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Petergoodhew last won the day on January 13

Petergoodhew had the most liked content!

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About Petergoodhew

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  1. I'v been using the SX AO for a few months. As Olly says, I use it to keep the second scope on my dual rig perfectly aligned and to compensate for differential flexure. At 1200m focal length, and with minor differences between the scopes (tube, focuser, camera, and adapters are all slightly different) - and for 30 minute exposures - the flexure is enough to cause problems. The AO fixes it perfectly. I wouldn't recommend it as an adaptive optics solution (SX call it Active Optics, not Adaptive Optics). Yes the device is fast, but as Sara says, when I tried it my Lodestar X2 just wasn't able to pick up a bright enough star to refresh at the rate of the AO unit. Maybe with a faster scope, shorter focal lent=gth, and wider field of view it should be better - but that's just a hunch, not experience on my part. Installing it, and getting it running with PHD2 was very easy. If the drift exceeds to capacity of the AO then PHD2 sends a pulse to the mount to nudge a little to recentre the AO unit. It's worth noting that the AO cannot function without a Lodestar - so this does get expensive as it's not just the cost of the AO unit. Peter
  2. Looking pretty good to me Rodd
  3. Thanks Peter. In my experience these ultra-faint targets can only be captured with very clear dark skies, and with the moon well below the horizon. Otherwise the signal gets drowned out by the sky background. Even in Spain, with 3nm/5nm Ha/OIII filters, I can't see any trace of them if the moon is above the horizon - even if it's on the other side of the sky. So now I just don't even bother trying until the moon has gone - unless I'm shooting a bright target (which I never seem to do these days!) Peter
  4. Thanks Goran, I had the coordinates from the original discovery so I knew where to look. I then keep increasing exposures, binning and stretching the images until something appears. In this case almost nothing was visible with 1800s bin 2x2 subs - hence I had to go bin 3x3.
  5. StDr 1 - a possible planetary nebula in the constellation of Taurus, discovered by Xavier Strottner and Marcel Drechsler in November 2019. This is the first time it has been imaged in colour. It is extremely faint - and so 1800 second exposures binned 3x3 were necessary. Astrodon Blue: 17x300" Astrodon Green: 18x300" Astrodon Red: 18x300" Astrodon Lum: 21x300" Astrodon OIII: 8x1800s bin 3x3 Astrodon Ha: 19x1800s bin 3x3 Total Integration: 20 hours Captured on my dual rig in Spain. Scopes: APM TMB LZOS 152 (6" aperture 1200mm focal length) Cameras: QSI6120wsg8 Mount: 10Micron GM2000 HPS
  6. Kronberger 24 is a faint planetary nebula in the constellation of Cygnus. It was discovered by Matthias Kronberger in 2010. Reference: <a href="https://arxiv.org/pdf/0910.0465v1.pdf" rel="noreferrer nofollow">arxiv.org/pdf/0910.0465v1.pdf</a> Astrodon Blue: 210x300" Astrodon Green: 20x300" Astrodon Red: 20x300" Astrodon OIII: 41x1800s bin 2x2 Astrodon Ha: 27x1800s bin 2x2 Total Integration: 39 hours Captured on my dual rig in Spain. Scopes: APM TMB LZOS 152 (6" aperture 1200mm focal length) Cameras: QSI6120wsg8 Mount: 10Micron GM2000 HPS
  7. Here you go Alistair - a typical unprocessed OIII 30 minute Bin 2x2 sub. The Ha is much much fainter. Peter
  8. Kronberger 63 is a planetary nebula in the constellation of Orion . It was discovered by Austrian Mattias Kronberger who is a member of the amateur group Deep Sky Hunters. It is very faint and thus rarely imaged. Indeed my searches have found only one other image, produced by the Chart32 team in Chile. Astrodon Blue: 21x300" Astrodon Green: 20x300" Astrodon Red: 20x300" Astrodon OIII: 48x1800s bin 2x2 Astrodon Ha: 26x1800s bin 2x2 Total Integration: 42 hours Captured on my dual rig in Spain. Scopes: APM TMB LZOS 152 (6" aperture 1200mm focal length) Cameras: QSI6120wsg8 Mount: 10Micron GM2000 HPS
