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alanjgreen

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alanjgreen last won the day on January 17

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About alanjgreen

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    Cumbria. UK
  1. alanjgreen

    20" DOBSONIAN

    Dave, Its f3.6 (same as mine) so NO step ladders needed! Here are the numbers (from TH site): DIMS total: 680x680x1790mm; Rockerbox 678mmx678mmx347mm; Mirrorbox 590mmx590mmx361mm; Trusses approx. 1084mm; Truss diameter: 25mm; Eyepiece height while pointing at zenith approximately 1,63m; 20“ Total net weight: 53 kg; 20“ Mirror Box + Altitude wheels: 35,8kg; 20“ Secondary Cage: 3,8kg; Rockerbox: 10,6 kg; 20“ 4 Truss pairs: 2,8kg; 20“ Primary mirror: 20kg https://www.telescopehouse.com/telescopes/explore-scientific-ultra-light-dobson-20-f-3-6.html At over £6K, I would be looking for a nice custom build and UK made mirror (for a little bit more money). Alan
  2. I managed to get SN2019va in direct vision this morning. Here is an excerpt from my observing report... SN2019va (NGC8577) – I started with the 18.2 DeLite (x115) and 610nm red filter installed. I could make out the galaxy faintly (which was an improvement on my last attempt) and sure enough with averted the tiny supernova came into view underneath the galaxy. I swapped in the 27mm Pan (x77) and again I could see the host galaxy (although fainter) and with averted and a little time and patience eventually the supernova too. The moonlight was dimming now and I removed the 610nm red filter and returned to the 18.2 DeLite. I got my clearest view of the supernova of the night. In all cases the supernova was not immediately obvious, it took some time and looking for it to eventually appear into view. Alan
  3. I managed to bag AT2019arb this morning, here is an excerpt from my posted observing report... SN AT2019arb (UGC7367) – This was a far easier supernova. With the 27mm, the host galaxy was bright and easy. An extended brighter section above the core was the supernova. I swapped in the DeLite 18.2 and then the Ethos 13mm for more magnification to try to get a “split” between the core and the SN, but each time the galaxy lost brightness and the detail was less easy to see! NGC3304 had moved too far west of my shed, so I was not able to attempt it. I will try again once the Devils Orb starts to wain... Alan
  4. Date: Friday 15th February 2019. 0300-0615am Scope: 20” f3.6 Lukehurst Dob with Paracorr (fl = 2089mm & f4.1). Night Vision: PVS-14 with Photonis 4g INTENS. Eyepieces: Plossl 55mm (f2 x38), Panoptic 35mm (f3 x60), Panoptic 27mm (f4 x77), DeLite 18.2mm (f5.8 x115). Ethos 21mm, Ethos 13mm. Filters: Baader 610nm red filter. Moon: 70% (until 0415) Preparation. With the Devils Orb big and bright in the sky, my plan was to have a sleep and then come out just in time to see off the Orb and try to get whatever darkness there would be before the inevitable dawn of the Sun. Yesterday, I created a “supernova” observing list in Sky Safari and marked up NGC8577, NGC3304, UGC7367 & UGC7534. These 4 galaxies contained supernova that I intended to try to observe. I had also had a pre-session play with Sky Safari and “Comets” to see which may be available to view from the shed, where the Dob is up against the West wall meaning that Zenith, South and East are “available”. Time to Wake Up The alarm went off at 0230 and I spent 10 minutes coming around before heading downstairs to get dressed into my three layers of clothing. My eyepiece case and books were pre-prepared and waiting to go (As it was going to be “warmer”, I was fancying my chances of using multiple eyepieces – usually when its cold then I just stick to one or two for the whole session). I was in the shed by 0245 and set about getting setup and ready to go… Right, Lets do some observing! M3 globular - By 0300, I had completed the 2-star alignment for my Nexus and I checked the alignment by observing M3 globular cluster in the Ethos10. The view was a bit washed out with the moon so I swapped to the 35mm Panoptic, added the Baader 610nm red filter to the Paracorr and attached my pvs-14 night vision device to the Panoptic. Now, the globular was bright and sharp against a much darker background. It was resolved to the core and I spent some time admiring it. It was interesting how the x200 of the Ethos10 seemed to show less than the x60 of the Panoptic 35! Comets up first… C/123P West-Hartley – With the help of Sky Safari, I quickly located a small fuzzy patch