© paulsastrophotography 2018
1: Image Capture & Camera Control I use BackYardEOS (BYEOS) which is made to support Canon DSLR cameras but I am sure that most image capture software work in much the same way as each other. Firstly, make sure that you have named your target. There is nothing worse than trawling through hundreds of different folders to find the target that you have just spent 3 hours imaging. In the settings you can change how your library is saved and organised. Mine is set up to this configuration: Target Name/Date/sub.raw The image to the left shows this set up on my laptop. When you type the target name in BYEOS it then creates a folder under that name and any image session also used under that name. It will then create a new folder within that named folder with the date that the session is being taken on. Once you have set the target name it’s time to set the actual run itself. Looking at the right image above, just under the target name is the capture plan. Each line has 5 columns. I call each line an “image run” as you can set different parameters for separate image runs. If, for example, you are imaging the Orion Nebula, you need to be careful not to over expose the core of the Triangulum which is the brightest part of the Nebula. The best way to do this is to take a load of subs at a higher ISO setting, to capture the fainter detail and colour of the Nebs Gases. Then you will need to capture either shorter exposures or lower ISO settings to keep the brightness of the core down. Once stacked, if you have got your “runs” correct here, then you will have a perfectly exposed image. So based on the above scenario (example only), you can have three lines filled out in the following way: Exposures Shutter Duration ISO (No of Subs) (Shutter Speed) (Exposure Length) (Light Sensitivity) 1 5 BULB 180 Sec 1600 2 10 BULB 180 Sec 400 3 10 BULB 120 Sec 400 The software will then do each imaging run in order so that you need no more input at this stage. It will be an idea to just keep checking that all is OK just in case your mounts alignment has drifted or batteries in the camera need changing. Any issues, just click on “suspend” and the software will pause the run after the current image has been taken. Congratulations, you have now hopefully captured a bunch of subs that are ready to stack. 2: Stacking Now that you have all of your subs, it’s time to get stacking. I use DeepSkyStacker but there are other stacking programmes out there that are perfectly fine for the job. This is where it can start to get complicated, but I will just explain a basic stack to get you started. By clicking on “Open Picture Files” loads your subs into the software. If you have taken dark, flat & bias frames then load them in to. You now need to ensure that all of the loaded files have been ticked by clicking on “Check All” The next step is to register the subs. this process analyses each sub and gives it a quality score. Click “Register checked Pictures”, If this is your first time using DSS un-check “Stack After Registering” in the box that appears. Then click OK. This can take a while depending on how many subs you have loaded. Once all the subs have been registered, right click on the sub with highest score and click “Use as Reference Frame”. This will align all of your other subs to this reference sub. You can also select a certain area in your image to be stacked by clicking on the reference frame image and dragging the mouse or cursor. You will see a red box and this can be made to any size within your image and DSS will only stack what is inside this area. This is handy if you suffer from vignetting (star elongation to the edge of your images). Once you are happy with your reference frame then its just a mater of stacking. In the left hand menu, click on “Stack Checked Pictures”. This will initiate the stacking process. Once again, this can take some time depending on how many subs you have loaded. When the stacking process has finished the resulting stack will appear on the screen. You now need to save the file. Under the Processing tab on the left, click on “Save Picture to File”, change “Save as Type” to TIFF Image (32bit/ch-rational). Name the output file, then make sure that compression is set to “none” and also make sure that “embed adjustments in the saved image but do not apply them” is selected. Then click “Save”. 3: Post Processing This part is based on PhotoShop CS3 as that is what I use to process. I am sure that other programmes are similar in how they work. Start by loading the file that you saved at the end of the last section. You will more than likely be presented with an image that is nothing like you saw in DSS. You now need to change the bit depth from 32 to 16 as for some reason you cant use some of the editing options when the image is in 32bit. To do this, click on the “Image” drop down menu at the top and then hover on “Mode” then select “16Bits/Channel”. Eventually a box will appear called HDR Conversion, just click OK to dismiss this. You can now fully edit the image. I always start with the levels. Click on the Image menu and then hover on “Adjustments” and select “Levels”. The image to the right shows the levels settings. What you are seeing is called a Histogram and basically the spike that you see is the make up of the image behind