that's perfect, Brad, thank you. I do mean it, even though it's difficult to not dream about something like an SCT with a longer focal length to get those amazing shots. But that will be next, once I've done some basic stuff. I will admit that I'm already planning that way, but... one step at a time. The thing that gets me excited are the nebulae and such, so I'm trying to stay focused (buh dum bump) on those.
For some time, months, not weeks, this will be about learning, rather than what you're imaging. And the small scope and big targets is better for that task. Corollary. For your first image, don't even bother with a nebula. Try a cluster, or even a random star field. You'll walk away from gathering the data, and processing it, with a significant "to do" list. <smile> So don't overly fuss about the target, simple is good.
@bobzeq25, can you talk more about the snr differences? We just blew past the boundary of my knowledge... thank you!
The key parameter is "image scale", the number of arc sec per pixel. You calculate it by dividing the focal length by 200, then divide the pixel size by the result. Closer to 1 could theoretically get you more resolution, but a number of things are likely to intervene, so you won't get much more resolution if any. Closer to 2 puts more signal on each pixel, making noise less important. Better signal to noise ratio, and the loss in resolution is unlikely to be a concern. Closer to 2 is also more forgiving of beginner mistakes.
I was laid back about the recommendation, but, since you asked, I think the 533 is a better learning tool. And well regarded here.
All much better described in this book that in a short post. I pretty much guarantee you it will be the best $40 you ever spend in AP. <smile>
I have a number of scopes and cameras, image between 1.0 and 2.7. Below is 2.7. Look OK? Better quality, and a lot more details, here.
Like you, I’m just getting started with a similar budget. Initially, I was going to get a doublet but found an Explorer Scientific ED80 carbon fiber on classifieds here for $630. Very happy with the sharpness! Just received my HEQ-5 Mount from Astronomics. Practicing polar alignment now. Instead of a Zwo camera, I already had a Nikon D5500. I’m sure it will give decent images but I will get a Zwo next year. Guys on the forum tell me to get a guidescope and guide camera right away. So now I’m looking for mount adaptors. I’m finding that there is always something new to buy! Lol
Good choices. I have astro cameras, still use my D5500 sometimes. If you an track well enough, the ideal ISO is 200. Build data with exposure time. Subexposure time is less critical, total imaging time is vital. Shoot more subs. <smile>. Higher ISO just limits your dynamic range. If you can track properly.
My rule of thumb is one hour total imaging time is minimal, 2 is better, 4 good. The image below is 7.2 over 3 nights. That (and some special filters) got me the dim stuff.
Edited by bobzeq25, 05 July 2020 - 03:00 PM.