sitting next to a star. It had a small dot core and there was a surrounding dust halo. I was using the Pan35 at x60 magnification. C/2016 R2 (PANSTARRS) – I spent quite a while hunting around for the R2 comet but failed to find it. The moon was still affecting the sky so I will put it down to that. Supernovas next up… I selected my supernova observing list in Sky Safari and made my first error of the session by nudging to the nearest galaxy NGC8577… SN2019va (NGC8577) – I started with the 18.2 DeLite (x115) and 610nm red filter installed. I could make out the galaxy faintly (which was an improvement on my last attempt) and sure enough with averted the tiny supernova came into view underneath the galaxy. I swapped in the 27mm Pan (x77) and again I could see the host galaxy (although fainter) and with averted and a little time and patience eventually the supernova too. The moonlight was dimming now and I removed the 610nm red filter and returned to the 18.2 DeLite. I got my clearest view of the supernova of the night. In all cases the supernova was not immediately obvious, it took some time and looking for it to eventually appear into view. SN AT2019arb (UGC7367) – This was a far easier supernova. With the 27mm, the host galaxy was bright and easy. An extended brighter section above the core was the supernova. I swapped in the DeLite 18.2 and then the Ethos 13mm for more magnification to try to get a “split” between the core and the SN, but each time the galaxy lost brightness and the detail less easy to see! SN2018hna (UGC7534) – This was the most confusing to identify the supernova but the supernova was the brightest and furthest from the core (making it look more like a field star). Due to the later viewing time the whole scene had rotated from my last visit which only added to my initial confusion. Eventually I got my bearings thanks to a triangle of bright stars on the edge of the FOV. And then I saw the oblong star shape. The brightest corner star also reveals hints of galaxy dust to one side. There is a field star in-between this bright star and the SN which was more easily seen than my last visit. But this one is pretty easy to get. I used the 27mm Pan for this target (x77). SN2019aik (NGC3304) – By the time I was ready to target this SN, the galaxy was too far west of the shed for me to get the scope on target. I should have targeted this galaxy first! I was disappointed as I had got all of the other three, but 3 from 4 isn’t bad. Spend time with the famous galaxies. M51 - Next up, I headed for M51 to see what I could get with varying eyepieces and magnification. After trying the 27mm (x77) for some scale and getting a decent view, I swapped to 55mm (x38) and 35mm (x60) for comparison. M51 looked decent in all the views but the 55mm Plossl provided just that bit more detail. The second fainter sweeping arm could be seen to extend almost around the back of the first arm. This detail was only seen in the 35mm “because I knew it was there”. M101 – Onto one of my favourite galaxies – M101. The 55mm Plossl provided the most instant gratification with decent views of arms above and below the galaxy. The detail was clearer close to the core and needed more time and averted to get hints of arms further out. I threw in the Ethos13 (and removed the NVD) for a traditional view. Once my brain adjusted to the 100 degree FOV of the Ethos then I started to notice coloured stars in the FOV (of course, these are not there with the NVD as everything is shades of grey). Then I started to notice M101 and at x150 it is really big. As I nudged around I came upon several NGCs from within the galaxy but the sheer scale of this galaxy needs the Ethos 21. (I walked back up to the house to get it from the cupboard…) With the Ethos21 loaded, M101 took on a smaller scale that my eye was more easily able to digest. I could see a lovely circle of arms close in to the core. The other arms started to appear as I worked the eyepiece and eyeball using time and averted vision as my aids in this task. Eventually, I eeked out as much as I had seen in the 55mm Plossl (with NVD) but it was more of a challenge and I enjoyed it. It seems M33 and M101 demand the Ethos21 to get the best from them. Although the instant gratification of the Plossl and NVD were great too. Time is moving on, can I bag a few more of the “brightest galaxies”… My 2019 galaxy task is a list of 211 brightest galaxies (I found and added another good one NGC4762 last time out). NGC4605 – With the 35mm Pan, I saw an edge-on galaxy with a swirly appearance. NGC5676 – A side-on with a similar swirly appearance. NGC5689 – A side-on with a bright core and swirly appearance to the disk. There is a faint galaxy pair nearby. NGC5005 – Bright core with extended bright halo/bar. Then a larger swirly disk beyond. NGC5363+NGC5364 – 5363 has a bright core with a surrounding dust halo. 5364 is larger and fainter, circular in shape with a dot core and bar. NGC5248 – Core with bar. Faint circular arms seen. One for another day when better placed. Nice. NGC5846+NGC5846A+NGC5845+NGC5850 – A nice patch of galaxies (with others outside the FOV too). 