it. Now, as you can see, the black in the image is not actually black, so we need to darken this down and also to brighten up and draw out the faint detail of the Orion Nebula. Just under the spike there are 3 upward pointing arrows. These arrows stretch the brightness levels. If you look at the spike carefully you will see that it is vertical on the left hand side but the right hand side has a sharp drop that curves out level. The left hand side is the dark parts of the image with the right being the light part of the image. So if you treat the left arrow as the dark, the middle as mid-tones and the right as white, so, moving the left arrow will darken the image and the right will brighten it. As you can see, the background has darkened and the Nebula has brightened up and all of the fainter detail has now been revealed. Notice that I have only adjusted the left & middle arrows. I would only usually use the right arrow if I am working on a very faint object. If I used it on this image then the bright centre of the Nebula will over expose. This image is now essentially developed but we need to do a bit more work to darken the background a bit more and to draw out the colour that is in the image. The next step is to use the “curves” option. Go back to the Image menu and hover over Adjustments then click on Curves. The curves are basically the same as levels but you can be more precise on how you tweak the dark and light parts of your image. Now you will want to look at drawing out some of the colour that is in your image. One of the reasons that we take long exposures is to be able to capture the colour in the objects that we are imaging. To bring this colour out we need to use a tool called “saturation” this can be found in the same menu as all the previous tools used. This bit is nice and easy. Just move the Saturation slider untill you like the balance of colours in the image. It is very high in this image and that is just for demonstration purposes, yours will be lower. You should now have a basic “developed” and hopefully colour image. There are plenty more tools in the Adjustment section under the image menu that can further enhance your image but I will be here for a month of Sunday’s if I go through them all and from now on anything else that you decide to do is for your own aesthetic pleasure. As I have mentioned at the top of this page, please don’t send me loads of emails if you do things differently to me. This is the software I use and I am happy using it and i like the results that I can achieve with my methods. I will obviously listen if I have made a genuine mistake. PROCESSING STEPS BY SOPHIE

Capture, Stack & Processing

© paulsastrophotography 2018
1: Image Capture & Camera Control I use BackYardEOS (BYEOS) which is made to support Canon DSLR cameras but I am sure that most image capture software work in much the same way as each other. Firstly, make sure that you have named your target. There is nothing worse than trawling through hundreds of different folders to find the target that you have just spent 3 hours imaging. In the settings you can change how your library is saved and organised. Mine is set up to this configuration: Target Name/Date/sub.raw The image to the top shows this set up on my laptop. When you type the target name in BYEOS it then creates a folder under that name and any image session also used under that name. It will then create a new folder within that named folder with the date that the session is being taken on. Once you have set the target name it’s time to set the actual run itself. Looking at the right image above, just under the target name is the capture plan. Each line has 5 columns. I call each line an “image run” as you can set different parameters for separate image runs. If, for example, you are imaging the Orion Nebula, you need to be careful not to over expose the core of the Triangulum which is the brightest part of the Nebula. The best way to do this is to take a load of subs at a higher ISO setting, to capture the fainter detail and colour of the Nebs Gases. Then you will need to capture either shorter exposures or lower ISO settings to keep the brightness of the core down. Once stacked, if you have got your “runs” correct here, then you will have a perfectly exposed image. So based on the above scenario (example only), you can have three lines filled out in the following way: Exposures Shutter Duration ISO (No of Subs) (Shutter Speed) (Exposure Length) (Light Sensitivity) 1 5 BULB 180 Sec 1600 2 10 BULB 180 Sec 400 3 10 BULB 120 Sec 400 The software will then do each imaging run in order so that you need no more input at this stage. It will be an idea to just keep checking that all is OK just in case your mounts alignment has drifted or batteries in the camera need changing. Any issues, just click on “suspend” and the software will pause the run after the current image has been taken. Congratulations, you have now hopefully captured a bunch of subs that are ready to stack. 