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My first imaging post and attempt

rockystar

By rockystar
in Getting Started With Imaging

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rockystar

rockystar

Posted
Posted

Last night (after I got home from an observing session) I decided to have a go at a night-scape shot, with just a DSLR and static tripod - I just want to have a go with what I've got, before investing any more, and seeing what I can do. There are many things wrong with this, I don't think I've managed to achieve focus properly, and I've got some  strange streaking going on, which must have happened in processing.

There are about 60 frames, at ISO-1600, F/4, 6 second exposure, then processed in Registax 6 (Taken in RAW but converted to TIFF for Registax).

Any help, much appreciated. Thanks

Orion 27 Dec.png

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vlaiv

vlaiv

Posted
Posted

+1 for DSS

But it will also have a problem with alignment. I think that out of focus stars are problem here - trails are due to some frames being poorly aligned (akin to star trails) - so when you stack you get "echo" of stars at different positions forming "trails"

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Glimpse111

Glimpse111

Posted
Posted
13 minutes ago, rockystar said:

Last night (after I got home from an observing session) I decided to have a go at a night-scape shot, with just a DSLR and static tripod - I just want to have a go with what I've got, before investing any more, and seeing what I can do. There are many things wrong with this, I don't think I've managed to achieve focus properly, and I've got some  strange streaking going on, which must have happened in processing.

There are about 60 frames, at ISO-1600, F/4, 6 second exposure, then processed in Registax 6 (Taken in RAW but converted to TIFF for Registax).

Any help, much appreciated. Thanks

Orion 27 Dec.png

Looks like your tripod was shaken, have you looked at the individual frames as one or two of those might be causing this. You can easily see that building's edge on right corner of the photo is out of focus as well which I am pretty sure is due to the vibration. Your focus to the star looks fine.

Otherwise its really nice photo :) 

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Tim

Tim

Posted
Posted

Hi,

Always nice to see somebody else sharing in capturing the night sky, so first of all, welcome to the club :)

You've started with a great target, Orion has it all! 

You'll need to find a way to nail the focus first and foremost. Processing out of focus shots is a fruitless and thankless task, and trying to get around the issues of soft focus wont teach you much about stacking better quality images.

If you can zoom in on your images, try to play around with manual focusing until you have the best position for the tightest smallest stars in the central region. It is worth noting that most lenses go a bit past infinity, so you need to wind them back a touch to get sharpest focus. It can be worth testing this on distant objects in daytime, then marking the infinity focus position on the lens somehow. I use slivers of electrical tape. 

Once you have achieved the best focus you can, you can test what length of exposure works best for you. Go as long as you can without the stars becoming obviously egg shaped, and without the sky background getting too bright. As a general rule, if you can pull up the histogram on your DSLR display, try to aim for an exposure that fills the left hand third of the histogram.

When you come to stacking, might be useful to download DeepSkyStacker, which is free. Then, crop out the edges of the image with lens distortion, and any static features. Stack what remains. The streaks on your image here are just smeared stacked stars by the look of it.

Hope that helps a bit.

When you have achieved the above, you can come back to us with an image to work on, and we can help you make the best of it :)

Enjoy your astrophotography :)

Tim

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Glimpse111

Glimpse111

Posted
Posted

I am not sure which lens you are using, if you try to zoom in then LP may get better and yes this is much better focussed photo. Try to reduce the ISO little bit to reduce the LP or take 4-5 dark subs and stack them to see if it is any different.

 

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iapa

iapa

Posted
Posted
23 hours ago, rockystar said:

Last night (after I got home from an observing session) I decided to have a go at a night-scape shot, with just a DSLR and static tripod - I just want to have a go with what I've got, before investing any more, and seeing what I can do. There are many things wrong with this, I don't think I've managed to achieve focus properly, and I've got some  strange streaking going on, which must have happened in processing.

There are about 60 frames, at ISO-1600, F/4, 6 second exposure, then processed in Registax 6 (Taken in RAW but converted to TIFF for Registax).

Any help, much appreciated. Thanks

Orion 27 Dec.png

A cheap bahtonov mask will help with the focusing. I got a couple for my Canon and Nikon lenses - will need to look out where they came form tho' Germany I think.

Where you using software to control the camera? Many such include routines to improve focus, even the free software you get with Nikon and Canon certainly.

The streaks you have look like you have some rotation but did not compensate when stacking? I use Nebulosity which specifically allows you to stack with correction for rotation and scaling. 

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AKB

AKB

Posted
Posted

This looks good!  Background can be suppressed to some extent with any number of tools.  I've used the Synthetic Flat Fielder in Nebulosity.  It's interesting to see the remnants of whispy clouds, but also some of the details in Orion.

Orion-2-background-removed.jpg

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happy-kat

happy-kat

Posted
Posted

Deffinately better using DSS.

Focus, the best place to focus for the most even across the image is not a centre star. The best star to use for focus is a star where the thirds intersect, a third in from the top/bottom and left/right side.

A few of us are not bothierng with darks but instead always using flats and bias. It's do to with that sometimes a few darks actually add more noise then the time lost that could have been better used to take lights.

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