Fulldome Fisheye Len Projection Problem

Asked by allen yu on 2011-07-06

I recently bought a fulldome fisheye lens and 5000 lumens Sanyo projector that I intend to project Stellarium in our 4m diameter inflatable dome. But the image produced is always partial, as in what we normally see on the computer screen when we turned on the software, not the whole sky. How do I project the whole sky? Is there any settings adjustments to be done? I already put it on fisheye mode, but to no avail. It seems my fisheye only acts like an ordinary projector lens. Please help. I already spent a lot to make this work, but no success yet.

If okay with you, I'll post here my report to the fisheye lens supplier, on why it won't work.

My report:

I include here two photos of screen shots from Stellarium, one is a portion of the sky in which we normally sees from the computer screen. Obviously, this is not what I wanted to see in the fisheye projection, because it does not show the entire sky and what is on the opposite side.

What I wanted to see is the second pic, the whole sky, that would fit on the entirety of the inside dome. The middle portion of the sky should be the overhead position, then the entire circle or margin is the horizon. If the lens produced this whole-sky image then we can adjust the position of the projector to fit in the entire dome. We can recognize that, and we would have done so if we saw the image looks so big that we have to “back off” so the projected image would sit squarely on the dome. I assume you will want the lens pointed upwards, so it can spill the light in all direction, thus, filling the entire dome with all-sky image.

But, what we saw is the first picture, only a portion of the entire sky. More accurately, what we see on the computer screen. This I tell you, is the limit of the image projected, it does NOT show the entire sky. And, if you agree with me, the farther back I go it will only make this portion of the sky bigger. It does not show the entire sky. And if I point the projector lens upwards, the horizon goes up too. That is a big difference. That is the problem.

That’s why, I ask if your engineer knows something about it. Maybe we need to adjust something inside the projector, or the lens, or the software we use Stellarium. May I ask you, if you have customers who had the same requirements as we do or we did, and please let us know what happened to them. Or, is there a scale system in the Stellarium software that let us minimize the image into a complete circle, so the entire thing fits exactly on the lens projection?

I think I’ve exhausted this report to the extent that we should now find a solution for this. In a sense, we know how to adjust the position of the projector and lens to try to make it work, these are common sense stuffs. We would not report this to you if the problem has not been this difficult.

We did changed resolution as my laptop does not work well if the resolution is not okay with the projector.

Kind regards,
allen

Question information

Language:
English Edit question
Status:
Solved
For:
Stellarium Edit question
Assignee:
No assignee Edit question
Solved by:
Alexander Wolf
Solved:
2011-07-08
Last query:
2011-07-08
Last reply:
2011-07-07
Alexander Wolf (alexwolf) said : #1

Where is the photos?

allen yu (allen-yu70) said : #2

Here it is Sir.

> To: <email address hidden>
> From: <email address hidden>
> Subject: Re: [Question #163905]: Fulldome Fisheye Len Projection Problem
> Date: Wed, 6 Jul 2011 09:51:06 +0000
>
> Your question #163905 on Stellarium changed:
> https://answers.launchpad.net/stellarium/+question/163905
>
> Alexander Wolf posted a new comment:
> Where is the photos?
>
> --
> You received this question notification because you asked the question.

allen yu (allen-yu70) said : #3

I'm not sure if this message board can accept my attachment jpegs, apparently not, but the 1st picture simply show the usual image as we open Stellarium the first time, that is, a portion of the sky with the horizon, and 2nd picture is an all-sky picture with the circle boundary as the horizon. I just thought this may be what is supposed to be projected in a fisheye to produce the whole-sky image.

Alexander Wolf (alexwolf) said : #4

You can upload your images on any image hosting and publish link to images via web interface?

allen yu (allen-yu70) said : #5

Dear Sir,

Okay, here are the links of the pics.

http://allenite.webs.com/apps/photos/photo?photoid=130811411

http://allenite.webs.com/apps/photos/photo?photoid=130811412

Thanks for reminding me, never thought of that!

kind regards,
allen

> To: <email address hidden>
> From: <email address hidden>
> Subject: Re: [Question #163905]: Fulldome Fisheye Len Projection Problem
> Date: Wed, 6 Jul 2011 12:21:23 +0000
>
> Your question #163905 on Stellarium changed:
> https://answers.launchpad.net/stellarium/+question/163905
>
> Status: Open => Needs information
>
> Alexander Wolf requested more information:
> You can upload your images on any image hosting and publish link to
> images via web interface?
>
> --
> To answer this request for more information, you can either reply to
> this email or enter your reply at the following page:
> https://answers.launchpad.net/stellarium/+question/163905
>
> You received this question notification because you asked the question.

Alexander Wolf (alexwolf) said : #6

You have tried to enable the projection of the "fish eye" and move the sky as shown in this screenshot? - http://astro.uni-altai.ru/~aw/stellarium/stellarium-fisheye.png

allen yu (allen-yu70) said : #7

Sir, I'm playing around with the software now, okay so I did the projection at fisheye, zoomed out to 180degrees and I see the whole sky now. Would this be enough to show the whole sky as well on the dome? I hope so, as tomorrow I'm carrying out another round of tests with our projector dealer.

> To: <email address hidden>
> From: <email address hidden>
> Subject: Re: [Question #163905]: Fulldome Fisheye Len Projection Problem
> Date: Wed, 6 Jul 2011 13:11:34 +0000
>
> Your question #163905 on Stellarium changed:
> https://answers.launchpad.net/stellarium/+question/163905
>
> Status: Open => Needs information
>
> Alexander Wolf requested more information:
> You have tried to enable the projection of the "fish eye" and move the
> sky as shown in this screenshot? - http://astro.uni-
> altai.ru/~aw/stellarium/stellarium-fisheye.png
>
> --
> To answer this request for more information, you can either reply to
> this email or enter your reply at the following page:
> https://answers.launchpad.net/stellarium/+question/163905
>
> You received this question notification because you asked the question.

allen yu (allen-yu70) said : #9

Thanks Alexander Wolf, that solved my question.

allen yu (allen-yu70) said : #10

Dear Sir,

I have a new problem, please see attached page. I hope you can offer a quick help. thanks.

Kind regards,
allen

> To: <email address hidden>
> From: <email address hidden>
> Subject: Re: [Question #163905]: Fulldome Fisheye Len Projection Problem
> Date: Thu, 7 Jul 2011 11:06:02 +0000
>
> Your question #163905 on Stellarium changed:
> https://answers.launchpad.net/stellarium/+question/163905
>
> Status: Open => Answered
>
> Alexander Wolf proposed the following answer:
> Hint:
> http://stellarium.org/wiki/index.php/Setting_up_your_own_dome_using_Stellarium%27s_spheric_mirror_distortion_feature
>
> --
> If this answers your question, please go to the following page to let us
> know that it is solved:
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