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Ricochet

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About Ricochet

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  1. Your eye won't need to adapt to the exit pupil if that is what you mean and of course you will eventually have a range of eyepieces to choose from. There is no need for these to all be from the same series or manufacturer, you can mix and match however you like to increase your options at each desired focal length. A barlow will extend the eye relief (distance you hold your eye from the eyepiece) so depending on which eyepiece you're using that may be an advantage or disadvantage. For instance I used to have both 16mm and 24mm ES68° eyepieces. With the 16mm eye relief was quite tight and so using the barlow was no problem, but with the 24mm I had to slightly hover above it so adding the barlow increased this already too long eye relief and made it uncomfortable to use. Using a focal extender instead of a barlow doesn't increase eye relief and won't have this problem.
  2. I know you say you don't want to get "too technical" with exit pupils but I think that is possibly the most important aspect of an eyepiece with regards to the scope that you will use it in. For someone most interested in DSOs then I would suggest starting with an eyepiece that gives an exit pupil of 2-2.5mm as that will give the best views of extended objects without a UHC/OIII filter (which I assume you don't have) assuming that the objects fit within the field of view. For an f5 scope (roughly) that means a 10-12.5mm eyepiece, which from the two ranges you're looking at has to be the 11mm ES82°. This eyepiece would then replace the 10mm which was supplied with your scope, but I don't think that should be a negative as the 10mm is generally not well reviewed.
  3. I SAW IT ..... i saw it ..... WOW

    I do not wish to derail the thread but in my experience this is not true for observational astronomy. It may be true for a light to which you have a direct line of sight but the problem arises with "indirect" light pollution from the lamp, that is light which is reflected from the road surface below back up into the sky. Being a broadband emission this light contains the blue end of the spectrum which appears much brighter to the eye than the yellow of sodium lighting. See https://en.wikipedia.org/wiki/Skyglow#Dependence_on_light_source for some discussion on the subject, which corresponds quite well to my experience of local roads being converted from sodium to LED lighting. The most key notes are: And a comparison graph of the effects of low pressure sodium lamps vs other lamp types.
  4. Eclipse Programme uk? Where is it?

    I like the way the sky news cameraman tried to get a sneaky shot through someone's tak.
  5. There are a couple of issues with using a spotting scope for astronomy as far as I am concerned: Spotting scopes come in either straight through or 45° angled versions. Neither of these are comfortable for looking upwards at the high angles that many astronomical objects appear at. A dedicated astro scope with 90° diagonal will be more comfortable. Spotting scopes don't use standard eyepiece fittings. Depending on the scope you may be able to use 1.25" astro eyepieces or get an adaptor that allows them to be used, but obtaining infinity focus is not guaranteed. If you can't get an adaptor then you will be limited to only those eyepieces that the manufacturer, which will be lower magnifications suitable for terrestrial viewing and might not cover the range you would use with an astronomical scope. Spotting scopes don't usually have very good sighting devices. Fitting a finder may require gluing a shoe to the scope which you may not want to do. That said, if I want to watch the ISS pass over I'll use my spotting scope, but otherwise it is the Dob every time.
  6. 32mm Celestron Ultima LX

