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Can you identify this bright spec ?

 
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I clicked a picture today. It has 4 tiny dots and one large one. Can anyone name what the largest one is ?

Hint, the 4 dots are:
Lo
Callisto
Ganymede
and Europa
4-Specs-of-light.jpg
[Thumbnail for 4-Specs-of-light.jpg]
 
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salvin francis wrote:Lo


I think you mean Io.

I recognized the large dot from the thumbnail before I opened the topic. I have been looking at the sky a lot lately.
 
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Stephan van Hulst wrote:... I think you mean Io.

I stand corrected   . I am a newbie in this domain.
 
salvin francis
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Hint to anyone else trying to guess: Fattest Neighbor !
 
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It's a bit too easy with the hint
 
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Saturn?
 
salvin francis
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Campbell Ritchie wrote:Saturn?

More Fatter !
 
salvin francis
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Campbell Ritchie wrote:Saturn?

speaking of Saturn, I tried my best to capture it. Was hoping to see rings, but it's very faint and all I could get was an out of focus "blob". My camera is not up to it.
DSCN5571-01.jpeg
Out of focus Saturn
Out of focus Saturn
 
Campbell Ritchie
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salvin francis wrote:. . . More Fatter !

I never knew you could overfeed planets.
 
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Those of us who sing would of course identify it as Thaxted.
 
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salvin francis wrote:Was hoping to see rings, but it's very faint and all I could get was an out of focus "blob". My camera is not up to it.


You need a telephoto lens and a tripod. The motion of the earth itself is enough to make the image blurry, so you need short exposure time.
 
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Doesn't work. I have tried it. You need a rotating mount as used for telescopes, aligned with the earth's rotation, otherwise the image will be smeared by the earth's rotation. There is a name for that sort of mount, something like azimuthal mount, but I am not sure. You can't use short exposures because the object photographed will be too faint to appear.
 
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Actually, it's "speck". "spec" is short for "specification". But in reality, the moons are specks. The Bringer of Jollity is a definite disk. Or maybe disc. I think both spellings work in astronomy (unlike hard drives and DVDs).

You can see Saturn's rings with even a small telescope, assuming that they are tilted. When Saturn's aligns with the Earth's orbit and you're looking at the edge and not across them, then they're to thin to easily see.

I've seen some really incredible amateur astronomy pictures lately. Stuff that you'd have expected to come from one of the big observatories or Hubble. They use filters to mask out light pollution, cooled units to reduce thermal noise and very long exposures to capture the most amount of light. And, of course, motor-driven telescope mounts, because when I say "long" I mean 24 hours or so, which means multiple nights where the telescope is kept aimed at the target while the Earth rotates underneath it. And finally, extensive computer post-processing to further reduce noise, screen out passing airplanes and satellites, and add false color to make features stand out.

It's really quite impressive and while not inexpensive, not something that requires a massive fortune to do.
 
salvin francis
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Campbell Ritchie wrote:... identify it as Thaxted.

Now, that's a very steep hint towards what it is. Our silent guardian and protector: Jupiter !!

Stephan van Hulst wrote:... The motion of the earth itself is enough to make the image blurry, so you need short exposure time.

Noted, I'll try that next time I venture out

Tim Holloway wrote:... When Saturn's aligns with the Earth's orbit and you're looking at the edge and not across them, then they're to thin to easily see.

Interesting point, I'll check some online websites to see what was the alignment on the 4th of August.

Tim Holloway wrote:I've seen some really incredible amateur astronomy pictures lately.

Do point me to any sources, I would love to see them. I don't want to invest in any gear yet, maybe looking at some great pictures might inspire me to do so.
 
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Campbell Ritchie wrote:Doesn't work. I have tried it. You need a rotating mount as used for telescopes, aligned with the earth's rotation, otherwise the image will be smeared by the earth's rotation. There is a name for that sort of mount, something like azimuthal mount, but I am not sure. You can't use short exposures because the object photographed will be too faint to appear.



It does work, but it's not a single shot.

What you do is take several shots, using shorter exposures than you would think (about a 5th of a second for Saturn, much less for Jupiter).
There's software to handle overlaying the best of these to get rather nice piccies.
 
Tim Holloway
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There are 3 two types of telescope mountings. One is pretty much unique to Celestron, I think, where the bottom of the scope is just a big ball and it rotates in a socket. These are very portable units.

More serious mountings are the alt-azimuth, where "alt" is short for altitude, and equatorial.

Alt-azimuth is the simpler/cheaper approach and it's used on some surprisingly large scopes. Often the assembly resembles a cannon in its gun-carriage. The size of the scope can offset the fact that you can't do long exposures. Alt-azimuth is also standard for terrestrial telesope stands, which are typically just camera-style tripods.

Equatorial mounts are best for star tracking over longer periods. Wherease alt-azimuth's motions are up/down and left-right, an Equatorial mount is tilted. In fact, it is tilted to an angle corresponding to the latitude it's being used in. Thus, as the stars rotate, the telescope only has to move in one direction in the other (declination).

Equatorial mounts are more troublesome because you have to have counterweights to balance the scope, whereas with proper location of the fulcrum, an alt-azimuth scope can be more or less self-balancing.

Today, however, we have computerized tracking which can use a cheap SBC like a Raspberry Pi to drive a pair of motors on alt-azimuth equipment and track nearly as well as an equatorial mount scope would.

Oh yes, here's a great pace to find astro-porn: https://www.reddit.com/r/Astronomy/ They also generally discuss their setups, so double-bonus there.
 
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salvin francis wrote:. . . that's a very steep hint towards what it is. . . . Jupiter !! . . .

Kudos for recognising the alternative name Gussie called him the Bringer of Jollity, as Tim H said, using the astrological meanings of the planets rather than the Roman gods with a similar name.
 
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I must have been thinking about an equatorial mount, if it needs to be aligned with the earth's axis.
 
Tim Holloway
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"Gussie" is Gustav Holst, for those who thought my reference was obscure.
 
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The piece was first performed by Sir Adrian Boult, whom I heard at a concert back in 1977.
 
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Campbell Ritchie wrote:Those of us who sing would of course identify it as Thaxted.



I didn't know that part of "Jupiter" had a name. It was the tune we used to set our walking pace when we walked from Leckhampton to Painswick a few years ago and found ourselves on the Gustav Holst Way.
 
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salvin francis wrote:

Tim Holloway wrote:I've seen some really incredible amateur astronomy pictures lately.

Do point me to any sources, I would love to see them. I don't want to invest in any gear yet, maybe looking at some great pictures might inspire me to do so.



For example the home page in my browser: Astronomy Picture of the Day.
 
salvin francis
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Paul Clapham wrote:... Astronomy Picture of the Day.

The pics on that site are lovely. I think they have a new one everyday. It shows "The Pipe Nebula" to me today and says "Tomorrow's picture: Somewhat Saturn" ... Let's see how it turns out to be ...  

Thanks for sharing that !
 
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