A brief overview of Webcams and Astronomy

Not all webcams are made equal.

For a webcam to be suitable for astrophotography it needs to be particularly sensitive to light. Webcams with CCD (Charge Coupled Device) chips are generally more sensitive than CMOS (Complementary Metal Oxide Semiconductor) chips, certainly in webcams, although some more recent makes of CMOS chips used in professional DSLR cameras are able to offer the required light capturing ability.

Generally if you are searching out a webcam for use with a telescope, try to find a CCD webcam, otherwise be sure that any CMOS webcam is sufficiently sensitive and has been tried by other astonomers. The Toucam Pro I and II models were the original favourite choice for astronomers. For example a very cheap webcam, the Philips SPC230NC is a 1.3Mpixel CMOS chip, but its Minimum Illumination is 5 Lux (the amount of light it can detect and requires to operate effectively), whereas the SPC900NC's CCD chip has a Minimum Illumination of < 1 Lux, and hence why it is so popular for astrophotography. A typical family living room is lit to 50Lux, the dark limit of civil twilight is 3.7Lux, the full Moon overhead at tropical latitudes provides 1 Lux, the full Moon on a clear night provides 0.27Lux, a quarter moon 0.01 Lux, and a moonless clear night sky with skyglow gives just 0.002 lux. Total starlight shining through an overcast sky provides 10 to the power -4 lux.

Specifications for video cameras such as camcorders and surveillance cameras often include a minimum illuminance level in lux at which the camera will record a satisfactory image. A camera with good low-light capability will have a lower lux rating. Still cameras do not use such a specification, since longer exposure times can generally be used to make pictures at very low illuminance levels, as opposed to the case in video cameras where a maximum exposure time is generally set by the frame rate.

The SPC900NC uses the same Sony ICX098QB CCD sensor as the Toucam Pro's with a pixel size of 5.6 x 5.6 microns (=0.0056mm), which allows a high resolution (320x240 Pixels non interpolated). This table shows the chip is a 1/4" Type which has 659 pixels horizontal x 494 pixels vertical, in a 14-pin Plastic DIP package with a CXD2450R Combined timing pulse generator, and a primary colour mosaic (Bayer) filter mounted.

The Sony ICX098QB CCD sensor is a 1/4" type with details as below:-

Type
Aspect Ratio
Width
mm
Height
mm
Diagonal
mm
Area
mm2
Relative Area
1/4" 4:3 3.200 2.400 4.000 7.680 1.930

 

As can be seen, at 3.2mm wide by 2.4mm high this chip size is quite small, which can make things a little difficult aligning objects when used with the XT10 on its dobsonian mount! You will see what I mean if you try using the Toucam or Philips webcams with a dob mount - it requires persistance and a lot of patience.

As I understand, the SPC900NC is now a discontinued model, but I was able to purchase mine from a supplier through EBay. Beware that more recent models of Philips webcams use a CMOS chip and may not be as sensitive as the CCD. A suitable alternative is the Philips SPC880 which can have the SPC900NC firmware uploaded into it using WcRmac (see resources section below).

Generally cheap webcams do not offer high resolutions for movie capture, the norm for affordable webcams being 640x480, or 1024x768. Anything greater than this generally starts to get more expensive.

The webcam software (and/or driver software) should also be able to control the Exposure and Gain, and additionally helpful is Brightness, Contrast, Colour or Black & White options. There may also be other options for special features or capabilities specific to that model of webcam which may be useful to control the quality of astro photos.

Most webcams are used for capturing movie at 5, 10, 15, 24, etc FPS (frames per second), or for taking single shot photos of brightly lit objects with short exposure times of anything from a few thousandths, hundredths of a second to 1/4 or 1/2 a second. Generally the moon, planets and similar bright celestial objects can be captured and enhanced using software such as Registax or K3CCDTools, which will align the many frames of movie footage exactly over each other, then stack them together, then sum all the frames into a single enhanced composite image which is far brighter, less noisy, sharper and clearer than any single frame would have been.

But to take single shots of dim night-time objects like stars, galaxies and nebulae requires the webcam to be capable of taking very long exposures, more like 5, 10, 30 seconds or even longer, sometimes 5 minutes, 30 minutes or an hour long!

