Historic nova

[jambouk]

Whilst looking for other things online I found an image of M27 from 1888 (https://www.repository.cam.ac.uk/handle/1810/225959). I'd seen some time lapse images of M1 over the years, but wondered how M27 compared from 1888 to modern day. I lined up a modern day image to compare the two and noticed one star was present in 1888 but not in modern times.  I've made a gif of the area, and the star in question just is at the outer extent of the main body of nebula, a little below the centre of the gif. I wonder if it is artifact from the 1888 image or represents a transient event at that time?

James

 

 

[michael.h.f.wilkinson]

Given that it is slightly elongated, I wonder if it is an asteroid, which moved during the duration of the exposure time (which must have been long, given the photographic emulsions available at the time)

[DHEB]

This looks very interesting and promising. Something worth checking against a literature search, in case it is already known by professionals. Think that you might have found something cool! In any case as amateurs, it is surely worth the exercise and the learning. Good luck!

[JeremyS]

Hello James,

To me it looks different from the other stellar images in the photo. Also it's elongated in a different direction from the others. I suspect an artefact. Interesting, though.

BTW, a few years back I thought for a moment I had found a nova in a CCD image I had taken - the star was present on a Palomar plate, but much fainter. On further investigation it turns out it was a red star that appeared brighter to the CCD because it is more sensitive to red light.

Jeremy

[jambouk]

Thanks for the replies.

I hadn't even entertained that it could be something in our solar system, but an asteroid is an excellent idea.

I also agree with Jeremy about it looking "different"; and I was fully expecting it to probably turn out to be articact. 

James

 

[wimvb]

Not just a different shape as compared to the stars, the object also seems to have a much sharper edge than the stars. This is clearer in the larger original photographs in your link.

[jambouk]

Well it's not there and no sign of it circa 1910 using this image [http://astro.uchicago.edu/AstroChicago123/presentations/kron-richard.pdf] from the Mount Wilson 60" (though I'm uncertain of the date).

 

[JeremyS]

Hello James,

if you are checking archival images of M27, perhaps you can keep an eye out for V498 Vulpeculae (see AAVSO chart, it's indicated by the circle and cross). This is a dwarf nova with very infrequent outbursts - the last (and possibly the only one recorded) was in 2005. We don't know how often it goes into outburst - stars of a similar type are typically every 5 to 30 years (or more!)

There are some comparison star magnitudes indicated. E.g. 89 is mag 8.9, 161 is mag 16.1 etc.

Jeremy

 

[jambouk]

Jeremy, is there an archive somewhere of old astrophotographs? I'm struggling to find others from the 1880s/1890s.

James

 

 

[JeremyS]

James, many of the observatories have archives, but not many on line. One of the best is HCO (Harvard College Observatory) - I think that may be online, or at least getting there. They are bound to have photos from that period as they ran a photographic patrol to discover new variable stars for decades. Have a look here: http://tdc-www.harvard.edu/plates/

 

Sonneborg obsy did the same.

Jeremy