Beginning Astrophotography

What would be considered the "minimum" equipment requirements to do
astrophotography? Is it essential to have a tracking mount, or can
short exposures be taken and then stacked?

Any advise for a newbie?

T.I.A.

Lurch

<[Registered users can see links. ]> wrote in message news:1162415942.737146.288260@h48g2000cwc.googlegr oups.com...

I'd appreciate comments too. I'm not a newbie, but a returnee.

From my reading, I expect stacking a CCD is fine for planetary and lunar, and not bad for the brghter nebulae.

For brighter galaxies the problem is the angular size. A 1/4 inch CCD will be looking at maybe 15 to 30 arc min. Eyepiece projection
means you lose intensity, and that means you hit the noise limit earlier, which has more impact on stacking images.

If you don't use stacking, you need (a) a realy good mount, and (b) guiding. What are the options for that.

Disclosure: I'm using a smaller celestron in alt/az, not equatorial. I could wedge it, but the slack in the drive means I would not
trust tracking. So stacking is best. If I spend more money on a good mount 8 inch+, and SBIG, I can track AND look deeper into the
sky.

T.

Tomasso wrote:

It depends on your equipment. The less the magnification, or if you
wish the wider the field of view, the better your chances when taking
short exposures and stacking. It's a question of trailing, and no
amount of stacking will get rid of trailing.

But planets need magnification, lots of it, so unless you want to see
dots instead of disks, you'll need to track, even with web camera
technology. It doesn't have to be tack-sharp precise tracking, but
you'll need to track steadily and consistently, or else the stacking
software isn't going to produce sharp images. This counts for the moon
also.


Usually for deep sky objects, prime focus imaging is used, where there
is no camera lens, no eyepiece, just the telescope and the eyepiece.
This gets rid of any unwanted magnification due to the eyepiece, and
more importantly reduces the reduction of light at the CCD by getting
rid of any glass that you don't need.

Of course, you could use eyepiece projection if you don't have a choice,
or if you want added magnification, but I'd avoid it if possible.



Three words --- money, money, and money.

Good tracking mounts tend to be expensive. The larger the telescope,
the more the mount had to be large and rock steady, with minimal
periodic tracking errors. This means forget that new car, forge that
holiday cottage in the hills, forget sending that kid to college. Open
up your wallet and abandon hope all who enter this.




Your field of view rotates as the mount tracks. You probably can't see
it, but it's there, especially on long exposures. Same is true if you
try and piggy-back a camera. Hence you'll need a derotator if you're
shooting through the scope.

I'd try web camera imaging the moon and planets first. Won't teach you
everything you need to know about deep sky imaging, but it'll give you
good experience on some of the problems. You can also get one of the
planet imagers from Meade or Orion Telescopes. I don't know if you'll
still need the derotator or if the software will take care of it.

For Deep sky you'll probably need a derotator, and you'll need to keep
the exposures very short.

--- Dave N.