What are these Variable Nebulae? They are reflection nebulae associated with Young Stellar Objects (YSOs) that have yet to arrive on the Main Sequence (of the Hertzsprung-Russell Diagram). The nebulae themselves show true changes in brightness, shape, or position on observable timescales. They are invariably found on the edge of Dark Molecular Clouds in our Milky Way Galaxy and there are probably many, but very few are observable at optical wavelengths as others are likely to be seen in the infrared. To date, just seven are known, with a handful of other suspects, but more may be discovered now instrumental techniques have become so sophisticated. The current objects are shown in the table below.

Of these, all but the Corona Australis nebula can be observed from the UK and are increasingly popular targets for amateurs as they do something on short time scales!

Clicking on the ‘Common Name’ in the above table takes you to a page giving further information on the variable nebula. If you do image variable nebulae please email the VNe Coordinator ( vne@britastro.org ) copies of your images (preferably calibrated FITS) as soon as you reasonably can after imaging, so they can put into the VNe archives. This is not just an academic exercise for they are then available to members doing research on VNe. It will also greatly assist compilation of the triennial report on VNe the first of which was published in the December 2024 Journal. Although images can be picked up from the BAA Gallery it would become a ‘turn-off’ to other members if every image we took of VNe was posted onto the gallery. Hence please copy your VNe images to the VNe Coordinator who maintains the archive.

Also, the more often we can image VNe the better since when changes happen they can sometimes evolve over periods much shorter than a month. If observers VNe images are ‘hidden’ in their own systems (and not in the archive) it makes analysis of changes less easy and maybe less likely.”