Last updated: 11 January 2004

LPI - First Photos

On 28 December, I had a clear (cold, for Southern California) night to try out some simple tests with the LPI. I didn't try anything fancy this first night out; just some straight forward shots of the Moon, Mars, and Saturn. There were two challenges: getting the object visible in the LPI, which provides about the same magnification and field-of-view (FOV) as a 6mm eyepiece, and focusing. You center the object in your eyepiece (I used a 26mm) and then replace the eyepiece with the LPI. If the image moves during this swap it won't appear on the "Live" screen on the LPI app. So a sturdy mount AND a well aligned finderscope are musts. Once you get the object in the LPI you then have to focus it. I discovered that the exposure setting affects the live view (which in hindsight isn't surprising) but since the exposure starts out at 0.001, it was too short to make the object (the Moon!) visible. Once the exposure is increased (either manually or by the "Auto Adj" button; I used both at times) then the object will eventually become visible. Once you get the image in view you can then focus it; this is a challenge if your mount is not sturdy, you are using an electronic focus (which may move the focus too much), you are using your hand (which induces vibrations in the image), or the telescope screen is not close to the telescope (when using manual focusing). You make as small an adjustment in focus as possible and then check the live view. Eventually you can get a good focus. There is a "focusing aid" on the LPI screen but I found it difficult to use while focusing. Once you get a good focus you should make an eyepiece "parfocal" using the supplied "parfocal ring". Meade suggests using the 26mm eyepiece, which I did, but upon reflection I later realized that a better eyepiece to use would be one that approximates the LPI FOV. (I'm going to try a 9.7mm eyepiece on the next night.)

Now on to the specifics.

ETX-125. I connected the Autostar Suite to the Autostar (using the shared network capability). I had an Autostar reset while trying to center the Moon in the LPI. Then the Autostar shutoff for some reason. The ETX was still ON but the Autostar wasn't; connections seemed OK. Odd. I started over and the problem did not reoccur. On launch of the LPI app the Moon would briefly appear in the "Live" screen and then disappear. Once I adjusted the exposure as noted above the image would be visible. I did select "Moon" as the object in the LPI app. I got a nice single frame shot of the Moon:


Back in the Autostar Suite starmap I pointed at Mars and selected to slew the telescope to it. It was centered but I couldn't keep it in the LPI FOV. The small FOV of the LPI really makes centering an object challenging. In the interest of time since I wanted to get some shots with each model telescope, I elected to move to the next telescope.

ETX-90RA. In order to demonstrate that you don't need an Autostar to use the LPI, I took these two single-frame photos with my ETX-90RA. The first is with the LPI in the normal eyepiece port and the second with it in the Shutan Wide Field Adapter.



ETX-70. Again, no Autostar was used. I did have to adjust the exposure for this single-frame shot as more of the Moon appeared in the FOV.


LXD55-8"SC. I didn't connect the Autostar this time either but just went straight to imaging with the LPI. I tried stacking (called "combining" in the LPI app). The first photo is a single-frame one of the Moon:


Compare the above to this automatically stacked image (I didn't note the number of images used):


I then moved to Mars. The "Live" screen continued to show the Moon. I had to quit and relaunch the LPI app to get it to "forget" the Moon. Here is a stacked image of Mars (was the focus bad or just atmospheric turbulence?):


By now, Saturn had risen above some obstructions so I moved to it and I noticed that the focus was definitely "soft". I spent considerable time trying to improve the focus. I managed to get this "interesting" photo of Saturn. This demonstrates what can happen if the telescope moves while images are captured and combined.


But letting the LPI take two images and combine them resulted in this not too bad photo of Saturn:


Bottom line: the LPI works and can do some nice astrophotography with any telescope. Using it can be a challenge (as with most imagers) but the results can be worth it. There are many more features and capabilities that I have yet to explore. In the future (when weather and schedule cooperate), I'll report more on the LPI and Autostar Suite. Stay tuned...

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Copyright ©2004 Michael L. Weasner /