Suggestions for a digital camera for astrophotography

[Screamin-D]

Can anyone give me some suggestions as to which camera works well for astrophotography? I am in the process of trying to choose one to purchase. I currenly have a 5.1" Newtonian and a 80mm refractor and want to take pictures of the moon/sun/planets plus dark sky objects (nebulas, clusters, etc).

I was looking at possibly either a CP4500, CP5700 or the new Canon Rebel 300D. Any suggestions (for these or others)? I'm looking for something half decent (but not outragiously expensive (under $1000) that will take great "daytime" pictures as well as "nighttime" pictures.

And, from what I've read so far, for digital cameras, short exposures with stacking are best?

Thanks.

[Lin Evans]

Hi,

Of the cameras you mentioned, the 300D is the better overall performer for long exposures.

Because of the CCD or CMOS production of "dark current" (heat increasing noise production with exposure time) digital sensors require super cooling (CCD Cameras for Celestial use) for serious celestial use. But for photographing the moon, planets and objects which are available without seriously long exposures, digital can be useful.

There are two issues here which one must consider. First, the issue of "power." To really use a digital camera with a telescope effectively for deep space, it's necessary to shoot afocal. This means that the eyepiece of the telescope as well as the objective lens must be used and the camera must "see" through the eyepiece in much the same manner as your eye.

Secondary is the issue of noise and exposure times. Considering these two issues we have technology which is a bit at odds with one another. The smaller lenses like those with the Nikon CP4500, etc., allow the camera to easily use a Celestial eyepiece in an afocal manner and avail themselves of the tremendous light gathering power of the Celestial scope. But the very principles which work in favor of this (small lens) work against the issues of noise, ISO capability and lens speed. On the other hand, the dSLR (removable lens SLR's) like the 300D have great high ISO capabilities and excellent (by digital standards) long exposure capabilities, but don't work well in an afocal manner because of the large lens configurations.

With sophisticated telescopes (read expensive) which have access for 35mm film cameras which avail themselves of afocal capabilities, the 300D will undoubtedly do better. But for the majority of telescopes which have only a fixed focal length port (Meade ETX-90, etc.) you would probably do better with something like the CP4500 and depend on "stacking" technology for improved image quality.

Best regards,

Lin

[Screamin-D]

Thanks for the info Lin.

You mention that the best method is afocal. What about using eyepiece projection for a DSLR? I currently am trying it with my film SLR, but haven't tried it on deep sky objects yet (only the moon) and I have to wait until I finish the roll before seeing how it is. How would this (eyepiece projection with the adapter and an eyepiece) with a DSLR compare to afocal with something like the CP4500?

Thanks,

Andrew

[djb]

eyepiece projection should work well for a dslr but afocal is about the only way with the prosumer cameras.

dennis

[Screamin-D]

Thanks Dennis,

By prosumer cameras, are you refering to something like the CP4500 - not something like the Canon Rebel 300D (DSLR)?

Thanks,

Andrew

[djb]

Andrew, yes, i was speaking of all the nicer non dslr cameras.

dennis