NGC2264 - Christmas Tree Cluster and Friends

[WolfieGlos]

Finally, I have managed to produce an image this year after the awful weather.

I initially started this in broadband capturing 3 hours of data, but then with the Moon period and clear skies, I decided to capture data with the l'enhance filter and have persevered this week with several nights of clear skies. In the end, I have captured 16 hours of data for this one, including 3 hours under a Full Moon. In the framing I wanted to pick up NGC2261, Hubbles Variable Nebula which makes an appearance in the lower left.

Stars were processed separately, applying SCNR, and then after Inverting the colours, a further run of SCNR and inverting back again, a saturation boost and it's able to bring out oranges and blues in the stars for a broadband-ish colour to the stars. Not perfect by any means, but some additional colour other than the boring "white" of narrowband I think works well here 🙂

Usual Starfield 102 + Canon 800D (modded) on HEQ5. 200 x 300s frames at ISO-400.

Comments welcome as always  

 

And as an added bonus, last week I picked up a Samyang 135 f2 lens, and sat it atop my scope for one of the sessions. I was blown away at the amount of nebulosity this picked up in 3 hours! Not the best of framing, but being sat on top of the scope...it kind of is what it is.

Imaged with my 585mc at F/2 and an Askar Ha/OIII filter, this is a quick edit with no noise reduction. There are horrible halos with this filter, so I will need to investigate something else. Not sure if it is suffering with tilt or backfocus here, but aside from that, really impressive lens.

Edited March 8 by WolfieGlos
Camera noted as modded

[geeklee]

Two great results Chris.  Great colours in the first especially still showing the contrasting blue in and around the Cone.

Nice one getting the Samyang piggy packed so it could take part and double your options/output!

[WolfieGlos]

1 hour ago, geeklee said:

Two great results Chris.  Great colours in the first especially still showing the contrasting blue in and around the Cone.

Nice one getting the Samyang piggy packed so it could take part and double your options/output!

Thanks Lee, appreciated 🙂 The first image I split the channels and combined with pixel math, adding a slight twist to the colours so it wasn’t “fire service” red. I don’t usually do this, but I actually quite liked it. The blue was the hardest part, I had to overly saturate blues to bring it out.

That Samyang is a beast of a lens! If I can figure out the filter and tilt/backfocus it’ll be superb. I think I need something like an optolong lextreme f2, rather than the Askar colour magic? - which I didn’t buy for this lens by the way. I was hoping to coregister the data with what I collected from the Starfield but Siril didn’t like it, assume the focal lengths and pixel scales are too different.

[geeklee]

10 hours ago, WolfieGlos said:

If I can figure out the filter and tilt/backfocus it’ll be superb.

It's tricky - aim for the typical values and go from there - 44mm + 1/3 filter thickness.  General consensus is aiming for the focus point to land under the "L" on the focus ring.  0.1mm spacing makes a huge difference.  I've just got my Samyang rig hooked up again (just in time for everything disappearing ) and had some comedy spacing challenges where I'd forgotten just how much small spacing changes affect things.

10 hours ago, WolfieGlos said:

I think I need something like an optolong lextreme f2, rather than the Askar colour magic?

Definitely worth checking Astrobin for anyone using the same combo with the filter(s) you're looking at. 

10 hours ago, WolfieGlos said:

I was hoping to coregister the data with what I collected from the Starfield but Siril didn’t like it, assume the focal lengths and pixel scales are too different.

If you'd like a go in AstroPixelProcessor, PM me a link to the files and I'll happily try it there.

[Richard_]

Lovely images, especially the first from the DSLR. Is this an astro modded camera or not?

[WolfieGlos]

1 hour ago, Richard_ said:

Lovely images, especially the first from the DSLR. Is this an astro modded camera or not?

Thank you Richard  Yes, it's an astro modded camera - I've just updated the OP to say that.

7 hours ago, geeklee said:

It's tricky - aim for the typical values and go from there - 44mm + 1/3 filter thickness.  General consensus is aiming for the focus point to land under the "L" on the focus ring.  0.1mm spacing makes a huge difference.  I've just got my Samyang rig hooked up again (just in time for everything disappearing ) and had some comedy spacing challenges where I'd forgotten just how much small spacing changes affect things.

44mm? Right, so my "L" is quite a distance from the focus point, but it was perfectly in focus with a bahtinov mask on a very bright star in the middle of the frame before slewing. The lens is held in one of these purchased second hand (the 17.5mm version), with the 585mc connected with the 11mm spacer that comes with it - making 17.5mm.

[geeklee]

41 minutes ago, WolfieGlos said:

44mm? Right, so my "L" is quite a distance from the focus point, but it was perfectly in focus with a bahtinov mask on a very bright star in the middle of the frame

It's compensating for the short backfocus while focusing at infinity, but if you think of the lens as a DSLR lens then the spacing from the back plate should start at 44mm (like all DSLRs - it's the distance to the sensor).  If you're short, it'll focus at infinity before the L, but still focus.

If your DSLR was attached, you'd see it focus just before infinity marking (under the "L") for stars.

BTW, that's a cool adapter system you have to mount the lens.

Here's mine - Camera (6.5mm), EFW (20mm), Spacer (16.5mm), Baader aluminium ring (1mm) = 44mm (+ extra spacers for 1/3 thickness of filters). 

I'll tag @Adreneline as I think he may have a photo of his DSLR attached to the lens and focused on stars.

EDIT: With the 585 sensor, you may get away with just getting it very close to the L, like just 44mm (and maybe a little for filters).  The issue is trying to get it spot on while retaining room to auto focus.  Too much spacing and you'll never get focus (as I found out the other week!)

Edited March 8 by geeklee

[Elp]

I've found with the SY135 if you're using filters especially narrowband the focal point is no where near the infinity marker.

The standard lextreme also works well with this lens.

Edited March 8 by Elp

[geeklee]

1 minute ago, Elp said:

I've found with the SY135 if you're using filters especially narrowband the focal point is no where near the infinity marker.

The lens won't go round to the infinity marker (it will go under the "L") but you should always compensate for the thickness of the filter - the fact its broadband or narrowband should make no difference (very very slight filter thickness tolerances aside).  It's like spacing for any scope, you need to get it right for the best results. 

[Elp]

I'm saying my lenses focal point is no where near that point. Without filters it is. The photographic lens you can also do the infinity focus adjustment on the focus barrel so it depends on whether someone has adjusted this prior or whether it's still at factory setting.

[geeklee]

2 minutes ago, Elp said:

I'm saying my lenses focal point is no where near that point. Without filters it is.

Do you compensate for the filters though?  At 44mm (like a DSLR) it will focus (on stars) under the "L".  If you add a filter, you need to add more spacing so it will then naturally push the focus point back under the L to compensate for the change in light path (due to the filter thickness).

I realise we all have different standards & quality measures though 👍

Edited March 8 by geeklee

[Adreneline]

33 minutes ago, geeklee said:

I'll tag @Adreneline as I think he may have a photo of his DSLR attached to the lens and focused on stars.

Here is my Canon 6D (unmodified) attached to my Samyang 135mm and perfectly focussed (to my eyes anyway) on a star field.

What's good enough for Canon and Samyang is good enough for me!

Right or wrong I do everything I can to adjust the backspacing between camera sensor and lens to ensure I get focus within the base of the 'L' for every filter.

I accept that each filter (L, R, G, B, Ha, OIII, and SII - all 2mm thick) does not focus in the exact same position but everyone does focus within the base of the 'L'.

I am not sure why I would want to image without a filter, but if I did then with the SY135 the focus mark will most definitely move outside the base of the 'L' as implied by @geeklee.

If it focuses anywhere else then I would suggest the spacing is sub-optimum.

This is my 1600 in my SY135 with 1mm Astronomik filters and spacing adjusted to ensure the focus mark is within the base of the 'L'. (Sorry it's a rubbish photo - I thought I had a better one but can't seem to find it  ).

