NGC5044 Galaxy Group

[gregbradley]

A pretty galaxy group NGC 5044 has a nice spiral galaxy and a couple of unusual ring type galaxies in it.

CDK17 and Proline. 2.5 hours, not a long exposure but it turned out not too bad.

http://upload.pbase.com/gregbradley/...53172384/large regular

http://upload.pbase.com/gregbradley/...72384/original larger size

Greg.

[renormalised (Carl)]

Nice piccie there, Greg

You probably don't need to go any deeper than what you have there, unless you want to shoot the galaxies individually.

[Stevec35 (Steve)]

Yeah I think you got it pretty right with that exposure Greg. Nice little group that I haven't seen before.

Cheers

Steve

[Larryp (Laurie)]

Nice work, Greg

[rogerg (Roger)]

Beautiful set of galaxies.

Surprised how nice it looks for 2.5 hours data all up. Wonder why I end up with such ordinary SNR in comparison to this after much more time (refer recent examples like http://www.iceinspace.com.au/forum/s...d.php?t=113195 ).

[renormalised (Carl)]

Roger, your SNR might be being impacted by a number of things. Site location, seeing that night etc etc. Might need to adjust the cooling on your camera. You may even have tube currents or air in the tube that's slightly hotter than the surrounds...may need to vent your tube. Who knows...a bit of experimenting might help.

[gregbradley]

Originally Posted by renormalised

Nice piccie there, Greg

You probably don't need to go any deeper than what you have there, unless you want to shoot the galaxies individually.

I think you are right. Its a broad view image rather than a closeup detailed view of a galaxy.

Originally Posted by Stevec35

Yeah I think you got it pretty right with that exposure Greg. Nice little group that I haven't seen before.

Cheers

Steve

Thanks Steve. That spiral is pretty.

Originally Posted by Larryp

Nice work, Greg

Cheers Larry.

Originally Posted by rogerg

Beautiful set of galaxies.

Surprised how nice it looks for 2.5 hours data all up. Wonder why I end up with such ordinary SNR in comparison to this after much more time (refer recent examples like http://www.iceinspace.com.au/forum/s...d.php?t=113195 ).

Yes I am surprised as well. Part of it was careful callibration of the data, part the processing but mostly the 17 inch aperture and whilst at my home observatory I don't have super dark skies they are reasonably dark especially from the zenith to the west. I think this was imaged to the west and gave better data than normal. A lot of the galaxies at the moment are rising in the east around Acemar.

Originally Posted by renormalised

Roger, your SNR might be being impacted by a number of things. Site location, seeing that night etc etc. Might need to adjust the cooling on your camera. You may even have tube currents or air in the tube that's slightly hotter than the surrounds...may need to vent your tube. Who knows...a bit of experimenting might help.

Depending on your light pollution 3 minutes is probaby a bit short unless you are going short for other reasons like tracking. The object you chose may be dimmer. The camera has to get above the read noise to show an image so too short and some of the faint stuff will not get above the noise.

On the other hand 10 minutes at 2.5+ metres requires some pretty accurate tracking so that would be tough as well.

Your exposure strategy should work fine on the brighter galaxies though.

Greg.

[Shiraz (Ray)]

Wow, that is a beautiful image Greg. It is a breathtaking grouping - hundreds of billions of stars, unknown numbers of planets and goodness knows what other gems - completely out of our reach, but it's ancient light can be fitted into one image...quite amazing really.

[strongmanmike (Michael)]

When did you get this one Greg? I imaged this in March

Nice result, it's a very cool looking grouping, I love the ring galaxies....though, again, it looks seeing limited or are you using a lot of noise reduction?

There ain't nuttin you can do about the seeing but do you think the seeing is bad from your spot in Sydney?

Mike

[multiweb (Marc)]

That's a great shot Greg. Really cool.

[Ross G]

A beautiful photo Greg.

So many galaxies...great!


Ross.

[RobF (Rob)]

I really enjoyed this one thanks Greg. One of your best in recent times I feel. Top stuff.

[gregbradley]

Originally Posted by Shiraz

Wow, that is a beautiful image Greg. It is a breathtaking grouping - hundreds of billions of stars, unknown numbers of planets and goodness knows what other gems - completely out of our reach, but it's ancient light can be fitted into one image...quite amazing really.

