Dusty Corona Australis

[richardo (Rich)]

Hi All,
with my tests inbetween clouds, rain and winter type weather,
I put together this image of one of my favourite objects with what I had.
I now have a Paracorr corrector and have moved my primary mirror back in the newt to
accomodate the increase in FL.
With this, getting the right spacing and fine tuning the squaring of the CCD
to the optical train, plus dealing with distortion in the corners by my 1 1/4"
filters, it's been never a dull moment.
Thank goodness for CCDInspector! But this image doesn't really show my final
adjustments.
Have some new 2" filters coming in the next week, should finally get all
these issues sorted.
Also have just pulled down the mount to relube and adjust...
So it's been a very busy week for me on my 2 weeks holiday.

Here's a link to my home page with a link to the 1.4mb image if you'd like to
have a look.
http://www.baytop-observatory.com/

Hope you're having as much fun as me

Thanks for looking

All the best
Rich

[multiweb (Marc)]

Phenomenal picture there Rich. Love it! You even managed to get color and details in a little face on spiral at 5 o'clock. Top shot.

[richardo (Rich)]

Originally Posted by multiweb

Phenomenal picture there Rich. Love it! You even managed to get color and details in a little face on spiral at 5 o'clock. Top shot.

Thanks Marc...
took me ages to sort my vignetting out as my flats didn't work well on my colour channels... I'm thinking it was a couple of LEDs to some of my devices. Lum corrected well though.
Just quietly waiting to get my new 2" filters then things will be soooo much easier.

Cheers again
Rich

[strongmanmike (Michael)]

Ah sigh, trials and tribulations can send us

Lovely subtle and well composed rendition of this Malin favourite

Not essential I guess but it would look even better if you just tweeked those elongated stars.

Mike

[jase (Jason)]

Fine work there Rich. The time spent working the imaging train configuration over seems well worth it. Certainly a flatter field than your previous image.

You allude that the image does not show the final adjustments meaning you're posting a mediocre image or is this just a play on words? Personally, by the looks of the data set, I'd be very happy if I were you.

Thanks for sharing your efforts on this. Corona Australis is undoubtedly a prime target for a reflection neb aficionado as yourself. Looking forward to seeing what the new filters will bring.

Cheers

[richardo (Rich)]

Originally Posted by strongmanmike

Ah sigh, trials and tribulations can send us

Lovely subtle and well composed rendition of this Malin favourite

Not essential I guess but it would look even better if you just tweeked those elongated stars.

Mike

Hey Migel,
thanks there buddy.
Been a busy time trying to get things where I'm happy. I'm just about there though, so it's been a good work out.
Have just tweaked the stars... yeah I looked at them and thought, ahhh, it's more a set of test images..(do it right man)
Yes, worth doing, worth doing as best as poss!

Originally Posted by jase

Fine work there Rich. The time spent working the imaging train configuration over seems well worth it. Certainly a flatter field than your previous image.

You allude that the image does not show the final adjustments meaning you're posting a mediocre image or is this just a play on words? Personally, by the looks of the data set, I'd be very happy if I were you.

Thanks for sharing your efforts on this. Corona Australis is undoubtedly a prime target for a reflection neb aficionado as yourself. Looking forward to seeing what the new filters will bring.

Cheers

Thanks very much Jase!
Was a challenge with my hicups... hicups

It's been a lot of trial and error to sort these things out with the new gear; But as you say, pays off in the end.
Made harder waiting for all the things I need. But has been a steady progression in the right direction.
The face plate on my H16 just needed a tweak on one corner, I've been using CCD inspector to help out as well as my eye... and did the final tweak after the data for this image.
As I collimate prior to every sesh, I really needed to have consistency with how the corrector sits in the draw tube so it's repeatable every time without too much fuss. Collimation is spot, but there was that nagging diagonal elongation to one corner while to the opposite side stars appeared elongated horizontally. In the centre stars were ok but slightly flattened.
I'm sure I'm pretty much there now.
So hopefully when the 2" filters arrive, this will be the test to if there is any of that distortion left and if I've arrived at the sweet spot for the corrector spacing with this setup.
Am seriously very happy with the Paracorr and the way it handles stars giving a nice airy disc. Much different than the MPCC I find.

Thanks guys for your nice comments.
Always appreciated as we work through our issues

All the best
Rich

[strongmanmike (Michael)]

Hey Migel,
thanks there buddy.
Been a busy time trying to get things where I'm happy. I'm just about there though, so it's been a good work out.
Have just tweaked the stars... yeah I looked at them and thought, ahhh, it's more a set of test images..(do it right man)
Yes, worth doing, worth doing as best as poss!

Yeh that's a bit better.

Actually you know what..? I recon your dust in the lower left quadrant is about as good as I have seen, very 3D, nice work.

Mike

[Paul Haese]

An excellent image which is smoothly processed and one I would be very proud of if it were mine. Are you aware that you captured what looks like a galaxy in the image? I really like the fine streaks of gas in the reflection nebula.

Cracker shot.

