Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
08-01-2019, 06:08 PM   #1
Pentaxian




Join Date: Oct 2011
Photos: Gallery
Posts: 830
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, 06:24 PM   #2
Site Supporter
Site Supporter




Join Date: Mar 2017
Photos: Gallery | Albums
Posts: 459
Did you do the Advanced Calibration? I'd recommend doing that every time you use Astrotracer.
08-01-2019, 07:02 PM   #3
Pentaxian




Join Date: Oct 2011
Photos: Gallery
Posts: 830
Original Poster
QuoteOriginally posted by SteveinSLC Quote
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
Site Supporter
Site Supporter




Join Date: Mar 2008
Location: Prince George, BC
Photos: Gallery | Albums
Posts: 2,996
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, 07:43 PM   #5
Pentaxian




Join Date: Oct 2011
Photos: Gallery
Posts: 830
Original Poster
QuoteOriginally posted by jbinpg Quote
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.
08-01-2019, 11:59 PM   #6
Pentaxian
Paul the Sunman's Avatar

Join Date: Aug 2011
Location: Melbourne
Photos: Gallery
Posts: 2,451
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
Site Supporter
Site Supporter
MossyRocks's Avatar

Join Date: Nov 2017
Location: Minnesota
Photos: Gallery | Albums
Posts: 1,345
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
Site Supporter
Site Supporter




Join Date: Mar 2017
Photos: Gallery | Albums
Posts: 459
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
Pentaxian




Join Date: Oct 2011
Photos: Gallery
Posts: 830
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
Senior Member




Join Date: Jul 2017
Posts: 137
Still a pretty shot! I always do a Precise Calibration once I get set up on location. I donít 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 ďOkĒ or your calibration might not be saved! It is good to take a couple test shots and make sure you donít 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 donít 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!
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
astro, dslr, k-3, k3, pentax k-3
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Astro photographers help with K1 settings CiaranCraigPhoto Pentax K-1 23 11-16-2018 02:14 PM
Night Astro Photography Trials alamo5000 Post Your Photos! 2 10-14-2018 09:33 AM
Looking for full res sample astro photos taken with K-1 & 15-30 2.8 awscreo Pentax DSLR Discussion 17 08-25-2018 10:18 AM
Recommended lenses for K-3 ii for landscape, astro & time lapses dxpand4 Pentax K-3 20 05-12-2018 10:18 AM
Island Point Astro balm Monthly Photo Contests 21 11-15-2017 12:26 AM



All times are GMT -7. The time now is 05:52 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top