I am a complete newbie, how can I get better images than these?

[Thenu]

I'm doing a uni astrophotography project and we were given a very simple Canon Powershot 490. I attached pictures we took last night (with just the camera).
Camera settings - ISO:1600, f/3.0, Shutter Speed: 15s.

I noticed that there seems to be a lot of grain/noise in these photos and that they are not very sharp. Is there any way to minimize this problem?
From what I researched, I think I need to try reducing the shutter speed and stack multiple photos with something like deep sky stacker. I just want to know whether I'm heading in the right direction.

 

Edited October 25, 2022 by Thenu
Grammar

[PeterCPC]

Re the exposure: You take the number 500 and divide by the focal length of your lens. For example, if you have a 20-mm wide angle lens, then 500 / 20 = 25. The 500 rule measures the maximum exposure time you can shoot before the stars become blurry or star trails appear.

Focus is found using liveview normally but I don't think you have that. All I can suggest is altering the focus very slightly until you are happy with it. Might be easier if the Moon is out and you can use that.

Noise can be reduced with after shot processing.

[Elp]

As it's a compact camera you are using you may struggle reaching infinity focus, some cameras have a manual focus mode where you can set it to infinity. The in built lens will also cause massive chromatic aberration at the edges but anything in the centre should be better. Generally with astrophotography you need to take lots of images (light frames) to improve signal whilst averaging out noise, then use calibration frames (darks, bias, flats, dark flats) to even out the light frames during the stacking process. Post processing plays a massive role in improving the images after they're taken.

 

[Varavall]

1 hour ago, Thenu said:

I'm doing a uni astrophotography project

Hi

What is the aim of the project? Is it to actually take photos of something or to demonstrate/discover the probems of astrophotography? The minimum focal length of your camera is 27mm equivalent, so you are limited to exposures under 18 seconds unless you can stick it on a tracking mount.

Edited October 25, 2022 by Varavall
Error corrected

[John Wick]

Stacking multiple images will help reduce 'noise', looks like alot of ambient light in some of the pics, that won't help. Perhaps check a light pollution map to see what options you have for low Bortle locations?

[AstroMuni]

1 hour ago, Thenu said:

From what I researched, I think I need to try reducing the shutter speed and stack multiple photos with something like deep sky stacker. I just want to know whether I'm heading in the right direction.

Definitely in right direction. As others have said it would be useful to know what is goal of your project. Take a look at the free Siril software too. It has some tools in it to reduce background gradients etc.

[Thenu]

Thanks a bunch for the responses. A few of you asked the purpose of this project - we had a few options to choose from but due to the lack of time we went with taking photos of identifiable constellations. I'm still in my first year so these are very simple projects. Nevertheless I'd like to get better at astrophotography.

Life would so much easier with a tracking mount but I think deep sky stacker has an option to align photos? I'm not too sure.

[Mandy D]

4 minutes ago, Thenu said:

Thanks a bunch for the responses. A few of you asked the purpose of this project - we had a few options to choose from but due to the lack of time we went with taking photos of identifiable constellations. I'm still in my first year so these are very simple projects. Nevertheless I'd like to get better at astrophotography.

Life would so much easier with a tracking mount but I think deep sky stacker has an option to align photos? I'm not too sure.

You can create great constellation photos with short exposures and short(ish) focal lengths. Orion is one of my favorites and is nicely positioned around midnight at the moment. If you want to make it more intersting you could go for creating diffraction spikes on the brighter stars. This will happen naturally with a Newtonian reflector telescope due to the secondary mirror mounts, but you can always stick some wires across the lens of a camera at right angles to create the same effect. Really, you probably will not need much processing of this type of photo. If you have a tripod and can adjust the exposure time, aperture and ISO (or any of those) you can improve results. High ISO tends to be noisy, so wide open, low(er) ISO and follow the guidelines for exposure time as given by others.

[Elp]

A tracking mount counteracts the rotation of earth so you can expose per image for longer (the subject to the camera appears to not move) gathering more photons which can be limited by local light pollution levels, camera sensor read noise, tracking accuracy etc. You need to strike a balance between what you're imaging versus what you don't want in the image. Constellations should be fairly straightforward without the need for a tracker.

Edited October 25, 2022 by Elp

[900SL]

4 hours ago, PeterCPC said:

Re the exposure: You take the number 500 and divide by the focal length of your lens. For example, if you have a 20-mm wide angle lens, then 500 / 20 = 25. The 500 rule measures the maximum exposure time you can shoot before the stars become blurry or star trails appear.

Focus is found using liveview normally but I don't think you have that. All I can suggest is altering the focus very slightly until you are happy with it. Might be easier if the Moon is out and you can use that.

Noise can be reduced with after shot processing.

The 500 rule only applies to full frame cameras, and is incorrect anyway for modern sensors, I shoot closer to a 300 rule on full frame, or track

[900SL]

1 hour ago, Thenu said:

Thanks a bunch for the responses. A few of you asked the purpose of this project - we had a few options to choose from but due to the lack of time we went with taking photos of identifiable constellations. I'm still in my first year so these are very simple projects. Nevertheless I'd like to get better at astrophotography.

Life would so much easier with a tracking mount but I think deep sky stacker has an option to align photos? I'm not too sure.

Sequator is easier for noobs

[Knight of Clear Skies]

You've made a good start. I'd recommend downloading Sequator for stacking photos taken from a fixed tripod. It's a free download (with a donation option), easy to use and more reliable than DSS. It also has options to create a mask for the foreground so it just stacks the sky, and can create stacked timelapses. I used it for the image and timelapse on this page:

https://www.caradonobservatory.com/articles/viewing-the-milky-way

Download page is here:

https://sites.google.com/site/sequatorglobal/download

I also notice some star trailing in the dome image which has been caused by movement of the camera, probably from pressing the shutter button. If you can turn on the camera timer it will help prevent that kind of thing.

Good luck and I hope that's of some help.

Edited October 26, 2022 by Knight of Clear Skies

[Varavall]

21 hours ago, Thenu said:

taking photos of identifiable constellations

Wait until midnight on a moonless and cloudless night away from light polluted skies, make sure the flash is turned off, set on a tripod, set a 10 second delay, exposures 10-15 seconds, point at a constellation and experiment with ISO settings to see what you get. As a student you may have Photoshop at college? If not, look for free image processing software such as GIMP. Get a free star atlas programme, such as SkySafari, for navigating the constellations if you are unfamiliar with them. Hopefully top marks await!