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M27, 1st try with the Atik


Celeste

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Thats very good Nicky.


The beauty of the Atik is it runs with so little noise you will not need to do darks.


Just do some flats to take care of the bunnies ect. and some bias subs and all will be good.


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Thanks guys :) I got to ask, what is the colour supposed to be? I see some red/blue and some red/green....which is it? Mine's come out red/blue. I can't wait to go for longer subs once i've set up my guiding :) Also need to work on processing, I will get there.


 


Graham, I used Atik Dawn to align/combine/debayer etc, I used a template OSC 2 (darks/lights/debayer/align/combine set) where do I put in the bias frames? I don't have anything to make flats with really, can't hold my laptop up to the scope as i'm using it to take the subs. What does everyone else use?


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well done on the image, i think for a first attempt it`s excellent and for such short subs it`s come out well, more subs will help and i think the colour is right, mostly blue and red on the outer edges.


i did a few test stacks when i had my 314 L+ and i found adding darks made the image noisy, adding to few can do that and to be honest the camera can cool so well that it hardly needs to bother with darks, you could do a few bias shots and add them to the darks folder in Dawn but i think i wouldn`t bother with them either, some flats might help, all you need is an evenly light light source so a linen cloth over the end of the scope on a bright day would do it, then take a sub of about 1 second, then look at the histogram or the screen ADU reading, histogram needs to be about a third of the way across or an ADU reading of about 25000 ish, change the exposure times to get the desired reading.


also i generally don`t use DAWN to stack, it works ok but saves the image as an 8 bit file which has then lost a lot of colour and gray detail, so i use deep sky stacker which is free and allows you to fully stack images to your liking using light, dark, flat and bias frame if you want to, it will also save files as a 32bit or 16 bit file, 32 bit being best as it holds the most information but you need a up to date copy of photoshop to open a 32 bit file, i use an old version of photoshop cs3 and it will only open a 16 bit file but when it`s opened in photoshop you can do loads more to the levels to bring out fainter detail and use curves and colour balance.


it`s a big learning curve, i should know as i`ve been at it for 4 years and still struggle, but you pick things up as you go along, there`s loads on youtube also  

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Guest StevenWhatley

Quote taken from the Deep Sky Stacker site,

 

I found it useful..

 

"A common misconception
It is a common misconception to think that the number of dark, bias and flat frames is related to the number of light frames.
A lot of people are using very few (sometimes even only one) dark, bias and flat frames while they could get much better results by using a large number of dark, bias and flat frames with the same set of light frames.

Following the square root rule you will have much cleaner masters if you use a lot of frames to create them. Remember that you are trying to remove the dark and bias signals, not the noise that is coming with it.

For example when you subtract the master dark from each light frame you are adding the noise of the master dark to the noise of the light frame. The smaller the noise of the master dark, the less noise you will add to the light frame. This is also true for the master bias and the master flat.

In fact by using only a very small number of frames for the creation of the masters you can easily triple the noise of the calibrated light frame (bias and dark subtracted and flat divided) compared to the noise of the light frame before calibration.

You will then need 9 times (3 squared) more light frames to bring back the noise to the level you could have had by using noise free masters."

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Very nice, looking good.


 




I got to ask, what is the colour supposed to be? I see some red/blue and some red/green....which is it? Mine's come out red/blue.




 


I found it was definitely very blue with a bit of red round the edge in my raw frames. But the wispy detail to the left and right, I only really had that in the green channel (and even then only very faint) and bumping that up so it was visible made the whole nebula very green for me. So I think your blue/red is the right colour.


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Thanks again peeps, I will say, I needed darks as I had quite a few dodgy pixels showing up in bright colours. The darks removed them. I was also under the impression flats had to be taken at the same time as lights/darks? Don't touch focus or move the CCD in anyway? I will have another read up on them again. People are saying totally different things lol! 


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I think the answer is to experiment a bit and see what suits you and what makes you happy! They're your photo's so do what you want to do after taking on board all the comments and help you can :) :)


 


Ron


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I think the answer is to experiment a bit and see what suits you and what makes you happy! They're your photo's so do what you want to do after taking on board all the comments and help you can :) :)

 

Ron

 

True!  :)

 

I'm hoping to get something better soon, I will keep playing around with it all  :P

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darks need to be taken at the same temperature as the lights , but flats and bias frames don`t although as you say don`t move the imaging train at all, bias frames very easy to do , just put the cap on the scope and set the camera to it`s fastest exposure time, with the 314 it`s about 0.001 second.


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I have some bias frames, do I need to do bias every time? They are very quick and easy anyway. How does everyone else get flats then? I can't imagine bringing my scope in with the CCD still attached  :huh: and take lights next day.


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So it cleared up nicely last night after my Zumba class, so I put the scope out and roughly PA'd. I knew I wasn't going to get much in the way of anything decent but I wanted to try my CCD out. I only managed to take 30 sec subs, and only managed 30 total (15 mins) Not all were good enough I think only 24 were used. I also took darks for the first time ever too lol. Not as good as you lot in here but it's a start  :P I had a delivery today, a nice big box full of new toys  ;) Hopefully soon I will have guiding sussed too.

 

M27_zpssv6vwfnq.jpg

Absolutely marvellous -especially first attempt. Gorgeous colours, sharp stars with diffraction spikes and nice black sky. Did you process and how?

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Absolutely marvellous -especially first attempt. Gorgeous colours, sharp stars with diffraction spikes and nice black sky. Did you process and how?

 

I aligned and stacked in Atik Dawn, did a little stretch then took the image into photoshop :) How? urm....long process, mostly playing with settings, trying, undoing then retrying again lol. I have no idea what i'm doing tbh  :P

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