First ever attempt at astrophotography with basic equipment

[Skyballer]

Hey guys!

Last night there was some decent breaks in the cloud so decided to have a play around with what I have (Nikon D5300, Nikkor AF 50mm f/1.8 Lens). The best part of the sky available to me was the constellation Cygnus, took 50 bias, blacks and flats and 600 x 2 sec exposure, 200 ISO at f2.8 (not sure if this was right or not, I have a lot to learn).

My picture is technically very basic, what I'd like to know is how do I get amazing images like this: 

Cygnus DSLR Shots

I'd love to be able to image the north american nebula for example, as it's completely invisible in mine

Here is what I was able to get, no amazing colours or anything, taken from my back garden. I'd appreciate any help and advice:

Edited August 3, 2020 by Skyballer

[CraigT82]

You will need to stretch the image to bring out the faint signal, have you done this? If not, start with curves and levels in gimp or Photoshop... Loads of info online to show you how to do this

[endless-sky]

Hi, the images you linked are most likely taken with an equatorial mount or a star tracker. Most nebulae are really faint and most DSLR are really blind to one of the most important part of the light spectrum (H-alpha).

I use a D5300 as well, for astrophotography. But, before astromodifying it to make it more sensitive to H-alpha, I was struggling to get any significant signal even with 1 or 2 hours of total integration time (I do, however, use an equatorial mount - Sky-Watcher NEQ6 Pro - so I usually expose for at least 60-120s, depending on the focal length I use).

Without a tracker and without modifying your camera, there's a couple of things that you can still do to get better results:

- raise the exposure time: with 50mm you should be able to go around 5-8 seconds, depending on where in the sky you are shooting, before stars start to trail. Experiment with this and keep raising the exposure by 1 second increments, until you start seeing star trails, then go to the previous exposure setting that didn't show trails and use that for the rest of the session

- raise the ISO. You should try to get the histogram shown by the screen of the camera, after you took the picture, to have a gap between the far left of the histogram (where 0 is) and where the foot of the curve of the data collected begin to show. If the curve starts "already high" at 0, then you are clipping (not collecting) data. If the exposure is not enough to show a clearly detached curve, raise the ISO in full increments (200, 400, 800, etc.), until you find a combination of exposure time and ISO that is good (goal is: no star trails and curve detached from the far left of the histogram).

Practice with these and see if your results improve. Eventually, if you like the hobby, consider buying a star tracker or an equatorial mount, depending on what load you plan on putting on it and eventual future upgrades.

[happy-kat]

With that many images taken I expect there's data to pull out

Budget astro on YouTube Doug's videos most of those you can follow using Gimp

You could expose for longer. With your sensor 400/50 gives 8 seconds so 6 would be a conservative use.

[happy-kat]

This is the summer triangle using static tripod and 24mm lens.

Link here

[Skyballer]

49 minutes ago, CraigT82 said:

You will need to stretch the image to bring out the faint signal, have you done this? If not, start with curves and levels in gimp or Photoshop... Loads of info online to show you how to do this

Yes I did stretch the image along with a couple other processes. I was loosely following this guide, though I went with iso 200 as suggested on another post here, something to do with the d5300 being iso less? 

https://youtu.be/iuMZG-SyDCU

[Skyballer]

Thank you all for the replies. If its clear tonight I'll try again with your suggestions on the histogram and higher iso and also raise exposure time. 

[alacant]

3 hours ago, Skyballer said:

600 x 2 sec exposure

Hi

All the data seems to have been removed from your .jpg. Could you post -a link to- the stack you made? I'm sure there'll be a bit more to be had from 600 frames although 20minutes isn't long enough to get the result you're after. For that you'll need hours of data. The easiest way is to guide your camera. 600 1 minute frames and you'll be at the level you're aiming at;)

Cheers

Edited August 3, 2020 by alacant

[endless-sky]

2 hours ago, Skyballer said:

Yes I did stretch the image along with a couple other processes. I was loosely following this guide, though I went with iso 200 as suggested on another post here, something to do with the d5300 being iso less? 

https://youtu.be/iuMZG-SyDCU

That was probably me, as I posted something similar in another thread.

The way I understand ISO-less is like this:

if you are correctly exposed at 200 ISO, say with 10 second exposure - and by correctly I mean the histogram is detached from the left by a good margin and you are not clipping any data - doing 10 seconds at 400 ISO won't give you any extra details: it will simply shift the histogram further right, but not collect more light, so it just boosts the signal that was already there at 200 ISO - sort of like a stretch. This is something that you can and will do in post-processing, anyway. So, by raising the ISO you actually don't gain anything in terms of light collected, but you lose in terms of more noise and lower dynamic range.

This reasoning only works if you compare a correctly exposed photo taken at 200 ISO with a correctly exposed photo taken at 400 ISO.

But if your exposure time is limited by having to take the photo without tracking, from a static tripod, and the highest time that you can use before you get star trails is not enough to expose correctly, without clipping data (histogram not detached from the left), then you have to compromise and trade off some dynamic range for a higher ISO, just so that you can expose correctly with that chosen exposure time.

This is how I understand it, I don't know if what I said is completely correct, but if someone knows more about how it works, please feel free to comment.

[happy-kat]

You could use astrometry.net to get a platesolve of the area captured.

