Nigel G

I restacked the H/H without the 6400 frames and the dodgy flats, the final image is a vast improvement on the original. The bright ark at the top is much less, it was easer to process too. I had settled on 800 - 1600 ISO settings as the best outcome generally but with the new LP filter it needed ago, still learnt about ISO now thank guys. I'll post both to compare, the first is the original image. The second is 46x30s @ 3200 ISO I may have over done the red levels. Cheers Nige.

Thanks for the link. I guess I Neen to find the best settings for my cameras, All knowledge and improvement though Nige.

While I was taking subs Tuesday night I did a quick test, a 40 second at 1600, and a 10 second at 6400, the images looked identical, now I'm sure there's a lot more to it than that but I don't know much about it yet..... The doughnuts, I recon either a result of 6400 ISO or over developing, to be honest I hadn't noticed, I think I need new reading glasses. Now I see them. StarTools can deal with them easy enough. The bright spot is quite big in the uncropped image and I think its to do with the flats, I had my telescope balanced on my shoulder like a bazooka aiming at the PC screen while trying to snap shots off, I bet it looked quite funny. Cheers Nige.

I tried something a little bit different last night, with the LP filter I upped the ISO to 3200 then 6400 and 30s subs just to see how it would turn out. Correct me if I'm wrong but a 30 second exp at 6400 ISO = 120s at 1600 ISO but with more noise. The subs were pretty good, both Flame and H/H were visible. There's 50 x 30s at ISO 3200, 45 x 30s at ISO 6400..... PC crashed second time at 01:15 so I packed up. Was hoping for at least 90 minutes. I didn't mean to take 2 different ISO sets but I wasn't going to bin the 40 or so taken so what the heck do it anyway. The offsets, 50 @ 3200 ISO bias, 50 @ 6400 ISO bias, 30 ISO 3200 flats, 30 ISO 6400 flats, 30 x darks of each too. Hmmm all flats darks and bias taken in the morning while still blinking cold in the conservatory observatory. Next will be normal settings to compare. Its not brilliant but not bad either. A lot of noise top centre I think due to flats. Cheers Nige.

Ken. I think I prefer the original image, darker back ground and brighter nebula, although as you said the new image has quite a bit more of the darker nebula visible. The stars are much sharper in the new. The crop is a bit different so I could be wrong about the brighter nebula I am impressed with the CCD images Cheers Nige.

Nice images, I like it when you do something that's no possible, keep it up guy's Nige.

Just had a look at astroboot, never seen it before, some good bargains there. Thanks, Nige.

My last night imaging session didn't go to well either. A nice clear night, 12:30 my target was in a good position, so with the LP filter in place I lined up and focused, took a test 60s to see what was visible, a good test, I can see the Flame and Horsehead. Grab a quick cup of tea and start with a batch of 40s. First sub looks a bit dull, no detail, second worse still, quick look outside to see clouds. within 10 minutes full cloud cover and temp rise of about 5 degrees. The star discovery is a good mount with good tracking and yes it can be moved by hand and sent straight back to a target by pressing enter. handy if I move the mount changing camera battery or orientation. It is easy to knock out of line though, just a gentle touch and it moves. Only the altitude has a clutch to tighten. Nige.

Don't give up hope, with a photon hoover like yours and quite dark sky's of Woodbridge ( Suffolk I guess ) you can get a lot with 1 or 2 second exposures stacked, it might take quite a few but certainly possible. Nige. PS, quite often sail to Woodbridge in Suffolk,

Hi SR and welcome to our playground As Jimbo asked is your mount motorised. If your mount and scope are balanced and smooth tracking then I can't see a problem. Ideally motorised mounts are better as they track but it is possible to get DSO images with 1 second exposures, just loads of them, you would be restricted to brighter DSO's with no motors. There's still plenty of them to capture though. Camera choice I can't really help there, I have only owned canons, the noise levels are not to bad considering the short exposure side of things, I just bought a clip in Light pollution filter which has made a big difference reducing the noise levels. Another thing to look out for is to make sure your scope with a camera connected at prime focus can actually focus on the target. I had to modify my telescope to be able to connect my camera as the focuser would not travel in enough to focus. Cheers Nige.

