Frequently Asked Questions

Q: Is there an introduction to QCUIAG for beginners?

A: Yes, Jan Timmermans has written such an introductio here. Also see What is QCUIAG?.

Q: What are stacking, averaging, summing, and off chip integration, and how are these things significant to QCUIAG imaging methods?

A: by Bev Ewen-Smith

Q: Will my camera take long exposures?

A: Currently, the ONLY webcam that is able to take true long exposures without significant modification is the greyscale CONNECTIX QuickCam. The only HARDWARE modification required is the cutting of a single wire. Long exposures are achieved by the use of special software that can be located in the Research section of this website. It is expected that software may be written to include the Connectix Color QuickCam and the Connectix Color QuickCam 2 in the future. It appears to be impossible to produce software that will allow long exposures in any other QuickCam or other webcam. This is due to the degree of control over the camera that is present in firmware in these cameras and not available for external software control. Hardware modification would be required to achieve this


A number of regular digital cameras such as the Casio QV8000SX have the ability to take exposures of the order of up to a minute or even longer. The owner of a digital camera should refer to the instruction manual. It is likely that regular digital cameras will be increasingly used for astronomical imaging in the future. (S.J. Wainwright)

Q: Which other cameras can be modified to allow long exposures?

A: To date, the following cameras have been modified for long exposures:

Please note that many camera models have similar names, but totally different circuitry. Only the exact models mentioned below have been found to be modifiable for long exposures.

Using variations of the Stephen Chambers SC modification

Using the Stephen Chambers CMOS modification

Using the Jon Grove video camera modification

Webcams tend to have a short production run and so quickly become discontinued. However, they can frequently be found for sale at a reasonable price on web auctions such as eBay.

(S.J. Wainwright)

Q: Is there a source of already modified webcams if I am unable to make a long-exposure modification for myself?

A: Yes.

Q: Are there any other astronomical imagers that derive from the research of QCUIAG members?

A: Yes. The Artemis family of cameras derive from the work of Steve Chambers and Jon Grove. These cameras offer the advantage of 16 bit image depth and other advantages.

Q: Is there a comparison table of various webcams?

A: Yes. Such a table is maintained by David Molyneaux: WEBCAM COMPARISON TABLE

Q: Is there any other way of getting long exposures from my video or webcam?

A: Yes. Members of this group have developed a method called Off Chip Video Integration which allows the synthesis of long exposures by adding together large numbers of shorter exposures. Video Integration software can be downloaded for Linux or Windows via the Research and Download page of this website. See the results of Off Chip Video Integration on this website.

Results obtained by this method can be found on the pages of J. Liesmann and S.J. Wainwright on this website (S.J. Wainwright)

Q: Are there any image browsers that will display FITs files ?

A: XnView is a good browser capable of displaying many image formats, including FITs. This software is freeware.

Q: What is the best free image processing software for Windows ?

A: The programs below are very good freeware Fits viewing and processing packages

1) An excellent program is The Gimp. for many images. This package is originally from the Linux stable. It has been ported over into Windows and has been described as 'The Photoshop of the Linux world'. The reasons why I consider it to be one of the best for astronomical image processing are:

2) Another good program is Fitsview. This can read 32 bit Fits files. It can load in a linear or non linear way and can adjust brightness and contrast and levels. It works in a 16-bit image depth.

3) The program Stellar Magic can be downloaded via Sky Publishing's website. Follow the links to Shareware and freeware and then PC programs. Then enter stellar magic in the site search engine and then click on the download bar. (not an altogether obvious graphic). This program has a number of processing filters and works in a 16-bit image depth. Colour images can be synthesised from separate colour channels.

4) Another list of software compiled by Axel Canicio

(S.J. Wainwright)

Q: Is there any image stacking software for the Macintosh?

A: Yes, an Image stacker by Keith Wiley

Q: Will a B/W Connectix QuickCam for a Mac work with a PC ?

A: No.

(S.J. Wainwright)

Q: Is there an FAQ for the COAA AstroVideo Video Integration software ?

A: Yes, here you will find the AstroVideo FAQ

Q: How can I connect my webcam or video security camera to my telescope ?

A: In the Research and Downloads section of this website you will find various methods of adapting and mounting cameras for astronomical use. However, Steven Mogg is producing high quality, Low cost 1.25 inch adapters that will allow the connection of a webcam (or many board video cameras) to the telescope. Steven also produces an adapter with a C thread that will allow a surveillance camera to be telescope-mounted when it's lens is removed.

Steven Mogg's webcam adapter

Visit Steven's website for more information

(S.J. Wainwright)

Q: Is there a manufacturer of webcam adapters in the UK?

A: Yes: Astroparts are a source of high quality anodised aluminium webcam adapters.

An Astroparts extender tube to double the length of the adapter, allowing sufficient out focus for fast refractors.

