December 20, 2017

Merope and IC 349 (Sept. 2017)


This is an oft-imaged nebula.  I have imaged it before (search in the window at top left for earlier images).  Merope is the bright star, and IC 349 is the tiny, fan-shaped nebula reflecting Merope's light, just to the right of the star under the diffraction spike.  The nebula may be responding to radiation pressure from Merope, being slowly swept away, but this is not known.  Anyway, the nebula is a challenge to see, and I've taken several images of it.  I think it looks like an angelfish, so to me it is the Angelfish Nebula.

This image was taken at 2353mm with the CFF Classical Cassegrain and the SXVF-H9.

December 17, 2017

Holoea! (November 2017)


This is the western half of the open cluster M36.  Please find the curious object that looks like a comet with an upward sweeping tail.  Look at about 6:30, halfway from center to lower left edge.  This is Holoea.  The three different versions of the image highlight different parts of this faint object.  After you have found Holoea, please see the write-up below.




Holoea means "flowing gas."  This object was discovered in 1995.  No one is certain just what it is, yet.  Spectroscopy and radio interferometer observations suggest that the object involves a K2 star, two young stellar objects (YSOs) that are moving toward star status, and one pre-stellar condensation of gas that is beginning to glow. Just how those objects are together in the sky is not clear yet, but something, probably one of the YSOs, is ejecting gas outward at 650 kilometers per second!  The system is considered a valuable information source for the stage of star formation between (i) condensing gas cloud and (ii) the point at which a YSO no longer accretes gas.

This image is 17x720" with the SXVF-H9C and Astronomik CLS filter through the CFF 290 Classical Cassegrain at f/8.1.  I thought I might make a color image, but the object is so faint that color would not have been pretty.

Reports are that Holoea has grown brighter, and perhaps it has since the 1950s, but my full-visual-spectrum image suggests it is around magnitude 18.5, something close to the measurement taken in the 1990s.  The faintest stars in the image are around magnitude 20.

My report relies on 2 Jeff Kanipe & Dennis Webb, Annals of the Deep Sky 156 (Willmann-Bell 2015); O. Morata, Y.-J. Kuan, P.T.P. Ho, H.-C. Huang, E.A. Magnier, and R. Zhao-Geisler, Millimetric and Submillimetric Observations of IRAS 05327+3404 "Holoea" in M36, 146 The Astronomical Journal 1 (2013), at http://iopscience.iop.org/article/10.1088/0004-6256/146/3/49/pdf ; and Magnier's original paper (1996) for the magnitude measured in the 1990s.  I learned of Holoea from Kanipe and Webb.

December 4, 2017

NGC 1514 (Fall 2017)


This lovely planetary nebula sits on the northern edge of the constellation Taurus, almost in Perseus.  It is visible in late fall and winter.  NGC 1514 was discovered by William Herschel in November 1790.  His study of it is supposed to have persuaded him that not all fuzzy deep sky objects were unresolved groups of stars; this one, he thought, looked like something else.

Perhaps what persuaded him was the very bright star at its center, such a contrast to the nebulosity surrounding it.  The star at the center is a spectroscopic double star.  A study released in 2017 shows that the two stars have a highly eccentric orbit of about 9 years!  (Thanks, Mike Ressler, for the tip (see the comments).)  This study followed other studies that suggested an orbit as short as 10 days (2003) or that the two stars did not orbit each other at all (2016).

In 2010, a NASA infrared telescope revealed that NGC 1514 has two, symmetrical rings around it.  The rings are located outside of the nebulosity shown above and glow in a part of the spectrum not picked up by my camera.  It is proof that even well-studied objects can present new mysteries.

This image is 19x600" through an OIII filter with the SXVF-H9 and 36x720" through an Astronomik CLS filter with the SXVF-H9C.  All sub-frames were taken through the CFF 290 Classical Cassegrain at eff. f/8.1 in Fall 2017.