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INDI Library v2.0.6 is Released (02 Feb 2024)

Bi-monthly release with minor bug fixes and improvements

Ekos previews

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Replied by Steve Cohen on topic Ekos previews

Thank you very much for this reply. I look forward to trying this.
1 year 4 months ago #88465

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Replied by Steve Cohen on topic Ekos previews


So we come to the first hurdle. How does one do this? I am using the previewer but I don't know what are reasonable settings for this. I point the scope at the sky, the sky is reasonably dark, but I can't capture anything that looks like the sky to focus on. In the attached screenshot you can see my settings and the preview that is not recognizably the sky. What should my settings be to make this initial preview so that I may focus the scope (must be a manual process, on my Celestron Nextstar 4se, no autofccusing available).

Also, I have no idea what the shadows, midtones, and hightights should be set to in the preview window. I don't understand what these controls are for.

Please help this noob!
1 year 4 months ago #88468
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Replied by JuergenN on topic Ekos previews

Hi Steve,
perhaps it would be good to focus the scope during the day on a distant object to get at least the rough focus. During daytime you maybe have to reduce the exposure time to 0.01s or even less, and also play with the gain. Then dont touch the focus until night ;-)

After you get this rough focus you can point your scope at night to a bright star and play around with gain and exposure time. The problem may be, that your 4se has 1.4m focal length and therefor a quite small field of view (*). This brings some more difficulties. I think to start with an exposure time of 2-5s should be ok, then you have to play with gain until you see stars. The stars then maybe not in exact focus but near to it (since the stars are even more distant than your object during daytime).

(*) Perhaps one recommendation: use stellarium to look, what you can get into your field of view. In stellarium you can set your focal length and your camera parameters (pixel size and so on) and you will see, what area you can see.

Good luck ;-)
1 year 4 months ago #88474

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Replied by Steve Cohen on topic Ekos previews

Thanks for this excellent advice about daytime focus! I will try it at my next session.

But I haven't thought of using Stellarium in this way. I tried it and felt it wasn't that helpful. I've tended to prefer the cleaner look of HNSKY or KStars. Please explain a bit more the feature that you find useful in stellarium here.
Last edit: 1 year 4 months ago by Steve Cohen. Reason: Needed to respond to the stellarium suggestion.
1 year 4 months ago #88480

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Replied by JuergenN on topic Ekos previews

You can enter the focal length of your telescope and the size of your camera sensor into stellarium and check, how "big" your field is, which you can see with your setup. At least for my stellarium (version 0.22.2) it is that way that you can click on the "wrench" in the upper right edge of the screen to go to the setup of "sensors" and "telescopes" and you can click on the circle with the rectangle in it (the third symbol from the right) on the upper right edge to get that red rectangel on the sky map.

A few pictures:look at the right upper edge with the symbols (you can also see an example for my sensor, and also the OAG but that is not important for you):


second picture shows the "telescope" list, my 8inch F% newton as example here:

And here the resulting sketch of the field of fiew for the setup (with info about pixel size and size of the FOV):

HTH
Last edit: 1 year 4 months ago by JuergenN.
1 year 4 months ago #88483
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Replied by Steve Cohen on topic Ekos previews

I have given daytime focusing a shot and still no joy. The scope is pointed at a mountain 2 or 3 miles away. It is clearly focused in the eyepiece. When I replace the eyepuece with the Svbony-305 I can see no detail whatsoever, focused or not. I can play with the Highlights/ Midtones/Shadows settings to darken or lighten the image but it's always a flat, undifferentiated rectangle, no detail visible. Similarly, playing with the Gain, Offset, etc.You can see the settings I used. Not sure what to try next. There are also some INDI camera settings I could play with. Grateful as always for any ideas.
1 year 4 months ago #88489
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Replied by Hy Murveit on topic Ekos previews

Steve, if you are pointed at a mountain and you can see it in the eyepiece, what that tells you is you are pointed well. It doesn't tell you about the correct focus when attaching the camera. They will have different focus positions. So, now, given correct focus connect the camera and start hunting with your focuser taking pictures and seeing if you start to see any detail at all with some reasonable daytime exposure**. You should take relatively large steps until you find some picture with some detail, then search near there in a similar way with smaller steps, etc etc until you have a focused picture.

