Category: Astronomy

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).

Saturday night was a good night at the River Ridge Observatory. It was cold, very cold, but it was clear and there was no wind. The Moon was just past first quarter so it limited what could be done until after 1 AM. I shot five objects but only the last two turned out okay.

The first object is the California Nebula, an emission nebula in the constellation of Perseus. It is quite large, about five times the size of the Moon on one axis and won’t fit in the field of view of my system. Perseus is in the northeast sky after dark next to the brighter crooked W of Cassiopeia.

The second object is the Rosette Nebula in the constellation of Monoceros and is also an emission nebula. It is a bit smaller and does fit in the field of view of my system. Monoceros is a dim constellation east of Orion which currently rises several hours after sunset.

Both are primarily reddish in the because the excited Hydrogen that causes them to glow is firmly in the red part of the spectrum. I’ve shot both before but these are object to return to again and again.