By old_eyes on Sunday, 21 February 2021
Posted in Syndicate Lounge
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I have been messing around with options for the vast nebulosity around Cygnus. There is so much that if you try to build a mosaic - even with the wide field of Pier 14, you get a very large number of panes. A mega job. However, although NGC 7000 is a common object, you can get a nice 3-pane mosaic with a wider and perhaps more interesting perspective. What do you think? We could then do the Sadr region separately and dream of the mega-mosaic. NGC7000 3-pane.png Pane, RA, DEC, Position Angle (East), Pane width (arcmins), Pane height (arcmins), Overlap, Row, Column Center, 21hr 02' 44", 43º 41' 37", 90.00, 323.40, 215.40, 25%, -, - Pane 1, 21hr 17' 37", 43º 38' 00", 92.57, 323.40, 215.40, 25%, 1, 1 Pane 2, 21hr 02' 44", 43º 41' 37", 90.00, 323.40, 215.40, 25%, 2, 1 Pane 3, 20hr 47' 51", 43º 38' 00", 87.43, 323.40, 215.40, 25%, 3, 1
Alternatively, we could use a 50mm lens ;-)
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3 years ago
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Hi Richard, Been there and done that on pier 6. At the time the camera on that pier, like pier 14 now,was also vertically oriented. I did a 2 panel with a largish overlap to avoid including  Deneb. Cost prevented my going for the left panel you show, so great to see it here.  I'd really welcome this as we now have a complete set of calibration files. The first panel I did was processed without any as they were not available at the time, and their absence showed. Cheers, Ray
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3 years ago
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Three pane mosaic submitted Ha 240 x 20 O3 240 x 30 S2 240 x 40
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3 years ago
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Nice submission, that will be an awesome mosaic when finished! I see the interim filter percentages are now in play Steve
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3 years ago
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Absolutely agree, just need the weather to cooperate at the right time.  BTW, is that the Flying Bat that has now completed Richard? Would be interesting to see how much of the Squid has been revealed, as I think we may have discussed capturing more data if it was looking achievable with a bit more time.  Cheers Ray 
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3 years ago
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Absolutely agree, just need the weather to cooperate at the right time.  BTW, is that the Flying Bat that has now completed Richard? Would be interesting to see how much of the Squid has been revealed, as I think we may have discussed capturing more data if it was looking achievable with a bit more time.  Cheers Ray 
Yes, that's the one. However, it has been at 100% for several days and not yet available for download. I am assuming it has reached that stage that downloads often get a bit stuck in, where it is showing 100% but it is not quite finished yet. I have been processing some of the data from the IKI observatory for practice (M16 to be specific) via Stargazers Lounge. The files are smaller as the camera is a Starlight Xpress 694 - a CCD with 2700 x 2200 pixels (the same geometry as my Atik 460 ex). So processing is quicker and trying things out easier. Also David Willis of Pixel Skies, who took the data, did a video of his processing sequence for it in Pixinsight, so I could follow along. Their total exposure times are much longer than ours. OK, slower scope, older design of camera etc, but interesting. I guess when we have a few more images processed we will know what works for Pier 14.
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3 years ago
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Absolutely agree, just need the weather to cooperate at the right time.  BTW, is that the Flying Bat that has now completed Richard? Would be interesting to see how much of the Squid has been revealed, as I think we may have discussed capturing more data if it was looking achievable with a bit more time.  Cheers Ray 
Yes, that's the one. However, it has been at 100% for several days and not yet available for download. I am assuming it has reached that stage that downloads often get a bit stuck in, where it is showing 100% but it is not quite finished yet. I have been processing some of the data from the IKI observatory for practice (M16 to be specific) via Stargazers Lounge. The files are smaller as the camera is a Starlight Xpress 694 - a CCD with 2700 x 2200 pixels (the same geometry as my Atik 460 ex). So processing is quicker and trying things out easier. Also David Willis of Pixel Skies, who took the data, did a video of his processing sequence for it in Pixinsight, so I could follow along. Their total exposure times are much longer than ours. OK, slower scope, older design of camera etc, but interesting. I guess when we have a few more images processed we will know what works for Pier 14.
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3 years ago
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Pete has not had chance to check the data set is all, we are both busy getting ready to go to Spain at present to get the last bits fitted and the new Piers 9 & 10 fitted So please forgive the tardy approach to checking the last data set :0) Steve
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3 years ago
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Hi Steve, Didn't realise that you'd be off so soon, so what you explained is fully understandable and far more important. If you read this Peter please make sure Steve removes his bucket and spade from the van, else upon your return you'll have a hard job convincing the authorities not to fine you both £5,000! Safe journey gentlemen. Cheers Ray 
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3 years ago
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Thank you here is the other reason we are packing and driving over rather than flying, This parcel has been in Spanish customs on and off for over 12 weeks after it came back to the UK the fist time, its the new Kepler camera for Pier-8 and has caused me much concern as well as delays for customer orders Brexit has been a nightmare and its proved almost impossible to get anything delivered to mainland Europe since the 31st December. add to this Covid and I am sick to the back teeth of it all! fedex.png
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3 years ago
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Pete has not had chance to check the data set is all, we are both busy getting ready to go to Spain at present to get the last bits fitted and the new Piers 9 & 10 fitted So please forgive the tardy approach to checking the last data set :0) Steve
Don't worry. I have plenty of data to be working on at present. Just processing some of the Leo LRGB stuff, with a 2-pane Virgo cluster waiting in the wings :-). Good luck with the trip.
