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Am I ready to start stacking?

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#1 oldtimer

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Posted 18 March 2017 - 03:03 PM

OK I'm an old film guy and a newbe to DSLR AP

 

Here is where Im' at:

 

Canon 450D unmodified

      Mirror lock up set

      Auto Dark frame set

      Manual mode (bulb)

      remote shutter cable

      ISO 1600

 

Tamron 400mm F4 lens with drop in 420NM filter

 

AVX mount

 

From a red Zone

 

Using live view to focus.

 

Results: I'm getting nice round tiny star images with no trailing but my exposures are limited to about 12 seconds before the histogram moves right of 1/3

 

Back to my question , Is there anything else I need to do or should do before taking multiple exposures to stack?



#2 bmhjr

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Posted 18 March 2017 - 03:34 PM

Did you set your file format to RAW or RAW+L?

#3 guyroch

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Posted 18 March 2017 - 03:56 PM

Forget about mirror lock, unless you have a flimsy setup and you suffer from vibration, most do not.

 

Forget about in-camera noise reduction, take darks instead and double up lights acquisition frames :)

 

Other than that you are up to a good start.

 

Regards,

 

Guylain


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#4 ismosi

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Posted 18 March 2017 - 04:42 PM

Exactly. Forgo the in-camera dark reduction. It wastes precious clear sky time. You can acquire darks when it's cloudy or during the day :)



#5 jimr2

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Posted 18 March 2017 - 04:53 PM

I've read on other CN posts that ISO 800 is the "sweet spot" ISO-wise for this camera, but then you'd have to expose for 2x as long to get the same exposure, so don't know if that would cause you problems w/ tracking??
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#6 Jim Waters

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Posted 18 March 2017 - 04:55 PM

If you are taking a 'single' image its OK and probably best to use 'In-Camera Noise Reduction' to help reduce camera noise.  If you are taking multiple images and plan to 'stack' them do NOT use 'In-Camera Noise Reduction'.  Turn it off...  The T3i MUST be set to RAW.

 

Start with ISO 800 and expose the sub so the T3i histogram is 20 to 25% from the left.  You can use BYE (BackYard EOS) to capture the subs.  If you use the remote shutter cable expose each sub for the same time.  I take a hour or more of total 'Light' subs, about half as many 'Darks' along with 'BIAS' and 'Flats'.  Example:

 

20 Light Subs at 3 minutes each = 60 minutes total exposure time - The more exposure time the better....!

10 Darks Subs at 3 minutes each = 30 minutes 

5 to 10 BIAS Subs using the fastest shutter speed of the camera - This depends on how noisy the camera is.

5 to 10 Flats

 

Its important that the Dark subs be the same exposure time as the Lights...!

 

Try using Deep Sky Stacker to stack the subs.  You will need to do post processing with LightRoom, Photoshop or something similar. 


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#7 Jim Waters

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Posted 18 March 2017 - 04:56 PM

I've read on other CN posts that ISO 800 is the "sweet spot" ISO-wise for this camera, but then you'd have to expose for 2x as long to get the same exposure, so don't know if that would cause you problems w/ tracking??

Yes - for the T3i ISO 800 is the sweet-spot.



#8 Jim Waters

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Posted 18 March 2017 - 05:09 PM

Request a demo version of BYE.  It will make your life easier in relation to focusing, framing an image, image capture and file naming.  

 

If you continue to shoot from a Red Zone look into clip-in light pollution filters for the T3i.  One important note here. Heat is an enemy of astrophotography.  The hotter it is the more noise is generated in your images!  To help control this turn off the Live View display and open the LCD panel of the camera.  Some of my best images where shot when it was very cold outside.  Also look into powering the T3i from a 12VDC Li or Deep Cycle Battery.  See below.

 

http://www.telescope...61/p/103511.uts

 

As you get more experienced look into processing your images with ImagesPlus or PixInsight.

 

Have fun.  Post your first image.



#9 Pete_xl

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Posted 18 March 2017 - 05:15 PM

For a beginner and to get an easy feeling for stacking I can (besides DSS) recommend the free software "Sequator". It is very easy to use and very very fast. So easy and so fast that you can experiment to get the best result. The software delivers a 16bit TIF file. Like in DSS you have to process the result in another software like Photoshop.

 

When I found it in the internet I started a thread about it here on CN: https://www.cloudyni...g-the-sequator/

Meanwhile I tested it a bit and like it very much.

 

Another thread with the link to the download, test an manual is here: https://www.pentaxfo...l#gmessage77007

 

Anyway - good luck with your first stackings - you will enter an new world.....

 

 

 

 

 


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#10 Jim Waters

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Posted 18 March 2017 - 05:22 PM

 

For a beginner and to get an easy feeling for stacking I can (besides DSS) recommend the free software "Sequator". It is very easy to use and very very fast. So easy and so fast that you can experiment to get the best result. The software delivers a 16bit TIF file. Like in DSS you have to process the result in another software like Photoshop.

 

When I found it in the internet I started a thread about it here on CN: https://www.cloudyni...g-the-sequator/

Meanwhile I tested it a bit and like it very much.

 

Another thread with the link to the download, test an manual is here: https://www.pentaxfo...l#gmessage77007

 

Anyway - good luck with your first stackings - you will enter an new world.....

 

Good info.  Thanks for the information.



#11 Samir Kharusi

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Posted 19 March 2017 - 09:05 AM

You are getting a lot of good information above, but perhaps overwhelming? Let's start with what you stated and how I would proceed:

 

Tamron 400mm F4 lens with drop in 420NM filter

Why the filter? Just leave it out.

 

Using live view to focus.

Make sure it's OFF to allow the camera to cool down before you take your sky pictures.

 

Results: I'm getting nice round tiny star images with no trailing but my exposures are limited to about 12 seconds before the histogram moves right of 1/3

Find out what is the longest exposure you can shoot before you see obvious trailing of the stars on many frames. The objective is to use the longest exposure that still delivers more than 80% of your frames well tracked. Let's assume that's 45 seconds (regardless of where the skyfog peak is on the back-of-camera histogram)

Now shift the ISO lower (but not below 200) so that the skyfog peak on the BoC Histogram is at between 20% and 40% with 45 second exposures

Shoot a 100 frames (Raw!). Go forth and stack. Have great fun contrast stretching and be amazed at what you achieve wink.gif




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