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Stu

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Posts posted by Stu

  1. The idea is to keep the eyepiece, objective or front plate JUST above the dew point, not to have it toasting away 😉. I agree with using them sparingly and on lowest setting to keep the dew away, but there are nights when the option is dew straps or pack away, so dew straps it is.

    • Like 2
  2. This little gem just turned up courtesy of @John. Looking forward to giving it a go. Hopefully might have a chance to compare with the 22mm Type 4 Nag, but that depends on the weather and when it sells. I hope I don’t regret the change, but doubt I will. This is either my second or third, I can’t remember 🤣🤣

     

    IMG_7834.jpeg

    IMG_7835.jpeg

    • Like 11
  3. 2 hours ago, Richard N said:

    It’s a good place to discuss clouds with geographically similarly challenged folks. 

    There is a certain irony that members of the other forum actually see stars but the name implies otherwise, and this forum implies we do, but we don’t 🤪🤣

    • Haha 7
  4. 6 hours ago, Flame Nebula said:

    O-III and UHC filter can enhance certain objects like nebula and planetary nebula

    They certainly can. It is specifically emission nebulae (and planetary nebulae) which are enhanced as the emit light at specific frequencies so that filters can be produced which just allow these frequencies to pass, blocking out most of the rest. This does dim the image a bit, but increases contrast by increasing the difference in brightness between background and target. They still perform best under dark skies and with good dark adaptation but will allow views of some objects under relatively light polluted skies.

    Reflection nebulae, and galaxies generally don’t benefit from filters as their light is broadband in nature so a filter just decreases the brightness of the whole image.

    Don’t listen to the ‘you can only use them in 8” or larger scopes’ comments, they are not true. Yes, you do need some dark adaptation and dark skies but filtering can give amazing views of some objects like the Veil in 4” scopes, smaller even.

    Actually, you haven’t talked about a 4” scope as far as I recall. If the same question was asked about 8” vs 4” you could add wider files views to the list. If you stick a 31mm Nagler in a Starfield 102mm you get a 3.5 degree field, enough for the whole Veil just about, whereas an 8” gives just over 2.1 degrees.

  5. 2 minutes ago, vlaiv said:

    Depends on where you put observer.

    If you stand on earth - then earth is moving with 0 units of speed relative to you and thus star A must move to the left and star B must move to the right.

    For some external observer, standing near star C - it can indeed appear that all three are moving to the left or to the right or some other combination - because motion is relative to the observer.

    Did I pass the test then Vlad?? 🤞🤞

    • Like 1
  6. @Flame Nebula bear in mind there may be a degree of ‘response fatigue’ going on as you have posted many questions, quite a few of them overlapping.

    I didn’t interpret your post as anything disingenuine if that helps, it seemed quite clear. Luckily you all seem to have played nicely and sorted it yourselves, so thank you for that from a moderator perspective 🙏🙏

    I have an FS128 and an 8” f8 dob. I think doubles are probably the main area where the frac probably shows things better than the newt due to the crisp round star shapes it produces. I probably find E & F in the trap easier in the frac, even things like the Double Double are generally cleaner splits. The frac does also show lovely contrast so competes fairly well but generally won’t show anything the newt won’t although perhaps some planetary and lunar detail can be better at times.

    Did I mention getting some miles under your belt before ? 😉😉

    • Like 3
  7. 15 minutes ago, Space Traveller said:

    Sure they are moving away from us but in which direction.

    Based on the basic diagram is Star A moving to the right and Star B moving to the left.

    Consider this, Star B is moving to the right at a speed of 6 units.  The earth is moving to the right at a speed of 4 units and Star A is also moving to the right at a speed of 2 units, thus the stars show a Red-Shift.

    However when we observe the stars, we are studying them from what I would describe as 'Thumb-Tack Earth', and there is nothing we can do about it.

    Everything has to be based on a frame of reference I think, as there are no fixed points in space. From Earth, the would be moving away (simplistically left and right in your diagram), but from another frame of reference they could all be moving right at different speeds, both could be correct.

    I’m sure someone far more intelligent will be along to help soon, where is @vlaiv when you need him 😉

    • Like 1
    • Haha 2
  8. 6 hours ago, Stuart1971 said:

    😂😂 no we won’t…it wouldn’t be around Yeovil anyway, looking more like Wells, or Shepton Mallet…👍🏻

    Wells is lovely, not so familiar with Shepton Mallet as haven’t been there for years but sure it is nice.

    • Like 1
  9. 7 hours ago, Elp said:

    the larger the aperture and hence increased focal lengths don't the stars get ever so slightly bigger

    Actually the opposite is true. As aperture increases, airy disk size decreases so stars appear smaller and finer detail can be resolved. This does however assume excellent seeing. You can see this effect in reverse when observing double stars through a small apo refractor. The small aperture gives large airy disk sizes which are easily seen even in average seeing and at more modest powers, so the effect is a very beautiful ‘bullseyes on velvet’ which is very aesthetically pleasing. With a large scope, the airy disks are much smaller and require higher power/better seeing to reveal themselves; often they are masked by poorer seeing so you end up just seeing scruffy stars which aren’t as nice to view, unless the seeing is excellent.

    • Like 4
  10. 42 minutes ago, mikeDnight said:

    I managed to spend an hour or so admiring the terminator tonight, despite not feeling too well after some rat bag gave me covid.  Anyhow, I decided to try using a 1.7X gpc in my binoviewer and a 2X Barlow in my diagonal. Not certain of the magnifications, but the views were gorgeous and far more detailed that the attached hand held phone pic's. Using my 35mm Ultima's and 25mm Parks Gold eyepieces,  the eye relief was very comfortable and would be great foe eye glass wearers. Sitting back in my chair it was almost like watching TV, or looking through a spaceship window. The scope was a FS128. Some pics were taken in daylight so a bit pale.

    20240417_205448.thumb.jpg.a34dd9b3c13ffdccc992c9192ca908c6.jpg20240417_205518.jpg.36aedc2f4cf38268a0809af589b12062.jpg20240417_202846.thumb.jpg.bbef9ca485d2da814a8fbbf5ca592b5e.jpg20240417_205336.jpg.c4b8f0c2754aeaa330682fe0503a181a.jpg20240417_205652.jpg.4719e7fd8f0752460597a8898151f24e.jpg

    Nice shots Mike, you caught the light ray across Hesiodus crater, did you spot it?

    IMG_7723.jpeg

    • Like 3
    • Thanks 1
  11. 25 minutes ago, Mr Spock said:

    I've got the 12" out again. Just put it out and without any cooling (it's cool in the shed) the seeing is far better than last night. I've just been looking at Clavius and Tyco at x253 and it's lovely and crisp.

    Don’t forget to have a look at Hesiodus as per this thread, should still be visible.

     

    • Like 2
  12. Clear skies here too. Seeing was bad earlier but seems to have settled down now. Solar earlier, with a very busy Sun but it wasn’t a ‘wow’ because of the poor seeing.

    Later on I switched to Astro mode and had a look at the Moon. Looking good, Hyginus Rille and Treisnecker Rilles particularly of note.

    IMG_7706.jpeg

    • Like 10
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