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Bill S

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Everything posted by Bill S

  1. I have been looking at one or two supernovae recently. SN 2021fxy is in NGC 5018 and was reasonably easy to spot at a magnitude of about 14. The supernova is marked in this selection. SN 2021hiz is in IC 3322A (also called UGC 7513). It's a type 1a supernova of mag 13ish. I am much less confident I have caught SN 2021J in NGC 4414. It was about magnitude 14 in mid-March and it may well have faded. Anyway it's snapshot of the galaxy at the very least. Nice to have some clear nights! They've gone now. Cheers Bill
  2. Last year I posted an observation of NGC 4550. This is unusual and surprised me that it is rotating in two different directions. I have been looking for other examples of this sort of thing. NGC 4365 is an elliptical galaxy (E3) in Virgo. It's believed to be the result of a merger because it has a distinctly counter rotating core. It is very old, 12 billion years or so. Counter rotating disks are an active area of study and they can result from the merger mechanism (NGC 4365) or accretion (NGC 4550 above). See for example: https://astrobites.org/2018/09/26/going-against
  3. Arp 220 The Nearest ULIRG I watched an interesting talk by Prof. Dimitra Rigopoulou on the BAA YouTube channel about Ultraluminous Infrared Galaxies (ULIRGs). These are amazing bright objects but only known in any detail thanks to the availability of infrared telescopes. See: The nearest of these is Arp 220 so I thought I'll have a look at that. It's not the most photogenic DSO but knowing about the object when you look at it adds to its beauty. It's 250 million light years away. Not 250,000 as shown on the Powerpoint slide above. This
  4. Very interesting observations. The background reading was fascinating. The 1899 paper is not a good advert for astronomy holidays in Uppsala (or Upsala). Bill
  5. Re. Double Spikes I came across this. https://www.cloudynights.com/topic/513973-double-diffraction-spikes-normal-out-of-focus/ The later posts about double spikes when in focus may be of interest. Bill
  6. Good one, Mike. Well done!
  7. Will be good fun chasing some of these down and reading up about them. Thanks for the information and the links to the background reading.
  8. I've been doing a bit of asteroid spotting prompted by the close approach of Vesta. My first shot is from 25 February so there was a bright Moon around. Rather pointlessly I put it through astrometry.net and then ASTAP to annotate it. My reason was that I wanted to try the asteroid annotation feature in ASTAP. Vesta is the second largest asteroid (although the biggest, Ceres, is classed as dwarf planet). Vesta is said to have about 9% of the total mass of the asteroid belt and is about 525 km across. Well that worked OK so I had a look at some others. Several were so clos
  9. Martin - what a fine set of observations. I’ll be adding some of these to my lists for future observations and background reading. Some clear skies would help...
  10. Hello Martin A great couple of snapshots there. Beautiful and interesting objects. The central stars are fascinating. I had not heard about pulsating white dwarf stars before. More to follow up. Good to hear your standard approach for getting reasonable observations for many PNs. Bill
  11. I could not resist having a look at my colour (LRGB) Jocular snapshot of NGC 2392. Tried out the various stretch options. With faint distant galaxies I usually settle on hyper but this object is a lot brighter (only 5 second subs). Anyway, I settled on either gamma or log. Log is the one below. Brings out a bit of detail. Mike JW's in mono with the bigger scope and more pixels shows more though. Always good to see different shots and compare.
