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Polar Alignment Check, NGC7023, Image Processing Tests

Posted: 15 September 2014

Friday night, 12 September 2014, was cloudy. Saturday evening I represented the Oracle Dark Skies Committee at the 2nd GLOW event of 2014 at Triangle L Ranch in Oracle. The weather cooperated and after sunset over 100 visitors got to view Saturn through my ETX-105PE. Loved hearing all the "oohs" and "ahs" as people, young and old, got their first telescopic view of Saturn. A few got to view M17 or M22 as the evening ended. When I returned home I was too pooped to open the observatory.

Opened: Sunday, 14 September 2014, 1927 MST
Temperature: 85°F
Session: 719
Conditions: Clear

1935 MST: Did quick look at Saturn and Mars, 83X. I then began using Michael Covington's "Polar Alignment by Iterating on One Star and Polaris". Since my polar alignment was already pretty good having previously done a normal "Drift Alignment", I skipped doing the regular "One Star Align" on the AutoStar II. Did a GOTO Polaris; it was centered in the 83X eyepiece so no need to remove "half the error". Did a GOTO Deneb; it was just slightly off-center in the field-of-view so centered it and did a SYNC. GOTO Polaris; it was centered; no adjustment made. GOTO Deneb; it was centered. I then did a GOTO NGC7023, which would be my imaging target for the night. While I couldn't detect the nebula at 83X, I assumed it was centered.

1959 MST: Began setting up for D7000 DSLR prime focus imaging on the 8" LX200-ACF. Mounted the camera using the 2" TPO Prime Focus Adapter. Did a focus test on Deneb using a Bahtinov Mask. I'm currently working on a review of the image processing applications "Nebulosity" and "PixInsight" so I did some "darks" (with the telescope aperture cover in place) and 30 "lights", all at 1 minute, ISO 800. You'll have to wait for the review to see how these turned out. I had previously imaged NGC7023 (nebula) on 17 September 2012 using a 2 minute, ISO 6400 exposure. After I completed the test images, I took this unguided, 3 minute, ISO 1600, image, processed in Neat Image to remove digital noise. The image was cropped and desaturated. Some star trailing occurred during the unguided exposure.


2104 MST: Completed imaging. Swapped the Wireless AutoStar II batteries. (I use rechargeable AA batteries and they only last 2-4 weeks during normal use.) 2125 MST: Viewed the double star Alpha Capricorni, 83X. Strong breezes were beginning to occur.

2134 MST: did some sky quality measurements at Cassiopeia Observatory. SQM-L = 20.86. Dark Sky Meter (iPhone 5s) = 21.55.

Closed: Sunday, 14 September 2014, 2147 MST
Temperature: 76°F

A "NASA Night Sky Network Survey of Astronomers - 2014" is now available and they request your inputs. If you have time (it could take 15-60 minutes) please take the online survey.

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