IC 4628 in H-alpha

[Peter Ward]

A work in progres...

http://www.atscope.com.au/BRO/gallery40.html

[AlexN]

have to be happy with that so far! :)

Nice image, and interesting target.

Alex.

[Alchemy]

ah the prawn,

be nice to see it colored up, HaRGB ,Narrowband, or some other blend perhaps?

[Peter Ward]

:lol:

A raw prawn at present.....

[strongmanmike]

Nice job so far Peter but the stars are so pin point (obviously not the RC) that those (like me) with a bit of astigmatism will probably say they are little eggs :thumbsup:

I never realised just how much my slight astigmatism affected tiny dots on the screen, lots of sharp images looked like they had guiding error, I now put my nose to the screen or enlarge the image just to make sure before coming to such a conclusion :)

Mike

[spearo]

nice detail in there
it'll change color as it cooks a bit!
:]
frank

[Ric]

Lovely work Peter, the wisps and folds of the nebulosity look fantastic.

Cheers

[Peter Ward]

Thanks one and all for your feedback....

On the subject of elongated stars ;) .... I have been doing some fine tuning of my RC system recently using CCDinspector software.

Some results can be seen here
http://www.atscope.com.au/BRO/tutorials/ccdinsp/ccdinspector.html

It's certainly a useful tool, but does give different colimation resuts by simply imaging a different star field, or with the same field but with different seeing or with a slight focus tweak :doh:

That said, subtle tweaking of a system can make significant differences the overall performance....just need some clear weather to see the
results!

[Jen]

:thumbsup::thumbsup: very nice Peter :thumbsup::thumbsup:

[multiweb]

Wow! :eyepop: Some real nice details in that picture and great dynamic range and contrast. Not an easy one to process. Can't wait to see the final with the color. :thumbsup:

[Hagar]

Very nice result so far Peter. Look forward to seeing the end result.
CCD inspector seems to be a quite usefull addition to the collimation process. I have recently been investigating it's use but need some clear sky and time to make it all happen. Do you know of any tutorials for it?
One more question, What length subs do you use for your Ha imaging?

[Craig_L]

Great shot Peter. So much detail yet so little noise for the relatively short exposure. What software do you use for noise reduction?

[Peter Ward]

I generally never use noise reduction software... certainly none was used here.

An 'oft mis understood feature of the camera I use (no prizes for guessing the manufacturer :) ) is their dead-nuts-accurate chamber temp (patented) so provided you take accurate darks and flats, the calibrated image noise is extremely low....provided you keep the shot noise down by using long enough sub exposures. With H-Alpha I typically use 15 minute subs.

20 minutes would be better, but they greatly increase the probability of my also capturing an aircraft ( living under an instrument arrival waypoint into Sydney)

My advice would also be...if the data is noisy, simply expose longer to get more signal.

[Craig_L]

Thanks Peter for the info. Looking forward to the completed 'work'.

Craig

[rat156]

Hi Peter,

There's something wrong with your AP155, it's producing diffraction spikes. Have you been cleaning the objective with steelo again? Other than that I really like the framing of this one.

Cheers
Stuart

[Peter Ward]

:lol: Nah....just Ajax powder cleanser

[Paul Haese]

Great data Peter. Looking forward to the end product.

[Martin Pugh]

Nice work thus far Peter.

but I cannot fathom how you are getting diffraction spikes on the brighter stars using a refractor. Never seen that before.

cheers
Martin

[AlexN]

my two guesses..
1. Software added diffraction spikes, added either to give the image a bit of flare until it gets some RGB data, or to keep us on our toes!

2. Diffraction mask on the scope.. Personally I dont see someone adding a diffraction mask in front of such an impressive objective lens, however I suppose, why not on the odd occasion?

[Peter Ward]

I suspect this data set has taken me into dead end street.

The diffraction spikes are real, (fishing line over the AP dew shield...) but are in retrospect not necessary.

My framing was intended to capture both the open cluster and nebula, yet it just doesn't have the right "eye pleasing" balance.....:(

I'm thinking a re-shoot at a shorter FL is the next step....of course only to be hampered on my days off by the usual waning moon rain!

[Octane]

Peter,

That looks superb. Can't wait for the finished product.

Oh, and I'm all for diffraction spikes; they're the way of the future. ;)

Regards,
Humayun

[marc4darkskies]

I think it would still make a nice shot Peter (of course) but I have to agree about the framing. Shoot wide and crop is my motto!



Oh GOD I hear you!!!!! I've completed only 2 images since DECEMBER!!! Bring back El Nino I say!!!

Cheers, Marcus

PS: I confess to experimenting with "fake" diffraction spikes but I just can't bring myself to offend the purists :lol:

[KenGee]

NGC 4731 is not far away Peter, Why not use the RC on it, it would make for an interesting subject I think.

[Tom Davis]

Love it so far. I'm still trying to gather data on this target as well. I like your framing.

Tom

[strongmanmike]

Hey Peter, I was just flicking through an old copy of AS&T Sept/Oct 2006 and on p87 I came across your ATS advertisment in the mag. I thought I recognised the image that forms the background of the ad and came back to this thread...it's the same image mate, just the Ha component!...seems like an aweful long "work in progress" :lol:

Nothing gets past Sidonio's memory for images ;)

Mike

[rat156]

Has it been cloudy in Newcastle for a while Mike, you're back to 2006 magazines.

Now I do keep my magazines, and I may reference them, but not six months out of sync.

Cheers
Stuart

[Peter Ward]

Well spotted. But it's not unusual for me to add more layers to old data. In this case I added to the H-Alpha data as I was pretty happy with that....and tossed the RGB as it was pretty crappy...and well, mosaics do take time ;) Particularly with the weather we've had of late!
:rain::rain::rain::rain::rain: