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jonathan

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Posts posted by jonathan

  1. Aye, was out this afternoon for a spot of sun eyeballing (with the Lunt).  A really long filament just near the big horny proms (the bits between them reminded me of The Great Eye from Lord of the Rings - the Sun is watching!), two fun sunspots with long lighter patterns around them, plus I noticed two prominences (or would they be filaments?) eminating out towards us from the almost opposite corner from the horny proms.  Lots of smaller hairy proms down the bottom there too (from my point of view).

    That pressure tuning knob makes all the difference, when there's so much activity going on at different levels it really feels like I'm revving a solar observing engine!

    • Like 2
  2. I'm wondering if I could use my 102 as a nifty bird watching scope, EQ mount obviously no use at all for this purpose so just wondering if there's a decent Alt-Az mount or photo tripod that can comfortably carry a 102 refractor plus maybe Baader Zoom Hyperion eyepiece.  I have the Horizon Heavy Duty tripod, the carrying capacity is said to be up to 100 aperture spotting scope but I think my 102 will be considerably heavier than a spotting scope, not sure how the fitting would go with a dovetail bar and rings.  I have a relatively cheap 45 degree erecting prism diagonal, does the quality make much difference for daytime use?  Also needs to be portable enough to carry a few hundred yards (with the scope in the other hand).

    I've already tried my 70 Travel Scope on the Horizon tripod, probably wouldn't compare that well to a £2k spotting scope on a carbon tripod but works reasonably well.

  3. 19 hours ago, GavStar said:

    Yes great views today, one huge prom and one nice group if proms. Some well defined surface activity as well.

    I tried single front stack, double front stack and triple stack (one internal, two external filters), mono and bino viewing.

    Today my favourite for fantastic full surface views was double front stack with binoviewers, consistent detail across the full surface.

    0E91F285-558C-4EF8-A9F3-542DC185EEE1.jpeg

    I have that exact same seat!  Also, can't even begin to think how much all that double and triple stacking setup must have cost (if new)...  I probably should aim to get hold of a mount like that too though, much easier than my CG-4.

  4. I fretted and worried over my own secondary (and briefly, primary) collimation for months, it sat in the end room collecting so much dust...

    The best thing to do is get outside when the stars are visible and perform the star test (Polaris is the recommended star, easy to find and doesn't move), look for concentric rings around the de-focussed star using a high power eyepiece, if it's obviously off-centered then do more adjusting.  Looking at your photos I think you'll probably find it's good enough for visual use.

  5. You could "try out" the various eyepiece specs using Stellarium, there's a function where you can enter different eyepieces along with your scope (many known / common scopes and eyepieces are already in there).  Just depends how wide you want your low power eyepieces to show, for example wide clusters or asterisms.  I usually start with my old (but good) Celestron 25mm Plossl for finding targets, it's definitely far better than the standard eyepieces that Skywatcher include with their scopes, and is still my go-to for most of the popular open clusters.

  6. Just to put a final note on this thread, I finally managed to get outside with the 150P tonight and did a proper star test on Polaris, definitely good enough for the likes of me!  

    Had a quick scan of a few targets, despite fairly poor seeing (whispy clouds coming and going) and a bright moon I was able to see the Trapezium in Orion quite well and the Pleiades looked sparkly as usual, and also the little companion of Polaris.

    • Like 1
  7. 13 hours ago, Nigella Bryant said:

    I too saw that and did some imaging but not processed them yet. There was a lovely large prom near the new AR. 

    Would really like to see what you managed to capture of it.  The images from NASA always look vastly different to what I see through my solar scope.

    • Like 1
  8. Had a bit of warming sunshine today (hurrah!) so out came the solar scope.  Saw a large prom that appeared to be tearing as it leaped out (or back?) and curved back to the limb, it also appeared to have several 'fingers' at one end touching the limb, probably the largest prom I've seen in a long time.  There were a few smaller but chunky prominences and a few filaments too, things look to be hotting up (excuse the pun) on our sun this season!

    • Like 5
  9. On 07/03/2021 at 21:46, Cosmic Geoff said:

    If the original poster has settled on a particular telescope, we can suggest a GoTo mount for it.

    Indeed.  My advice there would be to look at the complete approximate telescope weight including any typical accessories such as finder, diagonal, and eyepiece, then look at the weight carrying capacity of a mount - it needs to ideally have at least 1/4 additional capacity over what the telescope weighs in order to be stable, preferably 1/3 more.  e.g. if the telescope weighs around 10lb then a mount carrying capacity of 15lb would be ideal.  I quote lb because that's a typical weight unit used by Celestron in their mount specs.  This is relevant to visual and photography, though with visual maybe 1/4 would be acceptable but the more spare capacity there is then the less affected the scope will be when it comes to vibrations from touching the scope (focusing), wind, or vibrations through the ground.

