Category: Postcard from the Universe

A Starry Dawn over Mauna Loa

A photograph of serendipity.

The photograph was planned… Somewhat. I knew there were some picturesque trees on the lava field along Saddle road. The plan was to shoot one of these trees silhouetted against the Milky Way and Mauna Loa. That was the plan. At least until the plan met reality.

Shot as planned the results were less than stellar. Actually they were rather boring. The rising summer Milky Way was spectacular, nothing else worked. The enormous bulk of Mauna Loa became a bump on the horizon from the low angle with the 14mm lens. The trees did not look like much against the dark.

Serendipity intervened… First a passing car lit the trees with dramatic results. Car headlights caught the trees at just the right angle to light up the right bits, a lucky bit of geometry and road alignment. Looking at the image on my screen I was intrigued… I repositioned the camera and shot again when another vehicle passed… This was working!

As I waited for other passing cars the shots deteriorated, odd glows across the frame. Were the headlights catching the big dome of glass at the front of the lens? Blocking the light from the headlights on the camera did not help. I pull out a flashlight to check the camera… Ack! The lens was fogging up!

Retrieving the anti-dew kit and a battery from the vehicle I secured a dew strap around the camera lens. At this point I wanted the shot and was willing to work for it. I was lucky again… I had thrown the dew gear in the car as a last moment afterthought.

It took time for the lens to warm and clear. As I waited dawn crept into the sky. I took a last few shots as the light increased and the stars faded. The dawn light added a nice shade of blue to the sky with a hint of peach to one side, another serendipitous bit that added to the photo. A last wisp of fog on the lens was just enough to create halos around Mars and the brighter stars.

Not a bad result! With a little skill and more than a little luck. The shot has been entered in the Hawai’i Photo Expo. Hopefully the jurors think the shot is as good as I think it is.

Milky Way Dawn over Mauna Loa
The rising summer Milky Way, Mars and dawn over Mauna Loa

Postcard from the Universe – Pleiades

The Pleiades were not my primary target for the night, but that was setting and I was in no hurry to shut the gear down when there was a lot of dark remaining in the night. I glanced around the sky looking for a target appropriate for the field of view of the gear and just chanced to look at the star cluster.

Perfect…

Pleiades
The Pleiades, M45, a sum of 26 x 100s luminance frames and 5 x 100s RGB images assembled as an LRGB image, ST2K and 80mm APO

Postcard from the Universe – Rosette Revisited

For my first pass on the Rosette I used about an hour of data. Ten four minute exposures, ten one minute exposures and ten 15 second exposures. The stack is designed to capture a wide dynamic range by using several different exposure lengths. Multiple images taken at each exposure to reduce the noise inherent in long exposure astrophotgraphy. All of this data is aligned and stacked to produce the final image.

The Rosette Nebula
The first pass at the Rosette nebula with one hour of data, 10x240s+10x60s+10x15s @ISO6400
When looking at the result it was apparent that I had not been successful in reducing the noise far enough. More exposure time was needed. The shorter exposures were not the problem, I needed more of the longer four minute exposures to reach the faint nebulosity.

The next night I acquired and shot again, another 24 exposures on the Rosette, another 1.6 hours of exposure. A planned astrophoto outing to the MKVIS at 9,200ft elevation offered a chance to get even more high quality exposures. This time I got 30 more exposures, another two hours of total exposure time.

Combining all 3.8 hours of exposure resulted in a notably nicer image. The noise in the fainter sections of the image is pleasantly reduced. It should be with 54 four minute exposures used.

I need to do some sort of systematic comparison of the data gathered in my driveway versus the data obtained at the MKVIS up on the mountain. Having a series of exposures taken with the same gear, on the same target, and at the same time of night just a few days apart should allow a reasonable comparison. I was unable to expose any longer at the VIS despite the colder temperatures (the camera was about 10°C colder). How much better is the VIS? Can I get data nearly as good without packing up the gear and heading up the mountain?

The Rosette Nebula
The Rosette Nebula, NGC2237, NGC2238, NGC2244, NGC2246, Canon 6D and TV-76mm, 54x240s+10x60s+10x15s @ISO6400

Postcard from the Universe – The Rosette

A result from Saturday night. About an hour of integration all told… Good color, very nice stars, good detail. While encouraging, I really need more time on this one, there is too much noise in the fainter regions of the nebula. I can get more data and add it to the stack to continue to improve the result. From up on the mountain I should be able to use longer exposures with darker skies. Colder conditions will reduce the dark current in the camera, also aiding in longer exposures.

Rosette Subframe
A single unprocessed subframe of the Rosette Nebula, Canon 6D and TV-76mm, 240s @ ISO6400
Compare the processed shot with the single subframe I published yesterday. The final shot is a stack of 10 x 4min, 10 x 1min, and 10 x 15s frames, 30 frames for just under an hour of exposure. Also needed is another 10 x 240s dark frames and 10 flat field frames to use for calibration. This takes another hour, but was done after the telescope was rolled back into the garage and I went to bed.

The Rosette Nebula is a large star forming region just east of Orion in the constellation of Monocerus. It is quite large, the main body seen in the photograph is well over a degree across. The dark region in the center is about the size of the Full Moon

The Rosette Nebula
The Rosette Nebula, NGC2237, NGC2238, NGC2244, NGC2246, Canon 6D and TV-76mm, 10x240s+10x60s+10x15s @ISO6400

Postcard from the Universe – M82 with SN2014J

The brightest nearby supernova in may years is currently visible in the bright galaxy M82. I did want to photograph the supernova before it fades much more. It apparently reached a maximum brightness of magnitude 10.5 a few days ago and is starting to dim. But has so far only slid a few tenths of a magnitude.

So I tried to photograph a supernova, and Murphy came to visit.

The last week has seen me dealing with a sinus infection, which combined with terrible weather has kept me from setting up in the driveway for photography. Taking advantage of a few clear hours last night I did make an attempt. Things continued to go wrong.

A high thin haze would not go away, lit up by the light of a bright quarter moon it created high background and gradients in the imagery that would not calibrate out. I forgot to install the LPS filter, meaning that the low pressure sodium lighting of the village compounded the moonlight in creating a poor signal to noise and bad gradients. The autoguider would not behave. This was eventually solved by adjusting the tuning parameters in PHD guide. Not before ruining most of my exposures, I ended up throwing out 24 of 32 exposures. When I did get everything figured out and corrected, and the Moon had fianlly set, the clouds rolled back in.

The final eight usable exposures did result in a somewhat acceptable final product. It could have been so much better…

M81 & M82 with SN2014J
The galaxies M81 & M82 with SN2014J seen in the disk M82 at top