One of the prime reasons for me searching out this particular webcam was because after considerable research on the Steve Chambers (SC) Long Exposure mod, not only was the SPC900NC webcam still fairly readily available, and used a good sensitive CCD sensor chip, it also became apparent that the Long Exposure modification could be made much more easily than for some other webcam models, which require some very fiddly soldering (see Useful Resources section below for link to M.M.J.Meijer's web site, for more info on how to actually make the Long Exposure mod). While I realise that my Orion XT10 on its standard Dobsonian base won't be any use for long exposures, I wanted a webcam that could be modified, if and when I get another telescope / mount that is more suited to deep-sky astrophotography (Update: I now own a Celestron C6 SGT XLT SCT on EQ5 mount).

There are two main problems regarding long exposures:-

  1. The telescope must be able to track very accurately the apparent motion of the night sky as the Earth rotates, otherwise the image will become blurred and elongated.
  2. While the CCD chip is turned on to gather as much light as it can during the exposure, the electric current passing through the chip heats it, and this can result in "glow" effects or "hot pixels".

While point 2 can be dealt with using software to create a "dark frame map", which is then subtracted by post-processing the image, point 1 is absolutely crucial and means that Dobsonian mounted telescopes such as the Orion Skyquest range are simply incapable of taking long exposure photos, unless the Optical Tube is mounted on an Equatorial tripod, or the Dobsonian is modified to sit on an equatorially tracking platform, or the Altitude and Azimuth axis' are motorised.

To combat the heat problems described in point 2 above, it is possible to attach heatsinks to the imaging chip, and use fans to aid cooling. Additionally a special type of semiconductor called a Peltier chip is used in conjunction with a heatsink to act as a kind of "refrigerator" to cool the imaging chip down even more, often to temperatures well below freezing. For example Peltier chips are used in portable coolboxes to keep food and beer cold.

All these different things (cooling, heatsinks, fans, peltier chips, high resolutions, and better quality imaging chips) soon add to the expense of professionally manufactured astronomy cameras, and this is why some of them can cost hundreds or thousands of dollars!

Note that there is probably no point in making the Long Exposure mod to your webcam unless your scope has Equatorial tracking.

Anyway, for the paupers, newbies and experimentalists among us we can try our hand with a cheap webcam.

The Field of View Drift Method

It is possible to get reasonable pictures of the planets even with a Dobsonian mounted scope, using the Field of View Drift method, as I like to call it.

You line up the planet in one corner of the webcam screen view, then let go, leaving the scope static, and let the planet drift diagonally across the field of view as the Earth rotates, roughly to the opposite corner. With my Orion XT10, and just the webcam in place at prime focus (and no Barlow lens to increase magnification) the drift takes betwen 30-40 seconds.

This means a webcam movie capture of 10 FPS will result in about 300 to 400 frames which can be aligned, stacked and enhanced.

Golden Rule: Remember when capturing movie footage, that it is always better to under-expose, or reduce the gain of the webcam for a particular planet, i.e. deliberately give a dimmer picture, because the post-processing will tease out and brighten the image, and subtle details are better obtained like this than if the original image is too bright and washed out.

Preparing the SPC900NC for use with a Telescope

This is my Philips SPC900NC Webcam. The front lens can be rotated to focus the camera. Unfortunately it also has a nasty bright white LED lamp to kindly indicate when the camera is functioning (any kind of bright light is not good for dark-adapted eyesight! Cover it with some red tape).

Note: I recommend you become familiar with the operation of the webcam and its software under normal conditions before you start dismantling it, because after removing the original lens you will not be able to focus the image unless you put it into your telescope.

Using the flat edge of a screwdriver gently prise the focuser up and out of the camera body (this is made easier if the focuser is rotated roughly halfway between maximum and minimum focus). Try to ease the clips out evenly all round. Getting the clips to release is quite hard, so be careful not to break any of the three plastic lugs which clip the focuser into the camera body and hold it in place, so that you can continue to use the webcam for its normal function if you wish.

Here is the lens and focuser after removing both from the body.

The shot below shows the focuser removed, but the lens still screwed in place. Just unscrew the lens anti-clockwise until the lens comes right out.

The lens unit incorporates the lens and an infra-red filter, but we will no longer use this for astrophotography. Keep it, and the focuser, somewhere safe so that you can use the webcam normally again in future if you wish (e.g. experimenting/testing indoors without a telescope if you have made the Long Exposure modification).

Once the lens is removed you can see the CCD chip. Do not leave the chip uncovered for long - you don't want any dust particles getting onto the clear face of the chip as they may become visible on any photographs you take.

