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Trouble with stacking!


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Evening All!

I'm starting to take my first steps into the 'post-processing' of my images, and to be honest with you, I have no real clue of what I'm doing. Hence why I'm here tonight, to pick your brains :) 

This is just one of a large selection of identical images I took tonight of a randomly selected patch of sky:

DSC_0532.NEF

As you can see, I get a fair number of stars in the image, but it's nothing too spectacular. Exposure time is only 1.3 seconds so I wouldn't expect much too begin with!. Now my main issue is how to stack my images properly. I know that I should stack my images, to get those better quality final pictures, but even after reading a few guides I'm not quite sure of how to get to those final results. As you can see after my attempt of stacking everything up (Using 'DeepSkyStacker') all of the limited details I had are lost and the image just looks a complete mess.

Stacked.TIF

Being new to the processing side of things, I expect I'm missing the blindingly obvious answer, but in summary, is 'How do I stack my images correctly?!'.

- Stuart

( Also forgot how to attach my pictures as an image, so the file attachments will have to suffice I'm afraid! :p )

 

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Hi Stuart,

I am also very new to AP so really not the best person to help, however, I took your STACK.TIF and extracted the background in PixInsight; I also performed a single non-linear stretch. There is something there - definitely a galaxy! - but I am not able to offer insight into which one it might be from your "random patch of sky"!

I only started AP in October 2016 and as I owned a copy of PS CS6 I persevered with that for quite some time trying to extract detail from my stacked images. I then decided to try AstroArt, ImagesPlus, Nebulosity and PixInsight (all trials) before deciding PI suited me best and seemed to work for me in terms of extracting every last photon from my hard obtained subs. I am still at the very bottom of the learning curve so I am sure someone more expert with PI would make far more of your stacked image.

Hope this helps :)

Adrian

Stacked_ABE.tif

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Astrometry.net returns this information, identifying your 'random path of sky':

Calibration
Center (RA, Dec):(79.460, 44.009)
Center (RA, hms):05h 17m 50.450s
Center (Dec, dms):+44° 00' 31.860"
Size:10.9 x 7.29 deg
Radius:6.570 deg
Pixel scale:6.54 arcsec/pixel
Orientation:Up is -133 degrees E of N

and also this annotated plot:

Capella.jpg.476c00516c990aad19010817e6498493.jpg

So, in fact, it's not a galaxy, but a star (if we're looking at the brightest thing.)

This doesn't help you with stacking, except to show there is something there, but it does give useful information about your field of view and pixel angular resolution.

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Welcome to SGL

With only 1.3 second exposures, you won't register much more than stars, I'm afraid.

So, this is about the point where we tend to give the following advice:

Get a copy of 'Making every Photon count' by Steve Richards. It's available from our favourite supplier, FLO.

 

Good luck

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  • 2 weeks later...
On ‎26‎/‎03‎/‎2017 at 18:29, wimvb said:

Welcome to SGL

With only 1.3 second exposures, you won't register much more than stars, I'm afraid.

Good luck

I'm aware that 1.3 seconds is practically useless for anything other than stars, I've just been trying out another camera lens that allows me to get a bit more "zoomed in" on my target (providing I have one).

 

Thanks for your input guys, much appreciated!

 

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There is a good website that you can read and watch videos. Substitute GIMP for Photoshop and you'll find you can do a lot of what is covered.

Www.budgetastro.net

You'll find with the longer lens your exposure time will be even shorter. Take 400/lens gives time in seconds before star trails assuming you have a crop sensor. You best bet will actually be the kit lens at widest setting that came with your camera. There is much more you can do and learn with the equipment you have. For example aim east or west below 60° to minimise field rotation. Use a intravolameter to take the images it will cut any vibration out. Make sure you turned off in camera noise removal. 

 

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  • 4 weeks later...
On 3/26/2017 at 10:25, Adreneline said:

Hi Stuart,

I am also very new to AP so really not the best person to help, however, I took your STACK.TIF and extracted the background in PixInsight; I also performed a single non-linear stretch. There is something there - definitely a galaxy! - but I am not able to offer insight into which one it might be from your "random patch of sky"!

I only started AP in October 2016 and as I owned a copy of PS CS6 I persevered with that for quite some time trying to extract detail from my stacked images. I then decided to try AstroArt, ImagesPlus, Nebulosity and PixInsight (all trials) before deciding PI suited me best and seemed to work for me in terms of extracting every last photon from my hard obtained subs. I am still at the very bottom of the learning curve so I am sure someone more expert with PI would make far more of your stacked image.

Hope this helps :)

Adrian

Stacked_ABE.tif

I have had the same problem. I'm just starting to get the hang of it through trial, error, watching videos, and reading the manual. I use Registax 5.1. I don't know enough to say it is better than another program, but I'm getting some good results. I had to learn each progressive step by playing with the images on Registax 5.1  til it did something. I started and stopped my way through an instructional video taking numbered steps notes. That was my first breakthrough into the program. I advise "start/stop/take sequenced notes" while watching instructional video method.  Then take your images and process them using the notes. Best wishes. Bob

JUPITER 4.26.jpg

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1 minute ago, BrockW said:

I have had the same problem. I'm just starting to get the hang of it through trial, error, watching videos, and reading the manual. I use Registax 5.1. I don't know enough to say it is better than another program, but I'm getting some good results. I had to learn each progressive step by playing with the images on Registax 5.1  til it did something. I started and stopped my way through an instructional video taking numbered steps notes. That was my first breakthrough into the program. I advise "start/stop/take sequenced notes" while watching instructional video method.  Then take your images and process them using the notes. Best wishes. Bob

JUPITER 4.26.jpg

Jupiter 4/26/2017. Orion ED80, ASI120MC, CELESTRON AVX MOUNT, 520 FRAMES, REGISTAX 5.1. 

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Stacking images allows you to pull out more detail and reduce noise.

These are your two images after a little bit of post processing.

Look how many more stars are there in the stacked one, it also shows some slight light pollution coming in at the bottom edge of the image but its very minor.

No Deep Space objects of any size in your chosen area though.  

To capture DSO you really need exposures of at least 30sec at ISO 800 min ideally much longer.

Single.jpg

Stacked.jpg

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In order to get something to learn with take camera and (I assume) lens, you will/might need an intervalometer (not sure a hand operated cable relese will do it well enough.

Set ISO to 400 or 800, set the exposures time to 20 seconds. Manually focus camera (you seem OK with that), disable any Noise Reduction feature of the camera (not wanted at this time).

Take camera and tripod out (camera set to Manual), aim at something with an object in it, try a cluster as they are biggish patches - maybe the double cluster in Perseus.

Take ten exposures at the given 20 second duration. Wait a small period between each one say 10 seconds - allows a bit of sensor cooling and allows the camera to write to the memory card. Wait is either manually or set in the Intervalometer.

Now you will have 10 exposures to stack (play with) in DSS. With hopefully something in them to see build up.

I find 10 exposures 30 seconds apart (20 sec exposure+10 sec wait) are able to be handled by DSS.

One thing there is a view finder on the rear of a camera if possible cover that over in some manner, it allows light back up through it and causes a degree of light pollution on each exposure. Easy to reduce it so do that just in case.

As said that gives you a small set of exposures to get familiar with DSS, the (any) processing is via different packages and that is another area.

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