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Cosmic Challenge: Horsehead Nebula (Barnard 33)

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#26 Lkealey

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Posted 12 January 2022 - 05:31 PM

I saw it once, in a 6” newt w/triple bandpass filter, out in the California desert, a couple of hours east of San Diego, and a couple of miles up a wash from the road, back in the mid-90’s. It was a tiny notch in a dark cloud against a dark sky.  To be honest, my ex spotted it first. I had looked for about 15 minutes, trying to follow a path to it. It wasn’t until the flame nebula was out of view that she could discern it. Even then, it took a couple more tries to know that I saw it!

 

it was actually kinda disappointing at the time…. Not like pictures at all! I doubt that I will be able to see it here (Sugar Land TX), but imma gonna try. There are a couple of darker spots about 20 miles from here, but I’m not in great shape, so it’s hard to get out to the country these days…. I’ve got an ES ED APO 127 triplet, along with a few filters (h-a, h-b, OIII, UHC).  Maybe I’ll get really lucky, I do still have good vision, although not as good as 25years ago…

 

-Kealey


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#27 David Knisely

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Posted 14 January 2022 - 10:18 AM

A UHC style filter is not a great choice for the emission nebula surrounding the HH, because the nebula lacks much in the way of OIII emissions.  This matters because UHC filter bandpass is considerably wider in order to reveal H-beta and OIII lines.  Good samples of UHC have a bandpass about twice as wide as good H-beta filters.  

 

On the other hand, a good H-beta filter is considerably narrower (about twice as narrow), reducing the general glow of any light pollution and natural airglow without damaging the emission signal.   The signal to noise ratio of the H-beta on appropriate nebulae can be about 2x as great.

Actually, the very first time I ever got  to see the Horsehead nebula was in the original 1980 version of the Lumicon UHC filter at one of our Prairie Astronomy Club rural star parties some distance south of Lincoln, Nebraska.  I was using a friend's Cave 10 inch f/5 Newtonian with his "new" UHC filter and could see the dark notch of the Horsehead fairly clearly, although it was pretty dim.  I borrowed his filter and took it to my own 8 inch f/7 Newtonian,where again, I managed to see it, although not quite as well.  In neither instrument was the Horsehead visible without the UHC filter.  Although the H-Beta is a better filter for the Horsehead than the narrowband filters are, the use of a good narrowband like the Lumicon UHC will definitely improve your chances of seeing it.  Clear skies to you.


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#28 Lkealey

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Posted 14 January 2022 - 02:00 PM

I had a buddy a long time ago who lived on the Frio River, an hour and a half west of Austin, on the Edwards Plateau I think. Nearly perfect viewing conditions. We used to take a swim late in the evening and then lay on the big granite rocks along the shore. They would get heated up during the day and be nice and warm to lay on most of the night. The night sky out there was just incredibly beautiful. He taught me a little trick. If you laid on the rocks and looked up, let,your eyes adjust for a good half hour and then relax your eyes, so that you aren’t looking at anything, but everything - if that makes sense…. Anyway, after a while, you would start to see satellites- quite a few of them. Just with the Standard Issue Mark I eyeball!  
it took a little practice to be able to relax your eyes like that… this was in the early 90s. The one time I saw the horsehead nebula,  I had to relax my eye like that, as best I could. It’s a lot harder to do looking through a telescope than staring up from the hot rocks. As I mentioned earlier, it was my (now ex) wife who spotted it first, she came up with the ides of relaxing the eye like we did on the hot rocks. I had it dead on and couldn’t see it, until I tried several times to look, but not look, if that makes any sense.

on those hot rocks, when you spotted a satellite, if you tried to focus your eyes on it, almost always, you would lose it.  
 

I completely agree with “Surveyor I” - seeing it is almost a misnomer!

 

Blue Skies & Clear Nights!

 

-Kealey


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#29 Redbetter

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Posted 14 January 2022 - 05:38 PM

Actually, the very first time I ever got  to see the Horsehead nebula was in the original 1980 version of the Lumicon UHC filter at one of our Prairie Astronomy Club rural star parties some distance south of Lincoln, Nebraska.  I was using a friend's Cave 10 inch f/5 Newtonian with his "new" UHC filter and could see the dark notch of the Horsehead fairly clearly, although it was pretty dim.  I borrowed his filter and took it to my own 8 inch f/7 Newtonian,where again, I managed to see it, although not quite as well.  In neither instrument was the Horsehead visible without the UHC filter.  Although the H-Beta is a better filter for the Horsehead than the narrowband filters are, the use of a good narrowband like the Lumicon UHC will definitely improve your chances of seeing it.  Clear skies to you.

UHC would still not be my first choice, hence "not a great choice" in the post of mine you quoted.  It certainly would not have worked when I detected the HH in town with an 8" SCT and H-beta.  Even a good UHC is half as good for the job as an H-beta.  And of course there is the problem of various generic broader band "UHC" filters that have about twice the band width again, so that they are roughly halfway between a narrowband and unfiltered.  The progression is roughly:  H-beta 2x better than UHC (narrowband) which is 2x better than a wideband "UHC/light pollution filter" but even the latter should be about 2x better than unfiltered.

 

What I have not tried is an even narrower H-beta, ones with bandpasses in the low single digits.  Doubling the signal to noise yet again could make a big difference for hydrogen emission clouds in general.  Those filters could be tricky because of wavelength shift at fast ratios, but some folks swear by them.


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#30 Lkealey

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Posted 15 January 2022 - 01:17 PM

Beautiful night last night(Sugar Land TX) spent a couple of hours on Orion, but no luck with the horsehead…. Great views of M42 and the flame. Tried a couple of different filters, great on other stuff in/around Orion…  


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