Category: Astrophotography

Saturday night was a good night at the River Ridge Observatory. First we had a meeting, via Zoom, of the Central Arkansas Astronomical Society, then the three of us who came to the RRO to image after did just that. About this time last year I learned of this nebula and managed to get a middling image of it. Next year, I said.

This is a total of 4.5 hours of data shot with an 11″ SCT at f/1.9 (with Hyperstar) and an IDAS NBZ UHS dual narrow band filter. The filter lets the red of Hydrogen Alpha and the blue/green of Oxygen III through but not much else. The nebula is a bubble of gas being pushed out by the bright star near the center, a so-called Wolf-Rayet star. The reddish glow outside the bubble is hydrogen gas lightly glowing. The nebula itself is about the apparent size of the Moon but is estimated to be 60 light years in diameter and 5,000 light years away.

Stacked with Deep Sky Stacker. Processed with Photoshop. I used a trial of StarXTerminator to separate the nebula from the stars. Starnet++ is free but this product is much easier and faster. The stars and nebula were processed separately then recombined.

Here is a link to last year’s image.

It was a cold night at the River Ridge Observatory last night. It was 25F when I left at 10:30. But there was no wind and no humidity, just a soul sucking cold that wanted to kill me.

I started with the California Nebula in Perseus which I intended to shoot with my dual narrowband IDAS NBZ UHS filter but apparently I can’t read or had the filters in the wrong cases and shot it with my broadband IDAS LPS D3 filter. The intended filter would have brought out the red better and blocked most everything else. The NBZ filter is for nebulae that glow on their own, the LPS is for nebulae that reflect light from nearby stars.

Then I moved to the Witch Head Nebula in Eridanus which I did intend to shoot with the broadband filter so I was all set. This picture is actually upside down but it doesn’t look like a face that way. It is lit up by the star Rigel just to its left from out point of view and both are about 900 light years away.

Wednesday night was a good night at the River Ridge Observatory, at least until the Moon rose. I got there right at 5pm and set up my scope. It was dark enough by 6 to have finished the alignment and focus stuff. One target was the bright Comet Leonard but that was too low in the trees to try to image so I had to settle for viewing it in 100mm binoculars. It was very distinct and well formed. It looked like, well, a comet with a distinct green aspect that they often do.Once that was done, I switched to the main event – trying out my new IDAS NBZ dual narrowband filter. This filter is designed to allow only two narrow bands (hence the classification) of light through, the bands of light that emission nebulae tend to emit. This line of filters is designed specifically with fast systems like my f/1.9 11″ Hyperstar system. I picked the Western Veil Nebula in Cygnus which is getting low in the western sky at sunset and will soon go behind the Sun and return in the morning sky.The Veil Nebula is a large but dim supernova remnant that extends about three degrees (6 times the size of the Moon) in the sky. This is one section of it. To do it all with this setup, I would need to do a mosaic of probably six tiles. The bottom part of the nebula is also called The Witch’s Broom Nebula. The red tones you see come from the Hydrogen Alpha emission line and the blue-green from the Oxygen III emission lines (two of them).