NGC1365 Southern Spiral Galaxy CDK17 F4.5 12 hours

[gregbradley]

I've got the reducer setup working on my CDK17 so it now is working at F4.5 with the Trius 694.

NGC1365 is the famous southern barred spiral galaxy.

Just under 12 hours.

http://upload.pbase.com/gregbradley/image/153645565/large regular size

http://upload.pbase.com/gregbradley/image/153645565/original large size

Greg.

[Stevec35]

That's a very good NGC1365 Greg.

Cheers

Steve

[batema]

Beautiful

[RobF]

Fantastic work Greg. You're really getting value from the CDK right now with images like this and the HH. Its wonderful you've shown the full image. Looks like a final rendition something between the regular and large size might be kinder to the fine detail.

Heck, when you can see background galaxies that clearly, what am I going on about! :rolleyes:

[dutch2]

Wonderful shot, what a great image!
Well done.:thumbsup:

[pmrid]

Greg, that's a great image. I am envious of the subtle hand shown in the processing. It is an image to remember.
Peter

[h0ughy]

nice scale and composition Greg

[strongmanmike]

Yeah excellent Greg :thumbsup: the large (original) version shrunk to 50% on the screen looks awesome... at full size though there are a few harsh processing warts...better to keep the viewer at a bit of a distance ;)

A grand galaxy image that....go Starlightxpress :cool:

Oh and easily your best galaxy image so far with the CDK17 :thumbsup:

Mike

[allan gould]

Oooooh, one of my favouritist-um galaxies. Done to perfection.
The Trius is really holding its own.
Allan

[gregbradley]

Cheers Steve.



Thanks for that.



Thanks Rob. It can take a while to extract the best out of your gear. Various combinations, different processing approaches.



Thanks Ingrid.



Thanks Peter. I do try to keep it invisible. Not always successful but certainly a standard I apply to my processing.



Thanks Dave. I think I'll add more to this one it seems to be worth extra effort.



Thanks Mike. No doubt some subtle repro is on the cards! I had earlier versions that were better in some ways and worse in others. I should be able to get them all together.



Thanks Allan. Its an unsual and striking looking galaxy and quite bright too which is handy. I've been imaging a lot of the fainter ones lately.

Greg.

[RickS]

A very nice rendition of NGC 1365, Greg!

I have one night of data on this target myself. It will be interesting to compare how much I got in a shorter time with smaller aperture and a less sensitive camera.

Cheers,
Rick.

[TimberLand]

Fantastic shot, and a hand full of background galaxies because you can.

Great combination with your setup. Looks like it is working well. But I bet you know of a few issues that need to be tweaked, I can't see them in the photo though.

Justin.

[alpal]

Hi Greg,
A superb shot.
It results like that which make this hobby worthwhile.

cheers
Allan

[gregbradley]

Thanks Rick. Yes it would make an interesting comparison. The Trius is less oversampled with the reducer but still not 100% ideal match.

I intend acquiring more data for this one as some images work out better than others and this one is the best of my recent images so its worth adding to it. I'll try and get another 9 to 10 hours worth.



Yes you can always tweak your gear. Its rarely a static hobby.
No real issues with this setup at the moment although I would prefer an AO and an OAG to guarantee perfect tracking and tighter stars.
I also have to watch the stars when processing from this camera. They easily get a slight fuzz around them which can be accentuated by enriching colour processing so star masking correctly done becomes important.



Thanks Allan. That's a nice compliment. But its true. Every now and then one image just really works and it makes up for the ones not 100%.

Greg.

[Shiraz]

what a ripper of an image - well done Greg.

[gregbradley]

Thanks Ray. I plan to add another 10 hours.

Greg.

[Bassnut]

Yes, lots of detail there, excellent !.

[marc4darkskies]

Lovely Greg!! The detail is excellent - more data will smooth it out. Very nice indeed! :thumbsup:

That's some image scale ... 0.48 arcsec/pixel! But why did you reduce from the native CDK17's 0.63 as/p? Your sub length would need to be marginally longer at this scale than at your native F6.8 with 9 micron pixels, even considering the high QE of the SX694.

Cheers, Marcus

[gregbradley]

Cheers Fred.



