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The Lazy Astronomer

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Everything posted by The Lazy Astronomer

  1. I had a quick play in Startools; I won't post the result, because frankly what you've got here already is better. So I would say, in terms of pulling out detail, this probably not too far off as good as you'll get from the data. What I will say though, is I think you have slightly missed focus - what method are you using to focus?
  2. You can practically ignore everything you know about daytime photography - that's how different astrophotography is!! As @iantaylor2uk says, you won't go far wrong with 30 - 60 seconds subs.
  3. Darks are really only of use if you have control over the sensor temperature (eg cooled astro cam), else you end up potentially introducing more problems than you solve. For DSLRs, the usual advice is to take bias and dither between frames.
  4. If you find you need to add a very small amount to the optical train, your camera should have come included with a set of shims of varying thickness (my ZWO camera did, anyway).
  5. You could try usb over cat6? That's advertised to work up to 100m, but the hubs are quite expensive, and I've never used it myself so no idea if they're any good.
  6. I do the same as @PeterCPC. Dedicated scope-side laptop which runs everything, and just remote access it from another PC inside. My WiFi's half decent (most of the time!), so no ethernet cables needed either. If you've got a couple of PC's available, then this is a much better solution than looong usb cables.
  7. Looking good I would say though, don't worry too much about getting a dark black background - in fact, it's often commented on that startools processed images have too dark a background. Many people prefer a neutral dark grey background. I'm of the opinion that, as long as it isn't black clipped, the darkness of the background is to taste. If you haven't already, check out the unofficial startools manual (available to download as a pdf from the startools website) - loads of useful info and tips and tricks in there.
  8. Actually, I think it does work (in that rice will absorb moisture), albeit not that well, so really it should really be thought of as a poor man's dessicant sachet. Flushing with pure ethanol apparently the way to do it, so you'd better raid your spirits and get distilling! Edit: I've actually just discovered it's not possible to distill pure ethanol out of a water and ethanol mixture containing less than 95.6% ethanol without the use of benzene, so maybe don't do that...
  9. Just fyi, l cropped 3 pixels from each edge and masked off the dust bunny; wipe then seemed pretty happy to do its thing.
  10. As others have already done this, it's probably not so relevant now, but this was the product of 5 or 10 minutes in startools. Nothing fancy done, just a basic crop, wipe, autodev, contrast, hdr (reveal core), colour and superstructure (isolate). I then went and added a bit of skyglow back in film dev: I would have to agree with the others and say it looks like focus was slightly off and I would also say the focus looks slightly off in your IC405 image as well (although you have captured that lovely blue reflection nebula around AE Aurigae, which is very nice ). Below is the luminance channel from my recent attempt at M31, which I've rotated, cropped and resized to roughly match yours (all I've done to it is wipe and autodev) which I hope shows the difference, particularly on the smaller stars. As an end note, you may also have some chromatic aberration - this can be remedied with a UV/IR cut filter which cuts off the extremes of the blue and red light wavelengths (e.g. Astronomik L3)
  11. Fundamentally, l am in agreement with you about the ease of osc, and if l were to upgrade my camera now, l would probably go down the osc route for a bit less faff in my life. But, due to the short exposures it's possible to use with modern CMOS cameras, l can capture one round of all colour channels in just a few minutes and keep repeating the loop until the end of the session. Sure, it's still possible that some subs may be affected by cloud or something, but it would really be very unlucky if one channel was significantly disproportionately affected compared to the others.
  12. I was just thinking that - the CPU must've had a hell of a job stacking them all!!
  13. I would say the 1600 is 'old hat' now. If your choice is only between that and the 2600mc, then go for the 2600mc (and I say this as a mono guy). As a side note, I never really understand the weather argument against mono. With an autofocuser and filter focus offsets, you can run through the filters in a loop, rather than in blocks, and you end up with full colour data from each session.
  14. Ah, yes, wipe will do that if there are stacking artifacts around the edges or what startools refers to as "dark anomalies" in the image (e.g. dead pixels, or small dark dust shadows). From the image you've posted above, it doesn't look like there's any dust shadows, so l would suggest there's probably some stacking artifacts messing with wipe's algorithm (it really, really hates them!!). Try cropping the edges of the frame first. Feel free to upload your stacked fits file and I'll have a play around with it if you want? 2 minute exposures are probably fine. It's probably longer than you need to do, but you won't be overexposing.
