Rosette - HOO

[Adreneline]

This is my first serious attempt using my Canon 200mm lens with ASI1600, unguided with all data collected with a ZWO ASIair and focussed using a ZWO EAF.

The image has minimal cropping and the star shapes are pretty reasonable even at the extremities of the image. The image comprises 20x120s of Ha and 10x120s of OIII, processed in PI and PS.

Comments and criticisms welcome.

Thanks for looking.

Adrian

[tooth_dr]

Hi Adrian. Onto a winner there, looks like a great combo. 

[Adreneline]

4 minutes ago, tooth_dr said:

Onto a winner there, looks like a great combo.

Thanks Adam. I like my 135mm Samyang but I think I could get to like the Canon more. It's heading in the right direction for the 1600 pixel size.

Thanks again.

Adrian

[geordie85]

56 minutes ago, Adreneline said:

Thanks Adam. I like my 135mm Samyang but I think I could get to like the Canon more. It's heading in the right direction for the 1600 pixel size.

Thanks again.

Adrian

Fancy selling it? 

[Adreneline]

31 minutes ago, geordie85 said:

Fancy selling it? 

I’m afraid not. I’m thinking it is going to become a permanent attachment to my 414ex osc. The FoV is very similar and taking L plus NB with the 1600+200mm and colour with the 414+135mm should work well. I keep seeing people recommending 2x2 binning for rgb to combine with L and NB so should be about the same me thinks! Just got to sort a nice lightweight mounting arrangement. Brother-in-law with 3D printer to the rescue.

Thanks for your interest though. 😊

Adrian

 

[Icesheet]

2 hours ago, Adreneline said:

This is my first serious attempt using my Canon 200mm lens with ASI1600, unguided with all data collected with a ZWO ASIair and focussed using a ZWO EAF.

The image has minimal cropping and the star shapes are pretty reasonable even at the extremities of the image. The image comprises 20x120s of Ha and 10x120s of OIII, processed in PI and PS.

Comments and criticisms welcome.

Thanks for looking.

Adrian

Great image 👍🏻

 

Im curious how you focused the lens with the ZWO EAF?

[Adreneline]

6 minutes ago, Icesheet said:

Im curious how you focused the lens with the ZWO EAF?

I’ve mounted the EAF on the supplied bracket onto my TS Optics tube ring and used a toothed belt and pulley from Motionco. 

 

Thanks for the kind comment. 
HTH

Adrian

Edited November 7, 2019 by Adreneline

[Icesheet]

That looks like a fantastic little set up! How do you find the CEM25 EC? It’s been interesting me for a while as a set up for my ASI1600 and Samyang. Gets tiresome pulling out the EQ6 for that. 

[kirkster501]

6 minutes ago, Icesheet said:

That looks like a fantastic little set up! How do you find the CEM25 EC? It’s been interesting me for a while as a set up for my ASI1600 and Samyang. Gets tiresome pulling out the EQ6 for that. 

Yeah, I am looking for a somewhat lighter arrangment than the NEQ6 all the time too.  I think it will be too heavy for a Star Adventurer.  I am using a G2-8300 with Samyang, with guidesciope and autofocus.  It weighs in at about 6 KG.

Great image to the OP by the way!

 

[Adreneline]

33 minutes ago, Icesheet said:

That looks like a fantastic little set up! How do you find the CEM25 EC? It’s been interesting me for a while as a set up for my ASI1600 and Samyang. Gets tiresome pulling out the EQ6 for that.

I know exactly how you feel. I used to have an NEQ6 and it was all getting too much for my ageing back and hands to lug in and out each time I wanted to do some imaging. Also I didn't need and was never likely to use it's payload capability and there was never any prospect of a permanent setup or observatory. The CEM25-EC is excellent for my needs.

36 minutes ago, kirkster501 said:

I am using a G2-8300 with Samyang, with guidesciope and autofocus.

The best thing of all, other than the fact that it is much lighter, is the fact that I don't need to guide. I accept that if I was to start using a longer focal length lens/scope then guiding may become necessary but my interests these days is very much more about imaging large areas of nebulosity without recourse to mosaics. I can now be ready to image within 15 minutes and the recent switch to an ASIair makes things even easier and quicker. I would definitely recommend the CEM25-EC.

36 minutes ago, kirkster501 said:

Great image to the OP by the way!

Thank you!

Adrian

[ollypenrice]

Certainly a great combination of lens and camera - plus sympathetic processing.

Olly

[MarsG76]

Very nice rosette.... good imaging.

