NGC5128 at 3050mm FL

[Bassnut (Fred)]

Hi All

Its been many months since I imaged on this rig, here is 1st light with a newly acquired (S/H) ST10XME at the full bottle native 12" LX200R 3050mm FL (no reducer) which I have never attempted before. 1st external guide with a new QHY5 cam on a wobbly, overloaded G11 too . I was pleased with the external guide/G11 performance at this FL with 10min exposures, almost no flexure is evident, now I have clamped the guide scope/cam right at both ends of the main OTA. The G11 has no PEC and even overloaded gave 3 arcsecs RMS PE at the meridian.

Its also the 1st LRGB for over a year, quite a change from narrowband.

LRGB 160:30:30:30 min Lum bin1 and RGB at bin2.

I didnt fiddle with star processing this time (apart from deconvolution), although 1 prominent star caused me so much grief it got deleted

http://fredsastro.googlepages.com/home

[seeker372011 (Narayan)]

close up and personal all right....can't recall if I ever saw that blue bit fringing the dust lane before...I cant begin to imagine the issues involved with imaging at 3 metres focal length..

[jase (Jason)]

Originally Posted by Bassnut

Its also the 1st LRGB for over a year, quite a change from narrowband.

'bout time Sir Fred - show us what your made of! NB can be interpreted too many ways (i.e. you can never produce a bad image as there is no such thing a "colour balance" ). When is the ST10XME getting on GRAS15 or are you going to live the high life for a while.

Great image too. What happened to the central star along the dark lane?

On a serious note, your stars don't show any colour. I've experienced this too - something with NABG chips. Did you try taking any shorter subs for star "management" purposes?

[Bassnut (Fred)]

LOL, Peters NGC5128 was a reference (natch, although its hard to match an RC/PME, real hard ), so in went the blue. Is it really there like that..... Guiding is the hard part at over 3m FL.

[Bassnut (Fred)]

Jase

Um, given my propensity to bother stars to a messy distorted death, I excluded them from all processing, I think in this case L washed out the colour altogether right from the start before exclusion. The missing star had bloom-removal artifacts that just got way too hard fixing with the healing tool, so...., its gone, stuff it. Remember too this is with a meade at an awkward FL, with the ST10XME I dont have to upscale now, which is a relief.

Yes, G15 gets an ST10XME too very soon, just have to decide wether to dump I and U or SIII and SII to get imagers on board with LRGB (or spend on a bigger filter wheel, eek, it never ends).

Anyway, I recon its not a bad effort with an overloaded G11 at that FL, sometimes a challenge is more fun .

[Peter Ward]

Fred!

A ballsy effort!

Looks like you may have run an erosion (minimum filter) over the data. Nah.... don't do it again.

Colour? Hummm....looks coloursied to me. Star colours gone bagarup. Might want to loose the sharpening re-bound dark rings too.

But the intrinsic res shows great promise!

Cheers
Peter

[Bassnut (Fred)]

Peter

Gaud, min filter saga will follow me to my death . Nup, no min filter, no colourising (you guys must think im a PS fiend), but yes, some selective blue boost (your fault, you started it ). I tried star work with deconvolute, may have overdone it (umm, its a meade ). Star colour?, OK, Ill work on that.

Thanks for your feedback.

[Garyh]

Beaut image Fred!
Loads of fine detail in the dust lanes for sure!
That is no easy feat all on as poor old G-11 too!

[Zuts]

Hi Fred,

Great image, the amount of detail is incredible. A 3m FL is challenging to say the least, but I can see why you say narrowfield rules.

I am thinking of getting a 6 or 7 inch mak/cass OTA, a cheap option to get to a 2 meter plus FL. I would use this only for galaxies. Do you think this would work as long as i went for longer subs, or would it be a total waste of money for a 'galaxy imaging scope'. I would be using it with my EQ6 and SBIG 2K.

Paul

[Ric]

Very sharp and spectacular Fred, very enjoyable to view.

Cheers

[Bassnut (Fred)]

Originally Posted by Garyh

Beaut image Fred!
Loads of fine detail in the dust lanes for sure!
That is no easy feat all on as poor old G-11 too!

Thanks Gary, actually the G11 can be pretty stable overloaded and gude well, particulary near the pole (its easier there).

Originally Posted by Zuts

Hi Fred,

Great image, the amount of detail is incredible. A 3m FL is challenging to say the least, but I can see why you say narrowfield rules.

I am thinking of getting a 6 or 7 inch mak/cass OTA, a cheap option to get to a 2 meter plus FL. I would use this only for galaxies. Do you think this would work as long as i went for longer subs, or would it be a total waste of money for a 'galaxy imaging scope'. I would be using it with my EQ6 and SBIG 2K.

Paul

Paul. Optical quality really shows up at long FLs, the stars were fairly big on the Meade (compared to an RC say), but I found the secret there is mega data, as in many hours of exposures allows far more deconvolution and sharpening before noise shows up. Its not a substitute for a classy scope, but if you are patient, and spent time carefully processing, youd be supprised the results you get with a relatively cheap OTA. IMO, this form of imaging then requires a good camera. hi QE reduces the need for very long sub exposure times, which brings out mount deficiencies at long FLs. The SBIG 2K certainly fits there, even though its not as hi as a NABG cam, the ABG is a big bonus because the kind of longish sub exposure times needed can make forground stars bloom very quickly on a NABG cam.

In short, with an SBIG2k, yes you can do long FL on a cheap OTA, but mega data is required to be able to process to a reasonable quality image. I dont know how long a FL OTA the EQ6 will take though, that will be the limiting factor.

Originally Posted by Ric

Very sharp and spectacular Fred, very enjoyable to view.
Cheers

Thanks Ric, glad you liked it.

[EzyStyles (Eric)]

excellent FL there fred. can't wait to see some narrowband happening on the ST10XME.

[strongmanmike (Michael)]

Nice to see an image Fred. 3050mm FL huh?...not that long man, when ya gunna get serious dude

Sounds like your processing was a bit..?..deconvoluted

Some great image scale there but yuv tried too hard again me thinks.. and lost the natural look...too much narrow band work see?

Mike

[Tamtarn]

Excellent image Fred, nice sharp detail and as Mike has said great image scale.

[Bassnut (Fred)]

Thanks Dave.

Yes Mike, your dead right, overconvoluted and colour has gone seriously belly up (or gone). After viewing Ken Crawfords video tutorials, im raring to give it another go. And Im am cranking it up a notch for the next pic, a real challenge this time, collecting megadata nearly done.