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Heart and Soul Nebulae, Orion

Posted: 24 December 2011

I opened the observatory Friday, 23 December, at 1809 MST, 39°F. I had two goals planned for this night: image the Heart and Soul Nebulae in the constellation of Cassiopeia, and to photograph the constellation of Orion at several ISO settings. After opening the dome to clear skies, I took a quick look at Venus, 77X. At 1830 MST, viewed Jupiter, 77X. Four moons were visible. The Great Red Spot (GRS) was just rotating out of view. Using 133X, a lot of details were visible in the South Equatorial Belt trailing the GRS. I then began setting up to image IC1805 (Heart Nebula) at prime focus + focal reducer using the D7000 DSLR. Did a focus test on the star Deneb using the Bahtinov Mask.

Since I was just testing the capability of the D7000 DSLR to actually capture the Heart and Soul Nebulae this night, I did not try to guide (although I did use the Off-Axis Guider just in case a guide star was easily at hand; there wasn't). Beginning at 1905 MST, I took 1, 2, and 3 minute, ISO 6400, exposures, unguided, of the Heart Nebula (IC1805). Nothing was visible on the camera display but with lots of editing in Aperture (and using the software I'm testing), I was able to bring out the Heart Nebula in the two minute exposure (the three minute exposure trailed). This is the result (slightly cropped):


Not all of the nebula is visible in this short exposure. I will have to try longer, guided exposures on a future session.

I then repeated the exposures on the Soul Nebula (IC1848) at prime focus + focal reducer. Unfortunately, it was not visible on either the 2 minute or (trailed) 3 minute exposures. I will have to try again with a longer guided exposure.

I then mounted the camera piggyback on the 8" LX200-ACF and did some wide-angle imaging of the Heart and Soul Nebulae together. I used a focal length of 75mm. This is a full-frame, 5 minute, ISO 6400, unguided, exposure:


The Heart and Soul Nebulae are both visible just left of center, between the Double Cluster and the airplane lights trail. Also visible is the shadow of a bug that landed on the camera lens during the exposures. The bug appeared on several exposures and moved across the lens from one exposure to the next.

With the camera still piggybacked on the telescope, I slewed to the constellation of Orion. I waited until 2100 MST to allow the constellation to fully rise past a tree. I then began a series of 30 second exposures at several ISO settings: 100, 200, 400, 800, 1000, 1250, 1600, 2000, 3200, 4000, 5000, 6400, 12800, and 25600. The camera lens focal length was set to 33mm. This is the 30 second, ISO 1000, exposure:


M42 (Great Nebula in Orion) is visible in the "sword" and some nebulosity near the left-most belt star (where the Flame and Horsehead nebulae are located) is just barely visible in this very short exposure.

I closed the observatory at 2130 MST, 33°F.


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