[Adreneline]

11 minutes ago, ollypenrice said:

Certainly a great combination of lens and camera - plus sympathetic processing.

Thanks Olly.

[Adreneline]

2 minutes ago, MarsG76 said:

Very nice rosette.... good imaging.

Thanks for the kind comment - glad you like it.

Adrian

[MarsG76]

2 minutes ago, Adreneline said:

Thanks for the kind comment - glad you like it.

Adrian

The great thing about HOO is that the end result looks natural color wise...

[ollypenrice]

If you have Photoshop or equivalent you could, if you wished, get this even closer to natural colour by going into Selective Colour. You might not want to, of course, but it can be done.

[Adreneline]

36 minutes ago, ollypenrice said:

If you have Photoshop or equivalent you could, if you wished, get this even closer to natural colour by going into Selective Colour. You might not want to, of course, but it can be done.

Thanks Olly. I am always interested and grateful for any advice on improving my images and I will certainly give this a go.

I have played around a bit with Selective Colour but have to say I'm not sure quite what I am doing; my current approach is somewhat random and I usually end up ditching the end result. I am definitely a fan of trying to get something that looks natural.

Thanks again for the help and advice.

Adrian

[Adreneline]

53 minutes ago, ollypenrice said:

You might not want to, of course, but it can be done.

It can indeed! I chose to apply it as Selective Colour layer before I put the star layer in place so the colour modification is only applied to the nebula.

Hopefully this looks better.

Thanks again Olly.

Adrian

[kirkster501]

£1500 for the CEM25-EC.  I was expecting a lot less than that......  Will be keeping the NEQ6 in this role for now then.  I then get a free weight training workout every time I do my wide field then

[Adreneline]

29 minutes ago, kirkster501 said:

I was expecting a lot less than that......

The story of my life when buying AP equipment  

[Icesheet]

1 hour ago, kirkster501 said:

£1500 for the CEM25-EC.  I was expecting a lot less than that......  Will be keeping the NEQ6 in this role for now then.  I then get a free weight training workout every time I do my wide field then

You could always go for the CEM25p at £725. Still guaranteed +/-10 arc sec or less. That should be plenty good for unguided exposures at 135mm. Plus you have your guiding set up anyway 👍🏻. 

[ollypenrice]

12 minutes ago, Icesheet said:

You could always go for the CEM25p at £725. Still guaranteed +/-10 arc sec or less. That should be plenty good for unguided exposures at 135mm. Plus you have your guiding set up anyway 👍🏻. 

If I've got this right a 135mm lens with the 1600 CMOS chip is working at about 5.8"PP which really needs a tracking accuracy of about half that, so around 3 arcsecs. If this is so it isn't safe to assume that + or - 10 will be OK. The thing is that pixels are now getting so small that old rules of thumb regarding focal length and resolution are becoming out of date... The day may come when we need to guide at 50mm!

Olly

Edited November 7, 2019 by ollypenrice
Typo

[kirkster501]

My imaging scale with the G2-8300 and Samyang 135mm is 8.3 arcsec per pixel.  I get guiding accuracy of 0.5 arcsec on the NEQ6 with the small guidescope which is well within half (4.15" in my case) of the optimal Nyquist sampling rate for guiding.

I'd like to get a different mount for the above widefield so I can repurpose the NEQ6 for something else (my FSQ85 and a new camera)

So this CEM25P at +/- 10Sec is an *unguided* figure ???????  If I guided it I could get a better figure?

[ollypenrice]

1 hour ago, kirkster501 said:

My imaging scale with the G2-8300 and Samyang 135mm is 8.3 arcsec per pixel.  I get guiding accuracy of 0.5 arcsec on the NEQ6 with the small guidescope which is well within half (4.15" in my case) of the optimal Nyquist sampling rate for guiding.

I'd like to get a different mount for the above widefield so I can repurpose the NEQ6 for something else (my FSQ85 and a new camera)

So this CEM25P at +/- 10Sec is an *unguided* figure ???????  If I guided it I could get a better figure?

Plus or minus 10 arcseconds under guiding would be a total disaster. I'd consider that, under guiding, anything greater than an arcsecond RMS would be unacceptable. Mesu claim 4 arcseconds peak to peak unguided. 

Olly

[kirkster501]

Indeed, on the MESU I mostly have pancake flat guide graph.  But there are many nights here where the guiding is all over the place.  From my records on a decent night i get abou 0.2arcsec RMS on the MESU.  The NEQ6 is not as good - as it wouldn't at a fifth of the price - but still very, very good.  0.5 RMS.