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PeterW

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About PeterW

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  1. PeterW

    The night of the small scopes

    Alan reports success going after galaxies. Planetary nebulae have strong green emission, where NV is less sensitive than in the far red. If a target is bright, then no reason you can’t add a Barlow/couple to a shorter focal length eyepiece and zoom in more. We mainly chase hydrogen nebulosity as its something that there is pl titular and that human eyes are very poor at seeing. PEter
  2. PeterW

    The night of the small scopes

    You can just poke the NV into the eyepiece hole... the TNVC merely makes things all nice and solid. Normally I work at prime focus, taking the NV objective off and using a C-1.25” adapter and putting it in instead of the eyepiece. Partially as the PVS14 can’t do this and partially as it allows you to achieve dramatic focal reduction with ease the afocal has taken off. I have a cheap 55mm plossl that I need to make an “adapter” for... one that I can push the NV into, but not trust it to hold things robustly as I am not able to get things suitably threaded. PEter
  3. PeterW

    2" 3d eyepiece extension tube

    Round things need to be made with LOTS of facets so the print comes out smooth and not facetted. This is down to the CAD to STL conversion. I would print the tubes deliberately with about 0.6mm or so clearance, to allow for print errors so you’re not stuck trying to sand it out to fit!! Then you can add small strips of gorilla tape to the tube to get the snug fit you are looking for. PEter
  4. I’ve made plenty of small bits and pieces, Filter holders, binocular wing eyecups, binocular lens vale, custom 2x binoculars, bahtinov mask, synta base sun finder, syntabase lodestar holder.... print in PLA on an Ultimaker. PLA is pretty stuff, you can get carbon fibre loaded stuff if you need and other plastics might be more environmentally robust... though scopes are generally not left out in all weathers! Can’t guess the print time of filamant cost for the Printsonian, shows what’s possible though! PEterW
  5. PeterW

    The night of the small scopes

    ... 20mm UWA and coma corrector look very much like an Olympic torch in scale! PEter
  6. With a clear sky predicted after a wet day and a local club deciding it wasn’t meeting, I decided to clear the cobwebs out of my larger scope. Collected all the bits from all round the house and assembled the 8”f4 on the EQ6 and laser collimated it. As I live with many direct streetlights I used a foot long flocked light shield on the front end to make the scope look more impressive. Using the starsense made goto alignment and finding things a breeze (just let it get on with it) though it was only towards the end of the evening I bothered to refer to the manual to find out how to correct out the “finder to main scope” pointing error that was about half a field of view… good to know for next time, so goto is then always perfectly centred. I also seem to now need reading glasses to use the handset which has a 2line display vs th old one line. First aim was to work out the (rough) spacing for my baader coma corrector on the TS XWA 20mm ultrawide eyepiece as there’s been all this talk of “rich field” and I thought I might as well have a go. The huge field (2.5degree) frames many of the usual objects very well, of course it’ll work much better under darker skies, but still plenty of stars to play with (compared to the few visible naked eye). It’s nice to be able to “climb into” the eyepiece to look around, compared to my normal “narrow” Nagler view, lots of annoying little satellites crossing many of the views. Upping the magnification Mars was a nice disc, but a bit wobbly with little detail visible. I was mainly chasing globular and open clusters and bright nebulae in the area of the sky I have access to, partially inspired by looking at the images in the Cambridge Photographic star atlas for interesting looking things. M29, N6960, M13, M27, M11, M57, M92, M56, IC4665, N6883, M15, M26, event tried for some low objects before they went behind the tree, M22 and M25. Sagittarius has already gone behind the tree in the garden when it gets dark, should have tried this a few weeks back or set the scope up a few meters further away. After a while I thought it would be worth switching in the prime focus NV to pull in more stars and resolve the globs, now resolved (though small), using a 685nm long pass filter to take the edge off the local light pollution. Now I can see M71 which was too faint to see previously. Lots of very dense star fields with loads of nameless little asterisms. Picked up faint M71 and M33 as a noticeable dim fuzz, far fainter than M31 that extended beyond the field of view, with M110 and m32 clearly visible. Finally switched to hydrogen alpha filteration for going after nebulae. M27 took on the classic asymmetric apple core shape and M57 a bright, clear ring. The Western veil was lovely, the triangular wisp and eastern veil were much less obvious. The field of view is much smaller than I typically use and so many of my usual objects are now way bigger than the field of view and harder to pull from the sky background. The Gulf of Mexico in the North America obvious as a dark “cactus” shape between it and the pelican. Similarly IC1318 was obvious around the “butterfly area”, spilling off in all directions. The cocoon was nice and obvious, IC1396 not obvious at this scale. Wanted to go for other nebulae down in Cygnus, but they lack the NGC/IC IDs that Starsense knows about. Going to have to get round to making using the NV afocally with a 55mm eyepiece to enable a wider and brighter view, by running closer to f2. I also need to research options for connecting SkySafari to my starsense as many nice open clusters and galactic nebulae are not in the handset database! I’ll get an SQM Reading next time.. though 18.5 is “good” from here usually. I should see if I can get the council to consider part night lighting as if they went off after midnight it would have been a great help. Peter
  7. PeterW

    The night of the small scopes

    Aha, colour coded! Still a long old tube hanging off the back end, makes balancing tricky! PEter
  8. PeterW

    The night of the small scopes

    60mm with 2” eyepiece... make sure you don’t look in the wrong end! ... and you guys didn’t tell anyone you were going! PetEr
  9. Stellar magnitude depends on aperture, the greater magnification will darken the sky and make fairer stars easier to see, but also reduce the exit pupil and make fuzzies harder to see. Rich field scopes are best for good skies where they can effectively work at low power. Interesting 3.39x/in from Unk Ingalls, 7x50 is a perfect fit. Way off the 50x/in the optical nuts like to test their scopes at! PEyer
  10. Hence my “truncated” 80mm f4 jumbo finder, super convenient, though I wish it was mounted sometimes and for more scale you are looking at the 10” class fast reflector (or refractor, given @GavStar results). PEter
  11. Richfield is most stars in a single field of view.... could be any size, but typically smaller scopes feature. You need a fast scope with an ultrawide apparent field of view with an exit pupil as big as you can take. Mel Bartels has a good summary https://www.bbastrodesigns.com/rft.html he is an expert mirror polisher who can achieve some crazy results... he hunts down “galactic cirrus” type nebulae that no one else has ever tried to find. I have a 13” f3 mirror for this purpose that wants a scope putting round it. Binoculars are another option, but 7mm exit pupil binoculars with >70degree apparent field of view are not made anymore and you need to do a lot of hunting to find them... but as mentioned they give a good view. Of course you could just use a light pollution filtered image intensifier..... stupid numbers of stars. PEter
  12. For rich field viewing you want a fast scope, long focal length ultrawide eyepiece for a maximal exit pupil (how big do your pupils get). https://www.bbastrodesigns.com/rft.html gives some info. I have come across people cradling comet catchers, there aren’t many small, fast scopes out there, f4 seems the fastest you can find.. If you want to see “bucket loads of stars” then night vision at 1x with a suitable light pollution blocking filter works pretty darn well. Otherwise you’re almost down into binocular territory… eg 7x50, but finding ones with a very wide apparent field of view is tricky. https://www.cloudynights.com/articles/cat/articles/binoculars1405754339/which-binoculars-will-give-you-maximum-star-counts-r88 also has some useful info for most stars. For stability any simple mounting should be fine. PEter
  13. Also exchangable for family members, pets, pounds of flesh etc... PEter PS Balaclavas are not required, but can help you keep warm when observing and also add a touch of “ninja” when you are out observing with your superhuman night sight.
  14. .,,, or a bit over 2 for the lucky dip option... only a couple of Ethos, which can’t show you any of this good stuff..... Peter
  15. PeterW

    The Pacman!

    Eeeerrrrrgggghhhh the image is mirror imaged...... Looks like another tool in the arsenal, go heart and soul hunting with it, PEter
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