Category: Astrophotography

This image is my deepest view so far of M51. About twelve hours total exposure time, but it represents much more telescope time because I’ve discarded many hours worth. The night before last, for example, out of five hours total time I dumped four, because after I went to sleep fog rolled in, and all the exposures were flat gray.

A close crop:

The dark red coloration is consistent with images on the web, so I presume it is a reflection of reality.

How did this happen? What does it mean?

As fate would have it, more light was available last night. Not great, but better.

Here’s the larger view:

NGC6946 is dim. I only had about three hours total exposure; it would be better with twice that. Unfortunately, the weather is sketchy, and I probably won’t be able to collect those photons any time soon.

Stellarium has several fanciful names for NGC6939 — the “Ghost Bush Cluster”, the “Flying Geese Cluster”, and the “Silk Fan Cluster”. I prefer “Silk Fan Cluster”.

This image was cropped to balance the two objects. A closer crop of the galaxy shows lots of potential, but it would take time and good conditions to do it justice:

There’s a delicate hint of pink in the middle of the cluster — it is probably necessary to expand the picture to the max to see it. The pink is undoubtedly an artifact. (However, Wikipedia states that the brightest star in the cluster is a red giant… Could it be the color comes from that star??? Nah.)

The tiny galaxy to the Northeast (by accident, the orientation is roughly correct), NGC6207,  is quite pretty when seen by the Hubble.

I process images using PixInsight, plus GIMP for the final touch-up. The most important single step in the process is called “stretching” — even with long exposures, an unprocessed image is dim to the point of being almost black. Something like:

If you maximize the image and look very closely, you will see a few stars (I count 15) and, in the middle, a faint ghost of M13. (I cheated — this image has actually been stretched slightly — otherwise, there wouldn’t even be a ghost!)

Though big telescopes are fabulously expensive and finicky to set up, the computing power necessary for image processing is readily available to the common nerd like me. And a telescope is not required — for example, the enormous trove of Raw Hubble Data is available online, for free.

Another try. Slightly better processing and a dozen more five-minute exposures added. The tiny fuzzy ball above the whale is a companion dwarf elliptical galaxy, NGC4627. All three galaxies are about the same distance from us, and they interact. Hence the odd shapes.

Reprocessed with yet more data. I don’t know that this is significantly better than my previous results ( here and here and here ). But NGC7023 is a fascinating object, and I will probably return to it for the rest of my life. As always, the images available from Wikipedia are worth a pause.

IC2574 is the faint smudge in the center, 13 million light-years away. A dim dwarf spiral galaxy. According to Wikipedia, approximately 90% of its mass is dark matter.

Taken with a 110mm F/7 refractor. Total exposure time is about 13 hours.

 

Sometimes referred to as “the Sunflower Galaxy”. This image has about 7 hours total exposure time.  It is quite a pretty galaxy — if you zoom in (ie, click on the picture), it looks like a swirl of altocumulus clouds on a spring day.