Barred Spiral

[Peter Ward]

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. :shrug:

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

The link is here (http://www.atscope.com.au/BRO/gallery413.html)

[Atmos]

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 :P

[billdan]

That's beautiful Peter, you have some good detail in the galaxy as its only 5 x 4 arcmins in dimension.

[alpal]

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

cheers
Allan

[el_draco]

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.

[Peter Ward]

More colour data will come in time...as is Christmas. :)



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.



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 :)



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. :thumbsup:

[Placidus]

Looking very pretty already. Will be beautiful.

[Peter Ward]

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. :thumbsup:

[traveller]

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

[Peter Ward]

Green? No..... not at all possible :doh::computer::whistle:

[traveller]

right, time for me to go to spec savers!

[Andy01]

Nice image Peter - havn't seen that guy before - well done! :thumbsup:

[Paul Haese]

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.

[Peter Ward]

Frank and fearless. :thumbsup: See below



Ta Andy.



:lol:


Crimes against Astronomy? :lol:

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. :)

[Andy01]

Hey Peter, thanks for sharing this - mind if I share your thoughts on urban imaging with the ASV FB group?
Cheers

Andy

[Peter Ward]

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

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)

[Stevec35]

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

[Slawomir]

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-Blog/114-blog-Instrument-load-on-Telescope.html

[Peter Ward]

Ta...what can I say...indeed it is a beautifully engineered piece if kit.



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 :thumbsup:

[Peter Ward]

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