CCD camera G2-8300

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CCD camera G2-8300
Camera: G2-8300, Moravian Instruments
Sensor: KODAK KAF-8300 CCD, pixel 5.4×5.4 um
Resolution, size: 8.3 MPix, 3358×2536 px, 18.10×13.70 mm
Full-well capacity: 2.55x104 e-
Readout noise: 8 e- RMS
Dark current 0,2 e-/s/pixel při 0 °C
Dimensions, weight: 114×114×77 mm, 1100 g
Power supply: 12 V DC

Monochrome camera G2-8300 is one of the scientific CCD cameras with wide application possibilities. The advantages include precision mechanical and electronic design, low readout noise, overflow protection (anti-blooming gate), the possibility of cooling the sensor to 50 °C below ambient temperature. All these features make it a very useful tool for use in astrophotography, which has very high demands on the used technique. Unlike a DSLR, which works with an image aspect ratio of 3:2, G2-8300 uses a 4:3 ratio, which facilitates the tuning of composition and makes better use of rendered circular field of a telescope. CCD camera G2-8300 can be equipped with built-in filter wheel with 5-positions. For the purpose of astrophotography I chose a LRGB set (Luminance, Red-Green-Blue) of filters from Astronomik that are parfocal and optimized for use in astrophotography.

Disadvantage of the CCD camera vs. digital SLR is the need of computer (notebook) use and overall higher power consumption. The most energy demanding part is Peltier cooler. Camera operated at about 30-40 °C below ambient temperature consumes about 3-4A for cooling. Also power consumption of notebook must be taken into consideration. The above drawbacks, however, are easily balanced by difference in sensor sensitivity compared to DSLR, the advantages for narrow-band photography and elimination of repeated dark frames acquisition as usual for a DSLR.

propustnosti RGB filtrů Astronomik

Nebulae VdB14 a VdB15. One of the very first images taken with G2-8300 with high speed astrograph 585 mm, f/2.9

kvantová účinnost senzoru KAF-8300

Quantum efficiency of the sensor KAF-8300

propustnosti RGB filtrů Astronomik

Transmisivity of RGB Astronomik filters

Digital camera Canon EOS 300D

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Digital camera Canon EOS 300D
Camera: EOS 300D (Digital Rebel), Canon
Sensor: APS-C CMOS, pixel 8.6×8.3 um
Resolution, size: 6.3 MPix, 3072×2048 px, 22.7×15.1 mm
Sensitivity: ISO 100-1600
Shutter speed: 1/4000 sec - 30 sec, Bulb
Dimensions, weight: 142×99×72 mm, 790 g
Power supply: 7.4 V DC

This model of digital SLR camera from Canon was actually the first digital camera, which massively expanded between astrophotographers. This happened mainly due to relatively lower noise compared to other DSLR manufacturers. For successful use in astrophotography, especially for capturing of emission nebulae, glowing on the line of ionized hydrogen (H α - 656.3 nm), it is necessary to increase the sensitivity of the camera on the red end of the spectrum by removing the original UV / IR filter and replacing the filter with a wider transmitted bandwidth. In case of unmodified camera, quantum efficiency for this wavelength is less than 10%. Below is a comparison graph of quantum efficiency for Canon EOS and compared to the sensor KAF-8300. After Canon DSLR modification the quantum efficiency at H-alpha line is about 25%. Because the data for EOS300D and EOS350D cameras are not available, charts were created based on data for Canon EOS40D presented at web-page of Christian Buil

fotoaparát Canon EOS 300D

Sensitivity of unmodified EOS vs. CCD

Digital camera Canon EOS 350D

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Digital camera Canon EOS 350D
Camera: EOS 350D (Digital Rebel XT), Canon
Sensor: APS-C CMOS, pixel 6.4×6.4 um
Resolution, size: 8.0 MPix, 3456×2304 px, 22.2×14.8 mm
Sensitivity: ISO 100-1600
Shutter speed: 1/4000 sec - 30 sec, Bulb
Dimensions, weight: 126x94x64 mm, 485 g
Power supply: 7.4 V DC

