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Trifid Nebula

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#1 Djarum

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Posted 14 August 2014 - 10:19 AM

So I've been doing astronomy for the last 5 years or so. I've had an 8" reflector for the last few years. I recently moved a little north of the city with slightly darker skies. The Lagoon nebula in my 8" shows some slight nebulosity especially around the core. I've never seen any out of the trifid nebula. So last night I decided to take a look from our new backyard. I did see a little more nebulosity with the Lagoon nebula. I still couldn't see any out of the trifid nebula, even with a Baader UHS-C filter. Is this typical for a Red/Orange zone?



#2 Tony Flanders

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Posted 14 August 2014 - 10:47 AM

So I've been doing astronomy for the last 5 years or so. I've had an 8" reflector for the last few years. I recently moved a little north of the city with slightly darker skies. The Lagoon nebula in my 8" shows some slight nebulosity especially around the core. I've never seen any out of the trifid nebula. So last night I decided to take a look from our new backyard. I did see a little more nebulosity with the Lagoon nebula. I still couldn't see any out of the trifid nebula, even with a Baader UHS-C filter. Is this typical for a Red/Orange zone?


The fact that the city lies to your south surely doesn't help; it probably makes your red/orange skies a half zone worse when viewing Sagittarius.

Even so, I'm surprised that you can see only "slight nebulosity" in M8 and none at all in M20. With a filter, under such skies, I would expect M8 to be awash with nebulosity, and visible though faint in M20.

See my descriptions at http://mysite.verizo...46/id20.html#M8.

#3 Jon Isaacs

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Posted 14 August 2014 - 11:37 AM

Looking at the description of the Baader UHC-S, I suspect it's not an aggressive filter like the Orion Ultrablock or other true UHC such as the Lumicon filters.  This is the description:

 

"The Baader UHC-S manages to improve on the contrast of the typical broadband or so-called "Deep Sky" filters. Sky background is darker, and contrast of emission nebulae are noticeably improved. Most other "UHC" filters tend to excessively darken the sky and star fields, leaving the nebulae looking artificial and flat, set against an empty background."

 

To best see the Trifid Nebula from a red zone backyard, you want an aggressive filter that does darken the background sky as much as possible,  The reason filters are effective is that they improve the contrast by blocking unwanted light from the background sky, passing only the background light in the same narrow frequency bands as the nebula.  The darker the background sky, the greater the contrast, the better the nebulae is seen.  The fact that the Baader boasts about not darkening the sky as much as the other filters suggest that it is a poor choice for seeing fainter nebulae from light polluted skies.

 

Jon.. 



#4 youngamateur42

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Posted 14 August 2014 - 12:00 PM

Here's my sketch of M20 through a 4" refractor from my red zone backyard.

Attached File  img023 (1).jpg   32.47KB   3 downloads

I saw not much of anything in M20 for the longest time, even with a 14" reflector, until I went to a truly dark site.  It's much like the Veil Nebula, in that once you see it once, you don't forget and it's much easier to distinguish.  The UHC filter I used in this sketch was a Celestron, so it was not the full force Ultrablock/Lumicon.  I did get a nice view though.

 



#5 kfiscus

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Posted 14 August 2014 - 12:10 PM

What Jon said.  You owe it to yourself to use a good O-III or NPB filter.  You will see dust lanes and details that will take your breath away.

 

P.S.  To rub salt in your LP wounds, at the Nebraska Star Party, we could see COLOR and photo-like detail in the Trifid in my 12".  We saw all of the Trifid's dust lanes (I see 4, not 3).  The pink of the glowing Hydrogen clouds and the light blue of the dust in the reflection nebula next door were obvious to me and a newbie that stopped by to check out my scope.


Edited by kfiscus, 14 August 2014 - 12:13 PM.


#6 Mike G.

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Posted 14 August 2014 - 12:16 PM

Hi,  I live in an orange zone with naked eye limited to 4th mag or less typically.  I also have an 8" reflector and with a 26 mm EP can easily see nebulosity in the trifid and the lagoon is often mesmerizing, especially at higher powers.  usually it looks best without any filters but I have used a Zhumell UHC for marginal improvement.  currently have an NBP on order and waiting to see if I can finally catch a glimpse of the Veil neb!

 

clear skies!



#7 Djarum

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Posted 14 August 2014 - 12:18 PM

I appreciate the responses. Maybe I need to pick up a few other filters.



#8 David Knisely

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Posted 14 August 2014 - 12:42 PM

A good filter to use on emission nebulae is the DGM Optics NPB narrowband nebula filter.  It is a little less expensive than the Lumicon UHC and in some ways performs a hair better.  The Baader UHC-S is a broad-band filter, so it isn't aggressive enough to cut out much of the skyglow, although under darker conditions, it may be somewhat effective on M20.  Good luck and clear skies to you.



