Tuc 47 is high in the sky at midnight here so I have had one last try at it with my digicam,( my ccd should come soon). The thumb is really compressed so the link to the full pic is below.

Afocal LXD75 8" 2x barlow+20mm eyepiece.
7 megapixel digicam 18x15s exposures@f2.7.
Stacked in registax. Levels and noise processed in photoshop.

Oh and can anyone tell me how to incorporate the dark frame from registax into the stack?


http://i213.photobucket.com/albums/c...sa/tuc47sp.jpg

Attached Images

tuc47spc.jpg (107.3 KB, 33 views)

The link to the full picture is brilliant! You lucky guys in the southern hemisphere.

Very nice!, on your question on the top section of the first screen a small box with the letters dark select this and find your dark. Clear Skies

Looks about how I saw it through a heavy fog in New Zealand using a borrowed 14" scope. Fog rolled in and cut of viewing in a matter of minutes. This was the last object I saw. I was going to swing over to the small cloud but the fog had other ideas. Never cleared after that. Guess I have to make another trip down under though 14 hours on a jet is too much for this old body I'm afraid.

It is best if you combine many darks to make a master and best if the temperature they are taken at is the same as the frames were done at. Of course the exposure time should be the same as well.

I don't use Registax so don't know that part. I do my calibration, dark, bias (if needed because exposure or temp or both weren't the same as the light frames) and flat field before I stack the images. This is because each frame may have to be aligned to the previous one so the hot pixels, noise and flat field issues don't line up on top of each other. If the frames were all taken at the same pointing and the guiding wasn't changed in any way and I didn't dither the image (a lot of ifs) then the calibration can be done after stacking.

Most CCD programs for taking images will do the calibration step automatically as the frame is saved if you so wish. They save both the raw and calibrated frame so you can redo the calibration later if needed (you picked the wrong darks or flat field frames, etc.).

In astro CCD language the former is "calibration" and the latter "combining". Though stacking is becoming more common and may win out.

Rick

Hi Winensky.
This is a great photo. When using registax run the alignment and after its done go to the darkframe box and click on it. Do not run the alignment and then stack the frames, if you goto the stack the frames mode you can not use the dark frame mode. I dont know every thing about registax but if I can help let me know. Clear skies to you Paul

Thank you Efrain, Rick, Paul and Tim for your advice and kind words. I was trying to re-align with the generated dark frame so I will skip that. When the new camera comes I will take the multiple dark approach.

Yes New Zealand is renowned for fickle weather and while we are happily much drier here, I am afraid the blurryness in my shot can't be blamed on the skys. Its hard to get a really tight focus on what you can't see in the camera.

Clear skys to you all.

Kind regards
Matt

Actually I was in your country a week earlier but it rained on me every day, even three days of mist in Ayer's Rock and surrounding area. I never saw a star the whole time I was there, not even the sun! And I was there a bit over a week. Never rained much, drizzle mostly but it was the sky I wanted to see and couldn't. This was July of 2006. It had been decades they said since it rained there in winter. The only clear skies I had were in NZ (north island). I had two clear nights though the one that stayed clear all night was the one I had to be up at 5 a.m. to catch a plane so had to shut down earlier than I'd have liked. The other night the fog rolled in about 2 a.m. and that was that. Every day it was clear by day and mostly cloudy by night. Very frustrating.

Rick

What can I say? So sorry.

Kind regards
Matt