Re: Film SLR or Digital Camera?

SP---

I wanted to thank you for answering this same question for me a while back
but wasn't sure you'd see my reply---so thanks! I'm in pursuit of a 300D---I
like Canon anyway!

Doink
"Stephen Paul" <spaul219@xxxxxxxxxxx> wrote in message
news:442d7dde$0$16365$6d36acad@xxxxxxxxxxxxxxxxxxxxxxxx

"Sam" <sampath.vanimisetti@xxxxxxxxx> wrote in message
news:1143816790.776342.222850@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
In the last couple of years, the consumer electronics market has
witnessed a plethora of affordable digital cameras (even some of the
with CCDs), which some amateur astrophotographers have put use to take
some amazing pictures. Further, I have noticed in many articles that
cheap webcams can also be used to get some handy work done.

Now coming over to my question, I was wondering if some experienced
people out there can tell me what the best strategy should be. Should I
explore film based camera first and then move on to the digital
counterparts. I am aware that there are troubles on both sides. For
example, some digital cams donot provide infinite shutter times,
rendering them useless for deep space astrophotog and film based
astrophotog might be expensive and time consuming!

Been there.
Some things I've learned:
- Canon 300D Digital Rebel all the way, baby. If you are experimenting
with imaging, there is NO better solution out there to get you started.
This camera is capable of low noise RAW 5 minute exposures at ISO 400, and
digital data is easily manipulated on a PC using a plethora of software
options, some free, some not. A DSLR can be used at the scope without a
computer. Thirty second images are possible without anything but a shutter
button press on the camera body. Installing the mirror lockup enabled
firmware, means you can press the button, and use the mirror lockup delay
to let the scope settle (I use three seconds). That said, get a remote
shutter release, or better, the TC-80N3 with mod, or adapter to work with
the 300D. The TC-80N3 allows you to set the exposure time, the number of
frames, the time between frames, and an initial delay before the first
frame. (With computer control, this device is completely unnecessary...
but if you want to avoid the PC in the field... get one.)

The 300D also allows reasonable novice level focus using a bright star
through the camera's viewfinder. Do this before aiming at your intended
target with the finder scope. M42 is the best object to teach yourself
imaging. It's bright, and easy to find, and the camera responds to it
extremely well. With an F5 scope of 600 to 1000mm focal length, 30 second
subframes at ISO 800 in JPG Large mode, will be low noise, forgiving of
tracking error, and can be very satisfying for a novice when stacked
using Registax 3 (freeware). If M42 isn't available, use M8.

- Successful imaging with shutter times in excess of 30 seconds is all
about the mount. There are several clones of the "original" low end
amateur mount that allowed for reasonable success with light gear and
moderate exposure times, the Vixen GP and GP-DX. The clones are the EQ-5,
CG-5, AS CG-5 and their ilk from several retailers, ultimately all from
China. These can be surprisingly okay, but unless you get real lucky, out
of the box there will be sub-frames (single multi-minute exposures) that
get tossed from time to time. Maybe anywhere from 10% to 50% of all
frames. The mount can be re-worked, and improved by regreasing, and
adjusting the worms for backlash.

- Worm gear adjustment is necessary. No exceptions (well, as a stance at
any rate).

- Polar alignment is crucial for unguided images. The EQ-5/CG-5 Polar
Scope sucks, the Vixen GP Polar Scope is AMAZING, if properly installed
and calibrated to the mount. The amount of time you spend "drift aligning"
your mount is inversely, and exponentially proprotional to the quality of
the Polar Scope, and your skill using it.

- Once you're hooked, and yet start to feel that the amount of effort
getting a simple image is becoming burdensome, get an auto-guider and
learn to use it. The amount of time you spend getting your polar alignment
exact enough to track tiny pinpricks of light, is better spent setting up
an auto-guider. With an auto-guider, short focus DSLR imaging is perfectly
fine with a Polar Scope mount alignment only. It also overcome's the short
comings in the mount's clock drive and gearing (for minor problems). You
will definitely throw away less sub-frames with an auto-guider, which
improves data aquistiion productivity, and lets you spend more time
processing images, than gathering the photons, and worrying about errors.

- If you don't have a permanent installation, and you work from your
backyard, get a ScopeBuggy for rough terrain, or JMI "Wheelie bars" for
smooth terrain/pavement. The number one hindrance to imaging on any given
weeknight, after clouds and/or poor transparency, is the amount of effort
it takes to setup and breakdown. Hauling out 10 pieces of equipment to get
going, is time consuming. With a ScopeBuggy, a good mount, a good Polar
Scope, and an autoguider, you can be up and running in 20 minutes or less.
Of course, that only really works if you have everything permanently setup
on the ScopeBuggy. This will likely require some ingenuity on your part,
as you need a place for everything on the buggy.

- The last thing to making imaging a breeze, is to use your imaging setup
for imaging only. I have my DSLR permanently attached to and focused for
my Orion 80ED. The ST-4 autoguider is permanently attached and focused in
a 5" F6.5 achromat refractor that rides side by side with the 80ED on the
mount. I only pull the ST-4 when using the 5" refractor as a finder for
the 80ED/DSLR, and then selecting a guide star. To focus the finder
eyepiece, I slide it out of the 1.25' adapter on the mirror diagonal. That
way the ST-4 doesn't have to be refocused. When my DSLR focus starts to
look poor in the images, I use a Stiletto IV with 300 lpi Ronchi grating
to get it back in, but that's an expensive solution (which works
flawlessly, and is a LOT easier than using a laptop and FWHM software
method).

Finally, I am biased toward not using a laptop at the scope. My confidence
in the success of the method outlined above, precludes the need for
fiddling with a laptop. You will want to get at least a 256MB memory card
to allow up to 30 RAW frames to be taken. If you intend to do several
targets in one session from a remote location using 10 to 20 frames at 5
minutes in RAW mode, then get a couple 1GB cards and a couple of extra
camera batteries.

HTH,
Stephen Paul
Shirley, MA

*** Free account sponsored by SecureIX.com ***
*** Encrypt your Internet usage with a free VPN account from
http://www.SecureIX.com ***


.