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DSLR and iPhone Imaging: Comet Lovejoy;
Camera Lens Bahtinov Mask testing

Posted: 15 January 2015

Cloudy skies continued on Wednesday, 7 January 2015, preventing me from viewing and imaging Comet C/2014 Q2 (Lovejoy) at its brightest and closest. Cloudy skies continued until 14 January 2015, when the clouds surprisingly went away as sunset approached.

On Saturday, 10 January 2015, Oracle State Park hosted a Dark Skies Delegation from South Korea. The International Dark-Sky Association in Tucson, AZ, had been in South Korea last year to discuss the "International Dark Sky Park" (IDSP) Program with them. The Delegation came to America and wanted to learn how a park accomplished the designation and visit one. As Oracle State Park is close to Tucson and is now an "International Dark Sky Park", our Park was an appropriate place for them to visit. I gave a presentation on how we accomplished earning the IDSP designation in record time. Unfortunately, it was cloudy that night so they were not able to experience our dark sky and missed out on seeing the Zodiacal Light, Comet Lovejoy, the Winter Milky Way, and more. My report is available on the Oracle Dark Skies Committee web site. A local newspaper covered the event in this article.

On my last session in the observatory I discovered that one of the three ScopeStuff "Blinky" lights I had purchased in 2005 had failed. I purchased a new one ($11) from ScopeStuff and it arrived on 12 January 2015. The light has been slightly redesigned with a smaller and much dimmer red LED, but is otherwise the same as the ones I've used for almost 10 years.

During this period of cloudy days and nights I was able to learn and use Starry Night Pro Plus 7. My review is now online.

Open: Wednesday, 14 January 2015, 1821 MST
Temperature: 51°F
Session: 767
Conditions: Clear

When I arrived at the observatory, Venus (left) and Mercury (right) were nicely visible above some trees, as seen in this handheld D7000 DSLR photo, f/16, 1/4sec, ISO 6400, FL 70mm:


1831 MST: viewed Mercury, then Venus, 83X. Both had essentially full disks but were too low in the sky for good viewing.

1834 MST: tried to see Comet C/2014 Q2 (Lovejoy) using my naked eyes, but the twilight sky was still a little too bright. Slewed the 8" LX200-ACF telescope to the comet's RA/Dec as reported by SkySafari Pro on my iPhone 5s. 1839 MST: viewed the comet, 83X. Large coma, no tail. 1843 MST: the comet was now easily naked eye visible, 23 minutes BEFORE the end of Astronomical Twilight! I confirmed it using 12x70 binoculars. The coma was very large in the binoculars.

Began setting up to image the comet in the 8" telescope. Added a focal reducer, then mounted the D7000 DSLR at prime focus. Did a focus test on Aldebaran using my telescope Bahtinov Mask. Slewed back to the comet; it was easily seen in the camera viewfinder. Did several images at various exposure settings. This is a 2 minute, ISO 6400, exposure:


The tail is faintly visible extending left from the comet's coma.

I removed the DSLR and mounted the iPhone 5s for afocal imaging, 48X, using the iOS app "NightCap Pro". The comet was visible on the live screen, as seen here in this screen capture:


I then did 1, 2, and 5 minute, images with 1/2sec, ISO 2000, exposures. This is the 5 minute exposure, edited in Aperture, Neat Image, and GraphicConverter:


2000 MST: ended imaging Comet Lovejoy (for awhile) and began testing my new Gerd Neumann Bahtinov Mask for Camera Lens. I will post a review soon.

As I completed the mask testing, Comet C/2014 Q2 (Lovejoy) was very high in the sky and near M45 (the Pleiades). With my D7000 DSLR mounted pigyyback on the 8" LX200-ACF, I captured this photo of the Pleiades and Comet Lovejoy, 5 minutes, ISO 6400, FL 70mm:


The comet's tail is nicely visible, as is some Pleiades nebulosity.

2201 MST: ended imaging. Removed the focal reducer and took a quick look at Jupiter, 83X. The four Jovian Moons were visible.

Close: Wednesday, 14 January 2015, 2222 MST
Temperature: 41°F

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