StellaCam II camera with "c" to 1 1/4" adapter and remote camera control box M31 & M32, 80mm refractor @ f/3

In the beginning...

A the age of 12 I purchased my first telescope, a used and tattered Tasco 60mm refractor -- sound familiar?  While learning my way around the constellations, I not only realized the many short comings of my modest telescope, but, like most amateurs, discovered a desire to record what I could see through the eyepiece.  As you are reading this article, the latter likely sounds familiar too.  This was in the early 1960s when astrophotography was still a very specialized field limited to an extremely small community of dedicated amateurs, so photographing what I could see through the eyepiece would have to be put on hold....no doubt that sounds familiar as well.

Fast forward to 1999.

In that year I came upon two items that would totally change the way I pursued my hobby.  First, a Sky & Telescope article on the extreme video imaging exploits of Ron Dantowitz (Sharper images through video. Sky and Telescope 96, 48-54, 1998), and, the discovery of a web site by Australian amateur Steve Massey.  Through the S&T article I learned the potential of video astronomy and in Steve Massey's web site I found that video astronomy and video astrophotography of the sun, moon and planets was well within my means.

Thanks to the Internet, I soon found other kindred spirits such as the distinguished southern gentleman Rod Mollise, who had been producing amazing images with a telescope and handheld camcorder.   Arizona amateur David Moore, who was capturing fabulous tri-color video images of the planets, and, Illinois solar video astrophotographer Gordon Garcia who was producing stunning solar images in both white light and H-alpha.  I also discovered Adirondack Video Astronomy...more about them later.  With advice and suggestions from all of these folks, I purchased a simple, inexpensive video surveillance camera relatively well suited for imaging through the telescope; the venerable Supercircuits PC-23C.  Armed with a Snappy frame grabber, I was soon capturing fabulous views of the Moon.  .....OK, they weren't really fabulous, not by any standard, but they were a total revelation for me and the beginning of what has been a wonderful, occasionally excruciating, learning experience.

As video astronomy was still pretty much in its infancy for the general amateur populace, gathering information on equipment and techniques was somewhat daunting, and seeing results of others work was still limited to a handful of web sites.  In an effort to bring more of this information to a central location on the web, I started a discussion forum and web site called VIDEOASTRO.  It was very quickly populated by hundreds of amateurs, and a few professionals, that, like myself, were interested in exploring the potential of video astronomy and video capture astrophotography.

Then there was Adirondack Video Astronomy (AVA) of New York.  Owners John Cordiale and James Barot, Jr., had for several years been marketing a premium video camera for astronomy called the Astrovid.  Unlike the video surveillance cameras many of us were using, the Astrovid had manual control of shutter speed, gain and contrast, making it a far more versatile video system.  It was also more sensitive and utilized a larger CCD than most of the surveillance cameras then available [ article: Surveillance Cameras for Video Astronomy ] .  Of equal importance, AVA offered hardware specific to video astronomy, such as the much needed "c" mount to 1 1/4" adapter used to connect a video camera head to the focuser of a telescope.  They also carried a line of adapters, eyepiece projection systems, video frame digitizers and filters for tri-color imaging.  Plus they were a plethora of technical information and encouragement.

As interest among amateurs in video astronomy grew so too did the range of available cameras.  Not surprising, AVA began to offer further refinements of its original Astrovid camera system in the revolutionary StellaCam and StellaCam EX [ article: Deep Sky Imaging with StellaCam EX ], the first commercially available video cameras intended for deep sky viewing and imaging.  Color cameras were also added to the AVA line including the innovative color PlanetCam and a color versions of the StellaCam EX.  Most recently AVA introduced an exceptional camera for deep sky video astronomy and astrophotography; the StellaCam II.

Frame integrating video cameras:

The StellaCam, StellaCam EX and the StellaCam II are very specialized video cameras ideally suited for astronomy.  They allow the integration of a series of video frames which are displayed on the monitor as a single frame at the end of the integration period.  Which simply means that they add together the information from dozens of video frames to produce a final frame that is brighter, containing more detail than any single frame.  The original StellaCam integrated 128 frames, equivalent to a 4.0 second time exposure.  Almost immediately a more sensitive StellaCam was introduced which utilized the new Sony EXview HAD CCD.  This allowed the StellaCam EX to record in 4 seconds (128 frame integrations) deep sky objects 1 magnitude, or more, fainter than the original StellaCam [ comparison of camera sensitivity article ], or, more practically, a 6 inch aperture telescope could now record stars approaching 17th magnitude.

