescope adapter The standard 2 barrel adapter is included by default for G3 cameras G4 cameras are equipped with M68 1 threaded adapter If ordered the filter wheel is already mounted inside the camera head and filters are thread...

Страница 18: ...or an active USB extender cable can be used as a repeater to provide up to 10 m long connection Third party USB extenders allow USB connection tens or even hundreds meters long An USB Flash Driver or CD ROM with camera system drivers drivers for third party software packages SIPS software package with electronic documentation and PDF version of this manual A printed copy of this manual Optional co...

Страница 19: ...dered separately Replacing the whole filter wheel is easier than replacing individual filters It is possible to thread for instance LRGB filter set into one wheel BVRI set into second wheel and narrow band filters Hα OIII into the third one LRGB filter set High quality 2 LRGB filter set optimized for CCD imaging This set contains high pass Red Green and Blue filters plus Luminance filter covering ...

Страница 20: ... Visit our web site for current filter offering Telescope adapters for G3 cameras The G3 cameras are supplied with standard 2 barrel adapter by default but the user can choose any other adapter he she prefers Another adapters can be ordered separately It is possible to choose among various telescope lens adapters 2 barrel adapter Adapter for 2 focusers T thread short M42 0 75 mm inner thread 7 5 m...

Страница 21: ...anon EOS bayonet adapter Nikon F lens adapter Standard Nikon F bayonet adapter T thread M42 0 75 adapter or M42 1 adapter cause vignetting when used with G3 11000 Also common coma correctors often equipped with T thread cause vignetting with this large chip E g TeleVue Paracorr PSB 1100 with appropriate adapter must be used with KAI 11000 CCD If the mounting standard defines also back focal distan...

Страница 22: ...s adapter consists of two parts The first part attached to the camera head offers 4 5 mm long outer thread M68 1 The second part is a 12 mm thick nut with inner M68 1 thread screwed to the outer thread So the user can choose to use outer thread without a nut or 7 5 mm of inner M68 1 thread when the nut is screwed in The back focal distance is of course longer in the second case Illustration 5 M68 ...

Страница 23: ...four M3 3 mm metric screws Threaded holes on the camera body are placed on the corners of 52 mm square Custom adapters can be made upon request G2 and G3 cameras use smaller 44 mm threaded hole square on the camera head for mounting adapters so adapters for G2 G3 series and G4 series are not compatible 23 ...

Страница 24: ...y can use the driver already present in the operating system But this is not the case of the G3 and G4 CCD camera it requires its own system driver to be installed Although 64 bit operating system can run 32 bit application without any problems it is basically impossible to combine e g 64 bit process with 32 bit dynamic link library The same is valid for operating system kernel 64 bit kernel canno...

Страница 25: ...usually marked by a question mark on yellow background icon It is enough to click on such device by right mouse button to invoke pop up menu and choose Update Driver menu item Operating system then opens driver installation wizard basically identical to the one in Windows XP and Windows Vista Let us note that 64 bit versions of Windows 7 and Windows Vista require digitally signed drivers Drivers w...

Страница 26: ...zard Click the Next button to start the installation 1 Choose the Search for a suitable driver for my device and click Next button 2 Drivers are supplied on the CD ROM choose CD ROM drives and continue by clicking Next button It is not necessary to install files from CD ROM It is possible to copy the folder containing driver files e g to shared network volume USB Flash Disk etc Then it is necessar...

Страница 27: ...loaded from the web site Similarly it is enough to un zip the archive file to any folder the user chooses Un installing of the SIPS is also quite easy just delete the SIPS folder No matter how is the package installed the software is run by launching the SIPS exe main program file SIPS configuration files The software package distinguishes two types of configuration Global configuration common for...

Страница 28: ...or the particular camera is installed The driver for G3 CCD camera is include into the basic SIPS package and is not necessary to install it separately Every CCD camera driver for SIPS including the G3 and G4 CCD drivers is required to provide information about available filters if the particular camera has the integrated filter wheel of course But the user can order camera with various filters or...

Страница 29: ...ntioned information will be displayed e g in the filter choosing combo box this way If there are more filters in the camera than the configuration file describes another filters will be added with undefined name And if the configuration file describes more filters than the number of filter in the camera last descriptions will be omitted Using of multiple configuration files for different cameras I...

