Lum data for Grus quartet of three

[Somnium]

given the weather forecast, i dont think i will be able to finish this one off for at least a week so i thought i would post my progress to date. this is about 3 hours of Lum data on the Grus quartet, though with my FOV i can only fit 3 in :). the processing on this was minimal, i will spend a lot more time on the final product. it looks like my tracking issues are a thing of the past now, it has taken a year of tweaking and playing around but i think i have finally got this mount performing well.
Rick has definitely set the bar high for this object this year, hopefully this will end up being at least half as good.

[RickS]

Looks like an excellent start, Aidan! Good luck with the weather. The new moon weekend isn't looking very promising up here.

Cheers,
Rick.

[Somnium]

Thanks mate, i am unbelievably jealous of your FOV, makes me want to get a bigger chip.

[glend]

Aidan looks pretty good, i am about to process my subs of the Grus Quartet that i finished last night - ahead of the supposed rain event. Just one thing i wanted to ask about in your image, when i expand the attached thumbnail i can see dark centres in the bright stars, is that present in the final big image or is it just an artifact of downsizing for the forum?
Not being critical, and i know my star shapes will not be as good, just curious as to what causes the donut effect.

[gregbradley]

Nice round stars but some distracting halos and dark rings there. Has this had decon on it?

Donuts in stars could be either focus was a bit off or overexposed stars. I sometimes see them as well and that seems to be what causes them. Overexposure, it shows the secondary mirror in the centre of the star.

What camera is this?

Greg.

[Somnium]

I would love to have seeing conditions that would allow me to get donuts on the stars due to focus issues and still have it that tight ... no this is definitely due to dcon. the camera is an fli ml8300



so this is deconvolution. this was super rough processing, just teasing what is to come. i wont use the stars from the decon image, this is more for the detail in the galaxies themselves. when i spend time on doing a proper process i will crease a star mask then replace these donut stars with more consistent ones. they wont be as tight, but it will look a lot better.

i have attached a really quick version just using the deconvolved data for the galaxies. this gives you an idea of the star shape, the final processing will be done a lot more carefully

[gregbradley]

That new image looks nicer in my opinion. I don't mind a bit of softness in the stars, it looks more natural.

There are a few still with the donuts. I suggest they are slightly overexposed as the 8300 only has about 25K electron full well depth and brighter stars exceed that fairly quickly with large aperture.

Try a slightly shorter exposure and see if they go away. I think they will.

Greg.

[Somnium]

hmmm i will have a go at collecting ~3 min images and use that for the star data. i like the longer subs for the galaxy detail. though i was looking at the pixel info and it doesn't look like they are maxed out

[Somnium]

Looking at PS and then comparing it to the Jpeg, it appears that the donuts are not in the PS version. there must be something happening during the compression process ...

[strongmanmike]

That's a great start on this intrepid trio :thumbsup:

Tiny suggestion, be good to keep the centres just a little brighter in your final masterpiece...just so they don't look too flat.

From my experience, using imperfect DDP parameters will give stars with central holes. Decon tends to put rings around stars.

Mike

[Somnium]

Thanks Mike. and thanks all for the feedback, i have diagnosed what was causing the donuts, when i was stretching the data i was anchoring the white areas so i wouldnt blow them out but it meant the centres were anchored and the less bright parts of the star were stretched. so it wasn't the secondary, over saturation, deconvolution, or a compression artefact. good to know, i wont do that again. i have attached an example of the deconvolved image without donuts. hopefully i will be in a position to post the final version next week.

[strongmanmike]

Aaah, the old anchor the white point trick 99

That's about as much detail in the galaxies as could be expected from any scope sited a under 5000ft :)

Mike

[atalas]

Aidan,looks to me like It should end up a beaut image!great start and looking forward to seeing It finished:thumbsup:

[Atmos]

Looking really good Aidan! Very nice detail in the galaxies. Very nice to see that your mount is performing as would be expected now!

[Maurice]

Looks really nice Aidan. I like the composition, with faint fuzzies everywhere. That little grouping bottom right balances out the image nicely.

Cheers
Maurice

[Somnium]

yup, i was trying to be clever, i should know not to do that :). i was surprised about the detail i was able to pick up in these galaxies, perhaps i can make them a little less boring :P

Thanks, i am looking forward to getting a bit more data, just need the skies to clear.

Thanks Colin, when i first got the mount it was actually tracking worse than my Eq6, but now it is really performing. it is nice to watch the tracking logs and seeing them not dance all over the place



Thanks Maurice, i love this field too, so many galaxies when i add some colour you should be able to see them a little more clearly.

[Kunama]

Nice image Aidan,

(that is pretty close to how they looked in my 18" scope last Saturday from Allan's new DarkSky property.....)

[Somnium]

Thanks Matt, wow that must have been some kind of view, i would have love to have seen that.