In 2003, AVA introduced what could be viewed as the next generation of frame integrating video cameras, the StellaCam II.  Based on an entirely different CCD detector and in-camera frame integration, the camera not only overcame the short comings of the previous generation of StellaCam cameras, but up the resulting sensitivity 2.5 times or better.  The StellaCam II can integrate 256 frames, essentially an 8.5 second time exposure.  A 6 inch aperture telescope, in pristine dark skies, can now record stars approaching 18th magnitude.  Which brings us to where we are now.

So why do frame integrating video with a small aperture scope?

First, I do need to quantify "small aperture scope."  For the purpose of this article, I shall address, specifically, the use of both an 80mm f/5 and 120mm f/5 achromat refractor.  All of the video capture images that illustrate this article shall have been shot with one of these instruments at prime focus, f/5 or with a focal reducer, roughly f/3. .

To answer the first question; why do frame integrating video with a small aperture scope?  The answer is several fold; simplicity, immediacy and economy, but not necessarily in that order.

The simplicity side of it is:
- you use an easy to handle, light weight, portable telescope and mount
- you need  neither guide scope nor off axis guider to do astrophotography
- you need only a simple monochrome video monitor to view deep sky objects, you can even get by with an old portable television set
- you can use most standard video camcorders and VCRs to record video from the StellaCam II
- if you do choose to utilize a computer, a relatively inexpensive video frame grabber is all that is needed to digitize the video signal so it may be viewed on the computer monitor or recorded to your hard drive
- image processing requires only stacking a number of video frames, sometimes subtracting a dark frame and adjusting the resulting image for brightness and contrast, and maybe sharpness

On the immediacy side of it:
- you're working in your own backyard with a warm-up room and refrigerator only steps away
- you see the deep sky objects live on the monitor, great for sharing views with family and curious neighbors
- set up is quick and simple with minimal cables, power supplies and specialized hardware
- with freeware and shareware programs such as RegiStax or K3CCD, you can do the basic processing of images in minutes on a laptop right there at the telescope

On the economy end of it:
- you need only a modest telescope, probably the one you already own
- you need only a modest, driven equatorial mount, again, probably the one you're already using
- viewing, even some imaging can be done with alt-azimuth mounted scopes
- the StellaCam II camera system costs 50% to 75% less than a quality, entry level integrating CCD camera system, and, is comparable in price to the better commercially modified web cam systems
- you're working in your backyard -- no time spent loading a car, driving to a remote location, etc., etc.

OK....sounds good so far, but what can I see from my backyard?

The short answer; a great deal more than you probably thought possible...far more than you would ever see visually with the same telescope.

100mm to 150mm aperture scopes are going to clearly resolve the central star of M57 and tens, if not hundreds of stars across M3 and M13.  An 80mm short tube refractor will show you the dark lanes in M31 and stunning detail in M42; even the Veil Nebula.  And, a great deal of structure will be visible in brighter nebulae and galaxies.  Have you ever seen the Horse Head nebula from your back yard?

With frame integrating video your telescope becomes an instrument, conservatively, 2 to 5 times larger in aperture, depending, of course, on the extent of local light pollution and overall average seeing conditions for your location.

So how is it I can see more in light polluted skies with frame integrating video?

Technically, the extremely light sensitive camera is affected more by light pollution than your eye, the difference is primarily that you can electronically adjust the video image on the monitor using the brightness and contrast controls on both the camera and monitor.  The bright background can be reduced while maintaining a relatively bright image of the object being observed.  This, of course, has its limits, still, you can see dramatically more on the monitor than through the eyepiece of the same telescope in the same conditions.

How do the frame captured images compare to the view on the video monitor?

In most cases, the framed captured images, after image processing, are far superior to the live view on the monitor.  In part, this is due to the fact that you capture tens or dozens of frames to the computer, stack them together, which reduces the video noise in the image, then further adjust brightness and contrast using image processing software such as RegiStax, K3CCD or Photo Shop.  However, live images of most Messier objects, particularly clusters and planetary nebulae are most excellent, bordering on spectacular when viewed on the monitor.

The three images above were captured using the 120mm refractor at f/3.  The images are essentially what a slightly brightened single frame (left), a stack of 30 frames (center), and, finally, a processed image made up of approximately 75 stacked frames (right) look like.  The far left frame is a fair representation of what can be seen on a monochrome monitor with brightness and contrast adjusted for best viewing.  Actual single frames are a bit darker, but for this demonstration the image serves well as both a single frame and live monitor image.  It is clearly evident that stacking a number of frames reduces the video noise in the image which allows the image to be extensively adjusted for brightness, bringing up faint stars and nebulosity not visible in the single frame.  Frame stacking was done with RegiStax and adjusting of brightness and contrast was done using the Levels and Curves tools in Adobe Photo Shop.