#9 Tony Flanders

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Posted 14 August 2014 - 02:52 PM

It occurs to me that poor transparency may be a big part of your problem. I generally don't attempt to view faint fuzzies unless the air is quite clear -- the kind that looks deep blue during the day. That's reasonably common up here in New England, but not so common in the summer in the South.

Also, last night there was essentially no window at all between the end of astronomical twilight and moonrise. Neither twilight nor the Moon is conducive to viewing faint fuzzies!

#10 Djarum

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Posted 14 August 2014 - 03:42 PM

It occurs to me that poor transparency may be a big part of your problem. I generally don't attempt to view faint fuzzies unless the air is quite clear -- the kind that looks deep blue during the day. That's reasonably common up here in New England, but not so common in the summer in the South.

Also, last night there was essentially no window at all between the end of astronomical twilight and moonrise. Neither twilight nor the Moon is conducive to viewing faint fuzzies!

 

One of the reasons I went out last night was we had a high pressure system bring in some northerly air which was cooler in drier. Typical dew points at night have been running in the high 60s. Last night the dew point was in the mid to high 50s. Transparency was the best it had been all summer. All the good faint fuzzies in the summer are hard to see because of light pollution and poor transparency. And since I live in a valley seeing can be terrible too. I was viewing triffid and lagoon nebula righit at 9pm, just before moonrise and about a half hour after sunset.

 

One more note was that the Swan nebula was distinct even with my 10x50s, and looked very nice even without a filter. However, it sits higher above the light polution of the city. Looking straight into Cygnus, I can see the milkyway, but that stops about 45 degrees above the southern Horizon before Sagittarius.I kept telling my significant half we needed to move south of the city, but she wasn't going to have any of it, LOL!



#11 kfiscus

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Posted 14 August 2014 - 08:17 PM

When people ask if buying nebula filters is worth the money (good ones aren't cheap) I reply "How much would you pay for another sky?".  I use my Lumicon O-III and DGM NPB filters all the time on emission nebula.  Wait until you see the Veil, Crescent, Swan, Eagle, Trifid, and Lagoon on some magic summer night through someone's filtered scope- you'll be ordering your own O-III and NPB the next day.  If you have to choose which one, you can't go wrong with either.  They are the perfect 1-2 punch.  Some objects do better with one, some the other.  Most gaseous neb benefit from either.



#12 WesC

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Posted 15 August 2014 - 12:38 AM

From a green zone I can see amazing amounts of nebula detail with my Lumicon UHC filter in the Lagoon N Trifid nebulas. It's one of my favorite targets from a dark site. 



#13 REC

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Posted 15 August 2014 - 07:58 AM

I am in a red zone and was looking at it last night with my 4" Refractor at 60x.  Nice views of the cluster around the nebula that was there, but barely. I put on a minimum effect filter, Baader moon and skyglow and it did reduce some of the greyness in the sky with a little darker FOV.  The nebula with averted vision was better.  Next time I'll try my dedicated nebula filter on it.  BTW...always enjoy seeing those six stars that look like a dice.



#14 areyoukiddingme

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Posted 19 August 2014 - 02:44 PM

I started to doubt that the DGM NPB was much use. But that was from my decidedly poor balcony. Our clubs semi-dark site is probably green zone, and with the NPB the triffid and lagoon are a fantastic sight. Can't wait to try from a blue zone!


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#15 Jon Isaacs

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Posted 20 August 2014 - 11:26 AM

I am in a red zone and was looking at it last night with my 4" Refractor at 60x.  Nice views of the cluster around the nebula that was there, but barely. I put on a minimum effect filter, Baader moon and skyglow and it did reduce some of the greyness in the sky with a little darker FOV.  The nebula with averted vision was better.  Next time I'll try my dedicated nebula filter on it.  BTW...always enjoy seeing those six stars that look like a dice.

 

Remembering this thread, last night,  I took a look at both the Lagoon and the Trifid with my 4 inch F/6 achromat.  From my red zone backyard, I could see nebulosity around the Lagoon, and O-III filter enhanced it and at about 67x I could see most of the main features with the dark bands.  The Trifid was another story. I couldn't really see much without the filter, I could detect the nebulosity with a filter but it didn't look like much more than a faint haze around a bright star.. 

 

Jon



#16 David Knisely

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Posted 20 August 2014 - 04:08 PM

With the Trifid, I generally like using a narrow-band nebula filter like the DGM Optics NPB or Lumicon UHC.  However, from a true dark sky site, I will often just go with a broad-band LPR filter to kill off any residual airglow and preserve the continuum light from the reflection nebulosity next to the main section.  Indeed, I blew a  number of people away at the Nebraska Star Party using my Orion Skyglow just ahead of my binoviewers in my 14 inch Newtonian (143x), as the view looked almost photographic.   Clear skies to you.








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