Disclaimer: Rank Newbie opinions. Relationship to fact may be tenuous at best..
There’s often a bit of chat here about the “best camera” for astro beginners, so I thought I’d take some test shots with two cameras that were widely different in price and see if I could pick much difference.
So - just out of interest - here’s a few shots of the same area of sky, taken with different cameras. One is a 600D - an older and inexpensive entry level Canon DSLR and the other is a much more expensive Canon 7D Mk2 (which I usually use for wildlife).. The main difference in this case is the ISO range. The 600D only goes to ISO 6,400 while the 7D Mk2 goes up to 16,000. But does it make much difference?
Well, apparently it depends….
In my case, mostly not. I mainly want to make simple maps of areas of sky that contain a complete constellation - such as Scorpius - that I can crop down and use for a study guide while I learn the positions and patterns of the key stars and any objects of interest. I don’t really mind if the shots are a bit noisy as I’m not shooting to frame the pictures or enter competitions.
I like using programs like Stellarium and SkySafari alongside my own photos because I can adjust them all (e.g. by zooming, lightening and darkening, etc) until they come close to matching what I can see through a telescope. The better the view the more white dots you can see in a given area and the harder I find the task of picking out which are the key stars that determine the pattern for a particular constellation. So it’s good to have some shots with less detail to compare with more crowded ones to help me cope with the pattern recognition.
However, where a more capable camera might come in handy is shooting through a “slower” telescope than the 200mm lens used in some of the attached pictures. For instance, that 200mm lens is an F4 which is reasonably fast, but telescopes can vary a great deal from quick to very slow. And with higher magnifications you get less time to take the shot before the stars go out of shape. So being able to crank the ISO up and use shorter exposure times could be useful - provided the noise levels weren’t outrageously high. The usable ISO ranges have increased dramatically on many newer DSLRs, so that could be just the excuse I need to buy another new camera…that I don’t really need..
Or not…
All the pictures below are single shots with no stacking or post processing (with the exception of some lightening in the one widest photo. No.2). In the closer shots I’ve circled the key stars in the Corona to make it easier to compare with the wider views. All the closer shots are taken with the EF 70 - 200mm F4 lens at 200mm (a good quality L series lens) . Is there really much difference between 3, 4, and 5? Does an expensive lens really make much difference when the subject is white dots on a black background? For what I need, the cheaper gear seems just fine, but perhaps things will change if and when I ever get around to the business of attempting some tracking and stacking??
Photos:
- A screenshot from SkySafari 5 showing the main stars in the Corona Australis, which is a group of stars (in Sagittarius) that currently sit below the tail of the scorpion (in the constellation Scorpius), round about mid evening. The Corona looks rather like the sort of laurel wreath that Julius Caesar is often depicted wearing. It also looks a bit like a horseshoe.
- A wide shot of Corona Australis taken with a Canon 600D and an inexpensive 18-55mm kit lens at 18mm.
- Canon 600d ISO 6400 at 2 secs 200mm lens
- Canon 7D Mk2 ISO 6400 at 2 secs 200mm lens
- Canon 7D Mk2 ISO 12800 at 1 second 200mm lens (double the ISO, and half the exposure time)
- A close crop from a shot with Canon 7D Mk2 ISO 16000 at 2 secs. Very noisy at that degree of crop and ISO, but at least you can see the Globular Cluster is more than a single star. A shot taken through a 150/750 Newtonian telescope came out looking very similar as far as detail (or lack of it) went.
If you want to see a really good picture of NGC 6723 with some nice BIG white dots then check this out.
https://upload.wikimedia.org/wikiped...le_WikiSky.jpg
It’s certainly a lot clearer than mine! But you might need a spare 5 or ten billion dollars, as that one was taken by the Hubble telescope.
https://en.wikipedia.org/wiki/NGC_6723
What has been your experience?