[bottletopburly]

Your camera is iso invariant 200 iso is the sweet spot on d5300 processing will pull detail out you’ll gain nothing but noise using a higher iso , the d5300 is a brilliant Astro camera 👍 assuming shooting RAW 

Edited August 3, 2020 by bottletopburly

[Skyballer]

Yeah definitely shooting raw.

So suggested to stick at ISO 200 and increase the exposure time? I'll admit I forgot to check the histogram and on further review it's completely off the left side. Will try again with higher exposure time on the next clear night. 

The histogram on the D5300 is split into 4 channels, is this correct? Which do I need to read?

[Skyballer]

8 hours ago, alacant said:

Hi

All the data seems to have been removed from your .jpg. Could you post -a link to- the stack you made? I'm sure there'll be a bit more to be had from 600 frames although 20minutes isn't long enough to get the result you're after. For that you'll need hours of data. The easiest way is to guide your camera. 600 1 minute frames and you'll be at the level you're aiming at;)

Cheers

Here is the almost original stack, I'd done a first stretch and then accidentally saved over it:

https://mega.nz/file/uYFE0IoB#KQdFD1jIaFzHX9Jzez04F3bjUAnCKvIHJD0sucSLsq8

[alacant]

35 minutes ago, Skyballer said:

almost original

No. Has to be linear:

 

Edited August 3, 2020 by alacant

[Skyballer]

2 minutes ago, alacant said:

No. Has to be linear. 

What do you mean by that? (still learning)

[alacant]

1 minute ago, Skyballer said:

What do you mean by that? (still learning)

The stack, the whole stack and nothing but the stack. Not the stack with you having done something to it.

HTH

[Skyballer]

5 minutes ago, alacant said:

The stack, the whole stack and nothing but the stack. Not the stack with you having done something to it.

HTH

I'll redo the stack and upload, will take a while though. Wanted to do that anyway since I saved over it by mistake. 

[alacant]

OK. There's a big artifact along the bottom edge. Try to remove those frames first.

 

[Skyballer]

4 minutes ago, alacant said:

OK. There's a big artifact along the bottom edge. Try to remove those frames first.

 

I fear I have so much to learn yet, as I'm not sure what you're asking me to do. I can't recall seeing that artifact myself. 

Right now I'm following this guide for the most part, link to where he starts the DSS process:

 

Edited August 3, 2020 by Skyballer

[alacant]

OK. No problem. Just stack the lot:)

 

[Skyballer]

4 minutes ago, alacant said:

OK. No problem. Just stack the lot:)

 

Doing that now. I fear I may have messed up from the start anyway by not doing a long enough exposure, as the histogram on reflection is way off to the left. 

But you live and you learn. Unfortunately it's a cloudy night so can't go out and redo them. 

[Skyballer]

4 hours ago, alacant said:

OK. No problem. Just stack the lot:)

 

Here, stacked again, but for some reason the score for the highest image was a lot lower. Wasn't getting many stars detected even with a low threshold, unlike the guy in that video who had >200 stars and a score >1800

https://mega.nz/file/GEs3EBYJ#qPGiGSthWP5gODq376XNGFEBv97qh0Aj25WXvVsN3y4

**I think i made a big mistake and had my shutter speed set to 1/2 second rather than 2! Cloudy tonight but have a decent break on mars so going to have a little play with 6 second exposures in that area, though light pollution is greater that direction. 

Edited August 4, 2020 by Skyballer

[Skyballer]

Was having a wee play around last night with a shot of mars, 240 x 6 sec exposure. 

Facing that direction was multiple street lights unfortunately that left a horrible cast top right and bottom left of the image. How do I remove this? Any tutorial I follow doesn't seem to help much:

https://mega.nz/file/fZdWwQzY#9POmz0mfUqpOKLdN0-1bym-Se9YdwbTcbJbCffE1Gqg

[endless-sky]

6 hours ago, Skyballer said:

**I think i made a big mistake and had my shutter speed set to 1/2 second rather than 2! Cloudy tonight but have a decent break on mars so going to have a little play with 6 second exposures in that area, though light pollution is greater that direction. 

If you open one single RAW file with Camera Raw or some other compatible file reader, it should tell you the exposure settings (ISO, shutter speed, f/, etc.). You can check there if it was 2s or 1/2s. If it is 1/2s, then the difference is quite significant: 600*2=1200s=20min total integration, 600*(1/2)=300s=5min.

[alacant]

2 hours ago, Skyballer said:

Any tutorial I follow

Hi

it's unlikely that tutorials will cover the type of light pollution and severity of the same you have. Whilst they maybe a good place to start to get a hand for the basics, it's really down to you to get to grips with the software. That most likely means hands on. Even better if you can get along to an astro club and watch someone processing or if lock-down still prevents, zoom share with someone. It's much quicker to get started that way.

2 hours ago, Skyballer said:

How do I remove this?

 In this case, I cropped it. 

Next time, find a site away from artificial light and make sure that the camera field of view is what you want and does include e.g. trees or buildings. you'll see that you missed the North America Nebula but hey, for only 5 minutes exposure, this is a fine start. @happy-kat's post here gives you some guidelines for exposure for your next attempt.

HTH and post back the stack with a longer exposure when you get the chance