Astro

tuggie76 · 08-01-2019, 06:08 PM

This was taken with k3ii and 10-17 lens, July 31st. 42secs, f4, iso 1600, . I see a certain amount of star trails, but I had Astro Tracker on, did I not set it right? or is there some way to confirm it's working?

Thanks in advance for your always positive comments.

Tuggie76.

Last edited by tuggie76; 11-27-2019 at 02:45 PM.

**SteveinSLC** · 08-01-2019, 06:24 PM

Did you do the Advanced Calibration? I'd recommend doing that every time you use Astrotracer.

tuggie76 · 08-01-2019, 07:02 PM

Originally posted by SteveinSLC

Did you do the Advanced Calibration? I'd recommend doing that every time you use Astrotracer.

No, I didn't, I'll recheck before my next attempt. Should I do it at home or at the site?

**jbinpg** · 08-01-2019, 07:26 PM

It needs to be done at the site. Ideally, you would do it with the camera mounted on the tripod but most do not do this. And you should also recalibrate if you move the tripod more than a few feet.

tuggie76 · 08-01-2019, 07:43 PM

Originally posted by jbinpg

It needs to be done at the site. Ideally, you would do it with the camera mounted on the tripod but most do not do this. And you should also recalibrate if you move the tripod more than a few feet.

Great, thanks for that. This is when you rotate the camera on 3 axis's,tough on a tripod, surely.

Paul the Sunman · 08-01-2019, 11:59 PM

At what elevation angles are you seeing this? The PF review states:

One major factor in astrotracer accuracy was the angle and direction the cameras pointed. We found that the astrotracer performed the best when pointed at Polaris with decreasing accuracy the closer the camera came to being pointed due East or due West. We also found that angling the camera upward reduced accuracy the closer it came to a 45-degree pitch with accuracy at zero and 90 degrees being basically the same. So a 45-degree camera pitch to the East or West will likely deliver the poorest results where as a zero- or 90-degree pitch to either the North, South, or Zenith will likely deliver the best results.

Read more at: O-GPS1 vs Built-in GPS Guide - Astrotracer Reliability - In-Depth Articles

Also, the 10-17 fisheye is a fun lens, but nobody would claim it is very sharp near the edges. Not sure if that is contributing.

However, as others have said, calibration is important.

**MossyRocks** · 08-02-2019, 06:15 AM

I would guess it is a calibration issue. If you missed the precise calibration then that would be the cause. Be aware that one can go through and do all the calibration but have it still be off. I have had this happen and this is why I will always take a test shot with a longer lens to see if the calibration is good.

I also wonder if some of the trailing at the edges is just from using astrotracer with a fisheye lens. I haven't tried using it with my 17mm fisheye before but have wondered if similar trails would show up.

**SteveinSLC** · 08-02-2019, 08:15 AM

Yeah, it's not possible to do the precise calibration on a tripod. If you do it, and still see some trailing, try again.

Also, at very wide angles, like 15 or wider, you will see some trailing around the edges.

tuggie76 · 08-02-2019, 01:14 PM

Ok, thanks guys, so I need to calibrate it when arriving at the location and again if I move. Also the 10-17 isn't the best lens to use, I have an old 28-70 manual lens which I might try.

Thanks again.

MaineNative · 08-02-2019, 01:27 PM - **2 Likes**

Still a pretty shot! I always do a Precise Calibration once I get set up on location. I don’t do the calibration with the tripod attached to the camera, but I stand right next to the tripod and I have my quick disconnect plate on the camera.

At the end of the calibration, make sure to hit “Ok” or your calibration might not be saved! It is good to take a couple test shots and make sure you don’t have trailing in the middle of the frame. If you have trailing in the middle, you might need to recalibrate.

On ultra-wide lenses like the 10-17, you will get some radial distortion in the corners that look like trails coming away from the center of the frame. All ultra-wide lenses have this distortion, but it gets more obvious with Astrotracer. I don’t worry about it because the core of the Milky Way is what people pay attention to.

I have both the 10-17 on a K-5 and a Samyang 14/2.8 for my K-1. The 10-17 gives a little flare around bright stars but it shows constellations like the Big Dipper very well. Keep at it and have fun!

08-01-2019, 06:08 PM	#1
tuggie76 Pentaxian Join Date: Oct 2011 Photos: Gallery Posts: 1,215	Astro This was taken with k3ii and 10-17 lens, July 31st. 42secs, f4, iso 1600, . I see a certain amount of star trails, but I had Astro Tracker on, did I not set it right? or is there some way to confirm it's working? Thanks in advance for your always positive comments. Tuggie76. Last edited by tuggie76; 11-27-2019 at 02:45 PM.

