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AlcorAlly

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Everything posted by AlcorAlly

  1. Beautiful! My favourite was the Dumbbell nebula. Thank you for sharing!
  2. This is so helpful, thank you @SwiMatt @Franklin! I don't know why I didn't think of that, somehow I was completely stuck on trying to find north first, every time. True but I 'd like to have a system of some sort because I draw a lot of double stars and the sizes of airy disks and relative distances seem important when referencing past sketches.
  3. This is pencil on paper, inverted in a mobile app, which a tiny dab of colour applied where needed.
  4. Right now I'm struggling with two things. 1. Working out which way the view is oriented (NESW) when I keep rotating the diagonal. This maybe a very basic question, but how do you quickly determine which way is north when using an EQ mount and an diagonal at an unusual angle? 2. Maintaining consistent and accurate proportions across my sketches - e.g. 1st magnitude star at 230x is 5mm on sketches, etc. For example, the Castor above seems a little too large now, in proportion with the other two. Any tips on the two challenges above would be very much appreciated.
  5. Thank you @mikeDnight @SwiMatt I do take notes, i just cropped them out in the image (they're not great), here's the full version.
  6. Highlights from last night's doubles session under the glow of the full moon. All with 102mm f9 refractor and 4mm TV DeLite at 230x. Sketched at the eyepiece, there are probably some inaccuracies, constructive feedback is very welcome.
  7. Beautiful night even with the full moon. I focused on my favourite doubles with Castor and Tegmine being the highlights of the evening.
  8. Thank you @vlaiv Does the size of the offset make any difference relative to the size of the aperture being masked and the size of the aperture stop? Example: Let's say we have a 75mm and a 150mm aperture telescopes and we apply 80% aperture mask to both at a distance of 200mm from the objective. If the focal lengths of the telescopes are the same and we use the same 30mm 100 degree eyepiece we will get about ≈5.24mm offset for both with a 3 degrees FOV. Would the 5mm offset make more of noticeable difference to the smaller aperture telescope because it would take a larger proportion of the overall available aperture? What about reducing or increasing the size of the mask? Do we still expect the difference to be negligible regardless of those factors?
  9. @vlaiv sorry do you mean position A is better if there's significant source of indirect light that is in front of telescope e.g. street lamps? As in better for reducing light scatter? As for reducing the actual aperture, you don't think that the effects of an aperture mask are more pronounced when the mask is positioned at the location where the effective aperture is defined i.e. at the objective lens?
  10. I enjoy experimenting with various aperture mask sizes, particularly on double stars. My question is, which placement is better? A. Aperture mask goes over the dew shield B. Aperture mask goes close to the objective lens cell and the dew shield then goes over the mask I imagine A is better for light scatter because it creates a darker chamber inside the dew shield. However, I'm not sure that this placement would alter the optical characteristics of an instrument in the same way that an aperture mask over the objective lens does. I would appreciate any opinions – based on practical experience or theoretical. Image Credit: Jeff B on cloudynights
  11. I'm extremely fortunate to have your ED102S now. Didn't know it came with the plastic knobs – thank you for upgrading them. It's a beautiful telescope, I think it's just perfect and I've enjoyed every minute with it so far 😊
  12. I thought at £54 the N13 was a bargain by Takahashi standards!
  13. Thank you! Perhaps taping the undercut could help increase contact area with compression ring and make it more secure. I’d only use this set up for mono and light 1.25 eyepieces, so it’s probably fine. Thanks again for all the helpful photos and for taking the measurements.
  14. I'm trying to put together a good solution for switching between mono and bino mode for my telescope and was hoping someone knows the answer to this question. Would Takahashi Takahashi 2" Sleeve (N13) work with Baader ClickLock? From the photos I image probably not or it won't be a secure connection. This part: https://www.firstlightoptics.com/takahashi-adapters/takahashi-2-sleeve-tkp00113.html With this one: https://www.firstlightoptics.com/adapters/baader-2-clicklock-m56i-clamp-takahashi.html If the N13 works then I can use it with existing Tak visual back and avoid extensions.
  15. Wow this is so helpful! Thanks so much for sharing!
  16. Here's a helpful and detailed book I came across while researching this topic, in case it's of use to anyone else. HumanEye.pdf
  17. More questions on this topic. If you have myopia, say -4 diopters prescription, when is your eye lens relaxed? I assume it's not when focused on infinity because you can't focus on infinity. In the case of myopia the eye is focused in front of the retina rather than directly on it, causing distant objects to appear blurred. So for someone with myopia of -4 diopters, their eye is naturally focused at a point that is 1/(-4) meters in front of the retina. Therefore, the relaxed state of their eye, where distant objects are in focus, occurs at a point 1/(-4) meters away from the eye i.e. 25 cm in front of the eye. Is this correct?
  18. Depends how it's stored, doesn't it? If it's on the tripod with weight ready to go, then there's equal amount of fuss for Alt-Az vs EQ. But if the EQ is stored in parts and separate from tripod and other bits then it takes a bit longer. I like both
  19. Very positive experience here. It holds Vixen GP very well with a 4 inch refractor or 6 inch reflector. I compared it to the steel 1.75 '' skywatcher tripod I owned for a short time and the 90c was more stable.
  20. My first post in this thread. It's a good day. The postman brought a beautiful vintage Vixen ED102 f9. I was very nervous about having this rare telescope posted but the seller kept me informed and reassured throughout the process - thank you Ian! 👑 A quick test on nearby branches showed a nice sharp image with no false colour at 130x so I'm very excited. Looking forward to running it against the little Takahashi
  21. How does Vixen GP compare with AP for stability when all other variables (tripod etc) are the same? I assume GP can take slightly more weight (6kg AP vs 7 kg GP quoted) before stability is affected. Is that the case in practice?
  22. Just looked with eclipse glasses, I can see something at around 11 o’clock position.
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