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OpenOcular iPhone Experiment

It is the age of camera phones and electronic sharing, so I’ve been thinking about how our young astronomers might be able to participate with their Skyward 150 telescopes.

Fortunately someone was 5 steps ahead of me. Josue Gimbernard from Orlando, Florida developed a device called OpenOcular and put it on for free use by anyone under the Creative Commons Share Alike license. My first print of it was not cosmetically great however it was functional enough to take for a test drive.I used my iPhone 12 Pro, but almost any phone will work.

First I chose a standard, unbranded, inexpensive 20mm Plossl eyepiece and put it into the focuser. For those of you interested in such things, when you take the 750mm focal length of the telescope and divide it by the 20mm focal length of the eyepiece you’ll note that dividing these numbers tells us the magnification was 375X.

This was a quick daytime test and so I pointed the SW150 telescope at a utility pole and brought it into focus using my eye at the eyepiece. Here’s what the pole looks like with just my phone at 10X, which is the maximum zoom of my phone.

I locked the focuser position and then placed the OpenOcular device (the blue and black bit) on the eyepiece and tightened the collar screw.

Then came the fidgety part of trying to align the camera on the phone with the eyepiece. The iPhone 12 Pro has three cameras and they seemed to be switching back and forth between themselves based on illumination, focus distance and zoom. It felt a bit random but then I put it in video mode and set the zoom to 1.6X and things seemed to settle down for the alignment. Focusing was a bit strange because the iPhone was trying to focus at the same time I was. I found the limits of where the iPhone could bring the object into focus and set the focuser to a position halfway in between. Then I made a video using the iPhone.

Please note that this was done with the first prototype telescope, so the tripod and mount aren’t as stable as they are in later units. Also there are a lot of thermal currents due to the way I was shooting. Even with these factors I call this initial experiment a complete success!

Here is a cropped area of interest taken with my iPhone at maximum zoom and no telescope:

And here’s what it looks like at 375X using the same iPhone, an OpenOcular, and a Skyward 150. No enhancements done on any of these images- straight off the camera roll.

So yeah... I’ve already started a second 3D print of the OpenOcular device!

Quick Update:

It was clear tonight and I grabbed this with my iPhone- same setup as above. Used PSExpress on my phone for quick processing. Does it keep up with an expensive astro camera? No, there are obvious artifacts that may or may not be correctable. Is it fun anyway? Heck yeah!


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