As some of you know, I have joined in a project with the University of Kent which uses amateur astroimaging data to find young outbursting stars by monitoring star brightness:
http://astro.kent.ac.uk/~df/hoyscaps/index.html
4 areas of sky have been selected for initial study but I've decided to concentrate on one - NGC2264
As a by-product I've now acquired 5 hours of data in 3 sessions since mid December and I've just done a quick pre-process of the data to create an image. I think it shows potential. In early Spring, when I've stopped acquiring data (at least for this Winter) I'll do a proper processing run.
(http://www.markshelley.co.uk/Astronomy/2015/cone_workinprogress.jpg)
Mark
This is brilliant Mark.
Here's an animation showing some of the variable stars flashing like beacons. Ignore the groups of flashing green pixels - that's clearly the result of a new hot pixel that I now need to add to my hot pixel map.
(http://www.markshelley.co.uk/Astronomy/2015/NGC2264_animation.gif)
One star in particular, slightly down and left of centre dims and disappears entirely! I've looked that one up - it's in the catalogue of variable stars as "GCVS OP Mon" and it varies from mag 15.4 to dimmer than mag 19. Obviously, as demonstrated here, it can happen over a period of one month.
Imagine the chaos if our sun did the same!!
The colours are washed out in the picture because I used logarithmic scaling to show the relative brightness of stars better. You know what I'm going to say next ;)
Logarithmic scaling (like Photoshop curves) changes the R:G:B ratios and hence washes out the colour.
Mark
Excellent scientific work Mark. Really like the animation. The whole image will be stunning when you finished your processing.
John
Good work Mark.
What's that green irregularly shaped thing that flashes in for a short while by the bright star to the left? I'm presuming this is space junk.
Also as a side question, what format do you use for your animations Mark and how do you upload them?
Carole
Carol. ..
QuoteIgnore the groups of flashing green pixels - that's clearly the result of a new hot pixel that I now need to add to my hot pixel map.
The green "object" is a collection of green hot pixels. I should have stated that the 3 frames were imaged on 19Dec, 28Dec and 16Jan.
As for animations, for just a few frames I use animated GIF - the Animation Shop in PaintShopPro creates these. For longer videos more compression is required so I use VirtualDub and choose one of the available Codecs. I think some people use a Movie Maker download for Windows Media but I've never experimented with that.
I find uploading them to be a real pain because I get the video looking just as I want it and then YouTube/Vimeo compress it to death. So now I store in in DropBox and publish the link. The link again shows a video compressed to death but it does give the option to download the original and play it back on your own machine in the original full quality.
Mark
Mark am I right in believing I can see at least 4 variables in that animation ?
I can see 5 obvious ones and then a few more less obvious ones.
Am I imagining things or is that dark cloud of gas on the right moving to the right?
Bottom left star with spikes. Two stars to the left of it. The left most one seems to also be moving.
Quote from: Mike
Am I imagining things or is that dark cloud of gas on the right moving to the right?
Bottom left star with spikes. Two stars to the left of it. The left most one seems to also be moving.
I think it's just the noisy background playing tricks on the imagination!
I wasn't in last night so wasn't able to do any imaging until I got back late. So I did a bit more of NGC2264 and have added another frame to the variable star animation. It covers a larger area with many more variables.
http://www.markshelley.co.uk/Astronomy/2015/NGC2264_animationv2.gif
Mark
Look at this thing here (in the animation of course). It is definitely moving.
(http://i.imgur.com/dbTvNIQ.jpg)
More good work Mark. I think I spotted about 8 variables.
QuoteLook at this thing here (in the animation of course). It is definitely moving.
I agree. Could it be a binary system where the stars are orbiting each other? It's doing a wiggle.
Carole
Quote from: Mike
Look at this thing here (in the animation of course). It is definitely moving.
How interesting! You're right - its apparent position is definitely shifting. I wonder what's going on?
Mark
It's definitely a star - I've identified it here:
http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Cl*+NGC+2264+LBM+205&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id (http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Cl*+NGC+2264+LBM+205&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id)
I wonder if it is relatively nearby so we are seeing parallax? However, I can't work out how to find its distance in the database.
Mark
QuoteI wonder if it is relatively nearby so we are seeing parallax?
Nope.
The closest star Proxima centauri has a paralax of 0.76 arc seconds, but thats over the distance of twice our orbit radius( 186 AU),
so for that object to offer paralax over such a short distance it will have to be very very close to us.
You said that the animation was over a period of one month, so roughly speaking that gives us a base line of 186/6 which is 31 AU = 4637534001 ~ 4600000000km (I Know its not exact due to the orbit being circular and i've taken it as a straight line averaged out over the 6 months that it takes to go from one side of the orbit to the other.)
Looking at your image it's 718 pixels wide and assuming that the object has moved say 4~5 pixels (hard to correctly measure from the animation)
The image is 31.5 x 35 arc mins which gives a pixel scale of 2.63 arcsecs / pixel.
So the object has moved between 10 & 13 arc secs in 1 month so that object is either very very very close, or probably a very very fast moving binary (more then lightly) or a slow moving asteroid.
Assuming it is parallax it would give us an angle over the 6 months maximum movement of say 10~13 * 6 ~ 60 ~ 78 average of say 70. arc secs
Extrapolating.
d(pc (parsec)) = 1/p(arc sec)
d = 1/70
= 1/70 * 3.26 ly (1 parsec)
= 0.046 ly
= 0.046 * 9.46 x 10E13 km
= 4.3x10E12 Km
pluto is 7.5x10E9 km
Or in laymans terms. Pluto is 4 light hours away. This object is (8760(hours in a year) * 0.046) 402 light hours away or 100 times further.
BY JOVE I DO BELIEVE MR (LUCKY) SHELLY HAS FINALLY DISCOVERED THE MISSING PLANET SAID TO BE ORBITING BEYOND PLUTO. ;)
Still worth perusing though to see if it is a binary star or a slow moving asteroid.
Mac.
'kin hell Mac think you deserve another Astro degree for that response.... :-)