2: Stacking Now that you have all of your subs, it’s time to get stacking. I use DeepSkyStacker but there are other stacking programmes out there that are perfectly fine for the job. This is where it can start to get complicated, but I will just explain a basic stack to get you started. By clicking on “Open Picture Files” loads your subs into the software. If you have taken dark, flat & bias frames then load them in to. You now need to ensure that all of the loaded files have been ticked by clicking on “Check All” The next step is to register the subs. this process analyses each sub and gives it a quality score. Click “Register checked Pictures”, If this is your first time using DSS un- check “Stack After Registering” in the box that appears. Then click OK. This can take a while depending on how many subs you have loaded. Once all the subs have been registered, right click on the sub with highest score and click “Use as Reference Frame”. This will align all of your other subs to this reference sub. You can also select a certain area in your image to be stacked by clicking on the reference frame image and dragging the mouse or cursor. You will see a red box and this can be made to any size within your image and DSS will only stack what is inside this area. This is handy if you suffer from vignetting (star elongation to the edge of your images). Once you are happy with your reference frame then its just a mater of stacking. In the left hand menu, click on “Stack Checked Pictures”. This will initiate the stacking process. Once again, this can take some time depending on how many subs you have loaded. When the stacking process has finished the resulting stack will appear on the screen. You now need to save the file. Under the Processing tab on the left, click on “Save Picture to File”, change “Save as Type” to TIFF Image (32bit/ch-rational). Name the output file, then make sure that compression is set to “none” and also make sure that “embed adjustments in the saved image but do not apply them” is selected. Then click “Save”. 3: Post Processing This part is based on PhotoShop CS3 as that is what I use to process. I am sure that other programmes are similar in how they work. Start by loading the file that you saved at the end of the last section. You will more than likely be presented with an image that is nothing like you saw in DSS. You now need to change the bit depth from 32 to 16 as for some reason you cant use some of the editing options when the image is in 32bit. To do this, click on the “Image” drop down menu at the top and then hover on “Mode” then select “16Bits/Channel”. Eventually a box will appear called HDR Conversion, just click OK to dismiss this. You can now fully edit the image. I always start with the levels. Click on the Image menu and then hover on “Adjustments” and select “Levels”. The image to the right shows the levels settings. What you are seeing is called a Histogram and basically the spike that you see is the make up of the image behind it. Now, as you can see, the black in the image is not actually black, so we need to darken this down and also to brighten up and draw out the faint detail of the Orion Nebula. Just under the spike there are 3 upward pointing arrows. These arrows stretch the brightness levels. If you look at the spike carefully you will see that it is vertical on the left hand side but the right hand side has a sharp drop that curves out level. The left hand side is the dark parts of the image with the right being the light part of the image. So if you treat the left arrow as the dark, the middle as mid-tones and the right as white, so, moving the left arrow will darken the image and the right will brighten it. As you can see, the background has darkened and the Nebula has brightened up and all of the fainter detail has now been revealed. Notice that I have only adjusted the left & middle arrows. I would only usually use the right arrow if I am working on a very faint object. If I used it on this image then the bright centre of the Nebula will over expose. This image is now essentially developed but we need to do a bit more work to darken the background a bit more and to draw out the colour that is in the image. The next step is to use the “curves” option. Go back to the Image menu and hover over Adjustments then click on Curves. The curves are basically the same as levels but you can be more precise on how you tweak the dark and light parts of your image. Now you will want to look at drawing out some of the colour that is in your image. One of the reasons that we take long exposures is to be able to capture the colour in the objects that we are imaging. To bring this colour out we need to use a tool called “saturation” this can be found in the same menu as all the previous tools used. This bit is nice and easy. Just move the Saturation slider untill you like the balance of colours in the image. It is very high in this image and that is just for demonstration purposes, yours will be lower. You should now have a basic “developed” and hopefully colour image. There are plenty more tools in the Adjustment section under the image menu that can further enhance your image but I will be here for a month of Sunday’s if I go through them all and from now on anything else that you decide to do is for your own aesthetic pleasure. As I have mentioned at the top of this page, please don’t send me loads of emails if you do things differently to me. This is the software I use and I am happy using it and i like the results that I can achieve with my methods. I will obviously listen if I have made a genuine mistake. PROCESSING STEPS BY SOPHIE

Capture, Stack & Processing