Ha Imaging of the Crescent and Eastern Veil Nebulas

I have only tried Ha imaging once, and I was immediately discouraged by out-of-focus stars, long exposures, and complete absence of the DSOs I was trying to image. However, an individual on a Yahoo Group I frequent tried it with the same imager I have, and his results were really good.

I decided to give it another try. I fired up the Mallincam DSm, equipped it with the 7nm Ha filter and mounted it on the 8 inch f/4 astrograph. I found that the Ha focus was a lot different from the white light focus--and the exposure was much longer--around 3x the white light integration. The images here are stacks of around 15 images captured with 30-second integrations. I'm pleased with them as they show much more detail than the white light images of the same objects.

The Crescent Nebula in Hydrogen Alpha Light

Detail on the Crescent Nebula really popped compared to the white light image (below); the nebula is faintly visible, compared to the delicate structures revealed in Ha.

The next target was the Eastern Veil, which is much too extensive for most imaging systems to capture in a single exposure, so this image is just a part of it. I have never been able to image the Veil in white light, so I was very pleased by even this rather faint, smoky, ephemeral image.

AR2672--changes over one hour

The great things about H-alpha imaging or observing is that you can see significant changes over short periods of time. Here are four images captured today of AR2671 over a one hour period. Looking at these images is a little like looking at those images in magazines where you have to find all the differences. The differences are subtle at first, but the more you look, the more you see.

The Ring Nebula with Digital Binning

The new digital binning feature in the MallincamSky software adds significant new functionality to all the DS series cameras. Binning allows you to combine individual pixels into groups, so that they function as if they were larger, more sensitive pixels. Binning can decrease both noise and integration time, but at the cost of resolution. The most impressive part of this feature is that it enables binning on CMOS-based cameras. The DS16C is 16-megapixel camera, so even with 2x2 binning, it still has very high resolution.

Here is an image of the Ring Nebula taken with the f/4 newt and binned DS16C. I set a low gain (5) and the image is a stack of 5 x 10-second integrations with a mild histogram stretch. Noise is quite low--a little bit of amp glow is visible at the top and bottom edges of the image, but overall, it is very decent. The zoomed crop (the DS16C has a huge FOV with the newt) shows that resolution is not terribly badly affected by the binning process.

The Astrometry.net analysis of this image is interesting:

IC 1296 is just visible. It is a faint, face-on barred spiral of Mag 15.5--about the same magnitude as the central star of the ring. If you zoom the image, you can just see the spiral structure of the galaxy.

Total Eclipse!

The Eclipse Starts!

We traveled to Nashville, TN where my daughter lives (and saved the $1000 per night the hotels wanted for Eclipse weekend) and set up in her parking lot. I packed my white light solar grab n'go observatory--ST80 scope, iOptron EQPro mount, and DS16C imager. The DS16C has a very large imaging chip and gave a huge FOV with the ST80.

Crescent Shadows

I took single images as we waited for totality. The sky was about 50% clouded, which created some anxiety! At T minus 5, a dense cloud drifted across the sun, but it passed by with 2 minutes to Totality. As the Diamond Ring appeared, I put the scope into movie mode.

The movie was captured at 3 FPS using the native resolution of the DS16C, which is  4640 x 3506 in the .SER format (file size was 45G).  All the single images in this post were taken from this movie. I also did a 1080p AVI conversion.

Totality!!

The 1600 or so frames in the original movie cover the 1 minute 55 seconds or so of totality. Played back at 60FPS, the movie lasts 27 seconds. I also played with the exposure during capture to try (not very successfully) to capture coronal details. At the end of the movie, I place the solar filter back on the scope and the growing crescent of sun can be seen.

Here are some more stills from the movie:

A Quiet Corona--typical of a solar minimum

The End!

We also saw shadow bands! Ephemeral and difficult to see (many veteran eclipse watchers have never seen them) shadow bands occur just before totality and can also be seen as the sun emerges from eclipse. we were lucky enough to see them at both points, but this movie was taken in the moments before totality. The phenomenon lasts only a few seconds, but I had my phone out and grabbed 4 seconds of the faint ripples as they moved across the parking lot. The bands are much more visible in the original movie; the Youtube conversion seems to have removed some of the detail, but full screen will show the ripples a little better.

Link: https://www.youtube.com/watch?v=VBULvbggRqk

All-in all, it was an amazing--and all too short--experience. Totality lasted 1 minute 55 seconds. It was my first total eclipse and I'm now an addict. Roll on 2024!

Postscript:  I checked the records for my home weather station on eclipse day, and at maximum eclipse here in Indiana (where the eclipse was not total), the station recorded a drop in temperature. Whether it was just a coincidence, I am not sure, but here is the data:

The eclipse was 90% at 2:22 pm local time.

AR2672 and AR2671 -- White Light and Ha

It's nice to see some activity on the sun--especially after this week's eclipse (I will have a longer post on that later)!