(S.J. Wainwright)

Q: Which is the best video security camera for me to buy for astronomical imaging?

A: It depends whether you intend to do planetary/Lunar imaging or whether you wish to try deep sky imaging. An 0.5 lux camera will be able to capture good images of the planets and the Moon with many telescopes. If you wish to try deep sky imaging however, you must use a fast scope and a very sensitive video camera. Good results on the brighter deep sky objects have been produced with cameras rated at 0.02 lux or less (some cameras are rated as low as 0.00015 lux) and fast telescopes (say f/5) of reasonable aperture (say >8 inches), and using Video Integration.

Currently, the best camera that I have tested is the Mintron 12V1C-EX from Lechner TV. This camera has the ability to integrate up to 128 video frames into its own memory whilst outputting a continuous composite video signal which updates up to every 2560ms. This means that it is actually possible to see clearly on the video screen, objects such a M57, globular clusters, M82 etc if the camera is used in conjunction with a fast scope of reasonable aperture. For example, I was able to see Comet A2 Linear very clearly with this camera and a 250mm f/4.8 Newtonian. This camera is ideal for public demonstrations as it is possible to show people deep sky objects, live on a video monitor. In conjunction with video-integration software such as AstroVideo from COAA, this camera is very good for imaging deep sky objects by video.

(S.J. Wainwright)

Q: Which is the best webcam for me to buy for astronomical imaging?

A: Few people are owners of a wide range of webcams adapted for astronomical imaging, so statements about which is best should be viewed with caution. However, the best way to make your own decision is to browse this website and to examine the results produced by different members with different cameras. However, be sure to take note of the telescope with which the camera has been used, as clearly, this will be a strong determinant of the quality of the results. Currently, the Phillips Vesta series and the ToUcam seem to be the most favoured webcams for lunar and planetary imaging. Moreover, now that hardware modifications will allow this family of CCD based webcams to be used for deep sky imaging as well, these cameras have to be the current favourites. However, do check that the camera you are interested in, in this family is CCD based, not CMOS based..(S.J. Wainwright)

Q: Should I remove the IR cut filter from my webcam ?

A: Only if you intend to attempt to image deep sky objects. The IR cut filter blocks the Infra Red part of the spectrum and so effectively reduces the light sensitivity of the camera. However, if the IR cut filter is removed, the colour balance of the resulting images will be upset and less than true colour images will result. Not all webcams have effective IR cut filters. The B/W Connectix QuickCam is an example of a webcam with a true IR cut filter with very little transmission in the Infra Red. (S.J. Wainwright)

Q: Should I air-cool my modified webcam ?

A: Only if: a) You intend to image deep sky objects. b) Your camera generates significant amounts of heat. The aim of air cooling is slightly different from the aim of peltier cooling. Air cooling is to remove excess heat generated by the camera itself (some cameras get quite hot) to reduce the thermal noise resulting from this heat. This is only important if you are imaging dim objects and in particular if you are subtracting dark frames. Peltier cooling is to reduce the temperature of the CCD chip itself, usually to 20-30 degrees Celsius below ambient. This effectively eliminates thermal electrons due to the ambient conditions and allows long exposures to result mainly from photon generated electrons, rather than thermally generated electrons. Nontheless, good results can be obtained with long exposures from totally uncooled cameras. The B/W Connectix QuickCam, which, with Dave Allmon's QCV2 software, can take long exposures, only has a 6 bit ADC, which reduces the effectiveness of Peltier cooling. (S.J. Wainwright)

Q: Should I Peltier-cool the CCD in my converted webcam ?

A: Only if the camera is capable of taking true long exposures. Before you set about Peltier -cooling your camera, test its uncooled capabilities. (S.J. Wainwright)

Q: How can I make an eyepiece parfocal with my video surveillance camera or webcam ?

A: A parfocal ring can be improvised as shown elsewhere on this website, or better still, use a Steven Mogg low cost parfocal ring:

The camera is pushed fully into the focusser and the starfield focussed until the stars are sharp points of light. Then the camera is removed and the eyepiece with a loosely fitting parfocal ring is pushed into the focusser until the image is sharp. Then the screw on the parfocal ring is tightened so that the eyepiece cannot slide further into the focusser. The eyepiece is now parfocal with the camera. Thsi will greatly facilitate focussing in the future.

Visit Steven's website for more information (S.J. Wainwright)

Q: Can I reduce the focal length of my system to make it faster?

A: Focal reducers can be purchased and are usually quite expensive. However, Steven Mogg has produced a low cost focal reducer lens that will screw into the filter thread on the front of a Standard 1.25 inch scope adapter or a Mogg adapter. Preliminary tests show that good images can be produced with this focal reducer. More extensive tests are underway.

Visit Steven's website for more information (S.J. Wainwright)

More QCUIAG FAQ on Colin Webb's FAQ Page