NGC 206, an OB association in the Andromeda Galaxy (Fall 2021)

What looks like a cluster of blue stars in this image (and was called a cluster by Edwin Hubble) is actually a large association of young type-O and -B stars (hot, large, and bright) that shines 2.5 million light years away in the Andromeda Galaxy.

This image is 44x1200" with the Atik 460EXC, 203mm Synta ONTC Newtonian at f/4.95, and an Astronomik CLS filter.

M103 (Nov. 2021)

This simple but striking cluster in Cassiopeia was captured with 29x300" using an Atik 460EXC through the 203mm Synta-ONTC Newtonian at f/4.95 and an Astronomik CLS filter.  Seeing was actually pretty bad the night of capture.

M29 (Oct. 2021)

I've always been interested in M29.  It's a simple, beautiful little cluster in a constellation (Cygnus) cluttered with interesting things.

 

I didn't realize that controversy existed over which stars belonged to the cluster.  It turns out that some of the bright stars above---in what look like a cluster---do not!  The problem is that the stars are too far away to measure their proper motion across the sky.  Also, dust extinguishes light along our line of sight by several magnitudes.  Without knowing the stars' intrinsic brightness, their distance is harder to infer.

 

But a study published in 2014 helps resolve these concerns.  The study carefully compares the spectra of the stars with their brightness and the brightness of stars in the local vicinity to better estimate their distance and the effect of dust (another, larger 2015  study by many of the same authors examined extinction in the area of the cluster). The 2014 study estimates that at least 15 stars lie together at 2.2 kpc, about 7,100 light years.

  

The stars numbered in this image (linked here from the study) are probable cluster members:

 

 

Some of the brightest stars in the cluster fail the test.  The white star in the top row (HD194378) and another bright star in the bottom row (HD 229238) are probably not cluster members. The study reminds us that space is a busy place full of unexpected surprises; sometimes line of sight alignment tricks us into thinking items come as a unit.

 

My image is 22x180" with the Atik460EXC through the 203mm Synta ONTC Newtonian at f/4.95 and an Astronomik CLS filter.

 

M16 from Goldfield Observatory

This is nearly 3 hours of data from Goldfield Observatory in Victoria, Australia, taken with a Takahashi Mewlon 250CRS and ZWO ASI094.

Crescent Close-Up (NGC 6888) (August 2021)

 

I love using my CFF 290 Classical Cassegrain.  Here is an image taken (at f/8.1, 2350mm) of the brighter half of the Crescent Nebula in Cygnus.  This is a full narrowband image.  I took three hours of H-alpha then spent a night on what I thought was O3 but which turned out to be S2---ouch (slip of the brain when controlling the filter wheel)!  The S2 is blended in here.  I finally caught another 3 hours of O3.  Total time: 8 hours 50 minutes.  The H-a and S2 subs were 20 minutes long; the O3's were 30 minutes each.

After I finished the O3 subs and the Crescent slipped behind the trees, I put a diagonal and eyepiece in the big scope and enjoyed a tour of Cygnus.  Highlights included the Owl Nebula and Phi And (0.5" clean split; truly awesome to see those little diffraction patterns so close together).  As always, the scope performed like a champ.  I started observing at 3:30 a.m. and made myself put it away at 5.  I had to sleep sometime.

M27 in H-alpha (Summer 2021)

This data came from AG Optical. It was fun to process.  Things clouded up in the Gulf Coast from May through the end of July this year.  It's been crazy, so I'm glad to have some data to work on.

NGC 3628 (Spring 2021)

This is the Ham Sandwich Galaxy, but its friends call it NGC 3628. It's found in Leo. This image was processed from >20 hours of data from AG Optical Observatory's 14.5" iDK/Paramount ME II/ASI6200 system.