NGC5128 revisited

[Shawn]

Another go at it, and a bit of an improvement on previous attempt, focus still a bit soft...I think..

10 x 60 secs @ 800, unguided...14"er

[gbeal]

Shawn,
if you are getting that sort of results with a 14" SCT, unguided, then you are away. Yes it is a bit "blobby", but partly that will be the focal length (I assume it wasn't reduced?), and also could be the focus like you suggest. Seeing, at the sort of focal length I guess you were at, can also play havoc. A good result given all the above. Perhaps a tad green to me as well, but like beauty this is in the eye of the beholder. Mine for example is more red/brown.
Gary

[Ric]

That is very nice Shawn and for unguided as well, you have picked up some good detail in the image. I think you are right the focus probably needed another tweek.

Cheers

[RB]

Like I've said, you're getting better and better Shawn.

:thumbsup:

[Shawn]

Yeah thanks guys, Im pretty sure its focus, oh and there is this that I dont think would be helping...It appears off a fair whack do you think...I have really bad eyesight, stoopid huh,,, I never listened to that age old adage, "if at first you dont succeed, hang gliding is not for you" :D

[jase]

Yep, out of collimation wont help:lol:. I'm not sure if its focus, could be... If you're imaging native (i.e no focal reducers in the imaging train), then the 14" @ F/10 has a CFZ of 220 microns. This is a rather slow/long, so would be difficult to miss focus. If you use a 6.3 reducer it changes to 83 microns. My current scope is 55 microns and I wouldn't trust myself manually focusing as the CFZ is too fast/short. Its best left to a form of motorisation.

Look forward to seeing more of your images.:thumbsup:

[Shawn]

Jase, No reducer, at this stage, and I should really use the microfocuser, and some softwares. I have not chosen a software the focus routine yet, Im open recomendations....

Thanks Jase

..

[jase]

The Microfocuser would assist with how you are currently operating. Keep a close eye on the star FWHM values as you shift through the CFZ. Pause when you think you're close, wait for a few more exposures to verify as seeing can mess values (and your mind ;)).

Generally speaking, the microfocuser is fine for visual use. However, if you're talking specifically about the Meade #1209 Zero Image-Shift Microfocuser, keep in mind the limitations. The microfocuser uses a analogue DC motor which is not predictable. What I mean by predicable is that they don't have a defined step size of movement (that is delivered by a stepper motor). For imaging you need predictability so that you can return to the CFZ time and time again. A digital reader on a stepper motor will tell you exactly where the focus travel is allowing you to either manually push buttons to hit the CFZ or computer control it the movement (preferred).

Software... Its difficult to go past FocusMax. Its free, device support is plentiful (considering it acts as an ASCOM hub/client) and is extremely accurate once you get things set up correctly based on your imaging train profile (which can sometimes be tricky) to get the right V-curve. http://users.bsdwebsolutions.com/~larryweber/
The white paper is a good read in understanding its operation.

[Shawn]

Thanks for that feedback and the link Jase, I have considered an upgrade to the focus, as I have read what you just explianed, I put it the too hard basket for the time being,... Ill follow that link, Thanks mate


S

[Bassnut]

A 14" f10 Unguided?????????, excellent effort unguided, but why???, think what you could do guided (eg 5 min exposures, at least), sheesh. You need to guide with a rig like that, such a shame.

Sorry for the wind up, but you need it :P

Fred

[Shawn]

I have the 100ED for guiding, but Im still having trouble with overcorrecting , so I chose to have a bit of fun, and not use it, so Im limited to about 60 secs before things go pear shaped,,,:D. However I think I have solved the problem, Night or two will tell,

Tonite though Im going to try the hundred , with the 14 as a guide...:). See what happens

:lol:

[Shawn]

Now with the 100ED....

1 shot 200secs at 800...

look how small it is , NOw I can see what Im up against with the 14er,,,:D

[Octane]

Shawn,

Damn, at that focal length, and unguided, you're getting pretty spectacular results.

As you and others have said, the focus needs tweaking, but, boy, you're on your way.

Regards,
Humayun