[Garyh]

That`s a brilliant rendition Rich! I love this area and this has inspired me in getting more subs!
cheers Gary

[gregbradley]

A very good image. I had no attention on the stars when I viewed the image. But star elongation in one corner may be indicative of focuser sag. Newts are a bit funny that way in the sense of all that gear hanging off the focuser which is at 90 degrees to the tube. Must put more leveraged pressure on the focuser.

The image though seems to lack a bit of punch/impact. I think the data is there though. The central blue neb stars could benefit from a bit of lassoed curves or shadows/highlights and the dust areas a bit more smoothing to reduce the graininess. And more colour contrast or saturation. As I say a technically very good image but to me just lacks that extra kick that it could. Perhaps the colours channels need more.

I am leaning myself to abandon binned colour and do unbinned colour and combine them in the lum channel as well for extra clarity. I was surprised at the difference between unbinned and binned data using an FSQED and reducer. Perhaps the faster the optics the more unbinned data loses clarity and resolution.

Greg.

[Octane (Humayun)]

Rich,

Fabulous image. The dust does look 3D and that gorgeous little galaxy is an added bonus. Also, I can see what looks to be a diffuse nebula just to the right of the lower-left dust region; between the blue stars, and just a little under them.

This is a really subjective call, but, I'd love to see a bit more saturation overall. I think I see where Greg's coming from. Personal taste, though. The image still stands on its own.

H

[TrevorW]

Nice Rich

[Peter Ward]

All good. Noise well controlled, with great highlight and shadow, guiding and focus are spot on. Nailed the colour balance.

A top shelf image.

[richardo (Rich)]

Originally Posted by strongmanmike

Yeh that's a bit better.

Actually you know what..? I recon your dust in the lower left quadrant is about as good as I have seen, very 3D, nice work.

Mike

Thanks Mike and cheers for that!

Originally Posted by Paul Haese

An excellent image which is smoothly processed and one I would be very proud of if it were mine. Are you aware that you captured what looks like a galaxy in the image? I really like the fine streaks of gas in the reflection nebula.

Cracker shot.

Thanks Paul!
There's actually two fairly well seen galaxies with another what looks like an edge on right of the obvious one in the lower R/H area.. also with close scrutiny there's two extended minor planets making their way across, you'll see them as little lines. These were captured on Sunday night.
Yes i too think the reflective streaks look pretty cool!

Originally Posted by Garyh

That`s a brilliant rendition Rich! I love this area and this has inspired me in getting more subs!
cheers Gary

Thanks Gaz!

Originally Posted by gregbradley

A very good image. I had no attention on the stars when I viewed the image. But star elongation in one corner may be indicative of focuser sag. Newts are a bit funny that way in the sense of all that gear hanging off the focuser which is at 90 degrees to the tube. Must put more leveraged pressure on the focuser.

The image though seems to lack a bit of punch/impact. I think the data is there though. The central blue neb stars could benefit from a bit of lassoed curves or shadows/highlights and the dust areas a bit more smoothing to reduce the graininess. And more colour contrast or saturation. As I say a technically very good image but to me just lacks that extra kick that it could. Perhaps the colours channels need more.

I am leaning myself to abandon binned colour and do unbinned colour and combine them in the lum channel as well for extra clarity. I was surprised at the difference between unbinned and binned data using an FSQED and reducer. Perhaps the faster the optics the more unbinned data loses clarity and resolution.

Greg.

Thanks Gregg for the comments, observations and critique.
My draw tube lays under the tube so the imaging setup is upside down and always has been, so as to reduce non symmetrical flexure and off balancing in different parts of the sky. When I built the scope I added a 4mm aluminium backing plate that curves up around half the diameter of the inner tube. If anything, it could be the Moonlight focuser, but I can put a fair amount of pressure on it with minimum movement, or what would warrant movement as the scope tracks.
The new designed SX cameras now have the facility to adjust the face plate at the front of the camera: it was never squared up before being sent to me. So I've gone back to rechecking all my mirrors, secondary offsets, so I know collimation is spot. This I had to do before being able to problem solve. I've always religiously used the Jim Fly auto collimator and sight tube for spot on refinement. Needs to be spot at this F ratio.
It is the face plate as that last test run through ccd inspector, things were as near spot on as the seeing was permitting with +/- .1 % tilt in x & y... varying in different areas, far better than when I took these series of test images to compose this image.
I agree that the colours seem a bit mute... i've actually cranked the saturation up fairly well... but there is a point of over done and I pulled it back from this point.
It could be my flats weren't great... This chip is very sensitive in the green and lacks in blue and red... as I found out when I did a G2V cal.. I might have to change my tactics on ratios but this will all come together for ernest when I have full illumination with the larger filters.
Still your thoughts about binning might be worth a try.
All will be revealed.

Originally Posted by Octane

Rich,

Fabulous image. The dust does look 3D and that gorgeous little galaxy is an added bonus. Also, I can see what looks to be a diffuse nebula just to the right of the lower-left dust region; between the blue stars, and just a little under them.

