Circinus Galaxy in near infrared.

[sjastro]

It's taken a long time for a new image.:)

Discovered in 1977, this object is heavily obscured but it came out quite well when using near infrared as luminance.

(NIR)RGB image 4 hrs NIR, 1 hr R, 1 hr G, 1 hr B,
BRC-250 scope ST-10XME CCD.

http://users.westconnect.com.au/~sjastro/circinusnew.html

Clear skies

Steven

[SkyViking]

Wow that's awesome, what a beautiful and interesting image. And it looks to be M64's obscure twin :)

I recently got a NIR filter so now I can't wait to try it out - naturally it's been cloudy here ever since though...

[strongmanmike]

Very cool capture Steve :thumbsup:

Interesting though, Steve Crouch (http://members.pcug.org.au/~stevec/Circinus_STL6303_RC.htm) obtained a similar result without the IR filter..?

I know Steve does use a N-IR filter (co discoverer of a Glob even :D)...unless he made a mistake in his image credits..?

Mike

[dvj]

Outstanding! There are very few amateur images of this galaxy. Details are very clearly defined. What does it look like without the NIR filter?

j

[John Hothersall]

Thats an amazing result as NIR will get through the Milkyway dust, I used the IR Pro742nm on Terzans in Sag/Sco giving better contrast. These filters are little used in deep space so fantastic to see this result.

John.

[Ross G]

An amazing capture Steve.


Ross.

[sjastro]

Thanks Rolf, Mike, John, John and Ross for your kind comments.

I think the near infrared filter will do a good job on obscured objects that emit a continuous spectrum such as galaxies and globular clusters.

The same story can't be said for obscured emission nebulae.
I've tried the filter on the emission nebula RCW71 which is heavily obscured by the Coalsack. I'd estimate you would need to increase the exposure time by a factor of 10 or more to get a similar exposure to a clear luminance filter.

Clear skies

Steven

[Stevec35]

Nice capture Steven. I've been meaning to do this in NIR myself after doing it in visible a while back. Have to admit I'm somewhat surprised the NIR doesn't show significantly more detail than the visible though.

Cheers

Steve

[Terry B]

I think this is correct. There are emission lines in the NIR but not as bright as the Ha lines. Take a look at my spectra of M8 here http://www.iceinspace.com.au/forum/attachment_browse.php?a=120697
There are weak lines longer than 700nm but not very many. I actually imaged it out to ~900nm and there isn't much there.

[sjastro]

Thanks Steve,

There are a couple of reasons that offset the advantages of NIR imaging.

First of all amateur CCDs generally have limited sensitivity in IR/NIR range.
My ST-X10ME is one of the better cameras, its QE is around 65% at 0.75 microns but drops to 30% at 0.9 microns. The NIR filter starts from 0.7 microns.

Secondly NIR is absorbed by water vapour. NIR imaging is best suited for high altitudes.

Regards

Steven

[DavidU]

Very very good. Interesting what can be done with NIR.

[sjastro]

Thanks for info Terry.
Spectroscopy is a fascinating subject.
It's could to see amateurs doing real science.

Is your set up able to show redshift in distant galaxies?

Regards

Steven

[Terry B]

I can but am limited by their faint magnitude. I have imaged the quasar 3C 273 and was able to measure the redshift.

[sjastro]

Very impressive Terry.



Thanks Dave.

Clear skies

Steven