Страница 30: ... before the image is passed to SIPS Although it is possible to define sub frames directly in SIPS camera control tool limiting camera resolution this way is not very convenient when multiple frames of different types light dark flat are acquired If for instance the user wants to use only center area of a large CCD because the optics used cannot utilize such large CCD detector it is possible to rea...

Страница 31: ...puter with appropriate drivers installed it starts to initialize filter wheel The internal filter wheel starts to rotate and the camera control unit searches for the filter wheel home position This operation takes a few seconds during which the camera does not respond to computer commands Camera indicates this state by flashing the orange LED See the Camera LED state indicator chapter for details ...

Страница 32: ... notice orange blinks followed by 2 s red blink the filter wheel failed to initialize Although the camera continues operation like the model without filter wheel it is not recommended to start work with such camera it is not clear which filter is behind the CCD or the wheel can be in the inter filter position Return the camera to manufacturer for maintenance in such case Camera firmware finishes i...

Страница 33: ...stance one camera should be used for pointing another for imaging This is why every camera has assigned unique identifier ID number This number is printed on the sticker on camera body and it is also displayed in the list of all available cameras in the CCD Camera tool in SIPS This enables the user to select the particular camera he or she needs 33 ...

Страница 34: ...sary to scan for available cameras Select the Camera tab and press the Scan Cameras button Connected camera should appear in the displayed tree Select it click its name by mouse its name should be highlighted and press Select Camera button If the camera does not appear in the tree of available cameras check the following items 1 Check the USB cable make sure both connectors are properly inserted t...

Страница 35: ... 24UN thread designed for TeleVue Paracorr PSB 1100 coma correctors thread diameter is approx 55 mm Standard adapters for Canon EOS or Nikon do not cause vignetting even with large chip Illustration 9 G3 CCD camera connected to telescope focuser Photographic lens or some small refractor is the best optical system to start experimenting with the camera If you are using some bigger telescope at home...

Страница 36: ... cooler they are also used to cool down the camera power supplies etc Peltier cooler can be controlled from the Cooling tab of the SIPS CCD Camera tool Although the Cooling tab displays number of values and graphs only two values can be modified by the user The Set Temperature count box defines required CCD chip temperature and the Max dT count box defines the maximum speed with which the temperat...

Страница 37: ...e SIPS temperature change speed default value is 3 C per minute It is usually no problem to switch the camera earlier and to provide time for slow cooling However if it is necessary to cool the camera rapidly alter the Max dT value It is also easier to achieve higher temperature differences if the temperature is changed only slowly Switching the Peltier cooler from zero to 100 immediately provides...

Страница 38: ...e unable to regulate the temperature if the environment air temperature rises Set the target temperature which requires approx 85 of the cooling utilization This provides enough room for e g environment temperature changes etc The power supply voltage is also displayed in the Cooling tab Especially when the camera is powered from 12 V battery this information can be used to estimate when the batte...

Страница 39: ... check boxes checked uncheck other options for now we do no plan to save our first images Then click the Start Exposure button Camera will open the shutter perform 1 s exposure close the shutter and download the image Image is then opened in new image window If this is the first shot it will probably be far from sharp focused image Alter the focuser and try again Notice that options determining th...

Страница 40: ...t in images with pixels spanning this range Usually only a fraction of this range is used e g the black background can have values around 500 counts and the brightest part of the image can have around 10 000 counts If we assign the black to white range to the full possible range 0 to 65 535 the image with 500 to 10 000 counts will be displayed only in dark gray tones This is why image brightness s...

Страница 41: ...terms brightness and contract are not used within SIPS Calibration If you preform short exposure of bright object the signal to noise ratio of the image is very high Image artifacts related to CCD chip like hot cold pixels or thermal noise almost do not affect the image But all unwanted effects of unevenly illuminated field CCD thermal noise etc significantly degrade image quality when imaging dim...

Страница 42: ...tter to take more dark frames at last 5 and to create resulting dark frame as their average or better median Illustration 14 The dark frame corresponding to the above raw image Illustration 15 The raw image with subtracted dark frame Subtraction of the dark frame eliminated majority of thermal noise but unevenly illuminated field is still obvious Image center background is much brighter than the b...