08-01-2019, 07:43 PM	#5
tuggie76 Pentaxian Join Date: Oct 2011 Photos: Gallery Posts: 1,215 Original Poster	Originally posted by jbinpg It needs to be done at the site. Ideally, you would do it with the camera mounted on the tripod but most do not do this. And you should also recalibrate if you move the tripod more than a few feet. Great, thanks for that. This is when you rotate the camera on 3 axis's,tough on a tripod, surely. Last edited by tuggie76; 08-01-2019 at 07:51 PM.

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08-01-2019, 06:24 PM	#2
SteveinSLC Site Supporter Join Date: Mar 2017 Photos: Gallery \| Albums Posts: 568	Did you do the Advanced Calibration? I'd recommend doing that every time you use Astrotracer.

08-01-2019, 07:02 PM	#3
tuggie76 Pentaxian Join Date: Oct 2011 Photos: Gallery Posts: 1,215 Original Poster	Originally posted by SteveinSLC Did you do the Advanced Calibration? I'd recommend doing that every time you use Astrotracer. No, I didn't, I'll recheck before my next attempt. Should I do it at home or at the site?

08-01-2019, 07:26 PM	#4
jbinpg Site Supporter Join Date: Mar 2008 Location: Prince George, BC Photos: Gallery \| Albums Posts: 3,546	It needs to be done at the site. Ideally, you would do it with the camera mounted on the tripod but most do not do this. And you should also recalibrate if you move the tripod more than a few feet.

08-01-2019, 11:59 PM	#6
Paul the Sunman Pentaxian Join Date: Aug 2011 Location: Melbourne Photos: Gallery Posts: 4,843	At what elevation angles are you seeing this? The PF review states: One major factor in astrotracer accuracy was the angle and direction the cameras pointed. We found that the astrotracer performed the best when pointed at Polaris with decreasing accuracy the closer the camera came to being pointed due East or due West. We also found that angling the camera upward reduced accuracy the closer it came to a 45-degree pitch with accuracy at zero and 90 degrees being basically the same. So a 45-degree camera pitch to the East or West will likely deliver the poorest results where as a zero- or 90-degree pitch to either the North, South, or Zenith will likely deliver the best results. Read more at: O-GPS1 vs Built-in GPS Guide - Astrotracer Reliability - In-Depth Articles Also, the 10-17 fisheye is a fun lens, but nobody would claim it is very sharp near the edges. Not sure if that is contributing. However, as others have said, calibration is important.

08-02-2019, 06:15 AM	#7
MossyRocks Loyal Site Supporter Join Date: Nov 2017 Location: Minnesota Photos: Gallery \| Albums Posts: 2,982	I would guess it is a calibration issue. If you missed the precise calibration then that would be the cause. Be aware that one can go through and do all the calibration but have it still be off. I have had this happen and this is why I will always take a test shot with a longer lens to see if the calibration is good. I also wonder if some of the trailing at the edges is just from using astrotracer with a fisheye lens. I haven't tried using it with my 17mm fisheye before but have wondered if similar trails would show up.

08-02-2019, 08:15 AM	#8
SteveinSLC Site Supporter Join Date: Mar 2017 Photos: Gallery \| Albums Posts: 568	Yeah, it's not possible to do the precise calibration on a tripod. If you do it, and still see some trailing, try again. Also, at very wide angles, like 15 or wider, you will see some trailing around the edges.

08-02-2019, 01:14 PM	#9
tuggie76 Pentaxian Join Date: Oct 2011 Photos: Gallery Posts: 1,215 Original Poster	Ok, thanks guys, so I need to calibrate it when arriving at the location and again if I move. Also the 10-17 isn't the best lens to use, I have an old 28-70 manual lens which I might try. Thanks again.

08-02-2019, 01:27 PM - 2 Likes	#10
MaineNative Senior Member Join Date: Jul 2017 Photos: Gallery Posts: 280	Still a pretty shot! I always do a Precise Calibration once I get set up on location. I don’t do the calibration with the tripod attached to the camera, but I stand right next to the tripod and I have my quick disconnect plate on the camera. At the end of the calibration, make sure to hit “Ok” or your calibration might not be saved! It is good to take a couple test shots and make sure you don’t have trailing in the middle of the frame. If you have trailing in the middle, you might need to recalibrate. On ultra-wide lenses like the 10-17, you will get some radial distortion in the corners that look like trails coming away from the center of the frame. All ultra-wide lenses have this distortion, but it gets more obvious with Astrotracer. I don’t worry about it because the core of the Milky Way is what people pay attention to. I have both the 10-17 on a K-5 and a Samyang 14/2.8 for my K-1. The 10-17 gives a little flare around bright stars but it shows constellations like the Big Dipper very well. Keep at it and have fun!