geeklee

JAO (Just Another Orion)! A common object at this time of year and frequently imaged.  This was captured over 3 nights in January 2024.

A few of my goals - maintain some natural, subtle colour alongside depth and that dusty, nebulous look - it can be easy to saturate and flatten M42.  I also like a bright core so it still feels like it's almost too bright to capture. Lastly, I attempted to kerb the reds in some of the dust a little so that the strong Ha edges to them (middle left, top centre left) stood out more.

Some of these goals weren't fully met, but hopefully some were.  Please click through for a bigger size.  Pre-processed in APP, processed in PixInsight alongside the RC tools. 

This is ~6.5h - 180x120s + 40x30s.  Captured with my Epsilon 130 and 2600MC (at Gain 0).

Thanks for looking.

120s subs at Gain 0 on the 2600MC could almost manage the core of M42 with only the Trapezium blown out.  Adding some 30s subs using HDRComposition in PixInsight did the trick though.

58 minutes ago, Adreneline said:

I believe the SII has so much to offer in terms of revealing structure.

Completely agree, SII can offer a lot to some targets and subtle - but important - touches to others.  I still remember the recent Heart SNR data in SII, as it was such a surprise.

58 minutes ago, Adreneline said:

I might yet have to face up to putting the 1600 on the Samyang.

Hopefully there's a last hurrah in the coming weeks!

1 hour ago, Adreneline said:

This is eight panes of Ha taken with the Samyang 135 mm with ASI183MM.

Excellent arc of objects Adrian, showcasing the interacting Ha throughout this region.

1 hour ago, Adreneline said:

and the window of opportunity on Monoceros is drawing to close.

I hope you get another opportunity before it's gone!

15 hours ago, The Lazy Astronomer said:

An unexpected advantage was the wider FOV from the little Sharpstar allowed me to use the multiscale gradient removal technique on the Esprit data which helped no end - DBE was pretty much impossible on it 'cos there ain't exactly a lot of background there!

Ah, that's a nice bonus and something I've not had a chance to utilise yet.  I'm looking forward to PixInsight's MARS project.  Thanks for the extra details 👍

1 minute ago, Grimbles said:

Out of interest what gain / offset combination have you settled on ?

For my narrowband setup - Gain 100, default offset.  My data and processing will be the limiting factor way before tweaking the offset will make any difference     Keeps things simple for calibration too.

2 minutes ago, Grimbles said:

i think i need to walk away from the screen every so often and then come back with fresh eyes. 🙂

Nice first light @Grimbles This is a good idea - also compare against your master(s) integrations (usually Ha!) - look at detail, noise, background etc.  See if you've compromised anything to get the final image, and if you're happy with that compromise (if there is one).

17 minutes ago, Grimbles said:

533MM Pro, 150PDS

I'm currently using the same combo and enjoying it.  The smaller sensor feels less restrictive at slightly higher focal lengths.

16 minutes ago, Northernlight said:

HAE69C

16 minutes ago, Northernlight said:

especially on harmonics without encoders.

Hi Rich - will you be guiding at all with a mount using encoders?

FWIW, my ZWO AM5 (no encoders) currently guides fine and usually always below 1" (except when pointing at low altitude).  That's on the carbon fibre tripod instead of something really sturdy.

Superb result! Was is difficult working with the different data sets and bringing them together?  Looks like RGB from the lower FL/resolution rig and the L and Ha from the higher FL/resolution one?

1 hour ago, The Lazy Astronomer said:

which felt very satisfying. 

That must have felt good

8 hours ago, Yawning Angel said:

Ha per panel for around 8 hours total, processed in PixInsight

Looks fantastic Alex, good detail in the strong signal areas and the faint stuff in the periphery looks awesome.  

3 hours ago, pie_in_the_sky said:

That might be a bit rambling but am I on the right track?

Yeah, exactly.  You see some labelled "boost" or "booster" but they're not getting more of a particular signal through, just blocking more of the stuff that can get in the way.

3 hours ago, pie_in_the_sky said:

from what I've read crop sensors seem to be preferred to full-frame. Is that the case?