    32mm Celestron Ultima LX - £50 posted 2" 32mm/70° eyepiece in nearly new condition however please note the following: Top lens cap split by previous owner. I've covered it with black sticky black plastic as a repair, hence the crinkles around the edge as shown in the photo below. Lens cap is functional and holds firmly to the eyepiece. I believe Celestron advertised this as being compatible with their filters, however, the thread is not standard and therefore standard 2" filters can't be attached to the eyepiece.
  7. As you will have seen I've had the 8" for a couple of years now. In terms of weight I would say that the 8" is something that I can carry in one piece but for the sake of my back should probably carry in two. The 10" will be a bit heavier and so I would assume that you would have to carry it as two parts. This shouldn't be much of an issue though as the alt bearings double up as decent handles and reattaching the two parts is easy, the bearings just sit on the rocker box and all you have to do is check that the guides/friction brakes sit inside the box. The large bearings also do a good job of handling the weight changes when switching between eyepieces, so far I haven't had to add counterweights, just to shift the tube to the right place in the rings. Optically the mirrors seem decent but I am hardly an expert on such matters. I did improve things by adding a baffle on top of the mirror clips to prevent stray reflections from the mirror edge. This is something that will affect all mass produced Chinese mirrors and having seen the difference it makes it is something I would do to improve any in baffled Newtonian. The full list of modifications I have made are (although these may not all apply to the 10"): Fit Synta shoe to OTA for RACI finder Fit dob knob to OTA Replace eyepiece clamps with Baader clicklocks Fit baffle in front of mirror Flock OTA Increase height of rocker box to allow OTA to slide further back in rings Fit rear mounted primary mirror fan
  8. Eyepiece comparision tool

    There's also a link to it under the "Resources" button at the top of the forum (or in the hamburger menu on phones/tablets).
  9. As will be better explained by the article Charic linked, the point of the barlow is not to make the laser more straight, but to diverge the beam, effectively turning the laser into a narrow torch that illuminates the centre spot of the mirror. This means that it doesn't matter if your laser is slightly miscollimated, the focuser doesn't centre it perfectly or if you didn't quite get your secondary position absolutely perfect, because the beam still illuminates the centre spot. Instead of the usual laser method of primary collimation by getting the laser beam to return down the hole it is projected from, which with cheaper lasers might be harder to judge than it should be, you centre the shadow of the centre doughnut on the angled face of the laser (in my case I have a dot in the very centre of my primary as well as the doughnut so the shadow of the dot disappears down the laser hole as an additional check). For your case I would expect that your Hotech laser is of such quality that you can use it in the "normal" method with no issue, but the barlowed laser method allows the use of any any cheap laser and any cheap barlow to achieve the same accuracy. Note that it has to be a barlow, a powermate or telextender won't work because of the difference in how they work.
  10. A boo boo is a term for a minor injury that you might use when talking to a small child. What he is saying is not to worry about making mistakes.
  11. I suggest using the barlowed laser method for easily collimating the primary without the need to grow longer arms.
  12. Looking at the specs for your scope it would have come with a 20mm, 4mm and 3x Barlow. Of these only the 20mm was really of any use in my opinion. If you want to get three eyepieces to replace them then I would suggest something around 9mm for high power, 20mm as a mid power and then 30mm as a finder/low power eyepiece. FLO currently have offers on both Celestron and Vixen plossls which are decent eyepieces and better quality than the ones that came with your scope. The eye relief on short focal length plossls is a little bit short so you might want to go for something with a bit more eye relief. BST Starguiders are my usual recommendation but over your stated budget.
  13. skymax 127 eyepieces

    I am sure the Maxvision was just JOC blowing out old Meade SWA stock and the ES68 is the same eyepiece in an updated more TV like body. I had 24mm Meade SWA and ES68 and optically they seemed identical switching back and forth from one to the other. I sold the ES68 and kept the SWA for the twist up eye cup but I expect that I'll be selling the SWA soon now that I've bought a 28mm Nirvana.
  14. I think that the optimum exit pupil really depends on the type of object you are looking at. The 2-3mm optimum works for unfiltered extended objects like galaxies where you want to use the best corrected section of your eye lens to recognise shapes. However, if you're looking at nebulae with a UHC or OIII filter then you might need to increase the exit pupil to the "3-4mm for DSOs" to compensate for dimming of the filter. However, for globular and open clusters, which are made of multiple point sources, you can probably use a minimum exit pupil somewhere in the 1-2mm range if the object fits into the field of view. Planets can go even smaller. I read somewhere that the optimum pupil/magnification trade off is somewhere in the 0.85-1mm range.
  15. How many eyepieces are you thinking of getting and what's your budget per eyepiece?
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