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Thread: Leo I

  1. #1
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    Leo I

    Leo I is a dwarf galaxy that's a member of the local group at about 800,000 light years from us. Located just north of Regulus it is a tough object due to all the light from such a bright star. When I took this last year I had severe gradients in red and green rather than problems with Regulus. Seems a cap came off of a camera port letting in light from the red LED on my RoboFocus unit and green light from a USB hub's green LEDs. Until now I couldn't account for them very well. My processing skills are slowly coming up to speed. The image captured 3 quasars and 5 asteroids. Leo I has a large number of carbon stars. In the second image I identified a few of them as well as the asteroids and QSOs. Though I see I left a zero out of the label of the one at the lower right.

    I need to retake this but seeing is critical for this object and I've never had a night this good this low in the sky since so this will have to do for now.

    To meet band width limits I had to compress these severely. For images with better images see:
    http://www.spacebanter.com/attachmen...2&d=1207252690
    http://www.spacebanter.com/attachmen...3&d=1207252690

    14" LX200R, L=7x5', RG=3x5', B=2x5', STL-11000XM, Paramount ME

    Rick
    Attached Images Attached Images

  2. #2
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    Rick it is a good shot all the same (nice to see my birth sign close up)
    Last edited by chrissy; 2008-Apr-04 at 12:20 PM. Reason: ooooooops missed out a bracket !
    The real art of conversation is not only saying the right thing at the right moment but also to leave unsaid the wrong thing at the most tempting moment. -- unknown

  3. #3
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    Quote Originally Posted by RickJ View Post
    Leo I is a dwarf galaxy that's a member of the local group at about 800,000 light years from us. ...
    Leo I is also a Roman Emperor, Armenian King, or a 5th Century Pope (famous for convincing Atilla the Hun not to attack Rome).

    Very nice pictures. The galaxy looks very globular cluster-ish. Is there a firm line between a gravitationally-bound dwarf galaxy and a globular cluster?

    Nick

  4. #4
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    Well done Rick! Leo 1 is supposed to be a real toughie to image. I know its nearly impossible to see through a scope having tried on quite a few occasions.

  5. #5
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    hi Rick,

    these are excellent images!
    crisp and detailed!
    was it difficult to process? Regulus is quite close and I could imagine it might give some "glare" like artefacts which could be difficult to handle...?

  6. #6
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    Quote Originally Posted by stargazer_7000 View Post
    hi Rick,

    these are excellent images!
    crisp and detailed!
    was it difficult to process? Regulus is quite close and I could imagine it might give some "glare" like artefacts which could be difficult to handle...?
    Compared to the gradients from the red and green LEDs Regulus was a minor issue. I did have to try a lot of different framings until I found one such that Regulus didn't hit something reflective in the camera and cause problems. That's why it is decentered somewhat. I had to move Regulus far enough it didn't go through the filters and was blocked by the filter holder yet not hit the edge of the holder and reflect across a filter. Fortunately, the mount tracks without guiding for the 5 minute subs used (longer now with a few tweaks) so I didn't also have to find a guide star as well. I do now have an off axis guider but when this was taken I didn't. Just the on camera guide chip.

    Rick

  7. #7
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    hi Rick,

    congrats again!
    and also to the semi-professional set-up of mount, scope and CCDs!
    5 min without guiding at this focal length is something to be happy with!

  8. #8
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    Very Deep! Rick, Nice details and the stars looks great for such a dim subject. having regulus nearby is a task by itself avoiding lens flares-fantastic welldone and Clear Skies.

  9. #9
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    Quote Originally Posted by stargazer_7000 View Post
    hi Rick,

    congrats again!
    and also to the semi-professional set-up of mount, scope and CCDs!
    5 min without guiding at this focal length is something to be happy with!
    I can now to 10 minutes any place in the sky. 30 up near the pole. So while I now can use that off axis guider for H-alpha, I've never have used it. Sometimes guiding gives me worse stars as I end up chasing seeing. But then I don't have your good seeing very often. Maybe two or three nights a year at high altitude and only one or two times at the declination of Leo I. This shot also required super transparency to avoid glare from Regulus as well. Looking over the lake, that is very rare. Even frozen it sends up quite the haze layer.

    The Paramount makes extremely accurate polar alignment super easy and has so little periodic error that with the 6" f/4 and its 3" of arc pixels I didn't even bother program PEC. Have to with this scope of course as uncorrected it is about +/- 1.4" without it. Still that's better than most mounts with PEC.

    This is the time of year I have the most trouble tracking without guiding. Frost is going out of the ground, and even though the pier's base is well below the frost line it, the frost leaving the ground does move the pier a couple minutes of arc. It goes back to where it belongs once the frost is gone, it's just the two or three weeks that it is leaving I have a problem. That should start any time now. With a pier 16' above ground level that's quite a lever arm! Still I should be able to do 5 minutes during this period. Never a problem while freezing, only in the spring thaw. Snow is keeping things insulated for now but warm ground heat is thawing things from the bottom up this year while the snow prevents thawing from the top. Not sure what that will do, so far nothing. I did a quick T-point run last night to see how the pier was doing and its within 0.1 minute altitude and azimuth for now.

    Forecast is for several more inches of snow this weekend. Typical new moon!

    Rick

  10. #10
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    Quote Originally Posted by Nick Theodorakis View Post

    Very nice pictures. The galaxy looks very globular cluster-ish. Is there a firm line between a gravitationally-bound dwarf galaxy and a globular cluster?

    Nick
    It's thought a few globulars, such as Omega Centauri and M55 for example, were originally dwarf galaxies orbiting ours that had the majority of their stars striped from them after many passages through the disk of our galaxy. Finding evidence for black hole in the center of Omega Centauri that's the correct size for a typical such galaxy is lending support to this theory.

    Globulars though are composed only of very old stars, most are about 10 billion years old, except for a handful of "young" stars thought to have formed out of stellar collision of old stars. This indicates they lost all their dust and gas billions of years ago. Leo I on the other hand still has some dust and gas (very little) and shows evidence for star formation within the last billion years. So is different from a globular in its stellar evolution. Still, both globulars and dwarf galaxies like this one are very metal poor.

    Rick

  11. #11
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    Lovely crisp shot of this not so close neighbor. Thanks also for answering Nick's question as I wondered the same thing as soon as I saw your shot. Great work as always especially in handling Regulus.

    Kind regards
    Matt

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