Critters, Mercury, Markarian's Chain,
Centaurus A, Omega Centauri, M13, M57
Posted: 11 May 2015
Open: Sunday, 10 May 2015, 1756 MST
Conditions: Clear, breezy
Shortly after opening the observatory I had a visit by the Quail family. Momma Quail escorted her children while Daddy Quail kept a watchful eye on the proceedings from high up in a tree:
1813 MST: viewed Venus, 83X. Then Mercury, 83X. I then did a live video streaming session with the iPhone 5s showing Venus using Twitter Periscope. Used a Variable Polarizing Filter to avoid bright Venus overexposing. I had hoped to stream Mercury but it was too faint for the Periscope app. Ended the streaming at 1832 MST.
I then set up for Mercury imaging with the D7200 DSLR at prime focus + 2X PowerMate. This is a stack of 639 frames (10 seconds) from a HD video recording, 1.3X crop factor, 60 fps, 1/200sec, ISO 800, taken at 1910 MST, showing a slight crescent phase:
This is how Mercury appeared on the D7200 DSLR Live View screen (taken with the iPhone):
1916 MST: sunset. Mercury was now too low for imaging. The breezes had calmed down by now.
1920 MST: viewed Mercury, 166X. Had a pretty good view at times. Then viewed Jupiter and the four Galilean Moons. 1925 MST: took this handheld iPhone 5s afocal 166X photo of the moons (left-to-right: Callisto, Europa, Io, and Ganymede):
1928 MST: the Great Red Spot was rotating into view. 1950 MST: nice view of the Great Red Spot, 166X. Tried using 444X but seeing was not good enough. However, 222X provided a nicely detailed view of the Great Red Spot and the cloud bands of Jupiter.
2006 MST: slewed to M84 (galaxy). 2020 MST: began observing the Markarian's Chain of Galaxies in Virgo: M84, M86, NGC4435, NGC4438, NGC4458, NGC4461, NGC4473, and NGC4477. Also viewed NGC4388, NGC4387, and NGC4402. Added the focal reducer + extension and using the 2" 24mm UWA eyepiece I could see the entire Markarian's Chain in the field-of-view. Nice sight. I then began setting up to image Markarian's Chain. Did a focus test on the star Spica using the Bahtinov Mask.
I did several framing test exposures while looking for a guide star in the off-axis guider. Only found a faint star, which as it turned out was too faint for reliable manual guiding. I also did unguided 1 minute exposures at various ISO settings as a test to see how well the D7200 DSLR would do on the fainter galaxies. This is a single image, 1 minute, ISO 25600, converted to black-and-white:
Mouseover or tap on image to see labels
There were many more galaxies visible in the original image.
2133 MST: slewed to Centaurus A (galaxy), low in the southern sky and took several images, unguided, 1 minute, using various ISO settings. This is a slightly cropped ISO 25600 image:
And a slightly cropped image of Omega Centauri (globular cluster), unguided, 1 minute, ISO 3200:
2202 MST: slewed to M13 (Great Globular Cluster in Hercules) and took this unguided, 1 minute, ISO 5000 image:
And last, slewed to M57 (Ring Nebula), which was low in the east. I then waited for M57 to rise higher before starting imaging. 2300 MST: began imaging M57. This is an unguided, 1 minute, ISO 5000 image:
2306 MST: ended imaging. 2316 MST: viewed M57, 222X. Then slewed to Saturn and viewed it at 222X and 83X. The Ring system and the cloud bands on the planet were very nice. Several moons were visible.
Close: Sunday, 10 May 2015, 2330 MST
As you can tell from the above DSO images, the D7200 DSLR is a very good camera for astrophotography, even at high ISO settings. I'm getting more comfortable using Lightroom 6 for editing the images. The combination of the camera + Lightroom has been a good choice for me.
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