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Faint fuzzy in a random AP shot (near NGC5954)

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#1 steven_usa

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Posted 25 July 2016 - 08:55 PM

Attached is a recent "random" image I took earlier in July 2016.   I have a lot of light pollution and heat-noise to deal with (being a DSLR, not a cooled CCD; sensor temps were near 28degC).   But in my integrated image, I noticed a little fuzzy that didn't look like a typical integration left-over.  

 

So I converted the plate solved RA/DEC degrees into DMS, and found the same spot in WWT, then enabled the Deep Sky Survery imagery.  Rotating that image to match my own, it appears there really may be some kind of object at the same location (as highlighted in the attached image).

 

WTT has no classification at the location of the "fuzzy".    If anyone has other astro-sources to compare with (or maybe have larger or better equipment to collect an image at), the location is near:

RA center: 233.089 degrees

DEC center: 15.589 degrees

or

'15h 32m 21.36s +15d35m20.4s'   (July 2 2016, 1am CST)

 

get.jpg

 

Thanks, clear skies!

Steve

 

EDIT: I don't know what the read dots are across the center of DSS image below and right (I assume a kind of seam between two images stitches together)

 

EDIT: Halfway between the bright star and the faint-fuzzy point at, looks like there might be another smaller faint-fuzzy.   The brightest star in the frame is mag 8.4, so pretty much everything else is over Mag 13.

Attached Thumbnails

  • RANDOM3.jpg

Edited by steven_usa, 25 July 2016 - 09:04 PM.


#2 Jim Davis

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Posted 25 July 2016 - 10:05 PM

Maybe a comet?



#3 GlennLeDrew

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Posted 25 July 2016 - 10:10 PM

Be wary of ghost reflections from bright stars!



#4 steven_usa

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Posted 25 July 2016 - 10:58 PM

Hadn't considered a comet, hmm.    As for reflections, it's possible -- I'm familiar with reflections caused by the moon and misaligned optics (e.g. filters or the sensor itself not being perfectly perpendicular to the rest of the imaging chain).  But I wouldn't think the DSS would have an identical reflection.



#5 Rick J

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Posted 25 July 2016 - 11:02 PM

Your coordinates are somewhat off in RA.  Once corrected to j2000 coordinates from a plate solve I get its location as 15h31m39.038s +15d35m29.99s.  That is the position of the galaxy CGCG 107-001 aka PGC 055308 among other catalog names. 

 

NED easily turned it up once I had the correct coordinates.  Also The Sky plotted it when I looked around HD 138557.

 

Edit: The problem with the DSS image you used is that it tries to make a color image from red and blue plates.  If a satellite flies through one color it will be that color in the image.  Also since conditions vary color rendition of these images is highly unreliable.  I don't use that source for these reasons.  Better, for me at least is http://stdatu.stsci....i-bin/dss_form/ where you can see the red and blue as separate images as well as near IR images.

 

The coordinates for the other galaxy are 15h32m01.486s +15d37m18.69s  You can look those up at NED.  They show it about 350 to 360 million light-years distant.  Their redshift for CHCG 107-001 indicates it is relatively near by but the value calculated is quite wrong though I'm sure the redshift value is correct.  Problem is nearby galaxies (out to 30 to 60 million light-years) are so close their own motion through space is far greater than cosmological redshift.  In fact some really 60 million light-years away show a blue shift.  So I'd consider the distance to it to be undetermined but likely less than 50 million light-years.  If someone makes tip of the red giant measurements then it may be pinned down a bit better.

 

Rick


Edited by Rick J, 25 July 2016 - 11:28 PM.

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#6 steven_usa

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Posted 26 July 2016 - 12:18 AM

Thanks! I concur, I see it on TheSkyX now (PGC 55308), approximately mag 15.94

And thanks for the DSS info and link; I looked up PGC 55308.  I had to rotate the GIF they provided to better match my own image.     Neat stuff !

 

EDIT: Why does "Date" in TheSkyX say 7/10/2016 ?  Is that when its data was last updated?  (just 8 days after my image data was collected!)


Edited by steven_usa, 26 July 2016 - 12:27 AM.


#7 Rick J

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Posted 26 July 2016 - 01:00 AM

Because that's where you set the date and time in The Sky.  When you shut the program it asks to save.  If you say yes it saves the time and date and that's where it will open next time it is opened.  One reason I almost never let it save.  Click the clock box in the date box and it will jump to the current date and time assuming your computer's clock is correct.  Now save it and as long as you don't save again it will always open using the computer's clock.  Under Tools>Options you can uncheck the prompt to save box.  That should cure the problem.  But remember to save this time or that setting is lost.

 

I almost always orient my images north up then I always match POSS and Sloan files.  Makes finding objects in a plate solved image easier too.

 

Rick


Edited by Rick J, 26 July 2016 - 01:01 AM.


#8 tchandler

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Posted 26 July 2016 - 06:42 AM

Is it real or imaginary? Your post brought to mind something I recently came upon on.

 

While scanning the very detailed Tri-Atlas B and C this past week, my finger fell upon an object with an odd name: Baxendell's Unphotographable Nebula in Aquarius, a 1/2 degree N of Messier 2.

 

There are only a few records of visual observations of this object, including one by Dreyer, but it has never been photographed; many consider it to be a reflection of M2. But it begs the question why are there not similar ghost objects near other globulars, including the several that are brighter than M2? 

 

Perhaps you might check any images of M2 that you may have ??



#9 GlennLeDrew

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Posted 26 July 2016 - 09:24 AM

This is an old name, probably assigned something like a century ago (or at least quite a few decades.) Any object which can be seen can most certainly be imaged. Indeed, for DSO fuzzies the camera beats the eye handily.

