Basic Question

[Jnicholes]

Hi everyone,

I was doing some stargazing last night, specifically looking at Jupiter. I was taking videos to stack on Registax with my camera, an Orion Starshoot USB eyepiece Camera II. I then had a crazy idea with interesting results.

My camera is equal to about a 5mm eyepiece. This gives me a magnification of 180x with my F/11.25 telescope. My crazy idea was to add a 3x barlow to the camera and see what would happen.

I took a video before doing this, and saved it. then I tried my idea. I got it into focus as best I could. Then when I was done, I stacked both videos separately, then added them together.

This is the result side by side:

Barlow vs no barlow.

Now my question. What happened? Why does it seem like my no barlow picture of Jupiter has more detail than the barlow picture?

I am not really understanding this, can someone help me out?

Jared

[KathyNS]

To see if it was just the image scale, I reduced the barlowed image 3x. Aside from the colour cast, the difference in detail is less than it seemed on first glance. There is still some difference, but this could easily be attributed to a change i seeing conditions.

[Jnicholes]

Yeah, that’s what I thought, too. I’m just wondering if I over magnified the image.

[The Wave Catcher]

You may have hit a limit to the maximum useful magnification for the given seeing conditions and/or limitations to your telescope. More magnification will alway make the images larger, but at some point the ability to see more details is not increased. If 5 mm is the most power that the currents/setup can take, then adding a Barlow just makes a larger image and more glass for the light to have to go through.

Sometimes I find that a Barlow is useful for increasing the power of a lower power eyepiece that may have a nice field of view. However, using that Barlow on my shortest focal length eyepiece seldom brings more pleasurable results.

[Jnicholes]

You may have hit a limit to the maximum useful magnification for the given seeing conditions and/or limitations to your telescope. More magnification will alway make the images larger, but at some point the ability to see more details is not increased. If 5 mm is the most power that the currents/setup can take, then adding a Barlow just makes a larger image and more glass for the light to have to go through.

Sometimes I find that a Barlow is useful for increasing the power of a lower power eyepiece that may have a nice field of view. However, using that Barlow on my shortest focal length eyepiece seldom brings more pleasurable results.

Interesting. I guess I learned something today. Thanks for the input.

[JayTee]

Think of it this way, your telescope aperture will only allow a certain number of photons in at any given time. In a smaller scale the sensor sees a condensed image with those photons and it produces a rather crisp image. When you add the barlow and you multiply that image by 3x you are now producing a bigger image with the same number of photons spread across a larger area. Your sensor does the best it can but the limitation is in the number of photons that your aperture collects.

[Jnicholes]

Think of it this way, your telescope aperture will only allow a certain number of photons in at any given time. In a smaller scale the sensor sees a condensed image with those photons and it produces a rather crisp image. When you add the barlow and you multiply that image by 3x you are now producing a bigger image with the same number of photons spread across a larger area. Your sensor does the best it can but the limitation is in the number of photons that your aperture collects.

I see now, thank you very much.

[Jnicholes]

@JayTee I actually just finished processing a picture of Mars I took last night with the same set up. I got some interesting detail. If what you say is true about the photons, then shouldn’t it affect the Mars and Saturn photo I took recently? I seemed to get pretty good detail on both of those. It seems to be just Jupiter I am struggling with.

Then again, Jupiter was on the horizon, and my telescope was out of focus when I took that picture, it turns out. Mars and Saturn were higher up and in better focus when I took these pictures.

0CE58649-74AE-42F8-9FC0-A716A66226CC.jpeg (4.93 KiB) Viewed 751 times

It could be seeing conditions also, but I could be wrong.

[JayTee]

My answer was the basic physics answer. The problem we're dealing with now is that there are so many variables in planetary Imaging that are both seen and unseen. For example, most planetary imagers do not process their video in Registax6. We use AutoStakkert3 first then we take that result and put it through the wavelets function of Registax this is how you'll get the best image possible from the video you took.

Have you reviewed my Astro imaging software post in the software forum? Not the Astro software forum. I really should move that over to the correct spot.

Just moved it.

viewtopic.php?t=523

[Jnicholes]

My answer was the basic physics answer. The problem we're dealing with now is that there are so many variables in planetary Imaging that are both seen and unseen. For example, most planetary imagers do not process their video in Registax6. We use AutoStakkert3 first then we take that result and put it through the wavelets function of Registax this is how you'll get the best image possible from the video you took.

Have you reviewed my Astro imaging software post in the software forum? Not the Astro software forum. I really should move that over to the correct spot.

I’ll take a look at it in just a little bit. I’m a little busy at the moment. I will also keep trying to get better pictures of Jupiter with this set up. If it gets down to it, I will switch to a 2X Barlow and see what happens.