O'Neil Photo & Optical Inc.
Personal Advice on Web cam Astro-Imaging.
A few years back I bought a used, black and white QuickCam
off Ebay, and an old 486/DX 25 laptop with a "stunning"
4 meg of ram, 20 meg hard drive, and Windows 3.1. I used that
setup for a year, on my old Astro C90. Many of you have probably
seen the C90, but the old Astro C90 came with a single fork arm
drive, base, wedge - in short, ti looked like a C8 that somebody
fired a "shrink ray " gun at.
After a while the camera and the laptop both broke down, so
I fell away from Web cam imaging, but with new software out there,
a new laptop and many more webcams now available, I find myself
back at it with a passion. Before we start, a couple points to
set the record straight.
-This web page is ALWAYS under construction.
-This web page is NOT about how to install any camera. I am
assuming you have read the owners manual, and figured out how
to plug into a USB port and install the software. This web page
is about things not covered in the manual.
- Yes, I do use the Acuter Imager, and I also use a QuickCam
VC that I modified myself.
So, in no particular order, here goes:
1) What's the difference between CCD and CMOS.
The Acuter has a CMOS, not CCD chip, but as CMOS chips goes, it has a good one. It is sensitive to 3 lux, whereas the VC I use is sensitive below 1 lux. It is not just light sensitivity however, it's how they collect light. IN very simplistic terms, CMOS chips are like that old child's toy "Lite Brite", where you stuck coloured pegs though paper. CMOS works like that, it forms and images once light strikes the chip. CCD works more like a bucket, it collects light like water, and the more it collects, the more information for the image.
As such, CCD chips are very good in low light situations -
but not al of them. I have seen some lousy CCD chips too. But
this is the reason expensive cameras form companies like Sbig
that cost thousands of dollars use CCD chips, and not CMOS.
2) Does this mean CMOS based cams are no good?
No, not at all. First, for sake of argument, if the Acuter had a CCD chip instead of a CMOS chip, it greatly the price. You can image the moon and the planets (see notes below) with the Acuter or any CMOS based Web cam. I think the only two, currently produced CCD based Web cam are the "PRO" line form Logitech, and the Philips upper end webcams, which are not available in Canada, save form a couple of dealers who import them privately for resale.
But yes, CCD are better.
3) What should I start with first?
Try the moon. Planets are not as easy as they look. To image the planets with a Web cam, you will need a telescope on an equatorial mount, and a motor drive. I have personally tried the planets using a dobsonian, and save yourself the grief, you will just drive yourself bonkers.
Yes I too have seen people using dobsonains or other alt-azimuth
mounted telescopes to do planetary imaging, but I have also seen
people with safety pins through their eyebrows. If you are crazy
enough, you can try anything if you want. :)
4) The Moon
Now, before you start the moon, setup in daylight. Make sure everything is working - try the camera out in daytime, aim it at a far horizon, and get an idea of how to focus it during daytime. If you start at night for the first time, learning how to focus the camera while watching the screen, and learning to manipulate the brightness and contrast controls while doing the same will be simple frustration.
The first thing you will notice is webcams do not focus at the same point your eyes do, so once you get the camera focused during the day, mark or measure the position of your focuser for future reference.
To image the moon, you only need a small telescope. I have seen people even 60mm refractors. Of course, bigger is better, and the studier the mount the better, but even an 80mm, F5 short tube will work on the moon.
5) The Planets
Using any Web cam, it is difficult to get planetary detail using only an 80 or 90mm telescope of any brand or style, even on Jupiter. I know, I have tried.. I suggest at least a telescope of 130mm or 5 inches for planetary work.
The other problem is moon shots will look good on your screen right away, better after you process them, but planetary images look rather vague, frankly disappointing, until you stack and process them. You don't get the same satisfaction as with the moon, and it's easy to get discouraged if you are a novice.
Now the June, 2003 edition of Sky & Telescope magazine
has a very good article on planetary imaging with web cams, go
look it up and buy it.
6) Deep Sky Objects?
Naw. Unless you are willing to tear your CCD based web cam
apart, rewire it and cool it for long exposures, you should consider
all web cams, including the Acuter, for moon and planetary work
7) What about modifications to any web cams, including
Here's a tough call. First off, to use any Web cam, like a QuickCam, you have to remove the internal lens and add an adaptor. However, the moment you take the QuickCam apart, you completely void your warranty. Completely.
Also, both CCD and CMOS chips are very sensitive to infra-red
light. Now for guys who are reworking a Web cam for deep sky use,
you must remove the IR filter for maximum light sensitivity. However,
for planetary and lunar work, leave the IR filter in place, except
on black & white web cams. However, I believe all current
webcams, CCD or CMOS are now colour, so that's a moot point.
