Discovery Astrophotography with ZWO ASTRO

Reason of Field Tilt problems and how to solve it

Applicable Product(s) : For All ASI Cameras

Description: Field tilt problems usually happen in imaging.  Optical axis, flattener lens, adapters, and sensor tilt are all causes of field tilt in images. This post is to help diagnose which issue is causing your field tilt problem.

What do I setup to test?

Your imaging setup is connected to the computer and there are many stars in the field of view.

Q: How do Itest if a tilt problem is caused by my telescope or by my camera

A: Take an image with your camera then rotate the camera 180 degrees (the telescope telescope doesn’t move). Thentake another image of the same field of view.

Analyze the images with software, such as CCDInspector 2.5.3.

1

If the field has an identical pattern after rotation, then the camera has a tilt problem.

sensor tilt

If the field has the same problem, but it has rotated 180 degrees, the telescope has a tilt problem.

optics tilt

 

Q: How to make sure tilt problem caused by adapters

A:

  1. Remove suspect adapters, connect the camera directly to the telescope.
  2. Try another adapter.
  3. Take another set of images to test if the problem is gone

 

Q: I use a field flattener or a flattener/reducer, but I see coma in the corner of image.

A:

  1. Usually this is caused by incorrect back focus (spacing between the reducer and camera sensor). Use suitable adapters make sure your camera is at critical  back focus for that flattener or reducer.
  2. Your image circle for that flattener or reducer is smaller than the camera sensor.

 

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27 Comments

  • Brent
    Posted November 14, 2018 at 5:59 pm

    are you sure you don’t have this backwards ??

    if it is sensor tilt the out of focus corner should rotate with the camera rotation right ?

    • Sean Wang
      Posted November 19, 2018 at 2:33 am

      If sensor tilt on left-top, after rotate, the tilt problem still happened on left-top.

    • Neverfox
      Posted January 27, 2022 at 1:11 pm

      The confusion is that what this article is assuming (and they could have made that more clear) is that you’re always looking at the images from the perspective of what comes out of the camera, i.e. *without* de-rotating one of the images so that the content is oriented the same. In other words, if you compare one image with another that is, as a result of rotation, upside down (just as you would in your capture preview), the sensor tilt would be in the same corner of the screen. If you rotate the *image* so that it’s not upside down then, yes, what you say would be true. But they’re not talking about rotating the camera *and* one of the images.

  • Brent
    Posted November 21, 2018 at 7:44 pm

    that just doesn’t make sense, if the sensor itself is tilted then the out of focus corner should rotate with the camera rotation !!

    • Katherine Tsai
      Posted November 28, 2018 at 9:57 am

      If the upper right corner is the out of focus corner, after the camera rotation, the upper right corner is still out of focus. The out of focus corner will not affect by the camera roatation.

  • Mohammad Moulod
    Posted May 28, 2019 at 12:55 am

    It is correct. If sensor is tilted, when rotated 180 degree, two thing happens: Tilt direction (180) and sensor direction (180 degree). These two factor will neutralize each other. However, when optic is tilted, rotation of camera only changes the sensor direction and tilt is in the same place, thus field will be rotated 180 degree.

  • Jim
    Posted August 31, 2019 at 4:05 pm

    What is the recommended method for fixing if it’s determined the camera has the problem. I have the tilt device for my ASI1600mm-c but I don’t have enough backfocus to use it.

    • ZWO ASI Camera
      Posted September 2, 2019 at 9:36 am

      You don’t have enough backfoces? maybe try other adpter.

  • Srinivasan
    Posted September 1, 2019 at 7:09 pm

    Im new to astro photography and recently bought asi071mc pro. Please let me know where you mentioned the solution for tilt problem and if there is no tilt problem.how picture will look like? Or ccd inspector will tell that there is no problem?

  • Mohammad Moulod
    Posted June 12, 2020 at 6:56 am

    Brent, what you see on screen is the same position on camera not optic. I mean the screen shows a fixed point of camera all the time. Consider the sensor is tilted like this / ,assume we are checking top right. After rotation, it becomes like this \ . know the top right is gone to top left. So the same position of sensor sees the same focal length after rotation and focus does not change.

    • Post Author
      Moson
      Posted June 15, 2020 at 10:27 am

      Yes, of course the focal length is the same, and the focus does not change. Which we can know from your case is that the telescope might has a tilt problem.

  • Davide
    Posted June 18, 2020 at 5:09 pm

    Guys i have bought asi 2600,i was wonder the tilt plate should be nicely attached to the camera?when i have received the camera, had about 2mm of space and the tilt screw very loose?Thx

    • Post Author
      Moson
      Posted June 19, 2020 at 5:50 am

      You could publish a post in our Forum, you could post a photo of your camera as an attachment to show how the tilt screw loose.

  • Alessandro
    Posted August 22, 2020 at 8:41 pm

    The picture has to be rotated after exposing, in order to match the original picture, before comparing the issue in the field, or not? (I suppose no)

    Thanks

    • Post Author
      ZWO.Moson
      Posted August 24, 2020 at 3:43 am

      The picture does not need to be rotated after exposing.

  • Nikolas
    Posted March 5, 2021 at 11:17 am

    Really I don’t understand what you are saying…..
    On my left corner I have out of focus stars then I rotate my camera 90 degrees and the out of focus stars goes to the right side…. So which product has a tilt?

  • RJ
    Posted March 9, 2021 at 10:11 pm

    How do I solve for sensor tilt in a 1600GT?

    • Post Author
      Support@ZWO
      Posted March 10, 2021 at 10:16 am

      Same as 1600MM Cool in article.

  • Jane Lubenskyi
    Posted August 21, 2021 at 2:07 pm

    Hi,
    When adjusting the tilt on the back of the ZWO 2600 MCPro color camera…in order to correct the elongation on a certain side, say top left corner do I just work with one set of screws and then check the difference for star roundness or do I loosen all the 3 sets of screws and and then tighten…please tell me the procedure….also which screw tightens and which loosens in a set?

    • sara.liu
      Posted August 26, 2021 at 7:28 am

      You can refer to below:
      1. Take a starred image with the camera, you will easily find out the tilt part in the image through
      the software, and then adjust one or more sets of flange adjustment screws on the camera corresponding to the image.
      2. Take another image after the sensor tilt adjustment, compare the new image with the previous one in the software. If the tilt issue is reduced, that means the adjustment is correct. Otherwise, the adjustment is wrong.
      3. Repeat step 2 until the stars in all corners are perfect.

  • Gary Sizer
    Posted November 6, 2021 at 4:18 pm

    How is it possible to fix tilt on an ASI183MCPro? There are no instructions here. Which screws should be adjusted? Thank you!

    • sara.liu
      Posted December 8, 2021 at 10:02 am

      You can refer to below:
      1. Take a starred image with the camera, you will easily find out the tilt part in the image through
      the software, and then adjust one or more sets of flange adjustment screws on the camera
      corresponding to the image.
      2. Take another image after the sensor tilt adjustment, compare the new image with the previous
      one in the software. If the tilt issue is reduced, that means the adjustment is correct. Otherwise, the
      adjustment is wrong.
      3. Repeat step 2 until the stars in all corners are perfect.

  • Andrea
    Posted December 23, 2021 at 9:49 pm

    Hello My ASI Air 2600MCpro has tilt in the camera. The tilt exists with two different telescopes . There is no tilt on these same telescopes with the ASI2600MM. Can I get a replacement 2600MCpro
    Andrea

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