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Old 19-11-2017, 12:03 PM
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Barred Spiral

I managed to get the thinnest of colour data for this pretty little spiral in Sculptor.

Have to say the urban glow of Sydney is really annoying of late...and not likely to improve.... with developers lining political pockets to make the place look more like Hong Kong every day.

Anyway, hope you like my take so far, on NGC613

The link is here
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Old 19-11-2017, 12:36 PM
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Atmos (Colin)
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At least you've got some nice clean luminance to add to the scant RGB. It's showing up nicely though Peter. Looks like a distant galaxy clusters towards the top left that's lacking the reddish colour it should
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Old 19-11-2017, 03:06 PM
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That's beautiful Peter, you have some good detail in the galaxy as its only 5 x 4 arcmins in dimension.
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Old 19-11-2017, 07:33 PM
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That's amazing Peter to pick up a mag 10 galaxy from under Sydney's bright lights.

cheers
Allan
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Old 19-11-2017, 07:54 PM
el_draco (Rom)
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There is a beautiful; galaxy cluster in the upper right quadrant as well and lots of littlies scattered across the field if you take the time to look. Very nice shot in deed.
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Old 19-11-2017, 10:20 PM
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Quote:
Originally Posted by Atmos View Post
At least you've got some nice clean luminance to add to the scant RGB. It's showing up nicely though Peter. Looks like a distant galaxy clusters towards the top left that's lacking the reddish colour it should
More colour data will come in time...as is Christmas.

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Originally Posted by billdan View Post
That's beautiful Peter, you have some good detail in the galaxy as its only 5 x 4 arcmins in dimension.
Thanks. It is a pretty little thing. That said I used the RC's native focal length to help reveal the details. A FL of around 3.1 metres takes some taming..but I'm pretty happy with the results to date.

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That's amazing Peter to pick up a mag 10 galaxy from under Sydney's bright lights.

cheers
Allan
Thanks Alan. It can be done...just needs a lot more work than imaging from a dark site.
A lot more work. But what the heck...my observatory is literally ten paces from my back door. Swings and round-abouts

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Originally Posted by el_draco View Post
There is a beautiful; galaxy cluster in the upper right quadrant as well and lots of littlies scattered across the field if you take the time to look. Very nice shot in deed.
Ta. I cropped the field quite a bit...but I figured the distant cluster a top left needed to be included to give the scene some depth. They are very faint, about Mag 20 or so.
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Old 20-11-2017, 05:32 AM
Placidus (Mike and Trish)
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Looking very pretty already. Will be beautiful.
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Old 20-11-2017, 12:41 PM
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Looking very pretty already. Will be beautiful.
Thanks M&T. No doubt colour in the very faint stuff will improve with more exposure. Currently however, I’m getting rained on....next installment might take a while. I’d expect your monster CDK would also do well with this one.
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Old 20-11-2017, 12:57 PM
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traveller (Bo)
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Can't wait for you to add more data to this image Peter.
Also, is it my monitor or is there a bit of green in the core/nucleus of the galaxy?
Bo
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Old 20-11-2017, 01:23 PM
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Can't wait for you to add more data to this image Peter.
Also, is it my monitor or is there a bit of green in the core/nucleus of the galaxy?
Bo
Green? No..... not at all possible
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Old 20-11-2017, 01:25 PM
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right, time for me to go to spec savers!
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Old 20-11-2017, 02:36 PM
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Nice image Peter - havn't seen that guy before - well done!
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Old 21-11-2017, 08:24 AM
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Alright I am going to say it. - Having this scope at your home in a light polluted sky is a crime against astronomy Peter. It clearly produces sharp detail but the light pollution is messing with producing nice colour.
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Old 21-11-2017, 10:51 AM
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Alright I am going to say it. - Having this scope at your home in a light polluted sky is a crime against astronomy Peter. It clearly produces sharp detail but the light pollution is messing with producing nice colour.
Frank and fearless. See below

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Nice image Peter - havn't seen that guy before - well done!
Ta Andy.

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right, time for me to go to spec savers!



Crimes against Astronomy?

Actually...apart from the fact there seem to be no rural plots less than $300k to be had within a couple hours of Sydney...there is method to my criminality

Being an urban imager is all about maximising signal, and minimising noise. Hence perversely, large apertures do better (Max signal). Other things I do the get, let's call it MAXSIG, are:

1) High quality mount. The less guiding that needs be made, the more the signal fills the same pixels
2)Adaptive Optics whenever possible...which is just an extension of point 1
3)Use a really rigid mount and protect it from any wind buffeting...i.e. stick it in a dome
4)Well engineered OTA. Sag due gravity that causes any collimation error, or thermal expansion causing focus shift, or camera tilt simply doesn't help.
5)Have an OCD about secondary optics (primary mirrors can be left for some time)e.g. ultra-clean Correctors, filters, CCD windows. Scattering reduces signal.
6) Use a field flattener/corrector to concentrate the signal at the edge of frame

Reducing noise is also important, things I do to get MINNOISE are:

7) Use a CCD with low read noise and deep cooling. DSLR's don't cut it in the 'burbs.
8) Run the CCD as cold as possible (I typically use -30C)
9)Take many sub frames. with 20-30 subs there are many software tools that can perform magic on your data
10)Take many and accurate Darks
11) Take many and accurate Flats (sky flats are best).
12) Don't image on nights of tragic seeing . If you must, do ultra wide field or use a camera lens both will be almost immune.
13) Protect the scope from local lights. Any scattering..like that from my neighbours DMZ security lights...can have fatal sub exposure results. i.e. stick it in a dome.
14) Use a long focal length....or to put it another way. ...less sky glow per pixel.

