Taken with Cooled modded Canon 350D on 10" Meade LX200R
30 x 5 minutes ISO400 at F8 autoguided
Canon chip temp -1°c
Ambient 15°c
Humidity 55%
Calibrated in Imagesplus and processed in PS CS2
Started imaging this low on the horizon but generaly happy with the result.
Still have to deal with field curveture and that ugly donut I cant work out where it's coming from.
tony, couldn't you have taken a practice shot and rotated said cooled camera diagonally to take in said monstrous galaxy? Having said that, what great detail and wow factor again!
tony, couldn't you have taken a practice shot and rotated said cooled camera diagonally to take in said monstrous galaxy? Having said that, what great detail and wow factor again!
Houghy, you took the words right out of my mouth, just wondering why you didn't frame it better Tony?
Apart from that it's a stunner mate, amazing detail and great processing work.
tony, couldn't you have taken a practice shot and rotated said cooled camera diagonally to take in said monstrous galaxy? Having said that, what great detail and wow factor again!
Very true Houghy...it would have been easy for me to rotate the camera so it was framed better...my fault...no excuse Tony....wont happen again.
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I see what you mean about the donut Tony.
Curious to see what's causing it.
Has it occurred before in other images?
It sure has...all my images with the focal reducer does but it wasn't on my first images using the FR...?????....cant see the donut without the FR imaging at F10.
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Very nice Tony, what FL is that at?
Approx 2000mm focal length
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Are you finding that having a cooled camera is making a big difference?
Have you tested both cooled and uncooled?
Geoff there is definitely a small increase in performance with less noise but is less noticeable doing 3-5 minute exposures, where I think it will improve results is in summer time when it's hot up here and also doing extremely long exposures at a dark site...something like 20+min exposure's.
Basically anytime when heat noise becomes a problem there will be a beneficial increase to signal noise ratio.
Thanks guys and I am sorry I did not frame the image properly...somehow my mind was more on this stupid donut and how to fix it.
Also it can not be dust on the reducer because I just got it replaced this week with brand spanking new one...same results.
Surely if it was a sensor or filter related I would see some signs of it no matter what focal length I am imaging..as below...no reducer imaging at F10 with cooled camera.
I happy for some suggestions...getting very frustrated with this.
Also something that make no sence to me is that whatever the reason it should atleast flat field out..well it's not..?????
I think I should go back to online gaming and kill people in clan wars....less frustrating....lol
Tony, the donut may well be there at f10 but it is not obvious. By the size of that donut it looks a long way down the imaging train. Also it doesn't look like a dust donut, it looks more like a very out of focus star. I wonder if it could be an internal point reflection of light? Is it in the same place everytime you image; ie on the long side of the image? or does it move to the short side if you rotate the camera?
I'd even go so far as to take a stab at an internal light source (light leaking in around a loose fitting, back through the view finder, etc ) from the camera reflecting back on the inner surface of the FR. That's just a guess thought
My option are open....its very much possible Paul.
Here is a flat frame with the same set up done yesterday with reducer.....I cant see the donut on the flat but saying that I am sure I saw some flats with it....i'm going crazy.
Will do some tests tonight on different areas of the sky see if it moves.
My thoughts are similar to Paul, it seems way too big for a dust donut. Do you shoot with the cover on the viewfinder, could be a slight light leak from when they re-asembled the camera after the mod. Might be worthwhile trying a shot or two with the cover on, I have always made a habit of shooting with the cover on anyway.
I know I am getting an internal reflection from my Tak focal reducer and it shows as a round, greenish tinged donut but only when there is a bright star in the FOV.
Interesting, I wonder if you could be getting that dark river effect that 20Da owners complain about.
just had a play, you can see the main circle in the frame, so with internal reflection you have the rest of the puzzle. how you fix that I have no idea?
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Have you uploaded an uncompressed version anywhere yet?