The next thing to do is to replace the normal webcam lens with a 1.25 inch barrel adaptor nozzle. This will screw snugly into the webcam body, in place of the original lens, and the barrel is the correct diameter to fit into the eyepiece holder of your telescope. The adaptor should also be "baffled" inside to help reduce light reflections (this is a kind of stepped feature within the adaptor nozzle).

When purchasing the adaptor be sure to get the correct type. The first one I ordered was almost right, but the screw thread was not long enough to locate into the thread within the camera body, I think it was from an old batch or was for an earlier model of the SPC900NC. The supplier soon replaced my order with the correct part. Also be careful when inserting the adaptor into the webcam that you do not overtighten it or the nozzle might hit the CCD chip and damage the clear face of the chip.

The UK supplier I used was Scopes-N-Skies, and the exact part I ordered was the AC414n 1.25" Nosepiece Adaptor.

The front end of the adaptor is also threaded to accept filters. So in addition to purchasing the adaptor, I also ordered an Infra-Red & Ultra-Violet Filter to screw into place. Here is the webcam plus adaptor, with the IR/UV Filter on the desk.

Again, Scopes-N-Skies were able to supply the filter, which was the AC582 1.25” Infrared & UV block filter for web-cam and CCD imaging.

So here is the webcam ready for use with the telescope. You can see the baffled anti-reflection feature within the adaptor.

I would also suggest you also take a look at Robert Reeves SPC900NC Webcam page showing some additional photos of this webcam, and describing in more detail how to dismantle the unit.

Tips for using the Webcam

Make things easy to start with.

First, during the daytime, install the software that came with the webcam, and become familiar with its various functions, features and settings. Its best to do this before you replace the original webcam lens with the eyepiece adaptor nozzle.

The software supplied is VLounge. While VLounge is ok for getting started with taking astrophotography footage, it is better to use software dedicated to the purpose. K3CCDTools is specifically written for this job, and is also programmed to control webcams that have been modified to take Long Exposures. Another good free software is WxAstrocapture. You might also consider Nebulosity, which has some excellent documentation (manual and tutorials) where you will learn a lot about CCD cameras, and astrophotography image processing.

First try experimenting with the settings, in particular the Exposure and Gain settings. Have a go in a darkened, dimly lit room, pointing the webcam at something and making sure it is focused. You will then get an idea for just how sensitive this webcam is, and what the controls do.

I would also advise you to download the free WcCtrl webcam control software which allows much easier access to the webcam controls than going through the K3CCDTools menu to the Driver software for the webcam.

When you plan to try the webcam with the telescope, be organised about it. Here are some tips:-

  • Try the webcam in the telescope in daytime first. Setup the telescope to point at something at least 1/4 mile away (you're unlikely to be able to focus on anything closer). Get to understand the webcam settings.

    Also note which way up and which angle you need to orient the webcam to give an upright image. The software probably allows you to flip the vertical or horizontal axis to get a mirror image.

    Most Newtonian telescopes on Dobsonian mounts have the focuser set at a 45° angle to make viewing through the eyepiece more comfortable (instead of being on the top of the tube, it is rotated 45° down towards the observer), and due to the configuration of the mirrors this in turn requires the webcam to be offset 45° anti-clockwise from vertical to provide "upright" pictures (i.e. as you view the sky when looking up without the telescope).



    This is better for learning initially, but once you've got used to operating the webcam, you may find it more convenient to orient the webcam so that any movement of the target is along one axis only, and this will require watching the movement and twisting the webcam orientation to match (effectively aligning the webcam's vertical axis parallel to earths polar alignment, so that the earths equatorial rotation appears as horizontal motion in the webcam). Doing this can be helpful when photographing through a dobsonian mounted telescope, but also helps with other types of telescopes with proper EQ tracking (the image is stationary), for example when trying to align the webcam to create a lunar mosaic so as to ensure correct coverage of the target object when multiple images are "stitched" together.

    It's a matter of personal preference and depends on what you're trying to achieve. Of course you can post-process with imaging software to rotate the picture to the correct position if required.

  • Ensuring that your Finder Scope is well-aligned with the main telescope is crucial to aid accurate alignment on objects without having to swap the webcam with an eyepiece, which would otherwise mean refocusing constantly. This is something best checked during daytime on a distant stationary object. Stars don't stay still!

  • You will need plenty of time to get aquainted with using your laptop computer next to the telescope, so make sure the night has good weather and good long visibility time. Forget about looking for pretty stars or admiring the view - your mission is to concentrate on understanding the webcam and its software, and how to set it up to work with your telescope. This may take you several sessions to get used to everything, and poor weather may cut short your experiments, and resuming your trials may not be until next night or several days later!

  • Get a sturdy chair or table to sit the computer on so that it is close enough to work with, and conveniently at your side.

  • Make sure you are aware of where any cables, plugs, adaptors are trailing so you won't trip up on them in the dark. Keep your cables tidy.

  • Use a bright easy to find object to begin with, e.g. The Moon. Since you are working with the Moon which is very bright, and large, you won't be worried about dark-adapting your eyes, therefore you can afford to have some gentle light available (eg. back door porch light) to see what you're doing on your laptop keyboard, and become familiar with the extra equipment and wires setup around you. [Tip: I purchased a goose-neck LED light which plugs into one of the laptop USB ports for power, and put red-celophane around it. I can then aim this at the keyboard so it casts a gentle light so I can see which keys I'm hitting.]

  • Get setup and aligned on the Moon first by focusing with an eyepiece so you know that everything is ready optically.

  • Make sure the webcam is plugged in and operating correctly. Make a habit of always using the same USB socket to plug into. Same goes for any other USB plugs (e.g. if you have a serial to USB adaptor for your IntelliScope Computer Object Locator serial cable).

  • Using you software's Preview mode, see if you can get an image using the webcam. Do not use any Barlows or Focal Reducers yet, just try the webcam on its own first. Barlows magnify which means things will move across the view faster, and Focal Reducers may shorten the focal length too far, preventing you from obtaining focus.

  • Be careful not to turn the Gain or Exposure up too high to begin with, because it is easy to "white-out" (saturate) the camera on a bright object like the Moon, and you will confuse the white-out with not being able to focus the image.

  • Depending on the eyepiece you use to make the initial viewing/alignment, you will undoubtedly have to re-focus when you replace the eyepiece with the webcam, because the eyepiece is at prime-focus, and the image has to be focused onto the CCD chip. Try and remember which way, in or out, you normally have to refocus the webcam from any particular eyepiece.

  • Be very gentle when moving the telescope. The CCD chip on the SPC900NC webcam is very small, so it takes a bit of fiddling to get the image on the chip.  If like me, you're using a Dobsonian mount, you will find it's very easy to lose where the object is (particularly with the "azimuth stiction" problem), particularly for planets which are considerably smaller than the Moon. They traverse the field of view in about 30 seconds, so you have to get used to being quick. Quick to re-align, quick to re-focus if necessary, quick to hit the capture button! Getting the telescope nicely balanced also helps achieve smoother movements and prevents nasty surprises like tipping because the Altitiude CorrecTension knob wasn't tightened sufficiently! I use some simple home-made weights to help balance my dobsonian mounted telescope.

  • Take plenty of captures. Practice makes perfect, and you will have more footage to work with in K3CCDTools or Registax when you go indoors again.

  • Remember not to over-expose the image captures. Keep them dimmer rather than too bright. This gives better results when post-processing. Too much Gain results in "noise" in the image. The exception to this is if you want to capture the moons surrounding a planet, rather than the planet detail itself. If you want both together, you would take two separate captures, one for planet detail, one for moons detail, then use graphics/photo editing software such as Photoshop to combine and overlay the two, resulting in a single image.

  • I recommend leaving the Align/Stack/Enhance post-processing until you go indoors, because K3CCDTools/Registax are complex tools that require care and thought, i.e. don't waste your viewing/capturing time with processing time.

  • If you are using K3CCDTools and are using the field of view drift method of capturing (because you don't have equatorial tracking) I highly recommend starting the capture only when the planet has just become visible on the screen, and stopping the capture before the planet goes off the edge of the screen. K3CCDTools tries to calculate the edge borders (frame rectangles) around the image, and if the planet goes off the edge this can result in the automatic area calculation cutting half the final image off. K3CCDTools does offer controls to eliminate "planet off-screen" frames but it just makes things easier like this, and saves on disk space too.

  • LX Mode (Long Exposure) Tips:-

  • The following tips are for settings on the webcam if you have chosen to make the Steve Chambers Long Exposure mod (SC1 mod).