Hi there. Welcome. Subs or light frames are individual photos taken of your chosen object, so 50 subs x 30 seconds is 50 photos, offset frames are to reduce camera noise and telescope anomalies like hot pixels on your camera sensor etc. Offsets include dark frames, flat frames and bias frames. Dark frames are exactly the same settings as the subs or light frames but with the lens cap on so no light reaches the sensor, Flat frames remove the effects of the telescope or lens, (darker around the outside of the image), a flat frame is taken using the same ISO setting but with camera set on AV mode pointing the scope or lens at an evenly lit surface like a white computer screen. Bias are taken with camera cap on, same ISO setting, but shutter speed fastest possible. An example, say 100 lights or subs at 30 seconds , iso 1600 would need around 50 or so darks at 30 seconds and iso 1600, 50 or so flats iso 1600 and 50 bias iso 1600. adding the offsets helps in processing a lot removing noise vignetting etc. Darks and lights should be taken during your imaging session ideally but bias are re usable needing updating around 6 months. Hope this helps a bit. cheers Nige

Thanks guy's, when I first saw the difference between the M33 exposures I thought I had made a mistake buying the filter even while I was taking the M31 subs the visual difference between previous exposures appears doubtful. Once I started processing the difference become very apparent. I was sweating for a while. Cheers Nige.

Ian, it's the other way round, without flats much worse I reprocessed the same stack and binned the one with no flats, couldn't process it . Nige

This should be posted in the new discussion post, all the support would only improve the chance of a new topic

Reprocessed the 135mm image, with no flats much worse so in the recycle bin. managed to get a bit more but it does need the intended 2 hours of subs. original Reprocessed Nige.

Now the results of the LP test. The 2 following images are M31. the first my original of 120x30 and 80x45s ( a good example of looking for a post in this thread, I didn't log the subs so needed to find my original M31 post, funnily enough its on page 31 but took me some time to find it ) Second image is 30x60s with dark and bias, no flat. EOS 1300D with LP filter, 150P on Alt-AZ mount. DSS & StarTools. My conclusion-The detail is greater in the first but it is 2 hours against 30 minutes the second has more body if you know what I mean.. The second image, easier to process, less gradients, a bit easier to draw the colour, far less noise in the whole frame edge to edge. Positive I think. Nige.

I'm on to it now.

Which thread should a discussion on a new topic be posted? There isn't a general discussion topic. I guess its imaging discussion

Thanks Ian. I tried for 2 hours everything I could try in wipe, with mask without, inverted mask Gradient, vignetting, amp glow. small mask big mask lots of small masks. A combination of gradient and vignetting with no mask worked best. Cheers Nige.

Ken, No this it without the filter. I did take a batch of 60s on M31 with the LP filter which is in line for stacking after the re stack of the wide field image. Result will be posted. This will tell me if I wasted over £100 Mind you it could be good with the modded camera soon to be back in action. Cheers Nige.

Steve, this image has been wiped gradient and vignetting, isolated with a mask, less-more with a mask and isolate again to remove a very bad top left gradient

I agree a new thread to discuss this is a good idea. So, last night I had a battle with my imaging PC, It shut down on its own 3 times while gathering subs, 3 hours spent getting 1 hour of 30s on Horsehead, flame & Orion with my 135mm lens. then the fog rolled in. DSS refused a few subs. I took darks flats and added the stock bias. I had a very hard time removing gradients so i'm re stacking without the flats to see if that helps. The info is there, removing the gradients has taken so much detail out though. Canon 1300D 135mm lens, 94x30s light ISO 1600, 40 flat, 50 dark, 50 bias. Star Discovery Alt-Az mount, DSS & StarTools. Cheers Nige.