Another great day for solar observing

I did not have the opportunity to image yesterday, when conditions were ideal. Today, with severe storms some hours away, a hazy sky, and breezy conditions, I had the time to get out the PST-DS and Mallincam DS2,3+. Despite the conditions, the sun looked very good indeed when I imaged it, and I managed a 90-minute Night Skies Network broadcast.

There are a number of active areas visible on the sun:

At the top of the sun, is AR2677, an active area that is moving onto the sun's disk. The elongated area toward the center is AR2674, a extended archipelago of spots. The bright, horseshoe shaped area adjacent to it is AR2673, which is crackling with M-Class flares (M1) that are Earth-directed. ARs 2675 and 2676 are at the bottom edge of the disk.

Here is a close up of  ARs 2674 and 2673:

AR2673 is a twisted, magnetic knot: it looks very chaotic. Here is a zoomed-in image of the area:

Despite the loss of resolution, you can see the magnetic tension in the spot. No wonder it is flaring!

The Sun 9/02/17

Clear skies brought an opportunity to image a more active solar disk than we've seen in a while. The PST-DS/Mallincam DS2.3+ combination worked very well, producing some fine views of ARs 2674 and 2673 (the upper part to center of the disk) and AR2675 (the brighter area toward the bottom of the image) and AR2672 (the light area below and to the right of AR2675. AR2674 is growing rapidly and has the potential to release class M flares, which would be earth-directed, due to its position on the sun.

AR2674 and AR2673 Detail

Some prominences were visible on the lower limb of the sun (as observed)--a nice bonus!

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: