M33 in LLLHaRGB

[swag72]

Here is something I have been working on for a little while. This is the first galaxy image that I have ever been happy with as I usually don't take them as I can not process them. Thanks to help from Olly, I've got to this stage.

This is an LLLHaRGB image with the following details;

M: HEQ5

T: Pentax 75SDHF

C: Atik 314L+ and Baader LRGB filters

Capture:

60x300s L 1x1

60x300s R,G and B all binned 2x2

Ha was 'borrowed', so I don't know how much there was - Thank you Olly, did the job perfectly!

Guiding in Maxim, capture in Artemis. These are the first files I have ever fully calibrated, and that was done in Maxim. The processing was done in PI and CS5 as I moved between them both doing different bits I felt comfortable with. Pleased to be able to put this galaxy to bed now and move onto something else.

Would welcome any comments that you wish to make, all received and acted upon!!

[ultranova]

All the time and effort in this picture shows and from where I am sitting it looks marvellous

That's what I like about this Galaxy if you spend the time on it collecting the data it pays you back with some lovely colours and detail which your pictuure truly shows

Cracking shot well done.

[michael.h.f.wilkinson]

Beautiful image. I rather love the M33, its magnificent spiral structure can be spotted visually under good conditions.

[jezhughes]

Very nice!

How come you binned 2x2 on the RGB with the same data length as L on 1x1? I'm only curious, i read that if you're binning 2x2 on 1x1 you only need a quarter of that binned time?

[Gina]

That's a fabulous image Must go for that myself later on.

[space3]

super

[ollypenrice]

Very nice!

How come you binned 2x2 on the RGB with the same data length as L on 1x1? I'm only curious, i read that if you're binning 2x2 on 1x1 you only need a quarter of that binned time?

No. At best binning will double the signal but 1.6x is more like it. The much-missed Dennis (Roundycat) measured it and published his findings here. 4X is simply incorrect though you do read it here and there. Sara has strong colour (rare in M33) from her long colour run. However, the binned star colour does impact upon the stellar quality. I had a go myself with the data. What I missed was the option of building a background starfield from RGB only rather than LRGB but with binned stars there would have been no point. Binning depends on the sampling rate you have and with the short FL of the Pentax it came at a price, though the gain in galaxy colour is palpable. Compromises!

I think the Ha, in a poor halo-prone Astronomik 13Nm Ha filter, had about three hours. Sara would do better...

Great job Sara. Nice black sky, convincing colour, no gradients, deep, sharp... Apart from that it's rubbish!!!

Olly

[swag72]

Thanks all for looking and taking the time to make a comment.

The reason for 2x2 binning the RGB and using so much was something of an experiment really. I had read somewhere that if you bin the RGB and use the same amount of exposure time as for the luminance then you can get very good colour. As this was my first LRGB image with the Pentax, I decided to give it a go.

I suppose as Olly says, there's a compromise between colour and stars. Can I ask Olly, would you have expected less colour if I'd used 1x1 bin for the RGB? It may be that next time I'll 1x1 bin the lot, but still use the same amount of total exposure time. I'll see!

Unfortunately I couldn't wait for collecting my own Ha, however much better it would have been!! Once I'd seriously started processing this one, I wanted to get it all done!

Rubbish image from a rubbish teacher Olly?!!!! :grin:

[Earl]

Very nice Sara, have you considered a bit of star masked MT as per harry tutorials?

[stellawolf]

Very nice image well done

[Tom OD]

Lovely pic

I agree with Olly on the binned colour. I tried it out for a while, and while I don't hae any data, I never figured 34x was a correct value. more like twice. I also found that it gave me weird looking strs and stranger colour. Pink and Green etc...

I prefer to go with 1x1 no binning on colour; I do now shoot morecolou now than Lum in an attempt to not wash out the collur when Lum blended. By the way, why and even how LLL? in the mix.

Oh nearly forgot, super by the way.

Tom

[Martin-Devon]

Sara, this is superb for your first LRGB galaxy image, and it looks like you've nailed the flats calibrations as well. Only a few posts ago you were saying that you were struggling with the colour processing, but the result you've posted here is excellent.

[bazlan]

Amazing, well done!

[Stargazer Jack]

Wow, that is a fabulous image!

[swag72]

Thanks one and all.

@Earl - I've not tried the star mask in PI as I've frankly got so bogged down with PI that I cannot even make a star mask these days that seems to work. I find it very cumbersome now and really struggle to get much worthwhile out of it.

[Gina]

why and even how LLL? in the mix.

Yes, I wondered that. What does that mean Sara?

[Mark72]

Well done, Sara!

Do not give up on PixInsight. Star Mask is a click of a button thing,

Mark

[swag72]

LLL is 3 seperate layers of the luminance data. 1st one added at 20% opacity, a saturation boost and a little noise reduction, then flattened. The next added at 50%, then the final one at 100%. I read it in a magazine about a good way to boost colour and detail with the luminance channel.

@Mark - If you can tell me what button you click for a decent PI mask that would be fantastic. Mine always end up looking like a dogs dinner and creating more problems than they solve.

[ollypenrice]

I suppose as Olly says, there's a compromise between colour and stars. Can I ask Olly, would you have expected less colour if I'd used 1x1 bin for the RGB? It may be that next time I'll 1x1 bin the lot, but still use the same amount of total exposure time. I'll see!

Rubbish image from a rubbish teacher Olly?!!!! :grin:

For sure you'd have had less colour unbinned, or you'd have needed longer, that is. In the end I think the binning has worked for the galaxy but more unbinned colour would always be better where possible.

I'm not sure about the star mask in PI but I'm not convinced by the Ps version of the technique. I must try the PI one.

The advantage of unbinned RGB on targets with lots of clearly defined background sky (and not much starfield nebulosity) is that you can make a special starfield layer, in RGB only, with a very soft stretch to keep the stars tiny and colourful. Below you have galaxies stretched to the noise limit but stars hardly stretched at all. You just have to get the background identical in both layers. The rest is dead easy.

Olly

http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/i-TNbqhgh/0/X3/NGC7331-STEPHANS-X3.jpg

http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/i-pZ6TFK4/0/X3/M33-FIN-HamaxLRGB-nr2-X3.jpg

[Mark72]

Sara,

Masks are very easy there. May be mine look also as cat's tears but I just not care much.

You take your unstreched image and create a star mask with default settings. If too few stars are picked up you can create a clone, stretch it a bit and apply a star mask on it. You can use it on original image.

You can do both to pick up large ans small stars and combine in Pixel Math with MAX function.

Finally you can use the mask with "Masked Stretch" script. It will make sure the stars remain small.

Mark

[Gina]

LLL is 3 seperate layers of the luminance data. 1st one added at 20% opacity, a saturation boost and a little noise reduction, then flattened. The next added at 50%, then the final one at 100%. I read it in a magazine about a good way to boost colour and detail with the luminance channel.

Thanks Sara

[Jessun]

Sara that's beautiful! The LLL seems an interesting technique, and your result is great!

[James]

You've got oodles of colour there Sara, nice one. Star masks in PI aren't too bad - this example here on the PixInsight site, section 5.1 describes a way to create a starmask that I find a little better than the standard process. A few more hoops though...

James

[swag72]

Thanks Jesper and James. I went back to PI to try the masks, and unfortunately I couldn't remember how I got to this stage, so it all looked rather on the unpleasant side!! Hey ho!!

[cloudbuster]

Lovely sara. What more can one say!