Now a note about the Acuter. It comes in two versions - telescope and spotting scope. If you have a spotting scope version, leave it alone. But if you have a telescope version, here's a tough call for you.
The 1.25" adaptor tube on the telescope version of the Acuter has a 3 element magnifying lens set built into it. In my opinion, this lens set degrades astro-imaging, and makes the camera too high a power to use at night. It is the equivalent of a 10mm eyepiece, which gives you high power and a narrow field of view.
I found the Acuter a bit difficult to use at night until I took the lens assembly out. A simple retaining ring hold them in place, and a spanner wrench or even a flat screwdriver will turn the ring.
IMPORTANT - READ THIS FIRST!
Taking apart and/or removing anything form the Acuter will completely and utterly VOID YOUR WARRANTY. No exceptions. Even if you phone up SkyWatcher and say "hey, one of your dealers said on his web site he removed his lenses", sorry NO exceptions, it will not work. You take the Acuter or ANY web cam apart in any manner, and it's universal - all warranties are void. So it's your call.
In any event, leave the IR filter in, it makes focusing easier.
If ever a B&W, CCD based Acuter is made, then we pop off the
IR filter, but not until then. :)
8) What about software on the web?
I high suggest you download and try some - BUT - with a couple
suggestions. There are TWO kinds of programs you download. The
first is camera operating software and the second is image processing
software. Now some programs do both, so it can be confusing -
don't worry about.
First, the camera control software packages such K3CCD Tools do work with the Acuter, but regardless of what camera you are using, the learning curve is a bit steep for a novice, so you may wan to look at it, but use the software that the Acuter comes with.
This is true for all webcams. For example, with my QuickCam VC, I find it is easier to use the Logitech software for just blasting away at the moon. However for planetary imaging, the refined controls of K3CCD Tools is better, IMO.
Secondly not all features work on all cameras. You just have to experiment.
Thirdly, be care that you have enough disk space. You see, in the software supplied with most cameras, you can choose to record either a video or by single shot. When starting out new, choose single shot.
It is an accepted technique to record a video on disk, then
frame by frame take each image apart into separate files and stack
and process them. However, this is a lot of work time consuming,
and it takes up TONS of disk space real fast. If you are like
me and have a small hard drive, this may be a problem.
The second kind of software is stacking & image processing.
Stacking is where a program takes 10 or 20 or 100 images you have
taken of any object, and combines them into once image, to improve
the overall detail you can see. This is not as hard as it sounds,
but ti takes a bit to learn how to do it. Check out my web cam
links page for good web site that describe how to do this much
better than I ever could.
9) What about using more than one web cam on your computer?
Actually easy to do - with ONE WARNING! You can instal one, two or ten web cams on your computer at any time. You cannot run more than one at any time, but you can install drivers for more than one - AS LONG AS THEY ARE ALL DIFFERENT BRANDS!
I found this out the hard way. I have two different models of CCD based, Logitech QuickCams, but if I try to install more than one at once, they crash and lock everything up, on both my laptop (IBM Celeron 500) and my desktop (AMD Athalon 1600).
However, I can install drivers and run (not all at once) the
QuickCam, the Acuter and a 3Com web cam no probelmo. :) However,
try and install drivers for two different model Logitech QuickCams,
and everything barfs on me, on both machines.
The trick is, unlike when you install several printers on your
computer, Windows does NOT set any particular web cam as a system
default. Therefore, each camera control program you use, you will
have to go in and inside each program, setup manually (just once,
unless you change) which specific camera you are using.
10) I read what you said about focusing, but I am still having
This is to be expected - focusing is a complete pain in the butt. Guys who say otherwise are just the astronomical equivalent of macho dudes staking out bragging rights. Well, maybe not that bad, but it's hard. Some people use motorized focusing controls for fine adjustments.
The real trick is to lock down your mount - if possible - and use a light touch. Some people will clean out the grease on their focuser and re-lube it with a better quality lubricant.
There are several ideas out there, but be aware ahead of time
that mastering fine focusing is possibly the most difficult -
and frustrating - part of web cam imaging.
11) I am having trouble with contrast and detail
This is something you have to learn by experience. However, to try at first, lower the contrast down low, then set brightness about half way. It helps to bring up the contrast & brightness controls on the screen at the same time as you observe the image window. Pull the image window with your mouse off to one side, and bring up the control screen on the other side.
Do this first, as I said before, on a daytime object, and get
a feeling for how it acts and reacts. When you do get a shot at
the moon for a first time, you'll feel a bit more confident.
That's it for now. E-mail me if you have any questions, ideas, suggestions.
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