5846 & 5846A sit together like little & large. There are further galaxies (one either side) within the FOV. No detail seen in any of the galaxies but these are low down. NGC5746 – “Galaxy of the day” to finish. This is a bright edge on with a lovely black dust lane running along the leading edge. Nice. I tried the 55mm and 35mm on this galaxy with the extra scale of the 35mm proving worthwhile in seeing the dust lane better. With the sky brightening, finish with some Globs… M3 – Back to M3 as its closest to my current position. I switch to the Pan27 (x77) for better scale. The globular is bright and fully resolved. Globs really are great with Night Vision they just resolve and stay resolved no matter where they are in the FOV. It’s a very different experience to conventional view as they just drift across the FOV in all their glory. M5 – Wonderful. It’s a sight to behold with night vision. The stars seem to be in chains looping around the central very bright core. A highlight. M13 – M13 is very nice but I am now starting to think that M5 is king of the northern globs? It really is that good when fully resolved with night vision. I change to the 18.2 DeLite (x115) for one last look at M13 as the sky continues to brighten… Its 0615 as I decide to pack-up. Thoughts of the observer. 3 out of 4 supernova. Happy with that but with better planning I could have gone to the most western located galaxy first!! It was good to find that the 18.2 DeLite can be useful on tough supernova! The loss of brightness of image (when using night vision with eyepieces less than 27mm) will be an issue with some targets but stars (& SN) seem to be ok I would have liked to find a second comet but it will make it more meaningful if and when I find R2 PANSTARRS next time! I really struggled to move easily through my brightest galaxy list as they had passed the southern drop-down side of the shed at this early morning observing hour. NGC5746 was a surprise, I was just hitting some low down bright galaxies as they were about all I had left available. This provided the best galaxy view of the night. Night Vision is a game changer on these brighter galaxy targets, but the Ethos 21 & 13 remain key weapons in our arsenal for the larger dimmer face-on galaxies which include my two recurring yearly favourites M33 and M101. The close-up “fly-by” experience with the added 100 degree surround-sound peripheral vision is just a special experience between me and my scope. I really love M5 now. The view with Night Vision is really something different. It has inspired me to create a “globular” observing list in Sky Safari just now. I think that I will try to get a “run” at some of these in April & May to see if there are any more lurking surprises… It was nice to get one last session in before the Devils Orb takes over the skies for the next week or so. Hope we get a few more supernova above us while galaxy season is still here! Clear Skies, Alan
  5. Assuming we get some clear early morning sky (after the Devils Orb has left the building) then there are two faint SN that are well placed for observing: - SN2019aik in NGC3304 (mag 16.5) Type 1A - SNAT2019arb in UGC7367 (mag 16.6) Type 1A They are faint but if you don't look then you never know... if you find the galaxy then you should find the SN. They are both Type 1A so they should get brighter and last for a couple of months. http://www.rochesterastronomy.org/supernova.html?#2019aik http://www.rochesterastronomy.org/supernova.html?#2019arb SN2019aik Its is tight in so that may make it more difficult but it seems to stand out well against the core in the above recent image. SNAT2019arb The more the merrier! Alan
  6. I am using a 2” Chroma 5nm Ha filter with my night vision. It provides greater contrast and works with less “gain” than the Astronomik 6nm that it replaced - I believe this means that you photography types won’t need as long an exposure with the Chroma? I would definitely recommend it. Alan
  7. alanjgreen

