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Ricochet

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  1. You’ve not included what I consider to be a vital piece of information, the focal ratio of your telescope, so that we can consider the question in terms of exit pupil. In my opinion the most important (DSO) eyepiece in your set is the one that produces an exit pupil between 2mm and 2.5mm with your telescope. I believe that your telescope is f/8.6 so the eyepiece that I would spend the most money on, and plan the entire eyepiece set around lies in the range 17.2-21.5mm, so in this case yes, you do need to add an 18.2mm Delite to your collection. However, in my f/6 scope the 13mm would generate an exit pupil in the 2-2.5mm range and so the 18.2mm would only be a luxury eyepiece rather than a necessary one.
  2. I think that is the range I’d be looking at too. I’d probably start with the 10mm for the 10”, 13mm the 8”. I saw a 28mm pop up on eBay a couple of days ago for £150 which would be a great choice for (almost) maxing out the fov.
  3. Black stalked 9x50 RACI White stalked 9x50 RACI Same finder, different colour scheme. Pick the one that matches your telescope best if you're bothered about that or whichever is cheapest. The Astro Essentials version is available bundled with a foot if you need an additional foot for a multi-finder setup - assuming you can fit it to the telescope. On the filter front, I consider the Baader Neodymium a good planetary filter but I cannot recollect a single DSO that has been improved by using the filter.
  4. Some points on this: A star test must be performed with an eyepiece with a focal length equal to or shorter than the focal ratio of the telescope The star must be precisely centred in the field of view and stay centred during collimation. A off centre star looks the same as a uncollimated scope. For an undriven scope this means using Polaris, which at only 8° Nikolai may not be able to see. I believe the above instructions apply to adjustments made to the primary mirror, which cannot be adjusted for the scope in question. Based on experience, never attempt to adjust the secondary using a star test, it will not go well. Given the above, I would suggest a quick star test is a good way to check if the collimation looks ok, but if it is shown to be out it is better to accept the collimation is out and to just enjoy the views the scope provides in its uncollimated state, and then attempt collimation of the secondary the next day during daylight.
  5. 9x50 RACI plus some sort of red dot / Rigel / Telrad is pretty much standard on any large scope. On your Mak you probably want to save weight if possible so the Rigel or the Explore Scientific mini Telrad would be good choices. I would probably still go for a 9x50 over a 6x30 as there is a fair difference between the light gathering capabilities of the two finders. For your refractor it depends on what you've got and how wide a field you can get from an eyepiece. If you can get over 3° then you can probably get away without the RACI. As for light pollution filters, the Astronomik CLS used to be a good one, but with the increase in LED lighting it is hard to recommend any light pollution filter these days.
  6. This video is worth a watch. I guess it could be summarised as ‘you can see more with a 10”, but you will use an 8” more’. Personally, there have been quite a few occasions where l have been glad that I didn't have anything heavier than my 8" when putting it away at the end of the night.
  7. I don't get the ‘non slip' comment. Are they not PTFE? The pads supporting the mirror whilst not preventing thermal expansion/contraction of the glass is the entire point. As for a source it is the sort thing that you can often be found available cut to custom sizes on eBay.
  8. It is impossible to tell. You need to place some light coloured card or paper behind the secondary mirror so that we can see where the edges of the mirror and focuser are in order to judge whether they are concentric. You also need to smooth down the foil on your collimation cap so that the entire surface looks bright. The dark dot formed by the eye hole should be inside the doughnut on the primary mirror but with such a large dark section in your cap the hole is not visible. The three outer bolts are recessed and need adjusting via a suitably sized hex/allen key.
  9. It could also be a transient astigmatism present only while the primary or corrector is cooling, which is more prominent now the temperature has dropped than it was over the summer months.
  10. No, you would usually have to adjust both mirrors. However, what you have described makes sense. When you collimate with a laser any error made in the collimation of the secondary will result in double the error in the primary collimation. It sounds like your scope was collimated in the factory and during transport only the secondary moved, hence you saw that the secondary was out and the primary was further out. When you fixed the error in the secondary it also fixed the larger error in the primary because in reality that error didn't exist, it just appeared to due to the error in the secondary.
