Filroden

Olly may be right. Although my processor stabilises at 16C, I have no way of knowing if the sensor also stabilises. It's just my assumption that if the processor is heating to that temperature (it rises as it works harder, e.g. during live view) then it will also be heating the internals of the camera to a similar temperature regardless of external factors. I've read about people building coolers for their DSLRs but the bulky nature of the cameras means this is probably very inefficient. As I've said before, I'm not convinced the darks make any difference but given they are easy to take, I've applied them anyway. I took 4 hours to process that image as I had to learn PixInsight from scratch. However, there are some amazing step-by-step tutorials and I re-ran the process on 7 images of M101 to see if I could remember what I was doing and that took much less time (and I completed more of the steps once I'd figured how to do masks). With practice and the use of batch processing (which I avoided until I knew what the processes did), I think it could be reduced to about an hour's processing for a target. Given I think the image is more than 3 times better for the effort (and I actually enjoy the processing), it's an hour I will enjoy. I also learnt a new technique with Photoshop which uses the high-pass filter on a desaturated layer, then applied via a mask created by selecting a colour range. I tried it on the North America Nebula selecting the reds/pinks and it did sharpen the nebula, creating a little more "depth". One question that's had me thinking today: given we are exposure limited, do you think we could image using filters? I'm guessing not except for the very brightest of DSOs like M42.

It definitely has merits over DSS for calibration and stacking but it took 4 hours compared to 20 minutes. I need a few more serious attempts with it to compare results. There is no way I could have achieved the second image with Photoshop. There are batch processes that might speed things up but I first want to know what it's doing within each module.

Those are stunning. There is so much to see.

Yes. For the ZWO I have darks in 5C bands and multiple gains. For the Canon I only keep one set as it seems to settle to a standard temperature after about 30 minutes after aligning.

The one advantage of British weather is that our night time temperatures are fairly stable. I find my Canon starts at around 26C as I use live view to align and focus, and cools to about 16C where it stays for the entire imaging session regardless of actual outside temperature. That makes it easy for me to build a dark library.

Don't forget you can do your bias and darks during the day and they should be good for any future lights at that ISO and temperature. You can always cool the camera in the fridge or freezer to simulate night temperatures. Flats can be done at dusk so long as you can see a bright star to focus on. Arcturus is perfect at the moment.

I do plan on spending more time on the North America Nebula. I only imaged it the other night as a test. It was still very low in the sky. The forecast here suggests no clear nights for a week so I will probably have to wait. But it's going to be my project for a while now I know I can capture it. I'd probably be aiming for 200 more lights. Of your two images I do prefer the second even though it shows fewer stars. The background is less noisy and the colours look right. I also like that it gives M57 a little more space.

Well, I've just spent 4 hours reprocessing my North America Nebula subs. I gave StarTools a try and although I actually managed to create an image I liked, the process still felt like doing surgery with a mallet! So I downloaded a trial copy of PixInsight to see what a real pro piece of software could do. First I had to retake my bias and dark frames so my camera moved to the fridge for a couple of hours. With bias, darks and flats at the ready, I went through the whole calibration, stacking and processing using PixInsight with only a few minor modifications made in Photoshop at the end. BEFORE (44 x 45 seconds ISO 1600 with no calibration, stacked in DSS and processed in Photoshop) AFTER (43 x 45 seconds ISO1600 with 28 bias, 85 darks and 40 flats, calibrated, stacked and processed in PixInsight and finished in Photoshop) Very different images! (And I apologise that they are both low resolution. The final TIFF image for the second version weighed in at over 350Mb.) I think the biggest differences in processing were around being able to remove the background and controlling the stretching.

I should have said. I think I took them with the SCT and only managed 8 or 15 second exposures. By the time my refractor arrived, Orion and his friends had moved to the front of my house where all the street lights are, so I will have to wait until Autumn for round 2!

I can definitely see structure in the nebulosity but I can't see how much effect vingnetting is having and if there is also a background gradient. Again I'm jealous. I took 45 frames and got some beautiful stars but not a hint of nebulosity. Given its now raining maybe it's time to revisit the vault.

I love my refractor. The 80mm aperture gives a great field of view and it's so quick to set up and attach and focus the camera. It really is grab and go (if only the mount was as easy to lift). Not that it helps your decision!

No. Just a standard EOS60d.

I got 43 subs out of 45 taken at 45 seconds. With the wide field of view and the low altitude it was only the occasional slip of my mount's tracking that caused any issues. It was similar for M56. I don't think I rejected a single image.

About a third down from the bottom going from side to side. It's feint but easy to see in the full image. I can also see the planetary nebula, NGC 6765, in the hires image. Unfortunately I think it's lost in the lower resolution image I loaded into the gallery.