    When it comes to wind, obviously the bigger the scope the more it will be affected.  I've had an 8SE on an NEQ6 out in quite strong winds on a hillside and it's been rock solid, as it's quite a short scope there's less for the wind to grab hold of and 'twist'.  Had it been on an HEQ5 Pro there would have been more chance of vibration from the gusts of wind.  A slim, long refractor will catch the wind at the ends more, and the basic principles of leverage physics come into play, although on an NEQ6 I wouldn't expect any significant difference as that is such a heavy solid mount.

  10. While you're at it with your patio maybe consider making some subtle tripod markings / indentations so that you know exactly where to put the tripod feet every time.  I agree with discardedastro - there's no reason I've heard of why your NEQ6 shouldn't be able to track more accurately without the need for a pier.  You may want to look at the mount itself - investigate regreasing the gears and making sure they're meshing the best they can.

    • Like 1
    • Thanks 1
  11. 11 hours ago, dannybgoode said:

    Oh and they take some cooling - by crikey can they take a while to stabilise!!

    Indeed, typically 20 minutes minimum, possibly up to 40 minutes.  It's been a while though, I just haven't been out much at all in the past year or two and when I have it's usually been with a refractor.

  12. After experiencing Celestron's 8SE goto system (single arm mount) I wouldn't buy a similar system again, not with an 8" SCT on it at least (6" might be that mount's realistic limit).

    My two (or three) pence would be to look at an EQ system as it will allow you to mount different scope types, if looking at 8" SCT then probably HEQ5 Pro or equivalent as a minimum.  With the EQ mounts that offer goto or simple motorised tracking versions, you can normally just upgrade the hand controller to make a tracking mount a goto mount.  Personally I feel this is a good route to go from a manual push-to (dobsonian), get used to an EQ with simple motor drive first and all the setup that entails (polar alignment), a non-goto EQ mount is perfectly capable of long or short exposure photography, the initial setup required will be the same if you intend to do photography with goto.  Once you have goto then there'll be the extra steps required to calibrate the goto system each time it is moved (i.e. taken outside), and as with any complex system this is where errors and problems can occur, leading to frustrations and lost evenings, so having that fall-back of the simple motor driven tracking can certainly save an evening.

    If you're keen to splash the cash then there are all manner of automation gadgets (more things to potentially go wrong!) but in my experience they tend to be tied to specific setups, e.g. Celestron StarSense, which may not offer much by way of customisation or upgrade, e.g. one might be limited to a medium or small mount.  Even a 'basic' goto setup can be quite a big jump from a manual dobsonian, a steep learning curve!

    An SCT is a compromise of aperture vs size, to get a similar aperture you'd normally need a much larger newtonian, but an SCT has it's pecularities and is more susceptible to dew and less than ideal seeing conditions.  Expect to require a dew shield as a standard minimum, and also at least one dew heater tape.

    Just as a PS, the difference between an 8" and 9.25" SCT with the same coatings etc will be almost nothing, don't get hung up on size too much.  I'd say 9.25" is a comfortable size to handle, bigger than this becomes tricky especially when the tube is covered in frozen dew and your hands are cold!

     

  13. You can make a collimation cap using the cap that fits in the eyepiece holder (assuming you have it, I think most scopes come with one).  Measure out where the middle is and drill a 1 or 2mm hole (recommended to use a hobby hand drill, basically a handle for a drill bit, it's very soft plastic).

    A Cheshire should help but is not essential, ultimately you'll perform a star test probably outside on a clear night, pick a bright star (Polaris is a popular choice) and defocus until you see concentric fuzzy rings as per your telescope's manual.

  14. Zermelo summed things up pretty nicely.  OIII for typical nebulae is a pretty good bet, but keep in mind that OIII is Oxygen (blue/green), which won't help for red / infra red (Hydrogen?) nebulae; something to keep in mind is that our human eyes cannot perceive things like IR or UV, the typical grey misty nebula cloud we see visually is usually the green part of the spectrum as that's what our eyes have adapted to see in the dark. 

    I have been told that an orange / red filter is good for increasing contrast on Mars, and perhaps green can help with Jupiter, though I have yet to try this myself.  I have a Neodynium filter but have yet to try it on planets.

    I would recommend buying one filter at a time, buy good quality and spend a bit of money on each one, plus a lunar filter (ND) if you feel it's necessary for your eyes and scope (they're relatively cheap).  Remember that usually you can 'stop-down' the aperture if your scope objective cap includes a smaller cap that you can remove (or make your own out of cardboard), useful for bright objects such as moon and planets.  I use an ND filter typically when the moon is more than 1/3 lit as I find it too dazzling, also used one on Venus to see the phase which was obscured by the dazzle otherwise.

    One tip I heard the other day is to just place the filter between the eyepiece and your eye, it should work just the same for a quick preview and enable you to quickly see the difference it makes.  I have yet to try this but will be just as soon as I can get outside under clear skies (might be tonight, fingers crossed!)  Credit goes to Jurgen Schmoll for that one (it's where I heard it from anyway), he gives a great talk on filters so if you get a chance to join one (currently on Zoom or whatever) it's well worth it.