AR2672 and AR2671 have a slight chance (around 15%) of producing M-Class flares. None were visible in Ha when I took the image. Here is the white light image, taken with my 90mm Mak and DS2.3+. AR2672 is towards the center of the disk, AR2671 is at the edge. All images were processed in Autostakkert with wavelets in Registax 6.

Here is the Ha image, which shows some interesting detail around AR2672, as well as some dark, filamentary material. The uneven illumination is due to the etalons in the PST-DS:

The Lagoon, Eagle, Trifid, and Omega Nebulas 8/12/2017

Last night, I had the honor of doing a public outreach stargazing event for Niches Land Trust. The location was a beautiful dark sky site about 20 minutes out of town.

I took my f/4 newt, ZEQ25 mount, and Mallincam 16C with me, plus my projector to show large, colorful images of DSOs to the attendees. The only issue was that the location demanded the use of a generator, which always makes me nervous!  However, my little 1800W genny did the job very well for about 3 hours until the event ended.

With a public event, being able to capture images quickly is paramount. The binning mode of the DS16C enables rapid capture of DSOs with good resolution. Below are some of the images I captured. These are all 10-second integrations and are stacks of 10-15 images (except for the Trifid, which is a stack of just 5 images). Gain--and hence noise and amp glow--was high (20), but the images were fine for public consumption. Apart from a couple of histogram adjustments, these images are pretty much as captured with no dark field subtraction to reduce noise or amp glow.

For comparison, I've included a straight, unprocessed, raw capture (the second image below). It is interesting as the single image seems to show more detail (albeit with more noise) than the stack!

As a bonus, we also got to see some very bright Perseids with a rate of about one per minute!

Lagoon Nebula

Here is the single 10-second integration as captured:

and here is an enhanced version run though Corel Paint Shop Pro:

Eagle Nebula

Omega Nebula

Trifid Nebula

A Celestial Crescent--Imaged 8-8-2017

I have never been able to image the Crescent Nebula; even under dark skies, the nebula did not show in any of my images. Last night, I hooked my Mallincam DS16C to my f/4 Newt astrograph and turned on a new feature--digital binning. Of course, there's nothing new about binning, but, up to now, that capability did not extend to CMOS-based imagers like the DS16C.

This addition adds huge sensitivity to an imager like the DS16C. At 2x2 binning, I was able to image the crescent at gain 15 with a 15-second integration, with a full moon in the sky close by and with no filtration!  Here is a processed stack of  50 images:

A single, raw integration shows how sensitive the binned imager is:

The Crescent is an emission nebula--it is the result of a shock wave from a Wolf-Rayet star (a rare, massive, and highly luminous star) slamming into a slower moving wind produced by the star when it became a red giant, more than a quarter of a million years ago. The star is WR136 or HD192163. In this astrometry.net analysis of the image, the star is shown towards the bottom of the crescent (the labels of the star and the NGC designation unfortunately over write each other).

AR2670--A Shadow of its Former Self 8/8/17

AR2670 continues to decay as it moves across the solar disk. It now has a stable magnetic field, which means it is unlikely to produce any flares. The plages around the spot are also fading as the whole area settles down. I also took and H-Alpha image, but it shows even less detail of this image and I have not posted it. In a few days, I suspect we will be looking at a featureless disk again as the sun moves into a deep minimum.

AR2670 (formerly AR2665) in White Light and H-Alpha

AR2670 continues to decay. The white light image shows the spot and associated plages quite well, but the H-alpha image is rather disappointing, except for the interesting bright ring around the spot (which was faintly visible to the eye, but which imaging and processing brought out more prominently.

White light images were taken with a 90mm MAK and solar filter, H-alpha with a PST-DS. The imager was a Mallincam DS2.3+ . Both H-alpha and white light images are stacks of 100 frames from 200-frame .ser files, stacked and processed in Registax.

White light image

H-alpha image

Xterminator II Elongated Stars Fixed!

I was able to try out Rock Mallin's suggestions for fixing elongated stars in Xterminator II images. This fix involved setting the camera firmware from the camera itself. However, if I had realized that I could upload firmware settings from the imaging software I was using ( Miloslick), the fix probably would have worked the first time. Here are a few imaging stacks from that imaging session--these are all sub 8-second integrations. Note how deep even short exposures can take you with the Xterminator II, as witnessed in the the M101 Astrometry.net image.

AR2665 Returns (8-2-17)!

AR2665 has returned and is likely to be renamed AR2670. It appears to be significantly decayed from its huge self during its first transit. This image was taken between clouds in poor seeing. Note the plages (bright spots) surrounding AR2665 in this image. Plages are magnetic features in the photosphere associated with sun spots.

Imaged with ETX 90  and Mallicam DS 2.3+. Stacked in autostakkert with wavelets in Registax. 150 of 300 frames stacked.