  12. Martin - I'll put it on the list for a return visit to look for the fainter objects you mention. Bill
  13. This observation started off being about Hickson 56. Hickson 56 is in Ursa Major and I was looking at objects in this part of the sky because it was away from a nearly full moon high in the sky. The components of the group are identified in this shot. The group minus a is also Arp 322. It’s also VV 150. Here's a wider field shot. I noticed another interesting larger object – NGC 3718. I could see a lot more detail because of its size. This is about 52 Mly away and has a bit of an S shape. It’s a barred spiral galaxy but because of its slightly strange shape it was a
  14. A few days ago had a look at VV 85 in Perseus. A closer in view makes it a little easier to see the components. The main component is NGC 1129. I found the labelled picture below which labels this galaxy and surrounding ones, including NGC 1130. Surprisingly a paper by Vorontsov-Velyaminov et al (or more accurately completed in his memory, I suspect, since it was published 6 years after his death) seems to list VV 85 as consisting of NGC 1129 and 1130 as a pair. See: http://images.astronet.ru/pubd/2008/09/28/0001230678/717-959.pdf Other reference
  15. Just to add to the opportunities for confusion and missing things I notice that the abbreviation ShCG has also been used for Shakhbazian compact galaxy group. for example: https://iopscience.iop.org/article/10.1086/307726/fulltext/39976.text.html Alvin Huey's guide to some of these groups is interesting. It may have been mentioned in this thread already. I could not find it so here's the link: http://faintfuzzies.com/Files/ShkGroups v1.pdf Bill
  16. A bit late to the party again. This is a shot from late October 2020. It's pretty sensitive to the type and amount of stretch as shown in the two images with hyper stretch and asinh stretch. So I suppose we need to be careful when making comparisons.
  17. I thought NGC 925 rang a bell. I looked at this back in September and was pleased to find this other Triangulum galaxy. I see from Wikipedia and one other source that it is called the Amatha Galaxy. I have not found out where this name comes from. Any ideas? I also did a quick plate-solve + annotate to see what faint galaxies are in the field. NGC 925 is a member of the NGC 1023 group of galaxies. The group is part of the Virgo Supercluster, which is then part of the Laniakea Supercluster and so it goes on... Bill
  18. I like the look of that. It could be very useful for highlighting star forming regions etc.
  19. Martin - My work-flow has been to do the Ls first and then R, G and B in that order. So, I get a bit of thrill when the first B goes in and the stack miraculously becomes colour. I sometimes add a few more subs of various types if the stack is too faint to see what I'm looking for. I've ordered a clear (but hopefully parfocal) filter to try instead of the L filter to see if I capture a few more photons as I think you suggested in another post. Have you any suggestions for work-flow and relative numbers of LRGB? There's probably some guidance from astrophotographers but I have not been p
  20. Now a couple of Abell planetaries. First Abell 24. This is very faint because it's fairly big and spread out. I really could not see anything with just the mono (i.e. L) subs and it was only when the R , G and B were added that something definitely showed up. Still pretty faint. Maybe one to come back to sometime. Astrophotographers taking much longer have come up with clearer images but that's not what I'm about. If you want something clearer how about this: https://britastro.org/node/20299 Another faint challenge is Abell 21. This is also known as The
  21. A scope without a spider would help or even turning things so the spider vane wasn't on top. I noticed the green flare but did not check it out enough. The problem was that there was some movement during some of the subs, particularly the red and green ones. It was very windy. I've removed the worst and the result looks better. The green flare has gone and the nebula is easier to see. There's a bit of colouring of the diffractions spikes which can't be right but it's EEVA so I'll call it a result. Bill
  22. Returning to Abell 12 (The Hidden Planetary) with LRGB imaging. Pleased that this seems to be worth doing to see a bit of the colour. Another interesting one which seemed to benefit from the colour treatment was NGC 2022. This is sometimes called The Watch Nebula. There's not enough magnification in my shots to show a lot of detail but it is possible to make out a hint of structure in the centre. The central star is said to be more than 120,000 K. It's 8210 light years away. I'll post three more planetary nebula from the a couple of nights ago later. Best regard
  23. Like you, Mike, I was prompted to look at NGC 969 etc. because it is December 2020's Webb Deep Sky Society's Galaxy of the month. There looked to be a few small faint fuzzies in the area between the NGC 974 and 978 so did a plate-solve and annotate. (No I didn't. astrometry.net and ASTAP did...) Great fun! Regards Bill
  24. Abell 12 (also PK 198-06.1) This is sometimes called The Hidden Planetary because it is almost lost within the glare of mu Orionis. It is the Webb Deep Sky Society's Nebula of the Month for December 2020. See this for more interesting information: https://www.webbdeepsky.com/nebulae-clusters/2020/ It's that sphere of haze at about one o'clock under the diffraction spike. Its visibility does depend on the sky conditions. The glare from the star can be worse with more moisture. Could be worth a look another night and may benefit from use of filters. RGB perhaps or an O
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