  • When using LX-Mode, it is best to set Frames per Second to 5 FPS (1/5th of a second). Even though the LX-mod now has control of the exposure time, such as a 10 second exposure, and is ignoring the FPS, the FPS setting actually affects whether the data is downloaded from the camera compressed or uncompressed. Higher than 5 FPS usually results in compression being turned on, and this sometimes interferes with the exposure frame being read properly resulting in intermittent black or dropped frames.

  • The data read from each pixel in the camera has a 16-bit range of 0 (black) to 65535 (white). You need to make the most of this full data range to avoid losing the full potential of the light the camera captures.

  • If your capture software has a live histogram feature (WxAstrocapture and K3CCDTools do), you should adjust the Gain and Exposure times to bring the histogram peak 10% away from the left hand or black side of the histogram graph. Failing to do so may cut off the near black detail from the image, including that all important very faint light in deep sky objects.

  • Leave Gamma at zero normally, but if you do need to brighten the image use only small adjustments of Gamma.

  • Likewise with Brightness and Contrast these are normally left at their default values.

  • Freeze White Balance.
  • Set Auto Off.
  • Shutter is ineffective in LX Mode.

  • Aim to keep the Gain lower if possible. Usually a Gain value of 50% to 75% is sufficient but this depends very much on whether the target is a bright planet, or a dim DSO. The higher the gain the brighter the image but also you will get more Noise in the image (caused by the electronics artificially amplifying the light data from the chip).

  • Conversely you should not reduce the Gain too much as doing so will result in too much data being condensed into too small a range (remember each pixel has a potential 0 to 65535 value), and when you process the image later to "stretch" the levels in the image so as to give it more contrast (darker blacks and brighter whites), because the data was "flattened" by too little Gain or insufficient Exposure, the intermediate data values result in stepped values as they are stretched out, and this gives what is called an "onion-ring" effect in the final processed image. In this case dimmer parts of the image have many adjacent pixels of slighly different levels being assigned the same pixel value. Sometimes just upping the Gain straightens out the response of the CCD and sometimes Gamma adjustments are called for. For Gamma try changing it in such a way to make the image just a little brighter. Big adjustments are not a good idea for Gamma however.

  • Realise that it is just as important to capture as many frames as possible in the time you have, as it is to optimise the correct camera settings. The more frames you capture the better the effects of aligning, stacking and averaging will be at separating the electronic noise in the image, from the real light falling on the CCD chip from the stars and faint nebula. And the better the camera settings and exposure times are set to give a good spread of data in that 0 to 65535 range for each pixel, the more chance you have of dividing out the subtle details of dim objects from the general background skyglow.

  • Newcomers to astrophotography will find Craig Stark's Nebulosity Tutorials a great help in understanding Image Pre and Post-Processing, which cover Dark Maps, Bias Frames, Flat Frames, Aligning, Stacking, Sharpening, Tightening, Levels, Auto-Guiding and so on. I learnt a lot from purchasing and using this software and going through the tutorials.

  • For a better although more technical understanding of the above points you might like to read Samir Kharusi's article on Minimal Exposure times. While the article is aimed at DSLR cameras, the principles still apply to CCD cameras generally, and help you appreciate just why you should capture and stack as many frames as possible, and that high quality imaging can be achieved with shorter exposures and cheaper, less accurate mounts.

SPC900NC Technical Specifications

Video & snapshot capturing:

  • Sensor: CCD
  • Sensor resolution: VGA
  • Max. (interpolated) photo resolution 1,2 MP (1280 x 960)
    Max. (real) photo resolution VGA (640x480)
    Max. video resolution VGA (640x480)
  • Max. frame rate: 90 fps (Some e-shop sites claim that this webcam is USB2.0 and capable of 90fps, but when I see the screen shots from the drivers interface, I see 640x480@15fps is the maximum).
  • Lens: F2.2, D55°
  • White balance: 2600 – 7600 k
  • Min. illuminance: < 1 lux
  • Color depth: 24 bit

Download Tech Spec sheet (PDF)

Useful Resources

The following links and references may be useful:-

  • Wikipedia link for CCD reference -this page explains Charge Coupled Devices. This page also provides details of sensor sizes which you may need to read to understand the type of CCD in your webcam. Some software requires the dimensions of the CCD chip to be entered and you will need to translate the "Type" to the relevant Width, Height, Diagonal or Area.

  • Sensor Sizes - Digital Photographer Review page providing sensor size information.

