Supernova in Whirlpool Galaxy?

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ravnostic

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Last Monday I was up all night using my new cable for my Canon DSLR to take long exposure sky shots. I took a 4 minute exposure (telescope is an 11 inch Schmidt Cass) of the Whirlpool Galaxy. In the 10 oclock position, there's a star that seems to be in the Hubble shot, but its far far brighter than in the Hubble, while other stars/nebula seem comparable. Is it a supernova of the brightish star in the Hubble shot? I can't rationalize it to be anything else.
 
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amshak

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I cant say about that . But if You taken any picture You could Compare it and see. You can Send that picture. Did You Saw any other Bright or Dull Pacth or Some Object right next to it?
 
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SpaceTas

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I looked at the IAU Circulars http://www.cfa.harvard.edu/iauc/RecentIAUCs.html and the astronomers telegrams http://www.astronomerstelegram.org/[/url ]which lists all announcements of discoveries. There is no item for a supernova in recent days/weeks. Since the Whirlpool (M51 NGC 5194) is a favorite target I'd be surprised if a supernova would not have been reported by now. I just checked the archive for the LCOGT [url]http://lcogt.net/en/search/archive which runs 2 2m telescopes for schools and amateur astronomers. There are many images taken this month. That star is in them all, with no obvious change in brightness.

The position does seem to correspond to the star in the Hubble image and LCOGT. This is a very luminous and blue star, probably variable as well. Especially for very hot (blue) or for very cool (red) stars, the colour sensitivity of the camera can make a big difference in hour bright a star appears as compared to other stars in the field. This is my best guess of what you have found.
 
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ravnostic

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I do see it in those other images, too. Odd how Hubble's shot has it so much dimmer; it seems pretty consistantly bright going back a year at the website's pics you directed me to. Thanks for the info, though! Learn something new every day...
 
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MeteorWayne

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ravnostic":16ukyyd6 said:
I do see it in those other images, too. Odd how Hubble's shot has it so much dimmer; it seems pretty consistantly bright going back a year at the website's pics you directed me to. Thanks for the info, though! Learn something new every day...
That's why we are here, to learn and share :)

Welcome to Space.com

Wayne
 
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Fallingstar1971

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Also......

The star in question is trailing with all the others while the galaxy is not.

I believe this is because the stars are closer and the scope is tracking the more distant galaxy.

This would put the star in question between us and said galaxy, hense the common trails.

Also

Hubble has much greater resolution than your scope, as impressive as it is. Combine this with a two-shot (one shot focused on galaxy, one shot focused on foreground stars, and then combine them into one picture). The difference in brightness is because while the galaxy is in perfect focus, the stars are not. They are slightly off-focus, which could give the illusion that something is bigger/brighter than it really is.

Combine that with the trailing effect and now you have a huge white blob where there should be a much smaller one.

So.......

AWESOME equipment. Do the two shot technique I described, then stack them into one photo. I hope to see more work posted as you perfect your techniques

Star
 
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MeteorWayne

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The focus is the same for the galaxy and the stars, photogographically. They are all at infinity from earth. There's no difference in focus for a telecope and a camera for a star at 4.3 light years or a galaxy at 2 billion ly.
 
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ravnostic

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Regardless of focal length, I have much further to go in my astrophotography. I'm currently using an alt-az mount, which accounts for the star trails. I'm hoping (if, cross my fingers, overtime at work holds up) to get the wedge mount which will allow for polar alignment.

Meanwhile, I've ordered a f/6.3 reducer lens, which will take in 80 seconds the shot I took in 240, albeit with a wider field of view (the image as is is cropped, though). My hope is with the shorter exposures I can minimize the trails. Any suggestions for freeware stacking software? The one I have was recommended, but doesn't acknowledge things like planets or galaxies; it's pretty much a star-stacker (and thus far, a piss-poor one, at that.)
 
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SpaceTas

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Fallingstar.
Any star and any galaxy (or the Moon) are both so far away there will be no difference in trailing or focus. In both situations stars and galaxies can be taken as being at infinity.

The focus effect does show up when objects are close by: several times the focal length of the telescope. HST uses the same focus for planets, stars and galaxies.

When I looked at the image, the trailing was one thing I looked at. The galaxy and star have the same trailing (look at the faint red "stars" which are really gas clouds in M51). A satellite or maybe a close by asteroid might have had different trails.

Extra:
As to why the HST images of stars may look out of focus compared to the galaxy; here's my explanation.
Even with a telescope with perfect optics will not produce points for star images. The images are slightly enlarged by diffraction. This size gets smaller with telescope size (better resolution). Now brighter stars have larger spots on a CCD image (HST) because you are able to detecting further out into the wings of the image. A drawing would help; but I don't have handy drawing package.

Imaging a side on view of mountains of exactly the same shape (rounded top, steep slope, then a gentle slope to the base is the real shape, but use similar triangles) rising out of a flat plain. The level of the plain is the black background, and the height of each mountain represents the brightness of the star. Now draw a line above the plain (dark level). This is the level of the sky brightness (even from space there is some sky brightness; zodiacal light ...). Now you'll see that the brighter stars *higher mountains) have a wider width than fainter stars at the sky background level.

So brighter stars look bigger on CCD and photographic images. It's a crude way of measuring brightness; and is what is used by your eye-brain to say one star looks brighter than another.
 
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