Hello,

This is a small, faint planetary nebula in the constellation of Cepheus. There are very few images of it, either by amateurs or professionals, probably because it is small and faint!

It was discovered simultaneously (but independently) by amateur astronomers Laurant Ferrero and Matthias Kronberger. At the time the object was only a candidate planetary nebula. It was confirmed as a true planetary nebula by Pascal Le Du in 2016. See A planetary nebula in Cepheus: KnFe 1 ( Fe 2) - Splendors of the deep sky for details. As well as the name KnFe 1, it can also be found as Kn 48 (Kronberger’s catalogue), Fe 2 (Ferrero’s catalogue and its designation in SIMBAD). I have not been able to find any distance measurements for this object.

All processing was done in PixInsight. For the nebula, the narrow band channels have been blended using the NBColourMapper V2.0 script from Mike Cranfield. Ha was coloured hue 0, saturation 1 (basically red); N2 was coloured hue 44.46, saturation 1 (a sort of golden orange) and O3 was coloured hue 197.7, saturation 1 (blue).

Since the O3 signal is by far the strongest, I used linear fit to match the Ha and N2 to that channel then ran BXT on the data at 50% non-stellar sharpening followed by a default NXT. Prior to BXT, I ran the ExtractWaveletLayers script to see what structure might be in the image. This allowed me to check that BXT had not invented what you see in this picture.

After that, STX was used remove the stars so I could process the nebula itself. I kept the resulting star only images to help with processing the RGB data – more on that later. After the stars had been removed it was a case of further stretching and sharpening (using MTL) to help bring out the detail within the nebula.

There are several star-like features (blobs) that lie inside the nebula. Are these structures part of the PNe or stars in the line of sight? To answer that, before STX, I performed an extreme STF to see if any of these blobs would become very bright. If they did then that would argue for them being stars in the line of sight. Only one of the blobs brightened: the small one that lies just inside the inner edge of nebula’s ring at approx. the 3 o’clock position (or north in this image). Neither do any of these blobs, except the one at 3 o’clock show up in the RGB data, further suggesting that these other blobs are knots of gas within the PNe. Having said all that, they could of course be dim stars trying to shine through the nebulosity! The brightest one has a contribution from all three NB images, the others being various combinations of Ha and N2 signal.

The faint lines of gas inside the ring come mainly from O3 and Ha, but they are quite faint compared to the rest of the nebula. The ring that makes up the edge of the nebula is far from smooth, with most of the knotty highlights coming from the N2 signal. But due to the dominance of O3, this ends up as a brighter blue!

In an effort to get better star data (when the Moon was out if the way) I use the ZenithStar 61 (which is mounted on the back of the Edge HD 11) to capture RGB data. In this way I got very nearly 10 hours of RGB data as I simultaneously captured NB data with the Edge HD 11.Binning the NB data gives an image scale of 0.56” per pixel. The ZenithStar with the Uranus C camera has a native image scale of 1.66” per pixel. I drizzled this during processing to bring it down to 0.83” per pixel. This made it possible to match the RGB image to the NB image using the Ha stars only image as a reference. I was fortunate that KnFe 1 is so dim that there was no chance it would be picked up by the ZenithStar so didn’t have to do any tricky stretching to remove it from the RGB image.

I hope you enjoy this little planetary.

Cheers,
Ian