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About Penguin

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    Star Forming

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    Gloucestershire, South-West England
  1. Thanks for those suggestions guys, I have plumped for this StarTech one: https://www.amazon.co.uk/gp/product/B00SCE4E0I/ref=od_aui_detailpages00?ie=UTF8&psc=1 I am considering keeping it indoors between sessions, like I do with the observatory laptop after everyone's comments about the environment. Also, this ACF50 stuff sounds quite miraculous, do you recommend spraying the mount and other components as well? When I get to guiding, I fully expect the observatory laptop to need replacing, at least with something that has USB3 and maybe at that point I will also consider a 2nd hub. At the moment I am only really using 2 or 3 ports (mount, camera and a games controller) so the 7-port hub I have ordered is probably a bit of overkill but does look more rugged than the 4-port ones I have seen.
  2. I currently have a laptop in my roll-away observatory, connected to a powered USB2 hub on the pier, from which I then power and control the various bits and bobs on the rig. This is now the 2nd USB hub that has stopped working. Can anyone recommend a reliable one? I have seen a few threads mentioning USB hubs but none actually recommending a reliable one. The laptop only has 2 USB sockets so although my cables will reach it, without the hub I can only connect 2 things at once, one of which has to be the mount. All the stuff in the observatory is powered via an extension cable from the house.

    It now leaks to the point that I have covered it in a tarpaulin. Luckily, I am still able to use it. We're moving house in the summer so the scope will be back on a tripod for a while and that will give me a chance to fibreglass it before returning it to its observatory function.

    Oh yeah, it leaks, but only in a couple of places. I plan to fibreglass the roof soon in the hopes of fixing that.

    Here's mine, inspired by @lukebl's. Built over the summer by your's truly:
  6. Thank you so much guys, I am learning again! I took a load of bias frames at ISO 1600 (matching the lights/darks) and 400 (matching the flats) and re-stacked the HH image in DSS, which warned about differing ISO settings but seemed to apply them correctly. Then I applied Wim's workflow which was a slight re-ordering of steps and very different with DBE: I had previously been told to use 30 samples per row, which often seems to extract a very mottled background and I suspect may be a major cause of the problems I have been having. For colour calibration, I have never previously used the entire image for white reference, nor used structure detection. Here are the results, it's much cleaner but has also lost dome detail and definition, particularly noticeable in the Horsehead itself. Possibly some aspects of my previous processing were better than this attempt:
  7. Thanks guys, there's a lot to think about here, I shall take it away and cogitate.
  8. Hi Michael, that would be fabulous to save time or get an extra few lights. Can you explain how using bias as dark frames works? I thought a primary purpose of darks was to get the thermal signal with the light-frame exposure at the temperature the lights were taken at so that it could be subtracted from the lights. How do we achieve that without darks? Also, DSS complains if the darks are not the same exposure as the lights. Will it still work? Also, what do you mean by "you must Dither between shots"?
  9. Thanks Alan, there's some useful (and free!) things I can look into there. I have not tried TGVDenoise so I will investigate that. I normally do SCNR Green as the last step in my workflow but having just tried it on the Flame/Horsehead image, I can see that it is reducing the green so maybe I had missed that step. In terms of calibration frames I normally take 15 darks at the end of my session. It's a bit annoying having to spend another 1/2 hour taking 'blank' shots before packing up when its already 12:30am but I do understand the benefit. Is 15 frames/30 minutes long enough for the darks? I also take around 15 flats at the end of the session using this panel, which has several sheets of photo paper in front of it to allow the camera to take a long enough exposure that the LED refresh doesn't mess up the image, and is housed in a makeshift frame. I have also attached a single flat from the most recent session. Again, is 15 enough? Is there a better way to take them? Bias is easy and I gather I can prepare a set once and use them multiple times, I have just been lazy. I will prepare a set now and might try reprocessing a few of my existing images.
  10. Yes, I focus with a bahtinov mask, but I always end up with one of the axis spikes diverging into two, as can be seen with Alnitak on the Horsehead/Flame image and I don't understand what is causing that. I tend to focus at the scope since I don't have an auto-focuser so would have to keep going back and forth between scope and computer. Otherwise, I would post the focusing images for you.
  11. Hi Guys, just looking for some general help with improving my images I'm not sure what to concentrate on to get the best bang for my buck. Here are my latest couple of images: Both of these are taken with an unmodified Canon 450D through a Skywatcher Explorer 150P on an HEQ5 Pro which is on a permanent pier. I have no guide-scope or filters and just take colour subs. I am stacking in DSS and processing in PixInsight, blindly following a workflow I was shown a couple of years ago. The PixInsight workflow goes: Background Neutralisation DBE Colour Calibration Histogram Transformation HDR Multiscale Transform ACDNR, followed by another bit of histogram transformation Curves Transformation (I possibly overdo this a bit but I like the colours!) SCNR Both these images were with 2 minute subs. The Flame/Horsehead was 2 hours-worth (with 15 darks and no flats) and M81/M82 was 4 hours (with 15 darks and 15 flats). What do you think are my worst offences? I can think of lots of things I could improve but I don't know what to attack first: Better polar alignment Guiding (I do have an 80mm Skywatcher refractor that I can piggy-back but I don't have a guide camera) Bias frames (I believe I could just take one master set rather than taking them every session. Would they have much of an effect?) Using filters (maybe a light pollution filter?) Coma Corrector Better use of DSS Better use of PixInsight
  12. Cheers, so in summary, that heater is suitable but any dehumidifier would need to be a desiccant type, preferably with a drain hose. That's really helpful, thanks guys --- Alistair
  13. Budget Observatory under £250

    That is a really neat and compact observatory and a gorgeous first-light image!
  14. I am looking to protect the gear I have in the roll-away Tardis observatory I built this year (see this thread on the build if you are interested: A dehumidifier: https://www.appliancesdirect.co.uk/p/md400/electriq-md400-dehumidifier) A greenhouse heater: https://www.greenhousepeople.co.uk/products/3872/slimline-eco-heater-55w-tube-heater-with-thermostat/ The observatory itself is around 1 meter square and 2 meters tall. Ventilation is currently provided by the gap in the base around the pillar, a large vent behind one of the 'Police Box' signs at the top, and the gaps around the door caused by my general bad workmanship! Do these seem suitable for my needs? Is there anything else I should consider?
  15. Fixing these star trails?

    Thanks Bob, and I'm also very interested in your home-brew guide camera article. Definitely something to look into once I am happy with the alignment. I'm planning on following this guide to get the alignment sorted: Drift Alignment by Robert Vice since it should be easy and quick to verify if the adjustments I make are correct.