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tommygunn84 · 01-05-2017, 10:30 AM

Hi people!

So I have the k3ii and want to do some astro. I was thinking of taking multiple exposures or about 90 seconds using the built in astrotracer and then stacking them using the free program you get from the internet but I was just wondering..... if im going to take multiple shots of the same scene to stack up do the and if so how do the stars stay in the same place if its more than one shot?

cheers

Adam · 01-05-2017, 10:46 AM

The location of the stars would be different in between shots, and the overall impact on the stacked result would depend on your focal length. Do you want to have star trails or just a single long exposure of one part of the sky?

photoptimist · 01-05-2017, 10:51 AM

You'll need to re-align the camera after each shot. You can do this by memorizing the star pattern in the center of the viewfinder and adjusting the camera. Or you can make a simple barn door tracker mount to make it easier. Note that depending on where you are pointing, the sky is also rotating, too.

Good luck and we hope to see your images soon!

DeadJohn · 01-05-2017, 11:25 AM

Software like Deep Sky Stacker can align images by matching patterns when stars have drifted. If you stack many shots or use a long focal length, you may need to manually re-aim the camera so you have enough stars in common between frames.

FantasticMrFox · 01-05-2017, 11:30 AM

What do you mean by 'astro'? Deep sky, or milky way/night landscapes?

tommygunn84 · 01-09-2017, 12:19 PM

probably just milyway at the mo but I thought the tracker that is built in would still track on a mulit exposure, because how do you realign the camera!!! i hope star stacker does that for you

SKYGZR · 01-09-2017, 02:20 PM

IF you can get the AstroTracer function to calibrate, then you ought to be able to get 10 90s exposures w/o having to realign the camera.

GSWayne · 01-10-2017, 09:26 AM

I don't think calibrating the Astrotracer with eliminate the need to re-aim the camera over a time period of more than 900 seconds. It will only take care of the tracking during each 90 second exposure. You might not need to re-aim between each exposure, but you would surely need to do that several times over a 15 minute period. Also, depending on the focal length of the lens you will be using and the direction the camera is pointed, the astrotracer may not be able to handle 90 second exposures. It seems to provide about a factor of 10 improvement over the rule of 500. https://petapixel.com/2015/01/06/avoid-star-trails-following-500-rule/

01-05-2017, 10:30 AM	#1
tommygunn84 New Member Join Date: Oct 2016 Posts: 17	astro Hi people! So I have the k3ii and want to do some astro. I was thinking of taking multiple exposures or about 90 seconds using the built in astrotracer and then stacking them using the free program you get from the internet but I was just wondering..... if im going to take multiple shots of the same scene to stack up do the and if so how do the stars stay in the same place if its more than one shot? cheers

01-05-2017, 10:46 AM	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,609	The location of the stars would be different in between shots, and the overall impact on the stacked result would depend on your focal length. Do you want to have star trails or just a single long exposure of one part of the sky? Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

01-09-2017, 12:19 PM	#6
tommygunn84 New Member Join Date: Oct 2016 Posts: 17 Original Poster	probably just milyway at the mo but I thought the tracker that is built in would still track on a mulit exposure, because how do you realign the camera!!! i hope star stacker does that for you Last edited by Racer X 69; 01-09-2017 at 09:05 PM.

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01-05-2017, 10:51 AM	#3
photoptimist Pentaxian Join Date: Jul 2016 Photos: Albums Posts: 5,129	You'll need to re-align the camera after each shot. You can do this by memorizing the star pattern in the center of the viewfinder and adjusting the camera. Or you can make a simple barn door tracker mount to make it easier. Note that depending on where you are pointing, the sky is also rotating, too. Good luck and we hope to see your images soon!

01-05-2017, 11:25 AM	#4
DeadJohn Pentaxian Join Date: Jan 2011 Location: New York Posts: 4,834	Software like Deep Sky Stacker can align images by matching patterns when stars have drifted. If you stack many shots or use a long focal length, you may need to manually re-aim the camera so you have enough stars in common between frames.

01-05-2017, 11:30 AM	#5
FantasticMrFox Veteran Member Join Date: Oct 2014 Location: Munich Posts: 2,339	What do you mean by 'astro'? Deep sky, or milky way/night landscapes?

01-09-2017, 02:20 PM	#7
SKYGZR Senior Member Join Date: Dec 2014 Location: Milky Way Galaxy, Planet Earth, Speeding towards the Virgo Supercluster Photos: Gallery \| Albums Posts: 156	IF you can get the AstroTracer function to calibrate, then you ought to be able to get 10 90s exposures w/o having to realign the camera.

01-10-2017, 09:26 AM	#8
GSWayne New Member Join Date: Jul 2013 Posts: 18	I don't think calibrating the Astrotracer with eliminate the need to re-aim the camera over a time period of more than 900 seconds. It will only take care of the tracking during each 90 second exposure. You might not need to re-aim between each exposure, but you would surely need to do that several times over a 15 minute period. Also, depending on the focal length of the lens you will be using and the direction the camera is pointed, the astrotracer may not be able to handle 90 second exposures. It seems to provide about a factor of 10 improvement over the rule of 500. https://petapixel.com/2015/01/06/avoid-star-trails-following-500-rule/