Witch Head Nebula is faint ????

[kirkster501]

...or is it me, perhaps doing something wrong? Certainly the moon does not help.

I captured 18 x 10min exposures in Ha the other night through the Astrodon 3nm filter when the Moon was about 70 degrees away.  There is almost nothing to show for that time.

Last night before the moon came up I grabbed about three hours of RGB 1x1.  Again, yes I can discern the Witch Head but there is not a lot to show.

How does this object rank in terms of bang for the buck (aka time spent on it) please?

Thanks Steve 

[Phillyo]

You won't capture much in Ha as it's an extremely faint reflection nebula not an emission nebula. LRGB is required to capture it.

[Stuart1971]

16 minutes ago, kirkster501 said:

...or is it me, perhaps doing something wrong? Certainly the moon does not help.

I captured 18 x 10min exposures in Ha the other night through the Astrodon 3nm filter when the Moon was about 70 degrees away.  There is almost nothing to show for that time.

Last night before the moon came up I grabbed about three hours of RGB 1x1.  Again, yes I can discern the Witch Head but there is not a lot to show.

How does this object rank in terms of bang for the buck (aka time spent on it) please?

Thanks Steve 

I’m getting these same issues with my QHY268c, 5 min subs and in High gain mode and gain 56 and barely any data, and I am also wondering if it’s me….I was imaging the Heart nebula, and this was a 5 min sub, I thought it should show much more detail, how does this compare with your OSC subs…?

 

[kirkster501]

I am doing RGBHa on it Stuart, not OSC.  I'm not at that machine at the moment so will share later but hardly anything there.  Maybe due to its quite low altitude - unlike the Heart that can be overhead -  it needs better seeing and conditions (and zero moon).

[kirkster501]

26 minutes ago, Phillyo said:

You won't capture much in Ha as it's an extremely faint reflection nebula not an emission nebula. LRGB is required to capture it.

Ahh, is it? I thought it was an emission nebula excited by Rigel?  That may be the reason then.

[scotty38]

28 minutes ago, Stuart1971 said:

I’m getting these same issues with my QHY268c, 5 min subs and in High gain mode and gain 56 and barely any data, and I am also wondering if it’s me….I was imaging the Heart nebula, and this was a 5 min sub, I thought it should show much more detail, how does this compare with your OSC subs…?

 

For comparison here is one of my 5 minute subs, debayered and AutoSTF of the same target. This is with a 294MC and L-eXtreme filter.

 

Edited January 21, 2022 by scotty38

[Stuart1971]

22 minutes ago, scotty38 said:

For comparison here is one of my 5 minute subs, debayered and AutoSTF of the same target. This is with a 294MC and L-eXtreme filter.

 

Yes, there is no comparison….☹️ I begin to wonder if my camera is working as it should…or would I get more data like yours with the L-Xtreme filter, and not my IDAS P2 LP filter….🤔

[scotty38]

Are we doing an equal stretch etc, do you want to try doing with my file the same as you do with yours and see if there is still a difference?

LIGHT_2022-01-17_17-59-27_Temp-10.00_Exp-300.00s_Frame-0002_Name-IC 1805_Gain-121_Offset-8_Filter-LeXtreme.fits

[Stuart1971]

17 minutes ago, scotty38 said:

Are we doing an equal stretch etc, do you want to try doing with my file the same as you do with yours and see if there is still a difference?

LIGHT_2022-01-17_17-59-27_Temp-10.00_Exp-300.00s_Frame-0002_Name-IC 1805_Gain-121_Offset-8_Filter-LeXtreme.fits 22.31 MB · 0 downloads

Ok will check it…thanks…👍🏼

[iwols]

Must admit I've just tried this target And having same problem with the lum filter

[Stuart1971]

6 minutes ago, iwols said:

Must admit I've just tried this target And having same problem with the lum filter

Sorry, was that for the OP, or the later discussion…? 😄

[iwols]

The op😁

[ollypenrice]

3 hours ago, kirkster501 said:

Ahh, is it? I thought it was an emission nebula excited by Rigel?  That may be the reason then.

It is certainly a reflection nebula. Many renditions - even most - don't have a dedicated Ha input at all but your Ha is very well worth having because Barnard's Loop, which is bright on the east side of Orion, is still there on the west side though somewhat 'pushed in' by some kind of shock front or particle wind. My second attempt at the Witch was much enhanced, I thought, by Ha. A band of Ha intersects with the Witch almost at right angles.

https://www.astrobin.com/full/383965/0/

The Witch is very faint so avoiding the moon is pretty important and it can also be plagued by Geostationaries (which, being stationary relative to the Earth move across the sky.) The only defense against them is to take a lot of subs and use a sigma clip stacking routine. AstroArt did a great hob of this for me.

Olly

 

[kirkster501]

Yes I am noticing the Geostationaries as well.

[newbie alert]

How good are your skies bortle wise?

I'd be shooting lrgb without moonlight and don't expect to see much in a single sub

[Clarkey]

I think the Witch's head is pretty faint. I tried it from my house in bortle 6 skies and got very little. Definitely one for dark skies. (Having said this, I did try the spaghetti nebula with a DSLR - probably better taking advice from others🤣)

[gorann]

The Witch Head is a very faint reflection nebula lit up by Rigel in Orion so Ha will only help you to add the faint Ha clouds near it (which @ollypenrice talked about) but not detect anything of the nebula itself, since it does not emit Ha. So, the Witch Head is all about darkness and a moderately light polluted sky can probably be compensated by a lot of integration time. But pure RGB objects like this one cannot be done in light polluted skies with NB filters, since there is very little NB signal in there. However, you do not need much of a kit if you get to a dark site, so well worth a trip out of your urban garden. Up here at 60° North it is a bit too close to the horizon, but I once captured it on one short night with just a light traveling kit on Lizard Island way out on the Great Barrier Reef (so Bortle 1). An ASI071 and a Canon 300mm lens on a SW Star Adventurer and a dark sky was all the Witch needed.

Cheers, Göran

Edited January 21, 2022 by gorann

[Annehouw]

Not from Bortle 1 like Göran, but from Bortle 2-3 (somewhere on La Cumbre Vieja, La Palma, before it blew up). This is a 90 second frame made with a  Canon 5Ds DSLR (iso 1600) and a Canon 300mm 2.8 lens at 2.8.

I found it pretty dim on my individual subs. See below for a straight out of camera snaphot. Total integration was OK, although not much red since the unmodified camera did not register that very well.

Edited January 21, 2022 by Annehouw