    Another tip I would bring is to wear sunglasses if using binoculars on bright objects such as Moon or Venus, works a treat, but NEVER AT THE SUN.  Just needed to emphasise that last part.

    • Like 1
  15. I haven't used this particular offering but from what I've seen and heard of Bresser they're a reputable brand, and this looks like a decent setup for the money - solid dual-arm mount, nice looking red dot finder, polar wedge, probably very similar OTA construction to 127 Maks by Celestron and Skywatcher (possibly exactly the same, in fact).  I have looked through a smaller Celestron Mak and it was a very decent scope for the size.

    Note that to get the most out of it you'll need to also arrange a 12v power supply - either a mains fed step-down transformer or (my preference) a 12v leisure battery, I have one similar to this Halfords Leisure Battery but there are smaller and more compact battery solutions available for telescopes these days (using somewhat more exotic battery technologies), you 'd also need a suitable battery charger to keep it in good condition, and a power cable / adapter arrangement specific for your chosen battery and the scope - and probably a couple of extra eyepieces for different magnifications too.  I'd also think about a dew shield and possibly a dew heater tape for the front element as a future purchase.

    As it has a relatively long focal length it will be a 'slow' scope, so cheap and cheerful budget eyepieces such as Plossls should work well in it, or those in the BST Starguider range, 12 or 15mm might be a good one to go for initially.  Dim objects will likely appear larger but a bit fuzzy at high magnification compared to a faster scope (such as a refractor or reflector), this is the trade-off for the compact design of the Mak.  It may also be more sensitive to less than ideal seeing conditions (some objects will look dim and fuzzy if there's thin cloud or high winds etc).

    • Like 1
  16. 3 hours ago, MrFreeze said:

    The Svbony diagonal is real, not at all 'too good to be true'.  It's not a 'cheap Chinese knock off' at all. You WILL get full after sales support, at least as good as any UK dealer. I have been dealing with Svbony for years (far longer than FLO) and have had nothing but excellent service. Even got given a pre-production sample of their SV225 camera for evaluation - not had that from dealers in this country!

    ...

    I stand corrected, good sir!  Still always a good idea to be wary of cheap items and get opinions from people who've actually bought and used them (I haven't had that particular diagonal but I've experienced other cheap stuff from China, it's been... so so.  Some has been utter carp).

  17. Unless you have some specific requirement or desire such as very wide field (which probably will entail an expensive eyepiece to make the most of it) then I'd say 1.25" should suffice for now at least, especially if money is a bit tight.  The only reason I have a 2" diagonal is for one 2" SWA wide angle eyepiece, which weighs about the same as a bag of sugar so needs a strong mount and diagonal just to hold it, the views through it are magnificent though.

    That Svbony one sounds almost too good to be true, probably worth a shot for the money but only if you can afford to lose £20, with the cheap Chinese knock-offs you may find it's pot luck as to whether you get something decent or a total POS, and I wouldn't count on any proper after-sales support or parts availability.  Consider also that if it spectacularly fails then it could damage your scope and/or your eyepiece. 

    If you wanted peace of mind then go for William Optics or similar from a reputable astronomy retailer - https://www.firstlightoptics.com/diagonals/william-optics-125-dura-bright-dielectric-diagonal.html

     

    • Like 1
  18. From data I've seen, it's water vapour in the atmosphere that generates warming, which may or may not change (largely unpredictable) weather and climate patterns.  I find it interesting to note that almost all predictions and computer models produced over the years have proven to be inaccurate when it comes to climate science, there are just too many variables (if a butterfly farts, does it rain in the next country?)

    So, take that however you like, my conclusion from it is that climates change constantly, and with one as complex as the one on earth we just have to get used to it, especially in a temperate zone.  Also, the primary thing that drives or affects the climate on Earth is the Sun.

    I lived in Preston for a few years, always felt like it rained a lot more there than in the East, but we do seem to have had a lot of rain recently all over the place in the UK.

     

    • Like 1
  19. I use a large Curver plastic crate with the original foam packing that the scope came with (8SE, almost the same scope).  The Curver crate is orange so easy to see in the dark, fits nicely in the boot of my car.  If you don't have the original foam packing then I'm sure a substitute stiff foam arrangement could be organised (e.g. someone who just bought a big TV or whatever).

    • Thanks 1
  20. 19 minutes ago, Ricochet said:

    With your Cheshire in the focuser, adjust the secondary so that the doughnut on the primary appears directly under the cross hairs of the Cheshire. 

    Once that is done switch to the collimation cap and adjust the primary so that the dark spot of the hole in the collimation cap is inside the doughnut. 

    These are the only two things that matter. Don't worry about anything else. 

    I think I need lots of pictures, instructional diagrams, and probably a video showing the exact procedure because at the moment my mind is in major confusion mode!  Just wish I was able to take it to my local astro society (of which I am a member), I know someone there would probably be able to show me in a few minutes.  Damn you, lockdown!!

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