  9. Abell 24 (PK 217 + 14.1) is a faint planetary nebula in the constellation of Canis Minor. Astrodon Blue: 20x300" Astrodon Green: 20x300" Astrodon Red: 20x300" Astrodon Ha: 37x1800s bin 2x2 Total Integration: 23.5 hours Captured on my dual rig in Spain. Scopes: APM TMB LZOS 152 (6" aperture 1200mm focal length) Cameras: QSI6120wsg8 Mount: 10Micron GM2000 HPS
  10. Olly, in my case the rings ARE the alignment device - there's nothing else to align them! I decided to exploit Alistair's point that the slightest turn of a bolt moves everything. In my case, with focal length of 1200 and small sensor (my field radius is 0.36 degrees) I needed a very precise way of aligning. Assuming I want, say, 90% overlap between images I need to adjust the alignment to around 0.04 degrees. My simple solution was to stick heavy-duty steel brackets on the extra rings that are as close as possible to the focusers, with hex bolts connecting them. I can now, using an allen key, finely adjust to with 0.01 degrees. The other issue of differential flexure proved more problematic. I had naively thought that by having the same OTAs, both with Feathertouch focusers and QSI6120 cameras that both scopes with flex in pretty much the same way. However life is never that simple! One of the scopes was bought second hand a few years back, the other was brand new. So the tubes were slightly different, the Feathertouch focusers were different, one of the QSI cameras was an OAG version, the other had a separate OAG. The net of this was that the two scopes flexed in different ways. It wasn't just the tubes, but the gear hanging off the back of the tubes too. No amount of tightening could stop the second scope from having oval or trailing stars. The solution was to fit a Starlight Xpress Active Optics device to the second scope. I now have better stars on the second scope that I have on the primary scope!
  11. Thanks Dave. I do enjoy a challenge - and some of these are really challenging! It's good to get going again after two months of cloud and rain. Happy New Year to you and the family - and the best of luck with Pixelskies in 2020. Peter
  12. EGB 4 (a nebula discovered by Ellis, Grayson, & Bond in 1984) is NOT a comet, despite it's comet-like appearance. It is an emission nebula surrounding a catacylismic binary star system called BZ Cam in the constellation of Camelopardis. It has an unusual bow-shock structure as BZ Cam (with it's associated wind) moves through the interstellar medium, similar to the bow wave in front of a ship that is moving through water. BZ Cam is believed to be a white dwarf star that is accreting mass from an accompanying main-sequence star of 0.3-0.4 solar masses. It is around 2,500 light years away, and has a space velocity of 125 km/second. I can only find one previous image of EGB 4 online, a NASA APOD from 2000, so I believe this could be the first amateaur image and thefirst colour image. Yes it's incredibly faint! Astrodon Blue: 15x300" Astrodon Green: 15x300" Astrodon Lum: 20x600" Astrodon Red: 15x300" Astrodon OIII: 25x1800s bin 2x2 Astrodon Ha: 56x1800s bin 2x2 Total Integration: 48 hours Captured on my dual rig in Spain. Scopes: APM TMB LZOS 152 (6" aperture 1200mm focal length) Cameras: QSI6120wsg8 Mount: 10Micron GM2000 HPS References: apod.nasa.gov/apod/ap001128.html THE ASTRONOMICAL JOURNAL, 115:286-295, 1998 January © 1998. The American Astronomical Society. aanda.org/articles/aa/full/2001/36/aa1385/aa1385.right.html
  13. Many thanks Olly. If I hadn't visited Les Granges so many times I would never have learnt so much from you that has made shooting and processing such difficult images possible!
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