Native the Trius is .32 with the reducer as you say .48 and the 9 micron 16803 is .63 and .96 with the reducer. The KAF8300 chip is native .38 and with the reducer .57. Oversampling has some advantages. One is deconvolution works better than at 9 microns. This tends to reduce the need for an AO to some degree (of course primary tight data is always senior). Greater image scale. Also the camera has lower read noise at 6 electrons versus about 12 for the 16803 so SNR tends to be higher. There is a gain, how much I let the images be the judge. Some seem better. Others are OK. I think the reducer improves the sampling a lot better. I also got the camera for my TEC180 as its perfect sampling for that scope which is handy as its also portable and I can take it to my dark site. Its also a bit less of a wind prone scope.

Additionally 2x2 binning works well with this camera as Ray has tested binning is working near theoretical levels. The KAF8300 camera also works well with the reducer and I have taken some good Ha shots with that camera in the past. I seem to be picking up more detail and I still need to gather about 10-20 hours for an ideal image so no real shortcuts there. In Ha and O111 this camera is top of the list as both are around 66% and 60% respectively. That is very high. Small wells are a consideration so I keep an eye out for bright star bleed. Also 17 inches at F4.5 and 77% QE actually burns out the core of galaxy NGC1097 in a 10 minute sub! So a lot of photons being recorded.

I am also thinking of either a 09000 chipped 12 micon camera or a 6303e 9 micron pixel camera. Mainly because I have never used a 6303e and its a largish sensor and large wells and good QE. Blooming I hope is a matter of controlling sub length or CCDstack bloom removal.

Greg.

[Ross G]

A beautiful galaxy photo Greg.

Closeup with great colour and detail.

Love it!

Ross.

[gregbradley]

Thanks Ross.

I plan on adding more data next new moon and clear weather.
I think it would be worth it as its in my opinion one of the best images I have gotten out of my CDK17 so far.

Greg.

[DJT]

Tahts a great image Greg. Detail is quite something. :thumbsup:

[gregbradley]

Thanks David. I am very happy with it as well. I hope it bodes well for future galaxy images that I may be on to a hot setup here.

Greg.

[Peter Ward]

I'd probably not crop it so close...I think some more surrounding space would take it to the next level.

An excellent rendition. :thumbsup:

[Enrique]

Fantastic image. I am in the process of capturing my own. I hope I come close to yours,

Regards,

Enrique

[DJT]

That's pretty cool. I remember the thread earlier in the year on these Sony chips which was very interesting. Glad you dived in as its clearly working well for you.

[Jon]

Wonderful. Beautiful rendition of my favourite galaxy.

[Elio]

Stunning image, colours and details are lovable :thumbsup:

[gregbradley]

Thanks Jon.



Thanks very much Elio.

Greg.

[stevous67]

Beautiful result Greg - well done.

Steve

[Paul Haese]

Lots of detail Greg, nice colour too. Needs more data though. Still noise present.

[LewisM]

I agree with Peter - crop is a little tight for my tastes - needs space.

Otherwise, i like it, a LOT! The best 1365 I have seen to date.

[gregbradley]

Thanks Steve.



Cheers Paul.



Thanks Lewis.
Its a fairly large galaxy so yeah it takes up most of the frame and I can see that would not be what everyone would like.

Greg.

[cazza132]

"Also 17 inches at F4.5 and 77% QE actually burns out the core of galaxy NGC1097 in a 10 minute sub! So a lot of photons being recorded.
"
Wow, mate, that just sounds insane! I know DSLRs have the bayer filter (reduces spacial resolution by about SQRT(2), but you need colour filters that would reduce QE with the dedicated astro cam. They are talking 50% QE with the bayer filter on for DSLRs, and DSLRs have quite a well depth also. Yes you can cool a DSLR, but not as much as a dedicated astro cam. Is it the dark frame noise that the super-cooled astro cams have the advantage? Or the flexibility of the use of narrow band filters to reduce star size (maybe irrelevant with galaxies)? Are RAW files really Raw files with DSLRs? Or have I just answered my own questions? Any thoughts with this one? Great shot btw Greg! - You must be stoked with the brute photon capturing capacity of that 17" beast!

[David Fitz-Henr]

An awesome shot Greg, loads of details there :thumbsup: I think I agree with Mike; shrinking to 75% size reduces the noise but still shows all the detail.

[gregbradley]

Cooled CCDs are cleaner than DSLRs usually as well as each shot uses all the pixels and each count. As opposed to a DSLR where 4 pixels are required to get one colour pixel so there is a loss there. Most DSLRs QE is more like 30% with a few that are around 50% (D800, D4, a few Canon 1D cameras). DSLRs do well but it takes a lot of shorter subs stacked. That seems the best approach.



