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Donated 152mm Refractor Checkout, More iPhone Jupiter Tests

Posted: 3 February 2015

Open: Monday, 2 February 2015, 1810 MST
Temperature: 66°F
Session: 774
Conditions: Mostly clear

I set up the third telescope donated to Oracle State Park in honor of it being named the 1st "International Dark Sky Park" in Arizona. This one was donated by Explore Scientific and is a f/6.5, 152mm doublet achromatic refractor. They also donated a six eyepiece set (2" 35mm, 30mm, 25mm and 1-1/4" 20mm, 15mm, 10mm). Here is the telescope is on my observatory patio, with the nearly full moon in the eastern sky:


1832 MST: viewed Venus in the 8" LX200-ACF, 83X, then the moon, one day before full, 83X. A very slight terminator was visible.

1835 MST: began working with the Explore Scientific refractor:


A tripod was not included with the donation so I used my old Meade LXD55 mount. I have only one counterweight, which wasn't quite enough for good balance with this heavy refractor, but it was OK for my testing. I first aligned the finderscope using Polaris and the 2" 35mm eyepiece. I then did an AutoStar #497 alignment, which yielded excellent GOTOs during my tests. First viewed was Venus using all three eyepieces: 28X, 33X, 40X, 50X, 66X, and 99X. All 6 eyepieces had good views of Venus.

Next viewed was M42 (Orion Nebula) in all eyepieces. There was some slight distortion visible at the edge of the field-of-view (FOV) with the 2" 35mm and 30mm eyepieces; the 2" 25mm was sharp across the FOV. There was also some slight distortion at the FOV edge with the 1-1/4" 20mm and 10mm eyepieces; the 1-1/4" 15mm was sharp across the entire FOV. The best views of M42 were with the 2" 25mm (40X) and 1-1/4" 15mm (66X) eyepieces.

I then viewed Jupiter, low in the eastern sky. There was some purple fringing on the planet's limb with all six eyepieces; it was most noticeable with the 1-1/4" eyepieces (and their higher magnifications). Purple fringing on bright objects is typical of doublet refractors. But the planet and the four Galilean Moons were sharp at all magnifications, with the best view using the 1-1/4" 20mm (50X) eyepiece.

Lastly, I viewed the moon. Really should have used a moon filter; the moon was very bright through the 152mm aperture telescope. The entire lunar disk was visible in all eyepieces. There was also color fringing around the moon. The best view of the nearly full moon was with the 1-1/4" 20mm (50X) eyepiece. This handheld iPhone 5s photo was taken afocally using the 2" 25mm (40X) eyepiece:


2009 MST: ended the testing of the 152mm refractor. Overall a very nice telescope and eyepiece set donated by Explore Scientific. All three telescopes donated to Oracle State Park will see a lot of use at future star parties at the Park.

2015 MST: returned to observing using the 8" LX200-ACF. Slewed to Jupiter and viewed it at 83X. I then began setting up for iPhone afocal imaging of the planet. Mounted the modified MX-1 Afocal Adapter using a 1-1/4" 9mm (222X) eyepiece. Seeing was bad so focusing was difficult. I finally got a reasonable focus. The two images below are stacks of 1176 frames from a slo-mo video recording made using some digital zoom on the camera with some manual exposure adjustment. I used both Keith's Image Stacker and Lynkeos for the stacking.

Keith's Image Stacker


The Lynkeos stack looks a little better although neither are very good due to the poor seeing.

2030 MST: ended imaging tests due to the poor seeing.

Close: Monday, 2 February 2015, 2050 MST
Temperature: 52°F

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