Help me understand Deep Sky Stacker

[Cola]

Hello.. I am new in this.. can someone help me.. I can't go on you tube.. as I have suck my limited.. LOL. I just want to understand the exposures and times of on putting the light, dark flat.. etc.. I every time I try.. it doesn't stack one or more frames.. my exposure are like one mins on iso 800 or 2300 or I have a couple are iso 800 are 30 mins.. it's not reading those.. I try putting those as light frames.. so I might be doing it all wrong.. I have spend hours on it.. and never looks good.. I have a couple of dark shots and lights shots.. I guess the exposure or iso is wrong.. I guess I don't know what I am doing.. that's why I am here for help.. LOL:thanx:

[tlgerdes]

#1) have all your lights and darks at the same ISO and exposure length, it makes things easier and they will just work in DSS.

[Amaranthus]

Stack only frames of the same duration. Change the star detection threshold (make it lower, and/or remove median filter).

You need to give more info if I'm to give any further help. What camera? Are you processing RAW files? How many are you trying to stack? What is the exact error message? Take some screen shots. Etc.

We have a large knowledge pool here, but you need to help us help you.

[Cola]

I think I am exposure all the iso in different exposure and times.. I have Canon 60d and all my photos are in RAW.. I have notice its it gives N/A or NC. so I think putting all the photos in one ISO might make a different.. or changing the ISO on the program.. suppose that will work?? I have one is 3200 for 53 sec.. and one ISO 800 for 50 sec.. it only liked one.. so I will try stack all in the same ISO..

[Amaranthus]

Different ISOs won't be rejected, but you really need to stack them using the HDR method. Better to do all the same ISO and stack different ISOs in final post-processing (if you are seeking to capture a high dynamic range).

If they are slightly different durations, then right-click on the duration and change each of them all to the same value, e.g. 50 sec (DSS won't stack different exposure lengths, but you can trick it).

[Cola]

I like HDR.. oh.. thank you.. I will give that a try!! is there are setting in the RAW/FITT development setting??

[Amaranthus]

Just set to Canon 60D and it will select the correct debayer pattern for you. (There are more sophisticated settings where you can run the dcraw code yourself, but these are not for beginners!)

[Cola]

I am still getting score in NC or N/A.. I just don't understand... is there a step by website that I can read.. or link here with this.. I an new in this.

[Amaranthus]

Take some screenshots and post here.

[Cola]

I think I have finally worked it out.. as I am still on photoshop.. I having trouble saving it.. only allows tiff, and other I don't know of.. I was trying to save in Jpeg.. which I just crop by saving the screen.. so how did I go.. it's doesn't look good..

[raymo]

I wasn't aware that DSS doesn't like different ISOs and durations, so have always stacked various mixtures without any apparent problems.
My last posted pic of the Tarantula was a tracking test, so every sub
duration was different, varying between from memory 90 and 165 secs, and some were 800 ISO and some 1600. It stacked them all.
Incidentally, what is HDR?
raymo

[ZeroID]

I stack different time subs all the time with DSS. Last night was 16 x 45 secs and about 90 x 30 secs, no problems.

Cola, are you tracking or guiding during your exposures ? 30 mins is a long time and without understanding what you are starting with it is hard to recommend a solution or method.

My suggestion would be to take maybe 20-40 exposures all the same ISO and length of the same target, say ISO800 at 30 secs each. Open DSS and add them. 'Check All' in the left side menu and register them then stack them. It will save an Autosave file but also save the image yourself in another file. Try M42 in Orion, it's bright and easy to find and now is agood time for it. It should show you a stacked picture and a histogram curve and rgb peak graph below.
For now forget about darks etc, get the basic process working first. Once you have that under control you can refine the process.

[Cola]

I guess.. what I am doing it too many different exposure times.. I have done

2 photos in iso 800 60sec and 30sec
4 photos in ISO 3200 for 9, 10, 14 and 20 sec
2 photos in ISO 1000 for 53 and 59 sec..

all the photos comes out very washed not strong.. maybe I should try keep all in the same time and ISO. (next time when the weather is clear again.. .)

HDR is High-dynamic-range which I am saving in 32 bits..

I am not sure what to do with dark.. I have put in the low ISO times as dark.. it gives me an error.. I have been reading about to do dark is to put the lens cap on .. for how long?? then take it off.. and use that for dark..

so I am just like ahhhh.. :help:.. I know I will get there.. just frustrating as I am trying to achieve a nice look.. like a smoking gas like effect.. I have read somewhere you need to take long exposure like 12x600sec , 16x900, 10x480..etc all in ISO 200.. I am like huh.. can I shorted that exposure thank you.. (my math suck) anyone give me a nice idea.. as I am trying to take that Orion Nebula..

[ZeroID]

Cola, low ISO is not a dark. A dark is taken with the lens fully covered so it is in pitch blackness. It is to get an image of the hot pixels on the camera sensor to subtract them from the 'lights' you take of the object.
Forget about darks for now, lets get an image first.

I have given you a simple process above as you have requested. I suggest you start with that. Don't try to acheive perfect pictures first time. It has taken me three years to get a decent working system and process to take reliably good pictures and I am still learning how to improve on that.

[Cola]

Thanks for you advise.. I will go of what you've told me.. thank you:thumbsup:

[rustigsmed]

hi cola,

usually the end stack looks quite white in appearance. this can be fixed in Photoshop by adjusting the 'levels'.

In DSS also change the 'star detection threshold' down to 5% or so and it should help DSS detect and stack more images.

cheers

russ

[Cola]

oh... thank you.. I will try that.. turn down the star detection threshold.. :thumbsup::thanx:

[speach]

why not use Pixinsight and save the trouble of using DSS?

[Cola]

is that free??

[speach]

Given DSS the flick, PI does the job.

[raymo]

Simon and Cola, there is no trouble using DSS. It's only drawback is that the histogram sliders are a bit fiddly to use. It has quite a good user's guide under the help tab.
Russell, if the image has more than a few stars in it, setting the detector to 5% will result in DSS detecting hundreds, or even thousands of stars, and the comp taking a huge amount of time to stack. I was advised by a very experienced IIS member to set the percentage to a value that gives between 10 and 50 stars. If you have to set a value that detects large numbers of stars in order to get most of your images accepted, then in all probability, those images were not good enough to be stacked in the first place.
raymo