I'm pretty disappointed with this image. I collected a reasonable amount of data (over 11 hours) in September 2020. When I came to process it in May 2024 I found that almost all the sub-frames have an anomalous bright gradient extending across the top and down both sides. Because the subs were made on both sides of the pier this appears either at the top or the bottom of the image after rotation. Studying the original frames it became clear this was fixed to the sensor or other elements of the optical system and not an external effect like light pollution of something in the observatory.

It varies throughout the data-set and my best guess is that it is dew on the cover of the sensor (which is pretty big, at 36 mm square). It also became clear when checking the individual frames that there was a lot of cloud interference during the data collection – as I was running unguided the system kept on imaging regardless.

In this image, which I have not processed very far as the luminance frames are even more badly affected) I have tried to reduce the impact of the bright gradient, which here appears at the bottom due to the selected reference frame being that way up.

I have seen many excellent examples of this object and will definitely have another attempt when it gets high in the sky again. And the larger field of view of my new camera will help too.

The image is in the 1965 catalogue of Beverly Lynds (Lynds' Bright Nebula, LBN 552). There is an orange refelction nebula just below the centre and an unusual quasi-linear string of stars starting just to the right of centre. The object is part of a large molecular cloud and is located in the Milky Way in the constellation of Cepheus.