  11. As a visual observer how much did you find yourself using it as an EEA device, sitting there watching the image appear on the screen, compared to using it as an imaging device where you would set it on a target and then leave it until some time later to check whether it had produced an acceptable image?
  12. Jupiter is very susceptible to atmospheric seeing, which is the stability of the atmosphere, not the darkness of it. In fact many people report that their best planetary views occur when there is a light haze in the air as there is no wind to blow the water vapour away. Due to this requirement for stable air, observing from a dark site will not necessarily show better results than observing from home, other than avoiding any negative effects from the heat haze coming off roof tops. Given the recent weather I would not be too concerned about any potential lack of sharpness over the last couple of weeks and would simply continue to observe without worrying too much about the collimation of the telescope or any other tweaks that may improve its performance. One important section of atmosphere that is often overlooked is the air inside the telescope itself. When moving a telescope from a warmer location to a colder one there is a cooldown period where the components are cooling and this leads to air currents inside the telescope. For a 5” Newtonian this isn’t very long but within the first half an hour of observing I would consider this a possibility and see if the sharpness improves later in the session.
  13. There is no 6mm Starguider, but there is a 5mm. The 5, 8 and 12mm Starguiders are well corrected even in fast scopes whilst the longest focal lengths are best used in slow telescopes. This means that in the specific case of the 5mm Starguider vs the 12mm Starguider + Barlow there will be very little difference between them. However, as a general rule if you are using a fast telescope and cheaper eyepieces then adding a Barlow can often improve the correction of the eyepiece. I would choose a 5 and 12 over a 12 and Barlow as the eyepieces will be more parfocal, but if you were buying three items then there would be a good argument to buy 8, 12 and a Barlow so that you effectively have 4, 6, 8, 12 instead of buying 5, 8, 12, assuming that 4/5/6mm focal lengths are suitable for the telescope you will be using them with.
  14. I have a 72ED and use 24 Panoptic, 13 Delite and 3-6 Nagler zoom. The only change I might make is to swap the 13 Delite for a 13 Nagler T6, which is also a small eyepiece. Given you currently use Delos I think you would be disappointed with the correction level and reflections in the BHZ at f6.
  15. The benefits of the 127 lie in its larger aperture. The aperture of the 127 is approximately 25% larger than that of the 102 which translates into a 25% better resolution for planetary targets, 55% brighter stars and a 25% increase in optimum magnification on all objects. The previously posted field of view images don't really show this difference too well. When you look though the eyepiece the apparent field of view is the same, so the different circles appear to be the same width, with all the contents magnified that little bit more. Setting up the various scopes and eyepieces in the desktop version of Stellarium would show this more clearly. As a beginner you won't notice the difference simply because you don't have any point of reference but I think if you had the two telescopes side by side you would see the difference. If I were buying myself one of these telescopes as my only telescope I would go for the 127 but in my current position with a larger telescope I would also be happy with a 102 as a planetary grab and go option. The Skywatcher and Celestron models are made by Synta so they should be the same with some minor differences to the fixtures. Ed Ting has recently done a review of the Skymax 102 that you might want to watch. Note that any visual DSO views will be small grey smudges nothing like the colour images he manages to get by sticking a camera on the end for hours and doing lots of post processing. The Bresser Messier scopes tend to be a little bit better mechanically, but optically probably about the same as the Synta scopes. The one difference between the two manufacturers that is notable is that the Bresser scopes are f/15 whilst the Synta scopes are f/13 so for any given eyepiece there will be a slight increase in magnification with the Bresser and a slight increase in field of view with the Synta. It probably means that the Bresser is slightly better for planetary but the Synta is a bit more of an all round scope. Any of these scopes would be a good choice and you're probably best off choosing whichever one comes bundled with the mount that you want to get.
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