Long period variable or supernova?

[sculptor]

My colleague Mark Trudgett took the attached (very cropped) image of IC5152 (Indus dwarf) last night (10" Newtonian, Orion Starshoot pro, 16 mins), and noticed a new star (arrowed) which is not for example on my recent shot from 31 Jun 08 (Celestron C-11, STL-11000M, 60 mins), the DSS2 image on WikiSky, or in David Malin's AAT shot.

Please have a look through your library and let us know if this is an old friend (and therefore a foreground long period deep variable), a cruel artifact, or just possibly perhaps a supernova.

Mike BJ

[MasterMaster]

Thanks for putting this up for me Mike!
I seem to be fully registered and functional now - so I can add my apologies for the terrible image (taken 2008-08-24T11:43:59' /YYYY-MM-DDThh:mm:ss observation start AEST) - you can blame persistent cloud for that one! With any luck the cloud will disperse for long enough to allow a better image tonight.

[ngcles]

Hi Mike,

Hmmm ...

The image really isn't much chop and it is therefore difficult to draw any firm conclusions. My suspicion is that it is an artifact of some sort. The few other star images in the picture are trailed (elongated) in roughly the same PA as the mystery object is from the super-bright star, so my first thought is that it is likely non-existant.

One would expect it to be a little brighter if it were an extragalactic supernova (maybe about mag 11.5???) given the proximity of this galaxy. The star above the super-bright one near the top of the frame is GSC 8444:1155 at mag 13.5 (+/-0.4) and it seems as bright if not brighter than the alleged interloper.

Have you checked for asteroids?

There is no _known_ Milky Way variable star at the position.

Time to take another image me-thinks ...


Best,

Les D

[MasterMaster]

Yes, Les and Mike - inexplicable as it seems it must have een some sort of artifiact. Things were agains it in the first place: shooting through cloud is no fun - even this follow-up was through thin stratus but at least shows that there is nothing at all untoward in this region!

Thnaks for the thoughts - and the momentary exceitement!

Mark.

[Merlin66]

I tend to agree, it looks like a double image. Maybe a gust of wind, glitch in the drive; in the bad ol' days we'd regularly see similar bloopers caused by "nose bump" during guiding.