Supernova remnant IC 443 (Jellyfish nebula) imaged in three different dates: March 17th 2014, March 19th 2014 and March 23th 2014. Narrowband "nearly true" color image obtained through H alpha (red), OIII (green) and H beta (blue) filters. STL11000 camera, FSQ106N scope and ASA DDM85 mount. Each image: 90 minutes exposute (30 min exposure through each filter).

Which is the strange arc-shaped grey "nebula" on the bottom of the image?. Note it has changed in position and somewhat in appearance from March 17th to March 23th. Can it be an imaging artifact?. Note that:

1- The "nebula" appeared at the same position on each of the three filtered images, obtained at different times of the night over more than 90 minutes; so a reflection from a light on the ground is very unlikely to have produced the "nebula".

2- Experts who I have consulted believe that this "nebulosity" was caused by scattered or reflected light from a bright star in the scope optics. David Malin suspects that scattered light from jupiter is the cause of this false nebula as Jupiter is very close to IC 443 in March 2014 and it is a very bright object.

3- To confirm the scattered light hypothesis, I took a 5 minute luminance image on March 30th with a different image center, and the "nebula" appeared again but in a different location (image not shown here). So it is not a true nebula nor comet debris nor any artrophysical phenomena, it is very probably a pseudo-nebula caused by scattered light (from jupiter, very probably)

4- I removed a LPS filter which I had screwed to the 72 mm thread located behind the rear fluorite lens of the FSQ106N scope and shot several H alpha and luminance images on April 3th. The false nebula did not show in any of these images, it completely disappeared. So it is a false nebula caused by the LPS filter scattering or reflecting of jupiter's light