NGC 6888, Crescent Nebula, in Hα (May 2018)

This is 7x1200" with the SXVF-H9 through an Astronomik 6nm Hα filter and the ONTC_Synta Newtonian at f/4.95.  This has always been one of my favorite targets.  One of the neat aspects of this image is that the seeing was so good that the resolution of the sky was better than the 1.32"-per-pixel resolution of the imaging system; this image is undersampled and some of the stars are square.  It was an amazing night.  Seeing was nearly as good while I shot NGC 5585, posted below, with the CLS filter; to an extent, the Hα filter takes best advantage of good seeing.

Arp 117 (IC 983 & 982) & Arp 79 (April 2018)

I've always been fascinated by these galaxies.  They are out of my league for "pretty picture" imaging because my skies are not the best.  I think the dimmest spiral arm of IC983, the huge spiral galaxy on the left, is almost dimmer than my local skyglow.  Still, a guy can observe.

The thing is, these galaxies are amazing.  IC 983 and the smaller spiral IC 982 appear to me to be interacting.  Two of IC 983's spiral arms appear bent toward the smaller spiral.  In a way, these remind me of M51 and NGC 5195, which is Arp 85.  But whereas M51 is small, perhaps 50,000 light years across, IC 983 is huge, perhaps 400,000 light years across!  M51 is a mere 25 million light years away, but IC 983 is ten times further—254,000,000 light years away! Yet IC 983 still dominates the view in this image (taken with the exact same setup used to image M51 earlier this year; you can see how massive IC 983 must be!).

One thing that always intrigued me about IC 983 and Arp 79, the small spiral on the right, was that in most images I have seen, their spiral arms are bent at seemingly impossible, nearly 90-degree angles.  This seemed odd to me; how could gravity cause that?  Yet in my fairly deep and detailed image (equal to the most detailed images I've seen of these galaxies), the spiral arms of both galaxies look pretty normal, their angles normally curved.  I've decided that prior images suffer from lack of depth or over-processing.  I am happy to see this mystery ended.

This image is 28x720", taken over three nights (because these galaxies set behind a tree after three hours).  The camera was the SXVF-H9, and the scope was the CFF 290 Classical Cassegrain at f/8.1.

The best color images I've seen of this set are here and here.  The second of these is quite detailed.  Both are worth a look.

NGC 5585 (May 2018)

NGC 5585 is a satellite of M101, supposedly.  It lies at about the same distance, ~20-24 million light years, and not very far from M101 in the sky.  In this image, I can clearly see a spiral structure and a brightening at the galaxy's core.  The galaxy's image gives the impression of busy-ness, as if star clusters are popping up all over it.  As galaxies go, NGC 5585 is fairly small, probably only around 35,000 light years across.

In fact, the whole frame is busy and shows a wide distance scale.  The bright star above left of the galaxy is HD238342, 680 light years away and magnitude 9.43.  The bright star on the far right, magnitude 8.85, is HD 125918 and is 5,100 light years away.

Beyond NGC 5585 are many more distant galaxies. Some of these are nearly 2 billion light years away.  They must be enormous and very bright.

This image is 22x720" with the SXVF-H9 through an Astronomik CLS filter, a Baader MPCC, and the ONTC-Synta Newtonian at f/4.95.

M56 (May 2018)

M56 is a globular cluster visible in the constellation Lyra.  It is 32,900 light years or so away from us.  It appears to be traveling opposite the direction of most things in the galaxy, orbiting roughly backwards around the center.  Probably it was ripped off a small galaxy that was swallowed billions of years ago by the Milky Way.

This is just a monochrome image.  I enjoy imaging globs so that I can compare them with each other, so I have several of these taken with the same telescope and camera setup.  Then I can see their relative sizes and how many stars I can make visible.  For instance, compare M56 with NGC 7006 and M13.

This image is 10x720" with the SXVF-H9 through the CFF 290 Classical Cassegrain and an Astronomik CLS filter.

NGC 4565 (April 2018)

NGC 4565 appears in the constellation Coma Berenices but is around 44 million light years away.  It is a very large spiral galaxy, which we see nearly edge-on.  It is famous for the dust lane and how its thin shape seems to taper away to nothing at the ends, which are actually extended spiral arms.

The galaxy in the upper left is NGC 4565A and is perhaps 3 million light years closer than 4565.  The piece of fluff directly below the center of 4565 but about level with the lower tip of 4565's left end is IC 3571, perhaps 20 million light years further away.  Other little galaxies in the image shine from hundreds of millions of light years' distance.

This image is 69x480", about 9.2 hours, through the ONTC-Synta Newtonian at f/4.95, with the SXVF-H9C camera and an Astronomik CLS filter.