Full frame can be challenging for some (most?) optics.  This may be sensor illumination and/or star quality (although some modern tools can help with the latter)

1 hour ago, tomato said:

NGC 2903

That looks great - excellent colour and detail and the faint outer arms have come out really well.

4 hours ago, pie_in_the_sky said:

My understanding is that a Ha filter is redundant on the Ra. Is that correct?

All an Ha filter (or multi band filter) will do is block other wavelengths of light getting through.  Without it, the Ra still lets more-than-typical-DSLR Ha through but it will be alongside the rest of the broadband spectrum.  It won't be redundant, but could be useful if you want to bring out the Ha emissions.

1 hour ago, Elp said:

My a7s is blind to ha as it's factory, but when I used an lextreme on it the emission was there clearly and much better than imaging without.

It won't be blind or you'd get nothing all the time.  It presumably has an early cut off on red in the builtin filter or only passes a little amount at that wavelength (like most DSLRs?).  When you put an L-eXtreme on it, you block the rest of the usual spectrum and therefore the Ha looks "better".  It's still the same amount of Ha getting through.

2 hours ago, Swoop1 said:

20 x 120 sec lights

Great result for 40 minutes @Swoop1  Nice colour, running man coming through, good detail and the core is pretty good, with only the trapezium likely blown.

2 hours ago, Stu Wilson said:

.TIFF attached if anyone wants to try.

That's come out well Stu - with a very clear horse head against the Ha and the flame nebula showing good detail.  It's stretched quite hard with a little saturation so some noise elements are coming through quite strong.

Did you calibrate with flats as this could make your life significantly easier when processing - perhaps some of the processing decisions were made to hide the doughnuts?

A simple stretch of the basic TIF shows doughnuts and some other typical flat field stuff that flats should help tidy up.

The raw stack looks nice, you have some super colour & detail in the horse and flame.  Possibly some of this subtlety has been lost is the processed image?  No special tools run on the below - just star removal.

If you can calibrate the doughnuts out, I would only suggest to compare to the raw stack as you go, ensuring you've not lost anything along the way.  If you're happy with the changes as you go, that's all that matters and you'll be onto a winner.

5 hours ago, WolfieGlos said:

but do you shoot flats for each of filters? If so, do you do it with an integrated/moveable flat panel, or do you shoot them after the session?

Yeah, I shoot flats per filter - including LRGB.  I shoot the flats another day (before or after) and try and use them for as long as possible!  This particular setup was a RedCat+294MM.  I work towards getting the whole train as free from dust as possible, then shoot flats.  While I setup and tear down for every session, the imaging rig (scope, EFW, camera, guide scope etc) are always kept together so this flats approach has worked well for me so far.

For my reflectors with dew shields I'm even more careful with mono but am more amenable to shooting flats on an OSC each session.

My process is just a flat panel I place on top after slewing to zenith - nothing fancy.

5 hours ago, WolfieGlos said:

533mm pro with 1.25” LRGB filters

While I know all the pros and cons, I still find (L)RGB imaging in the UK frustrating at times and rarely do it.  It's the narrowband filters where I find so much joy and gains on mono.  I find HaRGB images very attractive though.

5 hours ago, WolfieGlos said:

533mm pro....a 2600mc

What a choice!  I enjoy both these cameras - the FOV on the 2600MC just blows the 533MM out the water of course but I enjoy using the 533MM on longer focal lengths where I'm looking for a tighter crop anyway. 

Hopefully something in there that helps!

Olly has kindly picked up those queries but on the filter,

14 hours ago, pie_in_the_sky said:

The Ha filter can be used in one shot colour cameras too right (assuming my definition of one shot colour is correct)? I mean it's not just for mono.

It can, but for OSC cameras it's more popular to get a multiband filter (the most common being duoband, that have peaks in Ha and OIII).  These multi band filters at least help the challenge Olly describes by making the most of an exposure - getting Ha onto Red and OIII onto Green/Blue (depending on the pass bands of the filter) at the same time.