 

A ghost image of a star or bright DSO would not be expected to be seen always in the same place on the sky. Simply moving the scope virtually always has and ghost reflections present wandering about.



#10 steven_usa

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Posted 26 July 2016 - 09:37 AM

Thanks again RickJ, that makes a lot more sense for the date time  (since the data shown would be relative to that time).

 

In TheSkyX Serious is it possible to insert your own imagery?  Does it get scaled/oriented appropriately by using some kind of plate solver, or is it done manually?  I've tried looking up notes for this online, and I see "My Chart Elements" and "Add Graphic" but it seems to only let me select SVG files. 

 

 

 

@tchandler:   I see Baxendell's NGC7088 referenced in TheSkyX, and read up on how it came about to be cataloged and reported on sporadically from ~1880-1930.  I suspect there would be "odd" things that happen just at the boundary of what we can "see".  For instance, imagine a supernova that started very far away, and just became visible (to our equipment) at its extreme brightness for a relatively short amount of time (even just 50 years) -- but in that duration, maybe it illuminated some dust that we couldn't otherwise see.   OR, it could be an M2 reflection as suggested, reflected on some stellar dust that happened to be passing at that time (obviously relative: had passed and became sufficiently illuminated for us to observe eons later) -- gas/dust in space do "flow" and move, but of course extremely slowly from our perspective.   OR, again a supernova that just happened to be completely surrounded by dense gas/dust (at least along our line of sight), so we just see a slight illumination for a brief time.  IRIS NGC7203 fascinates me for this reason, since you have a clearly visible star that illuminates these layers of gas or dust  (I say "clearly visible" -- maybe it should be "apparently visible" since it could actually be something else causing the illumination, but from our line of sight it looks so perfectly as if a little light bulb was deliberately set up inside that nebula with a clear window for us to see it).    Anyhow, those are just my speculations on NGC7088 -- maybe higher band equipment could confirm if there is actually any dust/gas in that area.

 

 

 

EDIT: And yes, anything that can be visually "seen" can be photographed (and CCD/CMOS sensors are much more sensitive than our eyes) -- the issue is more about timing, and having any imaging equipment setup at a time of the night/season that is in position/configuration (aligned, etc) to make the photograph.  So I can see what they mean by "unphotographable" -- not to be taken literally.  It was just that by the time anyone had a camera and equipment set up to take the shot, the object that used to be visually seen was now gone.   And yes, with so many cloud nights, I can see this really happening even over 50 years.

 

 

 

Here is a comparison of my very faint PGC55308 versus DSS ("inverted" from the normal north-up, which I refer to the stars on the left side as the Giraffe and the Arrow). 

get.jpg


Edited by steven_usa, 26 July 2016 - 09:40 AM.


#11 steven_usa

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Posted 26 July 2016 - 09:55 AM

To clarify GlennLeDrew (for those maybe not familiar with digital astrophotography), there may be a couple different types of reflections being spoken about here.     One type of reflection is light bouncing off gases or dust that naturally occur in space.    Another type of reflection is internal to the telescope itself, along the imaging chain -- bright objects (like Vega, Arcturus, Solaris -- the most brightest stars, or the moon even just half full) can make these reflections more obvious, as they reflect off the extensions and possibly mis-attached filters and equipment.   

 

"mis-attached" isn't quite a fair term -- as the telescope pivots/rotates, gravity naturally pulls the camera in different ways.  Higher end equipment would have this equipment securely threaded together, but most cases (myself included) thumb screws are involved for practicality, which are kind of an "art" and guess to get them secured evenly and correctly.  Even with the best of effort, those screws and the overall equipment and subject to temperature changes (maybe making one screw slightly more loose than others).   With the magnification involved, it doesn't take much "shift" to cause or move an internal reflection.

 

Baffles and other techniques try to reduce these reflections, but they can only work to a certain extent.   Even in the DSS imagery you might see halos around stars, which are another example of a reflection.  Some of that is just an unfortunate side effect of a "long exposure" (to extract out details further in the background, at the cost of over-exposing a bright star).

 

Then on top of that, you have dust either on the sensor or on the mirror, that can cause all kinds of weird effects -- "scattering" of the light.   "Dithering" (small shifts in the frame being imaged) can help identify these kind of internal reflections (they just "move" differently but consistently -- unless it's a moth or insect!).   Here is my (animated) example of internal dust/debris (of the telescope) causing a star to "twinkle" during one of my images:  (it is moving because of dithering, but "twinkles" only when the bright star hits certain spots of the sensor -- the dust could be on the sensor itself, on a filter before the sensor, or even on the mirror of the scope).

get.jpg

 

"Flats" are used to clean up a lot of image defects caused by internal dirt/debris.  You can compare areas on a flat that you expect to have some defect with the integrate image, but if there are "smudged" on the image that don't appear on the Flat, then odds are it's a target of some sort.

 

But for the deep space reflections, more observation over time is needed.


Edited by steven_usa, 26 July 2016 - 10:05 AM.


#12 steven_usa

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Posted 26 July 2016 - 10:20 AM

Centering on what TheSkyX gives for NGC7088 (Baxendell's Nebula)

21h 33m 22.022s

-00deg 23' 00.0000"

 

In the DSS imagery that RickJ mentioned -- I do see M2 in a larger 60x60 arcsec view.   But try a 2x2 arcsec view; hard to say if anything was ever there (separate from the remaining visible stars still there).   Plus don't think that stellar gases/dust flow like clouds here on earth, it can take centuries to notice them moving.    I still think the possibility of a far off/faint supernova could have been a possibility (or the tail end of a nova visible around 1900), which maybe just ended/finished (became non-visible) before anyone could get a camera towards it (on a clear night for any meaningful duration).




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