    Baader SteelTrack focuser for Newtonians

    Buyers should also note that this focuser will fit straight onto a LUNT LS60 solar scope. Just remove the flat mounting plate via the 4 grub screws found on the thin sides and then it goes straight onto the LS60 via 3 more grub screws on the LS60 A nice cheap upgrade to the poor chinese made standard focuser! Alan
  8. After spending a couple of hours on bright galaxies and comets, I turned my attention to Supernova (as the Plough finally appeared from behind the shed roof). First up was SN2018hna in UGC7534 (mag 14.9) in Ursa Major. - I had observed this one already so I was on a "confirmation" mission. I soon located the oblong of stars (at the centre of the images), one corner of this oblong is the SN. I spent some time and noted another faint close-in star (to confirm on the image today) and everything matches up. - With the 55mm Plossl and Night Vision the core of UGC7534 really lights up and all you see of the galaxy disk is a smudge to the south of the core. Next up was a new SN for me. SN2019va in UGC8577 (mag 16.7!). Its located near the arm of the Plough. - With the 55mm Plossl, I soon matched the star patterns to my sketch (that I made from the images earlier). There was no sign of the galaxy but there are other visible UGCs in the fov (to add confusion). There was no sign of the SN. - I swapped in the Panoptic 35mm (x60 magnification) and the fainter stars got a little clearer. I was now sensing a disturbance in the centre of the fov which must have been the galaxy disk. A point of light blinked in and out three or four times. I noted the position based on the star pattern and was able to confirm the blinking dot in the correct location. Hopefully, SN2019va will get a little brighter by the time I get another shot. Alan
  9. alanjgreen

    Widefield scanning of nebulae

    The view of M65, M66 & NGC3628 really surprised me the other night on my first visit using NV. The way 3628 just stands out and catches the eye (more revealing) whereas you expect to see the more famous pair stand out more. Your shot captures how the nicer galaxy just teases at the edge of the view and seems bigger than I remember with traditional viewing. I had my first trip down Markarians chain with NV last night and it was just as good with the 55mm plossl as I remember with the ethos21. Plenty of galaxies everywhere! Just a shame the conditions were not as good as earlier in the week. I also managed SN2018hna in UGC7534 just before I packed up, so I was pleased with that (although somewhat cold at 0230) Alan
  10. I managed to see SN 2018hna in UGC7534 last night at 0220am. I was using the 20” and my night vision device. I got a nice star pattern match on the surrounding stars (from a sketch) which was a good job as I did not see anything of the galaxy disk (which can be seen in images). Alan
  11. I managed to find C/123P West-Hartley last night at the first attempt. I had failed on Sunday to find it, I had updated Sky Safari’s solar system orbit data yesterday so that must have done the trick. I was using my Nexus and push-to on the 20” dob with Sky Safari. Eyepiece was a 55mm Plossl and PVS-14 night vision giving x38 magnification. It was around 0030hrs when I observed them. Of the three comets I observed last night, 123P was the smallest and faintest with a tiny dot core. I was pleased to find it at last. I also observed ... C/38P Stephan-Oterma which appeared as a small fuzzy patch with a bright dot core. It was easily seen. C/46P Wirtanen which was the biggest and brightest of the three but the large core was diffuse with no centre brightness. It was the easiest of the three to see and was positioned next to a bright star. Alan
  12. alanjgreen

    Can you explain this photo of the sun?

