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Moon interference with DSO viewing

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#1 PlanetNamek

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Posted 05 December 2020 - 12:19 AM

If I am trying to look at a DSO that is completely opposite of the moon, how much does it really effect the view? I honestly can't tell if it does.



#2 Sky_LO

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Posted 05 December 2020 - 01:20 AM

The answer is it depends on the type of dso and on the observing conditions.  

If the transparency is bad (less transparent) the moon lights up the whole upper atmosphere and washes out the views.

Open clusters are less affected by the moon.   


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#3 TOMDEY

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Posted 05 December 2020 - 03:11 AM

The classic old wisdom was that DSOs are best viewed when the moon is at least a few degrees below the horizon. That was back in the days when most observers suffered very little to almost no light pollution; enjoying what we would call good/great dark skies. Now-a-days terrible light pollution contaminates so much real estate that younger observers tend to take that as ~normal~, so the moon doesn't seem the brilliant beacon that it actually/still is. To enjoy what people did back in the 1950s and especially earlier... you need to get to a dark site when the moon is not in the sky at all. Only then and there will the "Deep Sky Objects" be seen as intended. Anything else is a terrible compromise.

 

Filters and other measures help... but nothing approaching what truly dark skies provide. Sad, but true. Reality has a way of asserting itself, even when we would like to ignore the white elephant in the room.    Tom


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#4 MellonLake

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Posted 05 December 2020 - 08:08 AM

My experience from very Dark skies is that the moon overpowers everything.  At Bortle 2 when the moon is not up, the milky way is magnificent.  At the full moon, the milky way is nearly invisible.  The moon has the same impact (or worse) on DSOs, especially galaxies and nebulae which, except for a few, not visible with the moon up.   One night I found about 70 galaxies in the constellation Virgo.  I would not find any of those galaxies had the moon been up.  The moon makes a huge difference.  


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#5 spereira

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Posted 05 December 2020 - 08:38 AM

Moving to DSO.

 

smp



#6 Sky_LO

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Posted 05 December 2020 - 11:53 AM

My experience from very Dark skies is that the moon overpowers everything.  At Bortle 2 when the moon is not up, the milky way is magnificent.  At the full moon, the milky way is nearly invisible.  The moon has the same impact (or worse) on DSOs, especially galaxies and nebulae which, except for a few, not visible with the moon up.   One night I found about 70 galaxies in the constellation Virgo.  I would not find any of those galaxies had the moon been up.  The moon makes a huge difference.  

+1 Agree, the Moon affects everything negatively.  I rarely do full moon observing, it is just not worth it. 

 

I will do 50% moon or less. 

 

I did a full moon light pollution shoot out with all three of my telescopes.   The views in all three were compromised, from the 6 inch to the 13 inch.    The larger aperture was better under a full moon, but still very compromised. 

 

-Lauren  


Edited by Sky_LO, 05 December 2020 - 12:09 PM.


#7 PlanetNamek

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Posted 05 December 2020 - 03:34 PM

Thank you all for helping with my question. I guess that definitely explains why I am not able to see some DSO's that I should be able to see with my 6 inch even though it's far from the moon. @Sky_LO I didn't know that the moon actually washes everything out with it's brightness no matter where it is and I found that interesting if not a little bit of a *DUH!* I should have known that moment.



#8 Keith Rivich

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Posted 05 December 2020 - 05:08 PM

If I am trying to look at a DSO that is completely opposite of the moon, how much does it really effect the view? I honestly can't tell if it does.

I'm not sure what you mean by "opposite the moon". I interpret that as opposite the moon in the sky which would mean there is no moon in the sky when you are trying to observe the DSO. Which is good!



#9 TOMDEY

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Posted 05 December 2020 - 06:03 PM

I'm not sure what you mean by "opposite the moon". I interpret that as opposite the moon in the sky which would mean there is no moon in the sky when you are trying to observe the DSO. Which is good!

I'm sure PlanetNamek was not being a geometric literalist, but meant that the full moon was up, but far from what he was trying to look at with the telescope.


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#10 Sheol

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Posted 05 December 2020 - 07:10 PM

             I'm pretty sure he met on the opposite side of the sky. If its full, only very few objects are not impacted negatively. I'll only do DSO if Luna is below the horizon or is at quarter phase or less. And that is at the opposite side of the sky. You simply cannot keep dark adaptation with Luna in the sky. I try at least to block it with my house or a grove of trees, or whatever is handy as a barricade.

 

 

                          Clear Skies,

                                Matt.


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#11 Love Cowboy

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Posted 05 December 2020 - 09:55 PM

yeah DSO observing should be done with the moon absent.  When the moon is up, observe the planets, or double stars, or most obviously, the moon itself!


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#12 Tony Flanders

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Posted 06 December 2020 - 09:17 AM

If you are observing from the middle of a city with streetlights all around you, then the Moon might not make a significant difference when it's on the opposite side of the sky from your target.


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#13 Jeff Morgan

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Posted 06 December 2020 - 01:56 PM

yeah DSO observing should be done with the moon absent.  When the moon is up, observe the planets, or double stars, or most obviously, the moon itself!

 

When the moon is up, I focus on the non-astronomy pursuits in my life. Helps the social calendar and smooths the tensions with the gf.

 

And more importantly, it helps clear the schedule for those moonless nights grin.gif


Edited by Jeff Morgan, 06 December 2020 - 01:57 PM.


#14 Love Cowboy

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Posted 06 December 2020 - 03:04 PM

When the moon is up, I focus on the non-astronomy pursuits in my life. Helps the social calendar and smooths the tensions with the gf.

And more importantly, it helps clear the schedule for those moonless nights grin.gif

I mostly do the same, but I provided those suggestions for those lucky enough to be able to observe whenever they like

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#15 Sheol

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Posted 06 December 2020 - 07:37 PM

               Fortunately or is that unfortunately, no gf around to worry about here. But I definitely get caught up on reading & television watching when the Moon is up & bright.It does have its uses. LOL. There are times, esp. with my 8 inch, that I have followed Luna quite a way through its cycle. Always interesting. I'm assuming with the 12 inch, it will be too bright for my eyes, at least.

 

     Clear Skies,

      Matt. 




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