I'm so tired after staying out until 1:00 and even then I almost stayed out longer. I'd just finished a sequence of subs and noticed both Saturn and Mars had cleared the tops of the local buildings. I was so tempted to set up the SCT and take some video but I know I had to be up by 6:00. The evening started taking some test shots of M13 at different exposures and ISO settings to see how far I could push it. I could only get to 60 seconds but M13 was quite high (about 55 degrees above the horizon) so I moved to M56 which was only 20 degrees above the horizon. I did manage to get a single shot of 90 seconds though only at ISO 400 because of the light pollution. Given how many bad subs I got, and even the one "good" sub still showed rotation, I think 60 seconds is probably my limit and 45 seconds is a good working limit as that gives me almost 100% good subs. Here's the single sub, processed in Lightroom. I then stayed on M56 just to see what I could get and managed 31 x 45 subs at ISO 1600. Again, I've not bothered with any calibration files. I need to get back into that habit soon. Here's the finished M56 after processing in Photoshop and Lightroom. Do you know what? I'm not entirely convinced I've got these the right way around! The second image is actually the single shot (the satellite trail gives it away) I then moved onto NGC7000, the North America Nebula. I'd previously taken 30 subs the week before but I'd either lost focus or dew blurred the images. I did manage to stack them and I could make out the nebula but the light pollution at such a low altitude made it look terrible. Still, I wanted another try. Here's a new set of 43 x 45 second subs at ISO 1600. It's very noisy and I've had to hit the pollution with a fairly crude bat (dehaze in Lightroom). I am going to download a trial of the Gradiant Xterminator plug in for Photoshop to see if it will help me. At some stage I will have to invest in a Light Pollution filter. In honour of Steve, I aimed for a Kenyan blend in my light pollution but in the end decided to cheat and make it a little more red. It's not a great image but I'm pleased I can see the nebula and hold out hope that when it rises higher I'll start to get better subs.

I prefer my coffee like my skies...black. Unfortunately all I get is milky (and not the way kind)

Could you paint my fence in the 70 sec exposure? I think I have similar levels, at least to the North (Bristol 20 miles) and West (Cardiff 15 miles) not to mention Weston-super-Mare between them at 7 miles. That said, I downloaded the sky quality meter for my iPhone and it claims I have a 19.65 sky or 5.6 NELM. I can barely see 4 stars in Ursa Minor so I think my phone is having a laugh!

Both M56 and M57 should be able to take very long exposures before you see rotation as they are very low and moving round to almost due East. I might give them a shot tonight and see how far I can push it. The killer for me is light pollution which limits my total exposure. I think my peaks were almost 2/3rds across the histogram after 45 seconds at that altitude. I might drop down to ISO800 or even 400 just to test.

So might evening didn't go to plan last night. I set up the 9.25SCT so I could see what it could do with M13. I'd checked ahead and it would fit the FOV of the Canon 60D almost perfectly. There was only a very light breeze. However, I must have rejected so many subs. I was sat there with BackyardEOS running, assessing the image quality at between 100% and 325% magnification. It went a little like this - bad, bad, bad, delete, bad, bad, maybe, bad, good, delete, bad, bad, bad, maybe, bad, bad. Almost every sub had something wrong. I threw all the good and maybe candidates into DSS and DSS threw them all back at me. I need to review them individually but I've had this before with the SCT. DSS really doesn't like the images for some reason and I have to really force it to find stars even though I can see dozens (not counting the 200,000 of them in the middle of the frame). I tried 30 sec, 20 sec, 15 sec and even 8 sec by the end. It just wasn't my night. So I put in the eyepiece and used the old fashioned camera! Great at 24mm. Zoomed in with an 8mm and I could't get a sharp focus. Turns out it was a very clear night but the seeing was terrible. It was like looking through an oil covered window at high magnification. So here's an image of M5 from earlier in the week that I processed last night instead. 30 x 45 sec lights ISO1600 with no calibration using the Esprit 80. Not as pretty as M13 (in my opinion) but still a wonderful sight! I downloaded the Photoshop plug-in, Hasta La Vista Green, and it really did help my colour balance. I applied it to my earlier M13 and it left me speechless. Lovely little free plug in! Now I need a plan for tonight's targets. Probably back on M13 to see if I can't reduce the noise further. Maybe another 60 subs at least.

That's a lot of fuzzies you've got there. Don't beat yourself up. Many of those are elliptical galaxies (I think) and therefore less photogenic than their spiral buddies. The spirals I do see are edge on by the looks of it, so again they are being coy with the camera It does look like you've clipped a lot of detail to reduce noise (there is a very blurred background which I guess is the result of noise reduction). I wonder what it would look like with a much lighter and noises background? You can probably then make out a little more detail around the galaxies?