Canon 5D, Heart Nebula (5 Hours Total Exposure)

That is one impressive setup and an inspriational shot

Andy

smasraum wrote in post #4775236
Steve,

Initially, I'd be shooting just with my camera and lens. I see this eventually turning into a hobby, but I won't be spending much money on it for about 1.5-2 years.

I've seen some advice that I thought was probably sound, but I'm going to ignore. First get in to just doing visual observation, then after you've been around a while and learned the basics start moving towards AP. I can see that similar to some other stuff that I'm interested in, if you try to go too cheap initially, you can end up frustrated and buying the good stuff down the road anyway.

My current tentative plan is to go very slow and cheap and learn and dream of doing the cool stuff with the good equipment like you, and then at some point down the road, get a good setup with good gear.

From what I understand, the cheaper gear is fine for visual or even wide angle photos (like 18-50mm), but the tolerances change a lot when you start taking pictures at longer FL.

Who knows what direction I'll end up going, certainly not me.

Thanks for the advice. I'd considered used gear. There's not much on ebay, but the other two sound like they're worth checking out.

Steve, you're wise to start modestly and go slow. You don't want to become frustrated to a point of throwing in the towel before you have a chance to get a feel for things.

The advice you were given is solid. Observing is a great way to learn the layout of the night sky and to ease into understanding the hobby including equipment, etc. Knowing the constellations and brighter stars will be particularly useful when you start aligning your mount for imaging. The constellations are your markers for object locations. And of course observing is just good fun. Sometimes it's fun to take a break from imaging and just look at the wonders, something I need to do more often provided I can get more time out(lousy weather this winter). And yes, long focal length imaging is difficult even with more capable equipment. Lower end gear makes it mega frustrating.

Good luck, let us know what you find.

NH

Thank you Mark and Andy, greatly appreciated.

NH

That's just ridiculously wicked cool. . .

Thanks Soliz387. Much appreciated.

NH

Ok, first off, I have to say what a killer shot that is! Second, I have a question, which I have not seen answered yet in my searches of astrophotography. My question is, are all of the photos of the same area, or of different ones, and then combined to form a larger image, or is it one area photographed a buch of times. The reason I ask is that I'm having a hard time understanding why multiple exposures of the same time incriment (in this case 5 minutes) are needed if the image is of the same area. Thank you if you answer this.

Sam_M wrote in post #4795127
Ok, first off, I have to say what a killer shot that is! Second, I have a question, which I have not seen answered yet in my searches of astrophotography. My question is, are all of the photos of the same area, or of different ones, and then combined to form a larger image, or is it one area photographed a buch of times. The reason I ask is that I'm having a hard time understanding why multiple exposures of the same time incriment (in this case 5 minutes) are needed if the image is of the same area. Thank you if you answer this.

Thanks Sam. This particular image is a single frame image that is a result of combining sixty 5-minute exposures. I repeatedly shoot the exact same spot that contains the object I'm after. The reason for shooting shorter exposures as I do is three-fold. Firstly because in order for me to even attempt one single 5 hour exposure I would have to own a very expensive mount(approx. 12K) and be shooting with a dedicated and cooled astro CCD camera(5K-10K). Even when high-end equipped the next hurdle would be image noise level. As DSLRs(Canon 5D in my case) or Astro CCDs are collecting photons they are also heating up in the process. The thermal noise in a 5 hour exposure would not be easily reduced without degrading the precious details of the object you are shooting. Cooled CCDs have a big advantage for combatting noise over a DSLR. And lastly the final hurdle would be light pollution and/or "sky fog". Even under very dark skies 5 hours of exposure will be collecting a LOT of light, some very faint that is projected in the atmosphere from very far away. The "sky fog" limit on exposures can vary from night to night and also depends on the optics/camera you are using. "Sky fog" is a major limiting factor in exposure time. To simplify it begins to flood the image with unwanted light that begins to neutralize the faint light that you're attempting to gather thus making that light less apparent in the final image.

So with my set up and my sky conditions, I keep exposures around 4-6 minutes and only shoot at ISO 1600 during the winter months when the cold temps help keep the camera cool. By combining shorter exposures the process reduces the noise level and raise the signal(good stuff) at the same time. So the end result is less noise to have to remove in processing which helps preserve detail and clarity.

One last note. There are times when multiple frames are combined in a mosaic. This allows use a a fairly high focal length to be used in each frame or section used in the mosaic. By piecing the sections together large areas of sky can be portrayed in stunning detail and at large scale.

This image is a mosaic of two horizontal frames pieced together in Photoshop. Each section is 90 minutes of combined or "stacked" exposures at 407mm(f/4). Had these been single 90 minute exposures the noise and sky fog would have been terrible.

That helped sort of. Not for lack of explanation on your part though, that's some good information, I'm just slow sometimes. Let me try to get this straight. You combine however many exposures of the same area, as a way to increase the layers of a particular area/ object, thus increasing its brightness and detail, while keeping noise levels low. Its like applying coats of paint to bring out the true color and shine right? That's what I make of it. Correct me if I'm wrong. Thanks.

In a sense, yes. There's no real objective to increase layers but yes it's simply a means of accumulating or combining exposure time while keeping noise in check.

NH

Ok, got it. Thank you very much for the explanation. Oh, and post more pictures please!

Here's a long-winded explanation
http://www.cs.unm.edu …graphy/imageSta​cking.html

breathtaking, thank you for sharing

You're welcome Sam.

Steve, thanks for the info link.

Thank you Brian, you're welcome.

NH

OMFG!

*jaw hits table*

That is so awesome!!!!!