14 hours ago, pie_in_the_sky said:

does using a mono cam mean that your photo count is tripled (when using 3 filters)? I.e. you have to take the same pic with each filter.

That's right, each filter needs sub exposures to make a final integrated stack, per filter.  These are then combined software.  An example of a final stack of R, G & B filters:

Combined and processed.

Hope this helps.

2 hours ago, Ouroboros said:

it made absolutely no discernible difference to the result. 😀  Weird huh? 

😅 I think the video describes why there can be minimal difference in some cases and goes on to use BackgroundNeutralization and ColorCalibration.  I do tend to use the latter and haven't tried SPCC for narrowband for a while.

EDIT: I forgot the final segment - did you use the last method where duo band filters are discussed on NGC281?

4 minutes ago, pie_in_the_sky said:

How do you end up with colour pics with a mono camera.

It's as you describe - particular filters with a mono camera but combined in software afterwards.  From a traditional R, G & B filter perhaps, adding Luminance, or using narrowband filters.  Narrowband filters are typically Ha, OIII & SII then adding these in the R, G or B channels of your choice (like the common Hubble SHO palette - SII into R, Ha into G and OIII into B).

6 minutes ago, pie_in_the_sky said:

Do Ha filters dual purpose boost light from nebulau and filter light pollution - or does this depend on the particular Ha filter?

They don't boost anything as such but block all other wavelengths of light, thus giving you just the wavelength of the filter.  Definitely one reason why some shoot narrowband only in light polluted locations.  You also get multi-narrowband filters that can be used on OSC (One Shot Colour) cameras to help capture certain objects.

8 minutes ago, pie_in_the_sky said:

I really like the mono pics.

I really like Ha images.  Ha is usually the filter that gives me the biggest smile when a sub comes in   It never fails to do this for me.

Apologies if I glossed over some of the above - I didn't want to info dump.

5 minutes ago, Ouroboros said:

I always use SPCC now.

This is a useful video from PixInsight themselves - explaining how to use SPCC (or ColorCalibration) with narrowband data (changing the White Reference etc).  Apologies if you've seen this / doing this all already!  

https://www.youtube.com/watch?v=LB22afHqIoI&ab_channel=PixInsight

What a great start @pie_in_the_sky !  Nicely balanced, good background, nothing pushed too hard (core aside) and some of that faint dust showing through all over in the first image.  Some great feedback from the other posters already 👍

14 minutes ago, cfinn said:

which demonstrates that this will be sensitive to the choice of reference point for the white balance. It's a stronger purple in my original image above since I used the entire heart nebula as the reference point

Very good point 👍 IIRC I used an even bigger area in my original wide field image which may have changed that reference further.  Thanks @cfinn

Not sure about a barlow but you can likely utilise a crop view ("Capture area" in SharpCap), tighter into the moon FOV to increase your frame rate and have a go as is.  As you've alluded to, it'll be small on a RedCat by default!

I took this on a 294MM camera - https://www.astrobin.com/ovuea8/  There's no point zooming, that's all there is 🤣

45 minutes ago, cfinn said:

I’ll need to have another look at the SII and OIII masters now to check!

I have some recent short focal length data.  I've quickly cropped and combined + calibrated in PI.  I can see the bigger variations you're talking about in the cyan Vs strong blue with hint of purple.  This is with no green removed and then some green removed.  Thanks for mentioning this - a new appreciation for the differences here.  

EDIT: The lower left here is very strong in SII (HB3 (SNR G132.6+01.5))

11 hours ago, cfinn said:

The purples are real and represent where there is an over-abundance of OIII emission.

Would it need some strong SII signal (R channel) in there to create the purple? As OP mentions, he found his more green and selectively altered it rather than got it naturally.

As you say, that area near the fish head has strong OIII.  I typically see very blue/cyan renditions showing this, but have seen the occasional purple too, so my interest is piqued!

My comments on the purple were the top and bottom of the image where it seemed like elements of the background were affected although another poster mentioned it was around a small number of stars. 

That looks great Alan - NGC 200 and NGC 198 especially stand out with their detail and colour.