  • K3CCDTools - This software allows you to take better control over your webcam to capture movie footage or still shots to your computer for later enhancement by K3CCDTools, or another software such as Registax. It is reasonably priced and has many advanced features that give special control over exposure and gain that your standard Webcam software may not provide. K3CCDTools is particularly of interest because it includes settings that hook into a "long exposure modified" webcam (Note that long exposures are useless without proper equatorial tracking).

  • WxAstrocapture - free software which allows capturing of video or single images from the webcam. This will also work directly with the SPC900NC when it has been modified for Long Exposures (Steve Chambers SC-mods, see below). There is no need to use WcCtrl as WxAstrocapture provides access to the SPC900NC camera controls.

  • Nebulosity - requires license ($60), but is an excellent image capture and pre-/post-processing software for astrophotography. It is worth investigating Nebulosity just for the manual and tutorials alone, which provide excellent explanation of the various processing techniques involved (Dark/Bias/Light Maps, Aligning, Stacking, Filters, etc). Nebulosity only works with the SPC900NC using LXUSB (a physical Long Exposure USB/serial adaptor) or Parallel port. Unfortunately it is unable to control long exposure by a standard USB to Serial adaptor, so you have to capture using other software like WxAstrocapture or K3CCDTools, then work in Nebulosity with the image files they create.

  • Martin Burri's WcCtrl Webcam Control software - an excellent utility WcCtrl enables easier control of the SPC900NC webcam settings (e.g. Gain, Brightness, Exposure, etc). The trouble with using the standard Logitech webcam controls interface is its window is far too big (covers part of the K3CCDTools preview screen), and when you are trying to quickly open up the settings before a planet disappears off the screen, speed is of the essence. This neat program stays on top, has several sizing styles, and will Save/Load settings for future sessions. And its free! Also K3CCDTools has a button icon which can be assigned to open WcCtrl.

  • Martin Burri's WcRmac - Normally the SPC900NC transfers data to the computer using I420 or IYUV2 compression modes. The WcRmac program is a utility which can upload different firmware to allow the SPC900NC to use Colour or B/W RAW mode to be used for the data transfer (i.e. a higher quality image).

  • Poor Meadow Dyke Observatory - The official site of Steve Chambers, famed for pioneering the use and modification of cheap, readily available, sensitive CCD webcams for use in astrophotography. Many people have followed his suggestions for making the Long Exposure mod to enable webcams (which normally just take very short exposure movie footage at frame speeds of 5 to 60 frames per second) to take exposures anything from 1 second to 1 hour!! This Guide page in particular is very interesting as it describes how the webcam sensor gathers more light the longer the exposure is, with diagrams showing how photons are collected and converted into electrons, and hence how the modification to the webcam works. For a list of webcams suitable for astronomy purposes refer to this page in his site.

  • Robert Reeves Celestial Photography - this website provides additional photos and information for the SPC900NC webcam. In particular check out his page How to remove the lens from a Philips SPC900NC webcam

  • Frank Brandl Webcam Imaging page provides some more useful information about the Toucam Pro (same chip as the SPC900NC) for astrophotography, and some further technical information on the CCD chip, and techniques to get the best images. It has a very good section on determining the correct focal length, angular field of view and resolution to use.

  • NHS & DSFC ASTRONOMY CLUB provides details of the Resolutions and Binning modes, and some advice on which resolutions are best for imaging specific targets.

  • M.M.Meijer's Astronomy Pages - This site provides even more technical information on the Philips SPC900NC and also provides exact detail on making the Long Exposure mod for the SPC900NC.

  • Conversion of a Philips SPC880 for Astro-Imaging - PDF details how to modify its firmware to be a SPC900NC, and how to make the SC1 Long-Exposure and SC1.5 Amp-Off mods. I like the simpler control circuit board suggested here for the USB-Serial interface into the camera.

  • ModernAstronomy.com - Supplies a pre-modified Mono version of the SPC900NC which is purported to be 3 times more sensitive than the Colour version of the webcam, and is re-flashed to allow RAW mode output, enhanced settings, and the white LED is disabled. This link also shows some photos taken using the webcam with other telescopes (see the What Can Be Achieved link).

  • Jim Solomons Astrophotography Cookbook provides an excellent guide to the whole astrophotography process; Planning, Acquisition (Polar Alignment, Darks, Flats, Bias, Auto-Guiding, Focusing), Processing,