Galaxy groups make great photos.

Originally Posted by strongmanmike

When did you get this one Greg? I imaged this in March

Nice result, it's a very cool looking grouping, I love the ring galaxies....though, again, it looks seeing limited or are you using a lot of noise reduction?

There ain't nuttin you can do about the seeing but do you think the seeing is bad from your spot in Sydney?

Mike

Yes I did this in April. It was inspired by your effort. Seeing in my spot is sometimes quite good. Ordinarily I think its OK.

Originally Posted by multiweb

That's a great shot Greg. Really cool.

Thanks Marc.

Originally Posted by Ross G

A beautiful photo Greg.

So many galaxies...great!


Ross.

Thanks Ross. Its a very nice grouping.

Originally Posted by RobF

I really enjoyed this one thanks Greg. One of your best in recent times I feel. Top stuff.

Thanks Rob I am glad you liked it that much.

Greg.

[Tom Davis (Tom)]

That's a beautiful grouping! Boy, I remember your first images. You are getting better and better as the years go by. I am getting worse and worse!

-Tom

[gregbradley]

Originally Posted by Tom Davis

That's a beautiful grouping! Boy, I remember your first images. You are getting better and better as the years go by. I am getting worse and worse!

-Tom

Thanks Tom!

Greg.

[RickS (Rick)]

A very sweet little galaxy group, Greg. It turned out very nicely for a relatively short integration.

[rogerg (Roger)]

Originally Posted by gregbradley

Yes I am surprised as well. Part of it was careful callibration of the data, part the processing but mostly the 17 inch aperture and whilst at my home observatory I don't have super dark skies they are reasonably dark especially from the zenith to the west. I think this was imaged to the west and gave better data than normal. A lot of the galaxies at the moment are rising in the east around Acemar.

Depending on your light pollution 3 minutes is probaby a bit short unless you are going short for other reasons like tracking. The object you chose may be dimmer. The camera has to get above the read noise to show an image so too short and some of the faint stuff will not get above the noise.

On the other hand 10 minutes at 2.5+ metres requires some pretty accurate tracking so that would be tough as well.

Your exposure strategy should work fine on the brighter galaxies though.

Greg.

Thanks Greg. 3 min is short, I'm going to try longer subs. I've got out of practice of doing them. Providing i can autoguide the PME will track fine for long exposures, I just have got out of practice and often don't have a guide star.

[gregbradley]

Originally Posted by rogerg

Thanks Greg. 3 min is short, I'm going to try longer subs. I've got out of practice of doing them. Providing i can autoguide the PME will track fine for long exposures, I just have got out of practice and often don't have a guide star.

If you are using a PME it should be no problem using self guide. A guide scope would be trouble at that focal length.

If you have ever used T-point it will make it easy to get your polar alignment really accurate. If you have a PEC curve then that should finish it off nicely and you should get nice round stars every time at 10-15minutes.

I have started using 20 minute subs on some images and getting nice round stars and that was before I did a 330 t-point model which tightened things up even more.

Greg.

[rogerg (Roger)]

Originally Posted by gregbradley

If you are using a PME it should be no problem using self guide. A guide scope would be trouble at that focal length.

If you have ever used T-point it will make it easy to get your polar alignment really accurate. If you have a PEC curve then that should finish it off nicely and you should get nice round stars every time at 10-15minutes.

I have started using 20 minute subs on some images and getting nice round stars and that was before I did a 330 t-point model which tightened things up even more.

Greg.

Yes, I really have no good excuse.

I've been using TPoint modes of 150+ points and PEC from day one, both are trained well. If I do actually have a guide star available 600s exposures never have a problem.

I guess it's a combination of in the past wanting quick results waiting a short time for the first exposure), that about 50% the time there is no guide star so it's easier to just not rely on one ever, and that until this discussion (including some PM's from people) I haven't realised the significance of the read noise of the ST8 compared to the signal.

Better crack that whip and get me back to 600s+ exposures. I used to do 600s & 1200s with my LX200 classic for crying out loud.

[broca (Steve Coates)]

Nice work!