Thanks David.

I am adding more data next new moon and I'll post it at that size as well.

Cheers,

Greg.

[PRejto]

Hi Greg,

Fantastic!! One of the best 1365s I've yet to see. I'm anxious to try out my Trius on this galaxy to compare to my result a year ago with my G2-8300, but I'm still trying to get to the bottom of my mount issues. What a royal pain, but I digress.

Peter

[gregbradley]

Thanks Peter. I intend to add to it if the weather clears up.
It did turn out better than I expected so its worth the effort to do more.

Greg.

[SkyViking]

Wow that is a nice looking NGC1365 for sure Greg. You've got plenty of detail at that image scale, impressive. The noise will disappear with more subs, so just keep going :) With more data it'll be one of your best images I reckon.

[gregbradley]

Thanks Rolf. Yes I think it came out very well and I want to make it the best it can be with this setup.

Greg.

[astronobob]

Mighty fine Image result Greg, awesome view & details definately, tho was a little surprised to see a smidge residual noise remaining, or some kind of fine color blotchiness or something with 12hrs of 5min subs = 140 odd subs ?
Im guessing the reason is because of the filters, less light, inturn, more processing, streaching ? tho, 5min subs arent long, sorry if awkward question, but just trying to understand further basic principles etc, as 10 x 10min subs with stock dslr can be as smooth in many respects. Id understand if some residual noise left in the darker zones, tho I'm seeing things in the med bright zones as well ?
Dont get me wrong, It is and awesome and inspiring Image mate and I am sure there are reasons unkown to me, re question.
Rgrds !

[cazza132]

I am very interested to see results from a DSLR in this scenario. Greg has extracted some good Ha data too - I am sure a full spectrum or Ha modded DSLR could do. Dark frame subtraction still does wonders without cooling and using results from different nights would also help (dithering?) I so should have had my mod 6d fitted with cooling :( Yes, long exposures extending more than 10 min would become an issue when cranking beyond ISO1600. But, still performs pretty good - QE as good as any DSLR with deep wells that rival the best CCDs. SQRT(2) or less for lineal res with bayer, but you shoot all colours at once :) It would be very interesting to see how a DSLR would perform vs CCD on that photon gathering monster :) My answer would be the advantage with Ha with the CCD. And my cat just caught a cicada - lol. Greg - good work mate - you have some awesome work and look up to you as an astrophotographer. I had a crack at M33 (Triangulum), that made me realize that you just can't do that galaxy stuff without proper gear!

Im guessing the reason is because of the filters, less light, inturn, more processing, streaching ? tho, 5min subs arent long, sorry if awkward question, but just trying to understand further basic principles etc, as 10 x 10min subs with stock dslr can be as smooth in many respects. Id understand if some residual noise left in the darker zones, tho I'm seeing things in the med bright zones as well ?
Dont get me wrong, It is and awesome and inspiring Image mate and I am sure there are reasons unkown to me, re question.
Rgrds ![/QUOTE]

[astronobob]

I agree cazza123, Its an awesome image, no doubt about it !
There is obviousely somethin I dont understand about CCD Mono cameras, filters etc ?
I see this type thing Im noticing in a few other images from various other IIS'sers also, so, im not picking fault anywhere here, just noticing something a few times and thought Id ask Greg as I understand he is very knowledgable in this/his field :cool2:

[gregbradley]

Yes there is some residual noise there. Funnily enough part of it is processing as an earlier version I had showed less of that so part is a processing thing. But its simply the time required to build up enough signal to get above the noise ( of the camera and the randomness of the light signal reaching the telescope called shot noise).

Bottom line is even with a sensitive camera and a large fast optic you will still need a relatively large amount of data to get something like a galaxy (and this is a bright galaxy) to be noise free with the kind of pushed/stretched modern processing we do with Photoshop and other programs.

As far as 5 minute subs. They could easily be made to be 10 minutes, possibly 15 although I think 15 will start to burn out the core. 5 minutes was an optimum of tracking considerations (no off axis guider on this setup), the fact of large fast optics so I didn't want to blow out the core.

[/QUOTE]

Thanks Cazza.
A modded 6D could be a hot camera. The main obstacle would be the Bayer filter array which makes the camera more like a one shot colour CCD especially if cooled. I think the modded cooled 6D would do very well.

Greg.