Category: Astrophotography

Peering into the dark with a camera

The Lagoon in Hydrogen-Alpha

With summer upon us the central core of the Milky Way galaxy dominates the late evening sky. This allows an astrophotographer a rich selection of targets well placed for shooting all night long.

Among these targets are the large emission nebulae… M17, M16, NGC4628, NGC6334, NGC6357, SH 2-54, and a long list of others. The brightest among these nebulae is M8, the Lagoon nebula, a rich and complex region of star formation, sweeps of gas, and dark globules.

With a new hydrogen-alpha filter added to the camera’s filter wheel it is time to re-image some of these old favorites. The filter is a narrow-band filter allowing through a slice of the spectrum only a few nano-meters wide. The filter pass-band is centered on 656nm deep in the red, the glow of neutral hydrogen gas, this allows sharp images of these glowing nebulae complexes.

M8, The Lagoon Nebula taken in H-alpha light at 656nm
M8, The Lagoon Nebula taken in H-alpha light at 656nm

Another Night, Another Supernova

Supernova 2020jfo in M61 is not the only supernova occurring at the moment. Actually there are over sixty supernova in progress at the moment that we know of. The modern transient search programs locate them by the dozens, and while the average large galaxy might have one supernova a century, there are an enormous number of galaxies we can observe while monitoring for those great explosions.

Currently the brightest supernova is 2020hvf at magnitude 12.4 hosted by galaxy NGC3643 in Leo. Unlike the pretty face-on spiral of M61, this small 14th magnitude galaxy is completely outshone by the supernova. Looking at the image one is struck by the realization that for a week or two that one star is outshining the combined light of the hundreds of billions of other stars that make up an entire galaxy.

NGC3643 with supernova SN2020hvf on the evening of Mar 15, 2020
NGC3643 with supernova SN2020hvf on the evening of Mar 15, 2020

M61 with a Supernova

M61 has been particularly bountiful when it comes to exploding stars. This should not be a huge surprise as M61 is also experiencing rapid star formation. With a lot of new stars around some of the largest stars will die early and die big.

Early this month the Zwicky Transient Facility noted a new supernova in M61, now cataloged as SN2020jfo. This explosion is now visible at 14.7 magnitude and can be seen by modest amateur telescope of at least 8-10 inches aperture.

Eight supernovae have now been observed in M61: SN 2020jfo, SN 2014dt, SN 2008in, SN 2006ov, SN 1999gn, SN 1964F, SN 1961I, and SN 1926A, an unusual number for any galaxy. In contrast our Milky Way galaxy last experienced a supernova in 1604.

Between shooting other targets I stopped by M61 last night to take a few exposures of the galaxy and see this supernova for myself.

NGC4303 - M61 with supernova SN2020jfo on the evening of Mar 14, 2020
NGC4303 – M61 with supernova SN2020jfo on the evening of Mar 14, 2020

Markarians’s Chain

Shot photos from the driveway again last night. Several hours shooing at the heart of the Virgo cluster and Markarian’s Chain.

I was shooting color data, but clouds rolled through the field before I got any blue data. Will have to shoot again another evening. In the meantime I put together a monochrome version.

The two big elliptical galaxies towards the lower right are M84 and M86. In the center is an interacting spiral galaxy NGC4438, notably distorted through interaction with NGC4435 seen right above it. The big elliptical at lower left is M87.

Do not try to count the number of galaxies here, zoom in and dozens upon dozens become visible.

The heart of the Virgo Cluster around Markarian's Chain.
The heart of the Virgo Cluster around Markarian’s Chain.

Astrophotography from the Driveway

A clear night finally appeared, clouds have been plaguing this particular dark of the Moon. What to do? Maybe do some astrophotography?

The nebula complex M17 in hydrogen-alpha
The nebula complex M17 in hydrogen-alpha

I have a new piece of kit, a ZWO ASI Air Pro that has been on back-order since November. With shutdowns in China and the rest of the mayhem it finally arrived this week.

The unit is a little dedicated astrophotography computer that makes a lot of the setup so much easier, while simplifying the snarl of cables on the telescope.

Controlling the camera, filter wheel, and guiding is done through a very nice app on the iPad. In less than an hour I had the basics figured out and was taking images.

A few technical issues to learn about through the night, such as how to best configure the WiFi for use with the home network, how to access and download the images to the desktop computer, etc., but no real problems. I took images through until dawn’s glow appeared in the data, running from twilight to twilight.

Comet C/2018 W2 Africano

A modest comet is currently crossing the evening sky, at about 8th magnitude C/2018 W2 Africano can be appreciated in small telescopes. Last week I decided to add it to the target list for a few images.

The many images are registered on the comet during processing. Each image showing the motion of the comet as it moves fairly quickly among the stars in the hour or so the camera was taking frames. Thus the stars become multicolored streaks in this combined image…

Comet C/2018 W2 Africano taken on the evening of Sept, 24th, 2019 as it passed through Pegasus
Comet C/2018 W2 Africano taken on the evening of Sept, 24th, 2019 as it passed through Pegasus

Pleiades in Color

OK, I have color. Getting there, but not quite happy with the result. This is my first attempt at LLRGB layering to assemble the color and luminance data.

Too much noise and structural information is coming through with the color data. I had to use a lot of noise reduction in final processing.

Some odd rectangular structure around bright stars that might be coming from the microlenses of the CMOS sensor. This shows in the color data, but not so much the luminance.

Still have some learning to do…

The Pleiades, color image through LRGB filters
The Pleiades, color image through LRGB filters

Pleiades

As I get back into astrophotography I am starting to conquer the little issues that make huge differences in the results.

I did get a nice session in last week, with several targets imaged. I am still struggling with processing LRGB color data and have some learning ahead of me. In the meantime the monochrome luminance images look pretty good.

I had hoped to get some more telescope time in tonight, the weather decided otherwise. May as well process photos while I listen to rain on the roof.

The Pleiades anyone?

The Pleiades in monochrome
The Pleiades in monochrome

A First Attempt

Just getting back into astrophotography after quite a few years of observing visually. A new camera, updated software, it seems like I am learning all over again.

For a first run I processed a monochrome image of M31, the Andromeda Galaxy. A quick run of fourteen luminance frames, 8 at 5 minutes, 6 at 60 seconds combined into a single frame.

M31 or the Andromeda Galaxy, with M110 visible above and M32 visible below the core
M31 or the Andromeda Galaxy, with M110 visible above and M32 visible below the core

I have color data for this image, but that will be a lot more processing. Given all of the various filters and calibration frames I really need to get the automated batch processing running before I do much color work.