    Sorry, but that dot is too small to be the actual sun. if you buy a cheap pair of solar glasses (<£5) then you will see the actual size of the solar disk with no magnification. It’s bigger than that tiny dot. https://www.firstlightoptics.com/solar-filters/baader-solar-eclipse-observing-glasses.html Alan
  13. Date: Tuesday 29th Jan 2019. 2015-2315hrs Scope: 20” f3.6 Lukehurst Dob with Paracorr (fl = 2089mm & f4.1). Night Vision: PVS-14 with Photonis 4g INTENS. Eyepieces: Plossl 55mm (f2 x38), Panoptic 35mm (f3 x60). Filters: Chroma 5nm Ha filter. Moon: 0% Make Hay While The Sun Shines. The Weather forecast changed and was now showing as two clear cold nights coming my way. I have had a couple of sessions already but we all know that you must “make hay while the moon is away” in this game! My plan was to hit Orion hard and make up for the disappointment of the windy night last Sunday which kept me inside until Orion had passed the drop-down side of the shed. Tonight I also planned to bring the Panoptic 35mm into play for a little more magnification (x60) on my chosen Ha nebula targets. An Initial Run with the 55mm Plossl. I had myself setup (in the shed) and aligned (Nexus 2-star) by 2015hrs and loaded the Chroma 5nm Ha CCD filter onto the Paracorr2. Then inserted the 55mm Plossl and attached the PVS-14 Night Vision Device to it using the TNVC a-focal astronomy adapter. Flaming Star – First up was the Flaming star. It provided a decent view with some wispy fine detail including the two right angles of the back corner and multiple bright fuzzy lines at varying angles within). The 3D view of “my best outing” was not repeated on this occasion so I determined that the sky was not “at its best”. IC410/417 – I nudged over to IC410 which was looking good with three black holes on one side and another large black hole on the other side. The nebula was more lush than the Flaming star and I enjoyed the view. Over to IC417 where the “spider” was visible but again not “at its best”. M1 Crab – I headed down to the Crab and was rewarded by 5 nice ovals shapes interlinked in a bubble like structure. It took time and averted to tease out the outer bubbles whereas the central bubbles were much easier. NGC2174 Monkeys Head – Over to the Monkeys Head and I was greeted with a very bright and “in your face” view of a neanderthal man. The edges of the facial features showed several bright areas. There was a tiny nebula spot set away from the mouth and a bright spot around the “ear”. The larger right patch to the neck (that I have seen previously) was there but took some averted to see it. Sh2-269 – small bright “angels wings” shape. Sh2-267 – medium sized faintish patch. Sh2-268 – Faint and large. Like an upside-down pear drop. I could see black detailing inside around a line of bright stars. Sh2-270 – FAIL. I am missing this Sharpless object and I failed to find it once again! I found a “candidate” but internet research this morning says that it was not it. I have compared sky safari location to an image and it seems they are slightly out so I have added a marked into sky safari ready for my next attempt. This object is only 1’ x 1’ size so maybe I need more magnification? HorseHead IC434 – Up to IC434 and Wow it’s really wide and bright. I nudged above Alnitak and there was a lovely shapely horse head. The head showed the snout and neck but I was also attracted to the bright white line that was running through IC434 as it was really standing out. As I nudged around, it really was amazing to see just how long and wide IC434 actually is. The whole of this region is just full of a faint nebulosity glow. Flame – I nudged down to the Flame and at last it was a view to savour. My last couple of visits have been underwhelming but tonight it was standing out bold as brass. I could make out many wispy black details to the RHS and see the small black circle to the LHS. It really was nice but I had to go back to the horsey as it was probably “beating it” for loveliness tonight! M42 – Fantastic. I swore out loud as M42 swung into view. God its bright and God its lovely. The swirling, looping nebula behind the fish head is overwhelming. The ray of black hydrogen spewing out of the mouth of the fish head is like an “oil leak”. There is so much to see that I settle in on my chair and let it float across my fov several times as I try to tease out a detail that I have not noticed before. Tonight I settled on a