I thought I needed a heavy, sophisticated equatorial mount to do deep sky astrophotography?

Technically, yes.  To do the close-up images of the smaller, fainter deep sky objects you need a very precisely built mount and drive.  As we are working with small aperture scopes at short focal lengths, image scale is quite small so minor misalignment of the polar axis and periodic error in the drive is not as major an issue.  We are only recording for 8.5 seconds at a time and most well polar aligned mounts can track sufficiently for that short of period.

I should point out that the camera is only producing an image 640x480 pixels in size, so you are not going to be able to make dazzling 8x10 prints.  However, 4x5, even 5x7 prints made from image processed video captures tend to be quite good to most excellent.  Think of them as heavenly postcards.

So what can I actually expect to see from my backyard with a small scope and a StellaCam II?

You should be able to view and image all of the Messier objects and a good many of the Caldwell objects, which, frankly, should keep you busy for quite awhile.

How do I locate deep sky objects I cannot see visually through the telescope?

With most objects you can use detailed charts printed out from programs such as The Sky or Starry Night.  With a well aligned finder scope you should easily be able to place the object in the camera's field of view.  Those mounts with go-to capabilities obviously make it simpler.  Should lack of detailed charts or go-to capability be the case, there are the old reliable setting circles, found on all modern equatorial mounts.  You will need the coordinates of each of the objects of interest and some of the brighter stars, available from a number of sources including the Internet.  As we are working with a wide field of view, either 1950 or 2000 coordinates should be more than adequate for all of the Messier objects.  The simplest means is to center a bright star that is fairly high in the sky, near the meridian and set your RA circle to the proper hour angle for that star.  Then move the telescope to the RA and Dec settings for the object to be observed.  More often than not, the object will be seen somewhere in the field of view.  After viewing/imaging, before moving on to the next object, re-adjust the RA to the hour angle of the object the telescope is now pointing at, then move to the new coordinates of the next object.  Obviously, the mount should be leveled and well polar aligned for the use of setting circles.

So what kind of images can I expect to capture to the computer?

The following is a gallery of images made with either the 80mm f/5 or  120mm f/5 achromat refractors mounted on a simple, commercial equatorial mount with a very basic R.A. motor drive.  In many of the images I used a focal reducer to image at f/3 -- the reduced image scale produces more image contrast so that faint objects appear brighter against the background sky.  The smaller image scale also reduces the effect of small errors in polar alignment and periodic error in the final image.

An infrared blocking filter is used for all video imaging because of the StellaCam II's extended sensitivity into the far red and near infrared.  Refractors and catadioptric telescopes do not focus visible light and IR light to the same point.  The out of focus IR softens the image, reducing contrast and overall image sharpness.  The IR blocking filter eliminates the out of focus infrared light.  Note that all-mirror telescopes, like Newtonians, do focus both visible and infrared light to the same point, so an IR blocking filter is not needed for video imaging.

I need to point out that all of the images required quite a bit of image processing.  However, be not deterred as the image processing is primarily adjusting brightness and contrast, essentially requiring a bit of patience and persistence to bring up faint details.  Except for mild sharpening of a few of the images, there is no other major image processing involved.

All of these images were shot from my front yard or backyard in Livermore, California, 40 miles southeast of San Francisco.  Seeing conditions tend to be turbulent here, year round, however, transparency is occasionally good.  My suburban location is heavily light polluted and I can seldom see stars over head fainter than 3rd magnitude.  There is a city street light at the end of my driveway, 25 feet from where many of these photos were made.

Making every effort to reduce the light falling on the telescope or immediate surroundings is important to reduce the effects of light pollution.  To this end, I often set up a black curtain on studio light stands so that my telescope is shaded from the most prominent direct light sources.  In my backyard, I work with the telescope below the height of the six foot fence in my yard so that direct light from neighborhood house lights and yard lighting does not fall directly upon the objective or interior of the dew shield of the telescope. 

I also try to image objects that are high overhead to reduce the amount of light reflecting atmosphere between me and the heavens.  Note that I use a right angle, 50mm finder scope.  After initially pointing the telescope, read; down on hands and knees craning neck, I then comfortably star hop with the finder scope.

Video frames are captured to my laptop with a ImperX digitizing card.  The software is very user friendly and the displayed live image is more than adequate for focusing and composing.  The individual frames are saved as a series of 1 megabyte BMP files.  I often stack a series of frames, up to 100, right there at the telescope using RegiStax.  Once I save the final stacked BMP file, I delete the original raw images to open up disk space on my modest laptop.  RegiStax is both quick and efficient in stacking the frames there at the telescope.