M44 from Glebe

[Zuts]

Hi Guys,

Maybe the focus on this one is a bit better? I only managed one shot before the trees intervened.

1 by 240s + darks
SBIG 2000 XCM, TV85

Thanks for looking

Paul

[lineout]

Great photo from your location. I'm over at Wollstonecraft so I know the battle you must have with light pollution.

How'd you get such good focusing?

Cheers

Rene

[Zuts]

Originally Posted by lineout

Great photo from your location. I'm over at Wollstonecraft so I know the battle you must have with light pollution.

How'd you get such good focusing?

Cheers

Rene

Thanks Rene,

My focusing remark was more of a question. I just got a ST2000 XCM and was having trouble focussing it. I posted some very poorly focussed ones and thought this may be better coz the dim stars are smaller. So I was hoping someone would compare...

Anyway, it is a battle but i find i can go for 3 to 5 minutes per sub from Glebe. Any longer and I use a Astronomic UHC filter.

Paul

[EzyStyles (Eric)]

keep it up Paul. the ST2000XCM has great potential. You need to clean your sensor though as there are a few blackholes on the right hand side

[gbeal]

Paul,
while I agree with Eric, forget the "imperfections" right now, and get the hang of crawling, before being expected to walk.
Focus is difficult to ascertain in an image, well I find it difficult anyway, unless there is sometime to benchmark it on. Lets say you have it pretty good here.
Now go shoot something like a galaxy, try the 4945, or something you can see. Do all the focusing bits again, and see what the star sizes look like with the galaxy in the shot.
If 5 minutes is all you can get, then do 5 minute subs, just do lots of them. Try some with and some without the light pollution filter too, but be aware that the filter may alter the focus.
Stack them and come back to us. A dozen 5 minute subs should be a good start. If you get a cloudy night, tinker with a library of darks and bias frames. Just settle in your head a temperature set point, I use -20º C, but it could be anything up or down from this. Settle on this and shoot some darks, at the same temp, and at the same exposure duration you figure you will be using. In your case shoot a dozen perhaps at 5 minutes, and another at say 3 minutes. Bias are simple, they are as short as the camera will allow. Store them in a folder, Bias in a sub-folder, darks in another. Then the only variable is the flats, and unless you have a semi-permanent setup (focuser/camera/focus point/scope) you need to do these at the time you image. Try one next time you image though, as this should alleviate the snags Eric is talking about.
Lots to do, but look on the bright side, if you didn't have a one shot colour camera you would need all this at least three times, LOL.
Gary

[jase (Jason)]

Paul,
Choose a star around the 4-7mag and draw a box around it to instruct the software to only download sub frames. Then monitor the FWHM or intensity values of the star as you tweak the focuser dial. Don't choose a star too bright as this will cause major fluctuations in the readings. Can't recall the specifics of how this is done in CCDSoft, but I used to do it in MaximDL before I went auto i.e. FocusMax and RoboFocus. Now I don't think about focusing, as all the mundane work is done automatically and I can assured I'm always within the CFZ. Need more subs too. You're getting there. CCD work is very different to DSLR.

Look forward to seeing more.