couple of black areas to the LHS lower of the fish head. I even though that I could see the Candle Star sitting in the fishes mouth. I could see all 4 trapezium stars clearly so maybe the transparency was improving… Running Man NGC1975 – Time to get into Orion and start with my on-going challenge to see the Running Man. I am gradually building up more mental notes to help with seeing this difficult target. I could easily see a very bright patch sitting over three stars below M43. I could see a black finger coming down the LHS of the 3 stars. I got distracted by further nebulosity down underneath an open cluster below and became confused as to where the black legs of the running man actually are? Sh2-278 – Triangular kite shaped nebula but faint and time needed to get to grips with it. Time to Increase the Magnification with the 35mm Panoptic. The image presented by the 55mm Plossl (when used with Night Vision and a fast focal ratio scope) leaves a lot to be desired especially around the edges of the fov. The 35mm Panoptic does not suffer from these issues and provides a sharp edge-to-edge view. However, the 35mm only acts as a 0.7x reducer so some image brightness is lost compared to the 55mm Plossl. Therefore, you need to use more “gain” (a knob on the PVS-14) to compensate for the darker image. From my experience the 55mm Plossl seems to always win out because the brighter image just shows more stuff and I just ignore the outer edges of the FOV. Flaming Star – Back to the Flaming star and I could see some nice texture and details within. The larger image scale meant more nudging was needed and I felt that I preferred the 55mm on this object. IC410 – Very nice and the extra brightness of the nebula meant that nothing felt lost on this target. I felt the 35mm was the winner here. M1 crab – A nice view. The bubbles were now a little larger but I felt that I was not seeing more than with the 55mm so I will call this one a tie. Fox Fur/Cone – With the 35mm loaded, I wanted to see if I could get more from the Cone than the other night. I started at the central star cluster and nebulosity was showing all around except for near the bright stars which seemed to have cleared a nice black patch over them. I nudged up and right to the Cone. It was pretty obvious as it came into view and a decent size too. It felt like it was an inch long and both sides were clearly visible running to a sharp multi colored double at the point. (With NV I cannot see colors but I can see shades and it was noticeable that the double stars were not the same color). I played with the gain control trying to get more out of the cone with not much success. It’s a difficult target and although I could see it easily, if the same view had been presented to my wife then she would have said “where is it?”. I nudged left and right in long sweeps for a while as I tried to cover the area of the Fox Fur nebula (Huge) and see the many lanes of bright nebula within. There was plenty to see but I prefer the Fox Fur view in the Borg107 where I can more easily take it all in. Rosette – Holy Cow, the highlight of the night! I would have to say this must have been my “best ever” view of the Rosette even allowing for the fact that I had to nudge around it thanks to the extra scale of the 35mm Panoptic. The Nebula was so lush and large. The extra magnification really allowed me to get deeper into the many intricate black lanes that run within the lower and left sides of this nebula. I found further black areas to investigate in the upper RHS. And I noticed three small nebula patches embedded within the centre star cluster (RHS) which I have not noticed previously. Sh2-280 – Nudge down to a large nebula patch with two black eyes. The RHS edge was brighter and also below. Sh2-282 – Nudge down to a triangular patch on its side. 4 stars were carving out a black area behind the tip. Sh2-283 – A tiny bright patch (located at star HD291952 in Sky Safari). IC434 – Over to view the horse head with more magnification and I was not disappointed. The Horse was there in all its glory – snout, neck and an ear. I let it drift across the view a few times. I also noticed that if I turn the “gain” down then the outer edges of the horse head took on a brighter glow? A win for the 35mm here. Flame – Up to the Flame which was big and bright. I think that the 55mm Plossl view was slightly more feature-ridden and the loss of focal ratio had taken something