Страница 43: ...ut astronomical cameras are only rarely equipped with color CCD chips from number of reasons The color and monochrome chips are discussed in the SIPS User s Guide refer to the Introduction to CCD Imaging chapter Although the G3 camera is equipped with monochrome CCD chip it is definitely capable to capture color images at last when the internal filter wheel contains RGB filters Instead of shooting...

Страница 44: ...d without filter using maximum chip sensitivity This technique is often called LRGB imaging Inserting the color filter into the light path significantly reduces the amount of light captured by the chip On the other side the human eye is much less sensitive to changes of color than to changes of brightness This is why the CCD chip can be binned when capturing color images to 2 2 or 3 3 to significa...

Страница 45: ...Illustration 18 L RGB Image Add tool in SIPS Illustration 19 and a resulting image 45 ...

Страница 46: ...rectly on individual pixels G3 cameras can be equipped with such detectors the name of the camera is then followed by the letter C to indicate color CCD Every pixel receives light of particular color only red green or blue But color image consists of pixels with all three colors specified So it is necessary to calculate other color from the values of neighboring pixels Covering pixels with such co...

Страница 47: ...ages allows immediate Debayer processing of images downloaded from the camera The button performs Debayer processing of currently selected image The Bayer mask displayed on the schematic image above begins with blue pixel But there are no rules specifying the color of the first pixel in principle there can be also green pixel from the blue green line on the upper left corner as well as green pixel...

Страница 48: ...s into more or less yellowish images yellow is a combination of red and green colors The effect described above is compensated by so called white balancing White balancing is performed by brightening of less intensive colors or darkening of more intensive colors to achieve color neutral appearance of white and or gray colors Usually is one color considered reference e g green and other colors red ...

Страница 49: ...49 Illustration 21 Histogram and Stretch tool shows histograms of individual colors ...

Страница 50: ...ging If the mount cannot keep the telescope on track or the telescope cannot create perfectly focused image result is always distorted and blurred Ideally the exposures should be automatically guided using guiding CCD camera or at last webcam or similar device Tracking errors caused by drive periodic error mount polar misalignment or other mechanical issues often unnoticeable by eyes cause streaki...

Страница 51: ...ly improve its appearance Nonlinear stretching called curves in some image editing packages special filters hot cold pixels removal noise reduction etc and other processing e g deconvolution enhances the image Warning Never perform these enhancing filters on images intended for data reduction processing It is always good idea to store original image and to enhance only its copy Scientific informat...

Страница 52: ...s If you are new to CCD imaging and terms like dark frame read noise and image binning sound strange to you refer to the Introduction to CCD Imaging chapter of the SIPS software documentation This chapter explains basic principles of CCD operation and their usage in astronomy discusses color imaging CCD chip dark current and camera read noise chip resolution and pixel scales in relation to telesco...

Страница 53: ...ca gel desiccant is placed inside the camera head This cylindrical chamber is attached to the insulated cooled CCD chamber itself Warning High level of moisture in the CCD chip chamber can cause camera malfunction or even damage to the CCD chip Even if the frost does not create on the detector when the CCD is cooled below freezing point the moisture can be still present It is necessary to keep the...

Страница 54: ...ntainer so dust particles cannot enter the chamber itself It is even recommended to keep the desiccant container cap off for a couple of hours when the camera is in the room with low humidity This helps drying the CCD chamber interior and prolongs the silica gel exchange interval The desiccant chamber used in G3 cameras can be filled with a hot silica gel without a danger of damaging of the contai...

Страница 55: ...while removing the camera cover After removing the screws carefully turn the camera head by the telescope adapter upward Gently pull the front part of the case Notice there are two cables connecting the filter wheel motor and the filter position optical bar plugged into the electronics board It is not necessary to unplug these cables to change filters but if you unplug them take care to connect th...

Страница 56: ... the case of changing filters The filter wheel can be removed when you unscrew the bolt on the center of the front part of camera case Take care not to damage the horseshoe shaped optical bar when replacing the filter wheel Changing the Telescope Adapter The camera head contains bolt square The telescope adapter is attached by four bolts If you want to change the adapter simply unscrew these bolts...

Страница 57: ...t connecting of inverted polarity power plug or against connecting of too high DC voltage above 15 V by a fuse If such event happens and the cooling fans on the back side of the camera do not work when the camera is connected to proper power supply return the camera to the service center for repair 57 ...

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