Images from saturday at Paul's

[Jim]

All using my Atik 1HS mono webcam, unguided on a Vixen Sphinx. Dark frame subtraction attempted (realise now I did it wrong, only did one dark frame for the whole night and should have done several after each exposure)

M42 with a UHC filter. 27 frames of 30 seconds


M57 19 frames at 30 secs


M27 19 frames at 30 secs.  Something went wrong here, the funny line effect occurs when I subtracted the dark frame.  It actually looks better without DF subtraction but you then get some amp glow in the corner.


I'm very pleased with these though realise I have a long way to go!  What fun, can't wait for my next go.

(BMP images replaced with JPG versions - Rick.)

[Rick]

All using my Atik 1HS mono webcam, unguided on a Vixen Sphinx. Dark frame subtraction attempted (realise now I did it wrong, only did one dark frame for the whole night and should have done several after each exposure)

Good stuff, Jim (though some format other than bitmap might have made for smaller files).

Something went wrong here, the funny line effect occurs when I subtracted the dark frame.  It actually looks better without DF subtraction but you then get some amp glow in the corner.

Yes, there's a lot of noise crept in there from somewhere. It might be worth taking a look at a small section of the original, the dark frame and the final image at a zoom that shows the individual pixels well to see where the noise is coming from...

[Mike]

Very nice Jim. I particularly like M57, the central star is nicely in focus and there is nice detail in the ring structure. Well done.

[mickw]

Nice work Jim, especially getting results when things go wrong, I like M42.

Now, you know that I haven't started imaging myself and I don't know the first thing about CCDs, so take a close look at the pics (I chose the bottom left) the "noise" looks to be a repeating pattern on all images, sort of streaks.  I would have expected noise to be more random.
Mick

[Ian]

I think those streaks will be much less evident when you get the DF sorted. Unfortunately, doing the dark frame is something you'll need to do each and every time you LX image (to be fair, you might be able to make a library, but I don't think anyone has, although the new Meade camera has software to make it easy...).

I also think you've got a debayer pattern. I would expect that camera exports raw images from the CCD. However, the software may be expecting it to need be interpreted as a colour image, which it isn't and you can get a grid like pattern over it. I would research TWIRG and bayer patterns in relation to Toucam webcams to get a better idea of what I'm on about...

Still looking good though mate

[Fay]

Jim, you are nearly there with the webcam. It will be hard to keep up with you as you are now turning them out in multiples!!!!!!!!


It was a perfect night, last night, & I took a crap image, can't believe it!!!!!

Fay

[Rick]

Yeah, I think you're on to something with the Bayer patterns, Ian...

[Tony G]

Well done with the images Jim,
Seems like I missed a good night Saturday, but I don't think Flis (she who must be obeyed) would have appreciated the comment "You continue with the fitted wardrobes and the flooring, while I pop down to see me mate Paul and the rest and have a great night and I'll see you tomorrow, don't forget to make me breakfast when I get back, see ya!!!".
Still by the sounds of it, a good night was had by all.

Tony G

[Jim]

Thanks everyone for your kind comments.  Will look into the debayer thing.  Will see if I continue to get it when I make some more images.

[JohnP]

Excellent Jim - The lines on the M27 are due to wrong darkframe... You are correct in that you need to do a set of DF exposures after each set of images (especially if you change exposure length or temp has changed a lot)... I'm sure you can correct for the amp glow in PS or like...

Great images & well done.

John

[Whitters]

Nice one Jim,

Tony we wondered where you had got to, I had Pear cider in especially

[Tony G]

Paul,
Alledgely it gets better with age, so can you save some for next time.

Tony G

[JohnP]

Tony Mate - I sympathize.... After making a commitment to my wife at last DSC about not doing anymore astronomy until the girls are in there newly decorated bedroom I still haven't tried out my new camera or looked through my scope... The last few clear nights are killing me... I hope to be all done in 2 weeks & get back to doing some astro stuff......

John

[Rocket Pooch]

Jim,

The issue is thermal nioise, do some darks before you image and it will ok in the future.

chris

[Rick]

I took a look at the site's webstats this morning. I've now replaced the BMP files in the gallery with JPG files, and changed the image links in this post to match.