away. It still looked great though, don’t get me wrong! Running Man – Back to the nemesis that is “the Running Man” and unbelievably I was able to tease out some black edge detail. I could see a vertical piece LHS and a longer horizontal piece under the three stars (more RHS). The black lane seemed to reach up and touch the middle of the three stars too. Another win for the 35mm. M42 – You have to don’t you? A great view but with diminished resolution compared to the 55mm Plossl IMHO. Medusa – An easy black crescent. It had a very bright tip at the bottom and also a less bright tip at the top. The Crescent sides seemed incomplete and I chalked this as another win for the 55mm. Sh2-241 – A small bright patch with a central star and a black area within. Sh2-242 – A mid-size patch with an off-centre bright star within. What Happens when you View an Open Cluster with a 5nm Ha Filter? By now I was getting cold and Orion was passed the drop down side of my shed. I headed up towards the zenith and decided to view M37 with the 5nm Ha CCD filter still loaded on the Paracorr2. M37 – A lovely bright open cluster fills the fov of the 35mm Panoptic. As I turn the gain down on the NVD something interesting happens… A black lane structure appears running in some of the gaps between the stars of the cluster. It takes on an appearance more reminiscent of Caroline’s Rose with conventional eyepieces. I continue to play with the gain. It seems some stars are within nebula lanes/patches and some stars are within or next to these black (Hydrogen) lanes. I stood there pondering whether the stars were clearing the nebula to reveal the blackness or the blackness was somehow connecting lines of stars within the cluster? M35 – Onto another nearby cluster M35. Once again, the same thing. With the gain down then black snaking lanes appear within the cluster. But there are lanes/patches of nebulosity too (or is it reflecting dust?) IC443/444 – I finished with a short hop over to one of my favourite objects, the Jelly fish, IC443. Wow, the detail showing within the pancake of the Jellyfish was great. The flat head had two clear sides and dimmer/blacker areas within. There were some shimmering brighter bits too. The outer edges had clear definition as it steps down and curves away. I could see a single thread heading away from the pancake head towards IC444 and followed it away from IC443. I eventually ran into four thick parallel lanes of nebula near the strangely named “Tejat Posterior” star. I went back to IC443 and followed the tentacles running away to the left this time. Thoughts of the observer. It was nice to get some use from the Pan35 at last. I seem to robotically load up the 55mm Plossl these days. I did prove on several targets that the extra magnification of the 35mm Plossl cannot compensate for the loss of focal ratio provided by the 55mm Plossl. BUT I did also see some benefit on several targets notably the Rosette, Horse Head & Running Man. Looks like I need to use both. The dark lanes in the open clusters M37 & M35 were an unexpected bonus and I think I will be trying the 5nm Ha filter on other non-nebula targets (M45 & M13 for instance) in the near future. I have looked on the internet for some Ha images of the open clusters but nothing was immediately found that showed what I was seeing? Perhaps one of the NV phonetography guys can get a shot of this feature? Its forecast clear again tonight so I packed up early so I could get some sleep in preparation. Hope you are getting some clear skies too? Alan
  14. Hi Joc, Ha Ha, yes I have plenty of eyepieces in my collection too. But for night vision use I only have three really: 55mm Plossl, 35mm Panoptic & 27mm Panoptic. These eyepieces allow me to get more mileage from my PVS-14 night vision. Firstly, they allow me to achieve large exit pupils (14mm for the 55mm Plossl!), which would overpower a human eyeball but the PVS-14 has a 20mm objective so it can use all the light. Secondly, any eyepiece over 27mm also produces the effect of strangely increasing the effective focal speed of my setup. The 55mm Plossl acts as a 0.5x reducer and effectively brings the dob to f2 which is much closer to the PVS-14's f1.2 thus increasing image brightness. Further info can be found here... HTH, Alan
  15. alanjgreen

    Supernova in NGC3254 (SN2019np)

    Type 1a, should be there for a couple of months or so
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