EQUIPMENT
THE PRIMARY INSTRUMENT in use at Land of Oz Observatory is an Astro-Tech AT-92 92mm aperture f/5.5 Apochromatic Triplet Refractor of 506mm focal length, used in conjunction with a Stellarvue SFFX1 field flattener and a ZWO ASI 2600MC CMOS digital imaging camera. This camera has a SONY IMX571 back-lit 23.6 X 15.6mm sensor with 3.76 micron pixels (26 megapixels). At the AT-92s native focal length of 506 millimeters, this results in a resolution of 1.53 arc seconds per pixel.
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FIRST LIGHT at the new LAND OF OZ observatory.
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On June 22, 2025, the first astro image was captured at my new location in Lee's Summit, MO. Shown at right is the Astro-Tech AT-92 refractor mounted on the iOptron CEM-70 mount, with the Stellarvue 50mm Guide Scope. The first image was a 90 minute integration of 90 second exposures of M-27, the Dumbbell Nebula.
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FIRST LIGHT
Here is a close crop of the "first light" mage. The full frame is
2.5 by 1.6 degrees, and the target looks small. This is a crop to zoom in on M-27. This image is a 90 minute integration of 90 second exposures through the Astro-Tech AT-92 92mm APO triplet refractor, using the 2600MC Pro camera, cooled to 0 degrees. Acquired in N.I.N.A, guided by PHD2, Processed in PixInsight and Photoshop.
This is a view of the N.I.N.A. imaging screen during the recent capture of an image of M-13. As can be seen from the guiding graph below the image,
the guiding during this session was very good, averaging about 1.15 arc seconds. The resolution of this scope/camera
combination is 1.53 arc seconds
per pixel. Also note that the HFR value is 4.47.
This is the "second light" image, captured on July 28, 2025. A 1 hour 32 minute integration of 90 second exposures. This is a close crop of the original 2.5 X 1.6 degree full frame. Centered on M-13. Also visible is the companion galaxy NGC-6207. The prior image, taken on June 22, showed that the back focus wa slightly off. This image was taken after a .15mm spacer ring was added. Corner stars showed improvement, but on the next try, I'll increase the back focus distance further.
