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John

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Posts posted by John

  1. 52 minutes ago, Splodger said:

    I'm with you. The Meade eyepiece I have is about as wide field as I can hope to get without spending a lot of money. At 40mm with 52° it's not at all bad.

    In the 1.25 inch fitting, the maximum apparent field of view you can get with a 40mm focal length eyepiece is 43 degrees. That is limited by the internal diameter of the 1.25" barrel.

     

    • Like 1
  2. 2 minutes ago, kirkster501 said:

    It makes me wonder how honest the reviews are in magazines too.  Are the magazines paid for these ads to review stuff or are they 100% independent and the reviewers can be 100% honest and if something sucks then they can say so?

    A few members on here have written reviews and other pieces for magazines so will no doubt have an opinion on that.

     

    • Like 1
  3. 21 minutes ago, GordonD said:

    ...M35 was very impressive and the 12" shows the nearby NGC2158 as quite a bright patch with some resolution across the face...
     

    It's nice getting those "2 for 1" DSO pairings :smiley:

    NGC2158 looked like a faint patch of light in the outskirts of M35 with my 100mm scope last night but it would have been much more obvious with your 12 inch :smiley:

    • Like 2
  4. 7 hours ago, Splodger said:

    I thought I could use a 2” to 1.25” adapter 

    If you do that you will not get the benefit of the 2 inch size eyepiece format because the adapter will squeeze the field of view down to what can be accommodated by the 1.25 inch end of the adapter. 

    Also the arrangement of having a bulky and heavy 2 inch eyepiece hanging off an adapter inserted into a 1.25 inch diagonal will look clumsy and could be insecure.

    As @Mr Spock says, you will need to get a 2 inch fitting diagonal for your scope. These come with an adapter so that you can still use your 1.25 inch eyepieces as well.

    • Like 2
  5. That's a nice and interesting image :smiley:

    Sometime back Tom Buckley-Houston produced this composite image which shows what Messier 31 might look like compared with the moon, if we could see it's full extent with the naked eye. I think the galaxy is perhaps a little oversized but apparently it's quite close to being correct:

    EpuhHJa.jpg.e23ac4d992067513a67436a182e09a8f.jpg

     

     

    • Like 10
  6. 1 hour ago, Space Hopper said:

    ..A well designed and figured triplet will always out perform a comparable doublet ?

    Often with regards to CA correction, but not 100% of the time though. I've read reports where a doublet that uses an FPL-53 element shows less CA than a triplet that uses a FPL-51 (or similar) element.

    CA correction is one aspect of performance - there are others of course.

     

    • Like 2
  7. Another clear half hour here. Despite the blustery wind and the scudding cloud patches, the seeing is really quite steady and the transparency not at all bad.

    I got a superb split of Alnitak at 225x and I may even have glimpsed the Pup star, Sirius B a couple of times. Sirius A was well defined at 257x with a tight airy disk and a nice set of diffraction rings.

    Clouds thickened again so I finished off with the Eskimo Nebula (NGC 2392) and it's mag 10.5 central star. Nice :icon_biggrin:

    Feel better for that !

    • Like 6
  8. These are big targets - Messier 31 (Andromeda Galaxy) is around 3 degrees across in full - 6x the apparent diameter of the full moon. The widest true field you can give with a 1.25 inch eyepiece in your scope will be just under 1 degree. If you can use a 2 inch eyepiece that can be 1.5 degrees.

    That is wide enough for many other DSO's though.

     

    • Like 1
  9. Well that was a surprise - 40 minutes of clear sky !

    So a whistle stop session with my 100mm refractor included "the best of" in Orion, a handful of targets in Gemini including the magnificent M35, some Auriga open clusters, the Crab Nebula and a few other familiar winter treasures. And then the cloud came back :rolleyes2:

    Short but especially sweet following so little observing lately :icon_biggrin:

    P1090986.JPG.741b05e5d713327cf3c403b1ff9181c2.JPG

     

     

    • Like 9
  10. The seeing conditions have to co-operate to make using very high magnifications on any target worthwhile.

    While it is not the highest magnification that I've used, if the seeing is steady then I often find that 300x-350x seems to give me the optimum balance of image scale, sharpness and contrast when using my 12 inch dobsonian for lunar observing.

    When I use more I usually find that seeing the finest details (eg: the smaller Plato craterlets, the central rille in the Vallis Alpes, small crater chains, floor markings in the Messier craters etc, etc) actually become harder to pick out, despite the larger image scale. 

    So it's about getting the balance right and judging what the seeing will make worthwhile I think. Some experimenting is always fun as well :icon_biggrin:

     

  11. I know of a a few folks a good decade older than myself who are still regular observers. So well into their 70's and that is encouraging.

    The best aid to astronomy as you get older though is, IMHO, retirement !

    I was able to retire rather early over a decade ago and that has been just so helpful in easing the impact of late nights :icon_biggrin:

    I do find cold nights off putting as I'm getting older. If there is something special happening or I get an urge to track down a particular target, I'll make the effort and, usually, enjoy the session.  Either that or I track down and observe my quarry and then quickly scurry inside to warm up !

    As many have said, having a quick to deploy / quick to tear down setup quickly becomes an important part of being able to fully enjoy the hobby as you get older, especially in the UK.

     

     

     

     

    • Like 5
    • Thanks 1
  12. I've just seen Capella and a couple of other stars in Auriga plus Dubhe in Ursa Major :icon_biggrin:

    No scope or even binoculars involved - the gap in the clouds was just a few minutes.

    Clouded over solid again now though. Seems to be the story of the past few weeks here :rolleyes2:

     

    • Sad 3
  13. 3 hours ago, Zermelo said:

    Very nice John. Even the colour looks right.

    Was there a lot of manual effort involved, or can the printer directly import models from, e.g. here or here?

    Thanks.

    We had to do some work on the image before it can be printed. I'm still learning the terms but basically we had to convert the image to a file which represents the form using polygons at a suitable resolution and then do a further piece of work "slicing" the data so that the printer can print it layer by layer. We had to chop the shape into 2 halves so that it could be printed as a hollow shape with an infill structure that we defined. There are lots of printing parameters that can be set with regards to infill form, infill %, wall thickness and temporary support structure which the printer uses to ensure that the shape is held as it hardens. We could also try using different printing filament types for a different finish.

    Luckily for me, my brother has been playing with these things for a couple of years now so knows his way round what can be done. It is a big learning curve for me !

    This is the work area he has set up with 2 printers that can be working simultaneously:

    1228977084_thegear.thumb.jpg.ece50d8bfb1f5fe569639b3fe2de558f.jpg

    • Like 1
  14. 3 hours ago, jasondvd79 said:

    So it's actually a thing! and I escape being astronomically slapped 🥳

    I'm not gonna lie @John I'm slightly impressed 🤣 that's a serious bit of kit!

    Is counter weight strip etc. available to buy or something you have built?

    Looks good. 👍🏻

    @Mr Spock has made a logical deduction - it's a magnetic kitchen knife strip. A few quid from e.bay. I had a couple of weights left over from an old telescope mount.

     

    • Like 1
  15. I guess the risk is that you might not like the 100 degree eyepiece experience ?

    Personally I enjoy them a lot but I know they are not everyone's "cup of tea".

    The Baader Morpheus seems to be popular with everybody who uses them.

    In terms of overall performance the two will be pretty much the same I reckon. The 13mm XWA will be a big chunk to have hanging out of a barlow or focal extender of course although the Morpheus is also quite sizeable.

     

    • Like 1
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