This is a really subjective call, but, I'd love to see a bit more saturation overall. I think I see where Greg's coming from. Personal taste, though. The image still stands on its own.

H

Thanks for the comments and observations H!
It's a hard area to process for sure. Lots of variation. Just trying to get the right balance without clipping, or over stretching..
Yeah like that little emission neb, just seems to set give a variation to the area which draws your eye to it.
(see my reply to Greg on colour) Maybe more colour data is needed. Wouldn't surprise me as the conditions were a little fuzzy. So perhaps extinction came into play here.
Still coming to terms with flat fielding... this could have had an effect when I calculated the background deviation when applying the flats.
Still, when the 2" filters arrive, will only be flat fielding the lum... the colour will be fine... maybe this will make a difference

Originally Posted by TrevorW

Nice Rich

Thanks Trev.

Originally Posted by Peter Ward

All good. Noise well controlled, with great highlight and shadow, guiding and focus are spot on. Nailed the colour balance.

A top shelf image.

Thanks very much Peter!
this is one of my favourites and wasn't going to post this image as I was simply running adjustment tests.. but once I started to put them altogether thought what the hey, I can do something with this.
Really loving having new equipment though, fun to work through the issues!

Once again thanks all for taking the time with your comments and critique.

Appreciated
Rich

[Hagar (Doug)]

Very nice Rich. A very interesting piece of sky well imaged. I would lift the blue saturation a littleand get those reflection nebulas bouncing off the page, but thats just me,...
Well done

[telemarker (Keith)]

Great image of a sweet part of the sky. So much going on, nebulas globs and dust wonderfully rendered.

[Alchemy (Clive)]

Has a nice crispness to it, the diffraction spikes have an rc look about them, very clean.

[gregbradley]

There was an interesting report by Richard Crisp about flats recently.

He proves that the least noise added by flats are those taken at about 80% level of your CCD rather than the common 1/3rd or less.

I'll have to trial that myself as I have had some flats that were quite bright and they seemed to damage the image. May have been some other factor though.

I use a white T shirt over the end of the scope and do my flats at dusk. That works well.

Greg.

[richardo (Rich)]

Originally Posted by Hagar

Very nice Rich. A very interesting piece of sky well imaged. I would lift the blue saturation a littleand get those reflection nebulas bouncing off the page, but thats just me,...
Well done

Thanks Doug, yes it is a beautiful area.
It's the first time I've been able to have the globular Ngc6723 in the fov. So it's a bonus added to the nebula.
I did a G2V calibration when I received the new camera, and also when I replaced my MPCC with the Paracorr corrector.
The colour weight shown in this image is the product of this plus extinction multipliers were applied.
I've given as much saturation as I dare, even to do a sat layer and paint,feather in the reflection nebulosity to further saturate it looks unnatural and induces noise.
No, I'm pretty happy with what I have.
The blue channel compilation was fairly mute in comparison to the R & G, and judging from many images on the net, the blue areas of reflection don't extend a great distance from the blue star, (perhaps in wider fields) or are overly saturated,(well some I've seen are, but overly so) unless of course you take more and/ or deeper colour channel subs.
But as you mentioned, this is all personal taste.

Originally Posted by telemarker

Great image of a sweet part of the sky. So much going on, nebulas globs and dust wonderfully rendered.

Thanks very much Keith!
This whole area in wider field images show just how dusty it really is.
Nice to have a bit of blue to set it all off with a glob to boot!

Originally Posted by Alchemy

Has a nice crispness to it, the diffraction spikes have an rc look about them, very clean.

Thanks Clive...
I think with the Paracorr corrector in comparison to the MPCC, gives a nice airy disc to the stars, quite similar to what I've seen with images taken with RC's.

I guess this scope is an RC... ah that is, to coin a comment from a friend of mine...... a 'Richie creation"

Thanks all for your comments
All the best
Rich

[richardo (Rich)]

Originally Posted by gregbradley

There was an interesting report by Richard Crisp about flats recently.

He proves that the least noise added by flats are those taken at about 80% level of your CCD rather than the common 1/3rd or less.

I'll have to trial that myself as I have had some flats that were quite bright and they seemed to damage the image. May have been some other factor though.

I use a white T shirt over the end of the scope and do my flats at dusk. That works well.

Greg.

Thanks for this Greg.
I've been using a light box.
I set my flats in all channels to around 29-30,000 ADU which is about 70-75% the full well depth of the KAI4021m chip.
While my Lum flats divided well after bias subtraction on flats and lights, I saw over correction in the colour channels to the corners where my vignetting is. Dust motes were corrected nicely though.
Has me baffled.
I've tried lower ADU levels with no success, I might give the 80% a go and see what happens.

Maybe I'll try the 'T' shirt flats with twilight and see how the colour gets on. Seems strange that the colour flats correct the motes but not correctly do the vignetting.
I'm a bit over it now as I've tried and tried..

As I've mentioned, once I get the 2" filters, vignetting will no longer be an issue. I still will be flat fielding the Lum however.
But hate it when things don't do as they should.

Cheers
Rich