DSLR vs CCD

I'd like to address this question to all of you who are taking such stunning images with DSLR's (you know who you are; don't be modest!).

I've been in the process recently of simplifying my astronomy hobby in order to take better advantage of my limited free time (and energy). I'm seriously considering selling my HX916 and using the proceeds on a DSLR. Good idea or will I likely regret it?

My scopes consist of a Borg 76ED and a not yet received 8" f/4.9 Newt bought via Astromart. I also have a 10" f/10 SCT that I may or may not keep.

Thanks in advance for your input.

Mike

With a DSLR its hard to beat the FOV for the price. 3000x2000 pixels is for a grand is a bargain in this hobby. You may not regret the switch, but you wont be able to do certain things like Ha or monochrome. Also extended objects like emmission nebula are very difficult to get with a stock DSLR because the camara makers put an IR blocking filter, optimised for daylight photography, that does not do well on Ha emmision lines. Lets just say, they didnt have us in mind in the design stage. If you could do it, i'd try to keep them both. I use a Nikon D70 and have on order an SBIG ST-402ME. I dont wish to hack my D70 and i would like to shoot other things besides clusters. If you do get the DSLR, i hear and read that the Canon 20D is very good for AP.

John Krawczyk

OK, there has been some good info here and some stuff that is way off. Things to think of:

DSLR Negatives:

The DSLR's have way less QE than the astro cameras. It's not even funny. Many objects will be too faint to image with a DSLR, ever, period.

The resolution is substantially lower. The 8mp of the 20D really compares only to a 2mp monochrome imager; it has to do with the Bayer interpolation to get full-color. Basically, it takes 4 pixels for each final color pixel: one red, one blue, two green. This also relates to the relatively low QE compared to a monochrome imager.

Narrow-band imaging is really mostly out. Between the AA filters and the relative insensitivity of the DSLR sensors to Ha and other narrow bands, topped with the Bayer filter issues, it's just not even close. Canon's CMOS sensors are quite insensitive to the IR and Ha bands compared to Canon's and Nikon's CCD-based imagers, as well.

No cooling, etc means that noise reduction is mostly achieved with in-camera or out of camera software adjustments, meaning even more lost resolution/accutance.

DSLR's are much more of a PITA to deal with from a software perspective, etc, for automated image capture and image reduction.

DSLR positives:

Larger FOV. A lot larger.

Relatively cheap.

You can can use it during the day for other photography.

All of that said, just so you know, I have both. I have owned nearly every SBIG camera made and couple FLI cameras. I own or have owned most of the Nikon and Canon DSLRs, and have a 20D, 1D MarkII, and D2H right now. I know all of these cameras.

A reference point: A good friend of mine who has gotten serious about astro-iimaging has started using my observatory with me. He is well-known for his work with the 10D and 20D, and has had many images published in Astronomy and Sky & Telescope. At first he found the STL-11000XM intimidating and stuck to his 20D. After seeing the images I got in less than half the time, and learning how to use it, he is selling his DSLR to get a large-format monochrome astro-imager.

The moral of this story: If you want to do great astrophotography, and that is your primary goal, get a great astrophotography camera--not a DSLR. If you just want to dabble and you would also like to do regular photography, and are happy with the limitations I listed above, then by all means, get the DSLR (and stick with either a 20D or a Nikon D70--both are superb).

As always, the right tool for the right job.

Jeff

...I still can't decide! If I still had the kind of income I had when I initially got into this hobby (outsourcing of high-tech jobs took care of that!) it'd be a no-brainer - keep the HX916 (or upgrade!) and buy a DSLR.

My main reason for wanting a DSLR, which I didn't state in my original post, is because I know I'll take many more non-astro pics than I currently do. My hope was that a DSLR would provide high enough quality astro images to justify selling the HX916.

I've seen what to my eyes are some really stunning astro images taken with DSLR's, though I suppose they have been predominantly bright objects. Of course, as limited as my time at the scope is, I have to wonder how many really faint objects I'll ever get around to imaging! I've barely made a dent in the bright objects, and the images I've achieved so far are hardly worth bragging about.

Anyway....thanks for the input. It's all been quite useful and very interesting. Now I just need to sort it all out and decide what I want to do.

Mike