  15. Did you run it through the wipe module first? There's no real way to completely escape light pollution during capture (except maybe going to out into the middle of nowhere!) but wipe, or other similar background extraction routines in other software, should help to remove/reduce the effects of it. Another thing to consider is your exposure length. What's the setup you used here and where on the bortle scale are you?
  16. Looks like inverse vignetting to me. Caused by flats over correcting - how did you take the flats?
  17. Lovely detail in the dust lanes. I also note you've got a blueish hue in m110 - l got a similar colour on my recent first attempt at m31, so, nice to see our results agree there at least (some images have it with this blueish tone, others, a more yellowish one). One way around it if you have an autofocuser and have set focus offsets for each filter is to shoot them in a loop, rather than in blocks. If I want to try and ensure I get all of the colour channels on a target, I do a sort of hybrid: I'll shoot 5 subs each of RGB, and 15 luminance and repeat until enough data gathered. Big advantage of modern CMOS cameras is long sub exposures are not needed, so you can complete one loop quite quickly.
  18. If your mount is the newer version which has the usb port on the mount head (see image) then you don't need any special cables, any regular usb cable will work Once connected to a PC, next thing to do is go into device manager (assuming you're on Windows) and check which COM port the mount is mapped to (note this will likely change if you plug into a different usb port on the PC, so try to remember which usb port you use, and use the same one each time) Then type eqmod in the search bar (again, I'm assuming Windows 10), and open the eqmod toolbox The window on the left will appear. Click driver setup and then the window on the right will appear. Under eqmod port details, set the correct com port as identified in the device manager and set the baud rate to 115200. This should now allow the PC to talk to the mount and you should be able to manually slew using the arrow keys in eqmod.
  19. 120 is probably your best bet as it's where the high conversion gain kicks in (read noise drops significantly, and dynamic range increases back to the same level as gain 0). 120 also happens to be unity gain on this camera (where 1 electron = 1adu). I have seen some people using high gain values with narrowband filters (e.g. 200 - 250) with pleasing results, but I've not seen any direct comparisons of high gain vs 120, so it may not make any appreciable difference. I have the mono version, and personally, I stick to 120 for now. Edit: I've just checked the specs, and unity gain is actually 117, so at 120 it's about 0.9ish electrons per adu, but, close enough!
  20. Ditto what's already been said. Leave the imaging train in tact, and you can reuse flats for a little while. Eventually you'll get some new dust motes or they'll move a bit and you'll need to reshoot the flats, but fortunately that's a job for the daytime/cloudy night.
  21. Thanks alacant. I follow all of the recommendations to get the data ready for st, but I find this tends to happen when the data is perhaps pushed further than it really allows, in combination with lazy/poor use of the star reduction and superstructure modules. It's definitely user error - I'm going to reprocess when I get the time to grab some more colour data (and redo the red channel completely, as it has not calibrated well).
  22. Images taken back in July or August sometime, finally got a process of it I'm happy with (3rd attempt at it). Approx. 4h45m total integration time, in the ratio of 3:1:1:1 Ha:RGB. I feel I may have murdered the stars a bit too much with star reduction, and my technique still leaves something to be desired, but I'm happy enough with this version for now. As always, comments and critisms welcome!
  23. Can always rely on you to spot all the issues! The background is one of things I was not very pleased with. I used Startools and l think it has a tendency to cause this type of background when the data is pushed too far. I probably should, as you say, be a bit more conservative with the processing. There was also indeed an issue with the red flats (and to certain extent, lum as well). I need to do a little investigating to find out why they didn't quite work. Unfortunately I've since disturbed the imaging train, but as it's only 40 mins of data, I think I might just throw it all away and redo the red channel entirely.
  24. Not necessarily that pleased with this one (neither capture nor processing), but as it's my first Andromeda, I thought I'd post anyway and hopefully will be able to show improvement in subsequent attempts. A bit over 7 hours integration, with the vast majority in L and only around 40 mins each R, G and B. Hopefully will be able to shoot some more frames over the coming months before Orion starts to take my attention away. As always, comments and critisms welcome.
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