HTH

Adrian

 

[Elp]

I have used 0.3 and 0.5 rings in the past but I find it easier to just to assemble with the standard rings and my filter drawer and focus to another point. I setup and breakdown every time so can't spend much time finely adjusting spacing every time. I know the stars are pin point as I use the asiair focusing routine and get similar FWHM figures every time and have been using this lens for four years or so, bear in mind though I am using the video version of this lens which is optically the same. The main issue with this lens is tilt and that largely depends on how it's mounted and whether the person has invested time into adjusting it.

Edited March 8 by Elp

[WolfieGlos]

Thanks @geeklee / @Elp / @Adreneline . Seem to have stirred quite a discussion, and not about my image sadly ......

😆

 

4 hours ago, geeklee said:

It's compensating for the short backfocus while focusing at infinity, but if you think of the lens as a DSLR lens then the spacing from the back plate should start at 44mm (like all DSLRs - it's the distance to the sensor).  If you're short, it'll focus at infinity before the L, but still focus.

If your DSLR was attached, you'd see it focus just before infinity marking (under the "L") for stars.

Yep, this was entirely my fault. Although I didn't realise it was 44mm backfocus for the SY135, I interpreted the 17.5mm stated on the Altair lens holder's website as being from the back of the lens holder. So camera (6.5mm) and spacer (11mm) gives the 17.5mm.

I have just measured the setup (scale rule...can't find the calipers currently...), and it measures 37.5mm from the lens connection to the front flange of the camera, so in theory 44mm to the sensor. Spot on.

So how that puts the focus ring "L" indicator so far out is now confusing me. My lens is a brand new copy, so unless they've changed it, I can only put it down to the filter effect of 0.5mm or so. I do have some spacers somewhere to try that out.

Although I don't have an adapter for it, I could try to mount it on my SA2i for some testing next time I get clear skies (at least a week away by the forecast). At the very least I could use it with the DSLR.

4 hours ago, geeklee said:

BTW, that's a cool adapter system you have to mount the lens

Yeah it's pretty neat. Incredibly it comes with a dovetail that has hole spacings that match the holes in the top of the SF102's tube rings; something that I cannot find ANYWHERE. Short of drilling a hole in a dovetail that is.

However, if the BF is correct, I am wondering too if the single lens connection isn't quite strong enough and perhaps the lens has drooped slightly. If it was in tube rings like this neat solution I could rule that out, and also utilise the filter drawer, with an EAF connection too in due course. In fact it also has a 1/4" mounting for the SA2i.....oh the money pit opens again!!!

Edited March 8 by WolfieGlos

[WolfieGlos]

4 hours ago, Elp said:

The standard lextreme also works well with this lens.

Oh? That's good to know and is a lot cheaper than the F2 extreme. What's the F2 extreme for then?

[Elp]

Likely you receive a bit more signal (or more precisely lose less) as they're designed to compensate for bandpass shift. For my SHO narrowband I use the Baader f2s.

Edited March 9 by Elp

[geeklee]

9 hours ago, WolfieGlos said:

Seem to have stirred quite a discussion, and not about my image sadly ......

Apologies Chris, I'm dropped you a PM instead of continuing the SY spacing stuff here.

[WolfieGlos]

1 hour ago, geeklee said:

Apologies Chris, I'm dropped you a PM instead of continuing the SY spacing stuff here.

No need to apologise Lee, if anything it’s good that the information is here for anyone else with similar issues. I was surprised how quickly it all blew up 😆 Sorry if that came across in a negative tone mate, that wasn’t the intention at all 👍 

[geeklee]

1 hour ago, WolfieGlos said:

Sorry if that came across in a negative tone mate, that wasn’t the intention at all 👍 

Not at all Chris, all good 👍 👍

[WolfieGlos]

Decided to have a re-process of this one, despite my initial post relating to the colour, I think I prefer this version.

Exact same data, with some star reduction this time too.