**In the daytime, you should likely be exposing well under a second. Perhaps .01? Not sure. Play with your exposure first and make sure you're not just getting all white over-exposures.

Of course, it is possible that your focuser doesn't allow the right amount of back-focus to put your camera sensor on the plane-of-focus. Usually there is some spec about what the backfocus of the telescope is and you can measure about where to place the camera sensor. E.g. many guide telescopes are like that, where the eyepiece attachment doesn't provide sufficient distance for a camera, and one needs to add an extension tube. However, I'd first assume that you're fine, and that you just need to hunt the full distance the focuser provides for an area that's in focus for your camera.
1 year 4 months ago #88490

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Replied by JuergenN on topic Ekos previews

Steve, regarding Highlights, Midlights and Lowlights I would keep the Automatic Setting on (this is the button right from "highlights"). In the case in your picture everything is on "0", this leads to a white picture.

Regarding exposure time: I made sometimes the experience if the setting is too low I get no good results. Try 0.01s instead of 0.001s, but play with it, since it always depends on setup. Gain I would set for daytime photography to 0 or 1.

Regarding focus: Hy is right, that it might be, that it is not possible to get into focus with your camera with your current setup. Maybe you need some extensions. To check that it would be a possibility to point your telescope at the moon (or try it with the mountains, that should work too) and hold a white paper behind the scope. Remove the camera and eyepiece, so nothing should be in the focuser. Move the paper back and forth until you see a sharp picture on the paper. In that distance the camera sensor should be.

I would first check the exposure time / gain. If you get there a reasonable (maybe unfocused but good exposed picture) result you can then go on with the focus. You can watch the focus getting better or worth when moving the camera in or out and then you can see if you may need extensions or not.

In principle its easy but long to describe and for a beginner it is sometimes a little bit confusing ;-)
1 year 4 months ago #88491

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Replied by Steve Cohen on topic Ekos previews


Thanks! Progress has been made!



However, why is the mountain upside down? EKos seems to default to this. And no, it's not that the camera is upside down. It isn't. In fact, I found that CCDCiel, with its larger window was a better way to dial in the original approximate daylight focus. CCDCiel makes the image right-side up. I found the "flip vertical" option but this only worked for completed previews. If I tried that option in a preview loop, it would always go back to upside down. Is there a way to make right-side up the default?

Also, CCDCiel allows debayering in the preview. It's not very good, the colors are off, but there's something. I did not find such an option in KStars.

Anyway, I will be eager to try observing in the night sky with this setup. I hope the focus will be good enough. It's still not great.
1 year 4 months ago #88520
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Replied by Steve Cohen on topic Ekos previews

In spite of my earlier semi-success with obtaining focus during daylight, at night it's still the same mess.

Leaving this focus untouched, I have pointed the scope vaguely at the direction of Mars. But all I get is this grainy indistinguishable mess. Tried playing with gain and exposure settings but to no avail. Every once in awhile I do so see some poorly focused "donut" crossing this screen indicating a poorly focused object but it moves quickly across the preview loop before I have a chance to try and focus it better. I can only surmise it represents an airplane. How do I finish focusing the scope at night and for what exposure?
1 year 4 months ago #88526
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Replied by JuergenN on topic Ekos previews

If you are in focus at daytime you may have to correct the focus when photographing the stars, because at that big focal length 3km is not infinity. So if you saw some donuts: these should be the stars. Try to focus the donuts and you will see stars. Set the exposure time and gain that you can see the donuts.

Dont you have tracking on your 4se?
1 year 4 months ago #88531

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Replied by Steve Cohen on topic Ekos previews


Thanks agiain, Juergen.

What do you mean by tracking? If the scope is aligned you can make it go to any visible target the software knows about, and it will stay on that target as it moves. Is that what you mean by tracking?

As for focusing on the donuts, these particular donuts were appearing at irregular intervals on the screen, for maybe five or six previews, moving across the screen each time, which made me think they were airplanes. I could never see any donuts that stayed fixed in location on the screen.

Also, do you know why my mountain picture was flipped upside down? And whether the focus quality of that picture would have been sufficient for alignment?
1 year 4 months ago #88556

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