[gregbradley]

Originally Posted by jjjnettie

Great image Greg. All those wee galaxies too!

Thanks JJ. It turned out better than I expected. It is a bit of a tough target.

Originally Posted by atalas

Sweet shot Greg....you've got to get that CDK to your dark site!

Yes I sure do. I think I'll get a tripod for the PME and take it down there for like a week or so when there's a good forecast.

Originally Posted by peter_4059

Nice going Greg. Love the detail and colour in the galaxies.

Thanks Peter. It turned out more colourful than I expected. It looks a bit like 2 ears!

Originally Posted by h0ughy

you seemed to be well tuned in on this one lovely image

Thanks Dave.

Originally Posted by John Hothersall

These are great galaxies engaging in a cosmic dance. Arms quite extensive.

John.

I like images that highlight these tidal streams. A very interesting
aspect of galaxy images.

Originally Posted by ballaratdragons

Nicely done Greg.

I love it when people capture the faint tail streams. I've never been able to.

Also a lovely galaxy cluster of very small very faint Galaxies at the edge of FOV at 7 o'clock

The tidal streams make it.

Originally Posted by ChrisM

Greg, another great shot. It certainly resonates with me!

Chris

That's great Chris. I am glad you like it.

Originally Posted by Paul Haese

Lovely image Greg. Love the colour.

Cheer Paul.

Originally Posted by Ross G

An amazing photo Greg.

Thanks.


Ross.

Thanks a million Ross.

Originally Posted by Gem

Wow! Amazing what amateurs can do today!

Equipment has advanced a lot.

Originally Posted by multiweb

Nice one Greg. That's a really tough one at best.

Thanks Marc. It is a tough target so I wasn't sure if it was going to be one reserved for the dark site.

Originally Posted by madbadgalaxyman

The small bluish knots at the end of one of the tidal tails are a really tough target. They are pretty obvious on some of the old blue-sensitive photographic plates, but not so obvious in CCD images.

The best I have seen them in an amateur image is probably at Rob Gendler's website.

The case for these knots being bona fide areas of very hot & very luminous OB stars is greatly strengthened when we consider the GALEX (Far Ultraviolet plus Near Ultraviolet) image of NGC4038/9 :

Attachment 96196

Blue in this image codes for Far-ultraviolet light.
(see the GALEX "how to" in the Observational Astronomy forum )
Note how there are star forming knots all along the tails!
They must be very faint indeed in visible light.....

Incidentally, the knots correspond well with those areas where the HI (cold neutral atomic hydrogen) in the two tidal tails is most dense....so there appear to be adequate raw materials (gas) to produce star formation in the tails.

Thanks for the interesting data on this target.

Originally Posted by renormalised

Nice shot, Greg. I like the colours you've captured here and the details in the main bodies of the galaxies. Good work

Thanks very much for that.

Originally Posted by Stevec35

Not bad at all Greg. I don't know if you ever use differential high pass filtering but you could probably squeeze some more detail out if you did.

Cheers

Steve

Thanks Steve. I do use some high pass filtering. I am not sure of the term differential high pass filtering. What is that? Is that multiple high pass filtering at different pixel values?

High pass filtering pushes up detail to a point. Then all it does is accentuate noise. So I feel I pushed this sharpening and high pass-wise as much as I could without the result being too noisy. But perhaps there is a technique that can extract a bit more without the noise?

Greg.