Canon EOS 350D is the successor model of the EOS 300D. In terms of using the camera for astrophotography, the Canon EOS 350D compared to EOS 300D is big shift with regard to noise during long exposures, which is significantly lower. There is also considerably higher write speed on memory card, which is particularly useful when debugging focus and composition. The camera is also smaller. However, pain of this model is electroluminescence. The problem is not with EL strength, but non-reproducibility that is manifested by changing of the intensity, by the shifts and dissapearence in the completely random manner. For this reason, satisfactory correction of EL using dark frames is impossible. From conversations with colleagues I know that this defect is manifested only at certain pieces of the EOS 350D, but so far we have failed to find the key for this strange behaviour. Changing firmware version has no effect. In the case that one have a piece of luck and buy camera without this problem and the DSLR is modified for astrophotography by removing the original UV / IR blocking filter, it is possible to reach excellent results, as evidenced by such images as produced by Hungarian astrophotographer Ivan Eder.

The EOS 350D that I use is not modified for astrophotography and I use it only for "daylight" photography, "time-lapse" videos and shots of "star-trails." Unfortunately, I have a piece that has above described problem with the electroluminescence, so night scenes processing requires slightly more "software" effort than using a flawless piece.

CCD camera Watec 902H3 Ultimate

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kamera Watec 902H Ultimate
Camera: 902H3 Ultimate, Watec Corporation
Sensor: SONY ICX259AL EX-View HAD CCD interline transfer, pixel 6.5x6.25 um
Resolution, size: 0.44 MPix, 752×582 px, 4.9 x 3.6 mm
Dimensions, weight: 34×39×50 mm, 98 g
Power supply: 12 V DC (160 mA)

Watec 902H Ultimate is a highly sensitive black and white TV camera with CCD sensor, originally designed for security systems. The camera is widely used by amateur astronomers in many applications, whether for shooting the moon, watching meteor showers, capturing of sprites or as a sensitive guiding camera. Its sensor is equipped with Sony HAD (Hole-Acumulation-Diode) Ex-View technology, which enables increase of sensitivity in low light conditions. It is possible due to increasing of the sensor spectral range to the near infrared region up to 1050 nm. The camera allows manual sensitivity adjustment and gamma correction. In addition, it features the automatic gain control AGC (Auto Gain Control) and BLC (Back Light Compensation).

I use Watec for pointaiton during astrophotography with conection to autoguider

relativní odezva senzoru ICX259AL

Relative sensitivity of ICX259AL sensor

modified webcam Logitech QuickCam Pro 4000

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kamera Logitech QuickCam Pro 4000
Camera: QuickCam Pro 4000, Logitech
Sensor: Sony ICX098AK HAD CCD internal transfer, pixel 5.6x5.6 um
Resolution, size: 1.3 MPix, 659×494 px,
Speed: >30 pictures/s
Dimensions, weight:
Power supply: through USB port

Together with Philips SPC 900NC one of the best webcams for capturing of such objects as planets or the moon. Unfortunately production of this webcam equipped with CCD instead of CMOS sensor is terminated. Disassembly of the camera is very easy.

For astronomical use, I made to webcam lobotomy, which consisted of several things: 1) Removing of the IR blocking filter, so the camera has become sensitive in the infrared region. 2) Replacement of the original lens with 1.25 "adapter for connection to the telescope. 3) Installation of the camera into metal housing.

astrofotografický speciál

Front size of PCB with lens removed

astrofotografický speciál

Rear side of PCB

astrofotografický speciál

PCB with lens in place

astrofotografický speciál

Lens housing with in-built IR-blocking flter

astrofotografický speciál

Relative sensitivity of sensor in R, G a B chanel

astrofotografický speciál

Design of the new camera housing

On the two images below, camera infrared sensitivity after IR-blocking filter removing is presented. Test was carried out in dark room. First image was captured without any filter. Second image was taken with IR-high pass filter which completelly blocks visible light and transmit only infrared light above 800 nm. Flickering is caused by on/off switching of an infrared LED diode glowing at the wavelenght of 950 nm with power approximately 15 mW/steradian.

bez IR filtru

Test image with IR-blocking filter removed. Test was carried out in dark room without any filter.

s IR filtrem 800 nm

Test image with IR-blocking filter removed. Test was carried out in dark room with Astronomik Planet IR Pro filter, which transmits only wavelenghts above 800 nm.

Spektrální charakteristika filtru Astronomik Planet IR Pro 807

Spectral characterisitc of Astronomik Planet IR Pro 807 filter.