Centaurus A and 47 Tuc

[Prickly]

Hi,

A couple of photos from last night I took with Michael (Tilt).

We used Michael's WO focal reducer with the 140 Neoachromat and a Baader UHCS from downtown Canberra and the unmodded 350D. (camera control via images plus and straight into deep sky stacker).

The exposures were as follows:
Cent A: 30sec x 40 with ICNR. ISO 1600
47 Tuc: 30sec x 12 with ICNR ISO 800

Bit of tracking error at 640mm fl. An autoguider would be nice but not bad for a first effort.

Cheers
David

[AlexN]

not bad at all for a first go mate! well done !

[leon]

David for a first attempt, these two images are fine, Tuc is probably a little burnt out, but I'm sure that will all come together as you gain experience, on the whole though you have done well.

Leon

[Prickly]

Thanks

Weve been trying a few at lower focal length but its a fair jump from 200-300 to 640. Tracking becomes a lot more critical.

I think you are right Leon about 47 Tuc. Not quite sure how to get around this. Maybe a few low ISO shots as well. I'm sure as you say its all in the exposure details and processing.

Cheers
David

[leon]

David, I will try and help, but I am no expert. maybe others here will chip in and make your experiences easier.

47 Tuc is a naked eye object, so 800 ISO is to much, 400 is plenty, your subs are fine, 10 to 12 is usually enough.

Obviously guiding is critical to your end result, to get good images guiding is the key., and of coarse alignment of the mount you are using is very important.


OK. having said that, for starters 30 seconds will work, it all depends on the focal length of the lens, or scope you are using.

Work your way up, forget about getting all the subs you are after in the first go, try many different exposures at different times say 1 at 15 sec's, 1 at 20 secs, and so on.

Have a look at these images and see what is the best time for what you are using.

However nothing will work well unless you have the guiding and alignment pretty much spot on.

Leon :thumbsup:

[Prickly]

Sounds pretty sensible advice Leon.

Next time on brighter objects might try a range of ISOs and see how it goes. You are certainly right 47 Tuc is very bright and even when imaging the core did look a bit burnt out.

much appreciated
David

[Tilt]

.......... >>> auto guider <<< ...........

Thanks for the info leon, we will have a go at less ISO on 47 Tuc next time. Was our first attempt and had no idea on what settings were needed (exposure duration/ISO setting).

Michael

[Kevnool]

Not bad for the first effort , put them in the photo album as the first Images are extra special....keep them coming because i enjoy looking at any image that is posted...Great work......cheers Kev.

[Prickly]

Thanks Kev,

Will do. Its also useful I think to give people an idea of what various scopes are like for imaging. We are also interested to see just how much we can squeeze out of the unmodded camera.

Cheers,
David