Gina

PI spotted it. Checked the rest in Blink and all OK. Couldn't find the 120s darks so taking again. Or reduce exposure to say 15s

Oh - errr no forgot that I'll check shortly on the ones I've done and redo if necessary - also the next set.

Found the set of 60s g440 -30C darks. Integrating pixels. There was one duff dark frame so this is with 79 frames.

Here's the auto stretched 30s integrated image.

Yes, that's how I see it Glad you have the weather

Already have 80 dark frames of 30s g440 and -30C so I'm integrating these in PI as I can't be sure which "integration.xisf" file is which. Once this is finished I can save the resultant image in my Masters folder as a final good master.

With the master biases ready I'm now onto the darks which the book says uses the exact same settings as the bias integration. With nothing new lately due to the weather I'm going back to the earlier collections. viz. So for these I want 30, 60 and 120 second dark frame exposures with a gain of 440 and temperature of -30C. I think I have captured these and processed them so will check what I've got.

I think that's the master bias business sorted out I might want a lower gain one for (L)RGB but that depends on which imaging optics I use. The current 135mm lens is too widefield for even the Andromeda Galaxy (M31) though I did take some RGB lights of it a while back. My plan is to image M31 a bit later on when it's in a more convenient position. I think I'll be using a 200mm f4 lens for that. The smaller aperture will mean longer exposures or higher gain than I used before.

It might have come with SharpCap - not sure now. I do use SharpCap for focussing and framing but APT seems more suitable for image sequencing. I agree that the 1ms exposure seems much better and that's what I shall be using. The extra concentration of lighter pixels at the bottom in the master bias with 32 microseconds corresponds with the errors I was getting in my integrated lights. I have just completed integration of 300 bias frames taken with a 1ms exposure for gains of 440 and 500. These look just like the 1ms stacks already posted.

Couldn't seem to stretch it enough in GIMP so here's a bit bigger image in the screenshot using PI's auto-stretch.

Here's the image stretched in GIMP and saved as PNG.

I've now increased the exposure to 1ms and the result is quite different. I can also increase the size of the image window as you think that may make a difference.

Just tried increasing it to 100 microseconds and collected 100 frames. Here is the auto-stretched result. I can't see much difference.

32 microseconds = 0.000032s exposure time - the minimum for the camera.

Now the difference between the integration of 300 and 600 bias frame with gain of 440 and 1s pause between frames. These are screenshots of the PI images. The real "proof of the pudding" will be to run two lots of processing to compare the results.

OK - let's separate this out. Firstly, 300 bias frames with 1s and 5s pause between frames.

Don't think there's much difference if any. First image is 300 bias frames with 5s pause and second is 600 with 1s pause. I think if anything, the first shows a little more noise than the second which indicates to me that the pause has made no difference but that maybe 600 give a bit better result. I'll do a process of 300 of the 600 frames for true comparison.

Thanks Russel - I'll try that Yes, I am running the camera for hundreds of frames with only a 1s pause between each - I'll try increasing that , still won't take long to capture several hundred bias frames.

Integrated image for 80 darks 60s gain 440 -30C.

Integrated image for 80 darks 30s gain 440 -30C.

Integrated image for 600 bias subs with gain of 440.

Thanks Ken I seem to be finding that a gain of 500 (actually 501 as that's as near as I can get to 500 in APT, which I'm using for capture). That with 60s subs seems fine for most of the DSOs I've captured so far with 30s for brighter ones. This ties in with getting the histogram close to the white end and getting as much data depth as possible. Higher gains and shorter exposures seem to go with greater numbers of subs.

My lights are with gains of 440 and 500 - a lot more than yours and the offset I've been using is 10. Could you tell me the reason for using an offset of 50, please? And have you done tests at various gains - is 300 better that 440 or 500? I'm still experimenting and learning and very interested in other people's settings and why.

Now capturing darks to re-do these sets of lights properly. Currently 30s subs and 80 of them which I gather should be plenty.

ImageIntegration of 600 bias frames for gain of 500 completed. Here's a screenshot with auto-stretch applied to result plus settings. Now processing same for gain of 440.