In my example of NGC613, yes, colours could be more saturated, but then is simply due the fact (due crappy weather) I could only get 4 subs of red and blue, and two of green.

I expect with 20-30 in each channel , order will be restored to the Force.
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Old 22-11-2017, 09:47 AM
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Quote:
Originally Posted by Peter Ward View Post

Being an urban imager is all about maximising signal, and minimising noise. Hence perversely, large apertures do better (Max signal). Other things I do the get, let's call it MAXSIG, are:

1) High quality mount. The less guiding that needs be made, the more the signal fills the same pixels
2)Adaptive Optics whenever possible...which is just an extension of point 1
3)Use a really rigid mount and protect it from any wind buffeting...i.e. stick it in a dome
4)Well engineered OTA. Sag due gravity that causes any collimation error, or thermal expansion causing focus shift, or camera tilt simply doesn't help.
5)Have an OCD about secondary optics (primary mirrors can be left for some time)e.g. ultra-clean Correctors, filters, CCD windows. Scattering reduces signal.
6) Use a field flattener/corrector to concentrate the signal at the edge of frame

Reducing noise is also important, things I do to get MINNOISE are:

7) Use a CCD with low read noise and deep cooling. DSLR's don't cut it in the 'burbs.
8) Run the CCD as cold as possible (I typically use -30C)
9)Take many sub frames. with 20-30 subs there are many software tools that can perform magic on your data
10)Take many and accurate Darks
11) Take many and accurate Flats (sky flats are best).
12) Don't image on nights of tragic seeing . If you must, do ultra wide field or use a camera lens both will be almost immune.
13) Protect the scope from local lights. Any scattering..like that from my neighbours DMZ security lights...can have fatal sub exposure results. i.e. stick it in a dome.
14) Use a long focal length....or to put it another way. ...less sky glow per pixel.

In my example of NGC613, yes, colours could be more saturated, but then is simply due the fact (due crappy weather) I could only get 4 subs of red and blue, and two of green.

I expect with 20-30 in each channel , order will be restored to the Force.
Hey Peter, thanks for sharing this - mind if I share your thoughts on urban imaging with the ASV FB group?
Cheers

Andy
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Old 22-11-2017, 10:15 AM
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Originally Posted by Andy01 View Post
Hey Peter, thanks for sharing this - mind if I share your thoughts on urban imaging with the ASV FB group?
Cheers

Andy
No problem Andy.
Just leave brown paper bag in the usual spot.

You might want to expand my multiple sub frame stacking reference from being "magic" to actually being PixInsight's image integration tool....well... one and the same really

The prognosis from my All-Sky camera this morning, for more colour data, was not all that promising however....(attached)
Attached Thumbnails
Click for full-size image (AllSkyCam00201.jpg)
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Old 23-11-2017, 07:19 AM
Stevec35 (Steve)
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The usual high quality image Peter. Sure - the colour is a bit subdued but the detail is fantastic. You do great work considering the conditions you image under.

Cheers

Steve
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Old 23-11-2017, 09:40 AM
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Echoing others - very nice resolution Peter!

BRTW, I read a bit about your beautiful telescope and came across this - a testimony to the first-class mechanics for sure!: http://www.alluna-optics.com/Alluna-...Telescope.html
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Old 23-11-2017, 12:22 PM
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Peter Ward
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Originally Posted by Slawomir View Post
Echoing others - very nice resolution Peter!

BRTW, I read a bit about your beautiful telescope and came across this - a testimony to the first-class mechanics for sure!: http://www.alluna-optics.com/Alluna-...Telescope.html
Ta...what can I say...indeed it is a beautifully engineered piece if kit.

Quote:
Originally Posted by Stevec35 View Post
The usual high quality image Peter. Sure - the colour is a bit subdued but the detail is fantastic. You do great work considering the conditions you image under.

Cheers

Steve
Thanks Steve. I’ll get the colour data eventually...currently however on on the West Coast (Perth) working on a BIG ‘scope installation, so might be a while.

Not much more to say really, in not a fan of re-hashing the same post to hang around like a fart in an elevator ....it is what it is for now
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Old 03-12-2017, 10:35 AM
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Originally Posted by MisterC View Post
I know you didn't want this one to bump to the top of the list again

But this is a stunning image that deserves some kudos.. Beautiful stars with a massive focal length.

Plus the fact you grabbed it from light pollution central.

I can only find one example that has better resolution...and it was taken by the Chart32 guys.


Too Kind.....but as I won’t be posting an annotated version ...time to move on now.
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