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3 years ago
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Good news, but maybe not so good news? Good news first. Providing that I manage to get the images to download for viewing you will see what you can get with minimal processing, warts and all. All subs that I considered as being acceptable were calibrated, aligned and stacked. These were then combined in PixMath to create a SHO image. The resulting image was processed in Background Neutralisation and Color Calibration. The predominance of magenta was removed and then the image stretched using the ScreenTransferFunction and HistogramTransformation. For the automatic stretch using STF I un-linked the channels. The results hopefully will appear below. No cropping or any background extraction or any noise and colour adjustments, apart from basic colour calibration, were performed. So the good news is I believe that these are impressive results when viewed at a distance. I haven't zoomed in, didn't want to burst my bubble! As soon as the additional subs I've submitted to replace those I rejected are received back then I'll then have a proper go. The not so good news? These 2 panels do not appear to align properly to create a full 2 panel mosaic. Have a look at the relative position of the common brighter star ( apologies I meant to say the small cluster) in each image and you'll notice that the left hand pane is basically lower than the central one. See the next paragraph. Hopefully the right panel, when we receive it will have a better fit and we can have a 2 panel mosaic. Not the end of the world as the left panel will make a great image on its own. When I did a similar but only a 2 panel pano on pier 6 last July, (the camera then on pier 6 was in same rotation as pier 14 is right now), I was ultra cautious given the extremely wide FOV and inability to rotate the camera, so opted for a huge overlap. I only used a separation of 7 minutes in RA and had no problems creating a mini mosaic, my cautiousness must have paid off. Basically I ended up with just 1 1/2 panels. Cheers, Ray Edit: Oops. 2 of each image, sorry. Also for some reason I mentioned comparing the relative position of a common bright star. Meant to be the small star cluster, not sure what I was thinking at the time?) 06_resize_40pc test SHO ROT 90 panel 2.jpg 06_resize_40pc test SHO ROT 90 panel 2.jpg 06_resize_40pc test SHO ROT 90 panel 3.jpg 06_resize_40pc test SHO ROT 90 panel 3.jpg
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3 years ago
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Good initial process. Very encouraging. I just started on this data last night. I just double-checked the coordinates in Telescopius and Cartes du Ciel, and they look OK to me. Once I have the Ha stacked for both panes, I will platesolve and see what coordinates come out. I agree that the left pane looks lower than the centre pane. If there is a consistent error we need to understand what is going on. I had a similar slippage for the Heart and Soul mosaic, but I put it down to incorrect coordinates. I must go back and see if that is the case.
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3 years ago
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OK, I now understand what has happened. I stacked the Ha for both panels, aligned them to each other and used GradientMergeMosaic to make a crude combined image (no fiddling about to deal with artefacts at the boundaries). Gives this: TestMergeMosaic2resize.jpg So the same kind of slippage between panels we saw with the Heart and Soul mosaic. I used ImageSolver on each panel to check actual coordinates, and they are correct. HOWEVER, I noticed that the camera orientation is 104.8 degrees, not the 90 degrees we had been assuming for portrait orientation. This has a big impact. The correct layout for the mosaic should be this: Correct mosaic.jpg With distinctly different coordinates for each frame. We are only 14% into the right panel, so it may be worth reframing. We need to revisit any mosaic in the queue to see what effect the coordinate error has and replace jobs if necessary. I am glad I did not submit the 4-panel Sadr region mosaic. That would have been a disaster.
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3 years ago
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Cool, at least your getting to grips with it Did you see the other thread I have opened re to reduce or not to reduce on P14 ? Cheers Steve
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3 years ago
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Correction, the angle is of course the other way: Correct mosaic.jpg
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3 years ago
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Hi Richard, Well done, I should have checked the equipment page rather than making assumptions. It says 80 degrees, but after applying a 14 degree rotation to one of the images it then pretty much aligned with one taken last year. I assume the camera on that pier was pretty much vertical. Hence I had no problems myself. Need a bit of time to consider what to do now, but I can definitely pull a few of my recent submissions if that would give time to resubmit that pano. Could have been worse if you'd put the Sadr region in first.
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3 years ago
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I have submitted a new job (1014) to replace job 998 (North America mosaic right panel). This has corrected coordinates to line up with the centre panel we have already received. It is a bit of a kludge, but will give us a nice 2-panel of the North America and Pelican nebulae. if we continue with 998, I think we would have to crop part of the NA out. I hope this works out.
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3 years ago
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Cool, at least your getting to grips with it Did you see the other thread I have opened re to reduce or not to reduce on P14 ? Cheers Steve
Steve, I have commented on that thread. I think it is OK. Please note that new job 1014 replaces 998 (only 14% complete). It is a correction for the camera angle being different to the assumption I made (idiot!!). I will hold off on any further mosaics until we get the reducer removed. I will check through outstanding jobs to see if there is anything that would be nice to finish before the change.
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3 years ago
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I have just realised with the angle changed, we had the OAG removed and added some spacers a couple of months back if you remember and then took new flats Obviously the angle acted a little
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3 years ago
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