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Ricochet

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About Ricochet

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  1. I would say that actually the 20 and 8mm would suffice to find out if astronomy is for you. The 4mm is about half of your scope's focal ratio and thus only really suitable for splitting close double stars. At this magnification you will clearly see stars being diffracted into airy disk patterns and on planets this same effect will blur the details. For planets you want an eyepiece that is 0.85-1x your scope's focal ratio, so a 7 or 8mm. For deep space objects you will usually want an eyepiece with an exit pupil of 2-3mm, so a focal length of 2-3x the focal ratio which is about 16-24mm. Here your existing 20mm will do for now although as you progress you might decide to replace it with something of better quality. The other eyepiece that may be of interest to you at this stage is one that maximises the true field of view. For 1.25" eyepieces that can be achieved by a 24mm 68° or 32mm 50° (i.e. a Plossl). At this stage I would not bother with filters. Many people don't find much benefit from the coloured filters and you might not need a moon filter either. If you do decide a moon filter is required then a variable polarising filter is the best one to get in my opinion.
  2. That you have also changed the position you are viewing from by 90° so that the image you see still makes sense with respect to the scope.
  3. Very nice you'll have a lot of fun with that I think. I approve of the clicklock upgrade, they make changing eyepieces so much easier. Is the thumbscrew where the focuser joins the main tube to allow the focuser to rotate in the tube?
  4. It doesn't matter which way the RACI eyepiece is pointing. Being able to angle it to the most comfortable angle is the entire point. However, the 90° angle makes the initial alignment more difficult and so they work best in conjunction with a red dot/circle finder. If you can't use a RDF to get the initial alignment you might find one more difficult to use than the straight through variant.
  5. What is the diameter of the clamp that holds the eyepiece adapters? The extension clicklocks are 2" wide so if the existing clamp is wider there is the risk that it won't be held quite squarely. There is also a clicklock with the dovetail fitting if that's what your eyepiece adapters also have. You can screw 2" filters into the bottom of the 1.25" clicklock with enough clearance for eyepieces but not enough to use with a Barlow (but you probably wouldn't be using a Barlow for an OIII filter). If you go with the 2" 47mm extension and screw filters to the bottom of that then you will have loads of clearance. The 47mm refers to the length of the clicklock that protrudes from your focuser and doesn't include the length of the nosepiece which is probably another 30mm or so.
  6. I agree with Richard, an 8 or 9mm eyepiece is going to be the optimum planetary eyepiece in your scope. As planetary viewing is dependant on atmospheric conditions you may want to consider getting an 8-24mm zoom so that you can adjust the focal length to match the atmosphere on any given night. The Baader zoom is well regarded but there is also a cheaper 8-24mm zoom sold under various names (Skywatcher, Seben, Vite to name a few) that gets decent reviews (unlike the 7-21mm zooms).
  7. Proving that sometimes it pays to ask, today I received a package of three items from Baader, two of which they don't usually sell. So from left to right; an M68 Clicklock, an M68x1mm to M68x0.75mm inverter ring and a Morpheus eyepiece holster. The inverter ring is the special piece here because it has allowed me to directly fit the Clicklock to a Bresser Hexafoc focuser and dispense with the low profile 2" clamp that comes as standard and doesn't hold any eyepiece or adapter with an undercut squarely (!!!). And finally a picture of the Clicklock actually fitted to the focuser. It was quite a relief when it went on given that it fitting was dependant on my ability to use callipers correctly.
  8. It is difficult to definitely say as I haven't used the equivalent models from other manufacturers to compare but overall I would say that it is a good telescope and that on any given night the limiting factor is the atmosphere and not the telescope. Star clusters are very good and nicely defined with only the brightest stars showing diffraction spikes. For planets and the moon contrast can be improved upon by masking the mirror edge as discussed in the following thread. Once done the views are excellent although they weren't bad to start with. Tracking at high powers is also easy as any vibrations are damped instantly and so there is no waiting for things to settle down.
  9. That is true about the 8". In the out of the box configuration the rocker box is the exact height required which doesn't give any leeway to slide it backwards for heavier eyepieces or adding a heavier finderscope like I did. I don't know if they have raised the height of the rocker box for the 10" but the description does mention the ability to move it back in the rings which suggests they might have. It is also possible that new production runs of the 8" might appear with higher side bearings based on customer feedback from those of us who bought the early models. In the end I added a riser to my rocker box to get rid of the additional weights as even that small increase made me less likely to get the telescope out.
  10. Firstly, happy birthday. I Now with regards to the telescope there are two good points that we can take from this immediately. The first is that Amazon gave you a refund and so you have been given a free telescope. I'm sure pretty much everyone here would love a free telescope, no matter how many telescopes we already own. The second good thing is the "horrible" red dot finder that came with your scope. It actually isn't horrible at all. The original finder that was supplied with these scopes was horrible. It might have looked nicer but it didn't work very well and there have been many, many complaints about it. Enough so that it appears that Celestron have modified the design and now provide a proper, usable, finder like the one you received. Now, onto the bad point, the secondary mirror obviously shouldn't have come off in the first place. The good news is that you had difficulty getting the threaded insert back into the hole which means it should still grip well once it is back in. The threaded insert should be pushed in so that it is flush with the surface and not sticking out as it was in your picture. If you have left it half way out I would be inclined to take the secondary out of the telescope again so that you can push it all the way in. It only grips with the wider serrated sections at the top and bottom so it is best that both sections are correctly in place. Once you've got the secondary mirror back in place you need to collimate the telescope as best as you can. Given that you said that you said you got the mirrors aligned I assume you've already found out how to do this. If not, then google for Astrobaby's collimation guide which will give you step by step instructions on how to collimate the telescope. If you're unsure of any of the steps just ask here and someone will be able to help. After the telescope is collimated you need to align the finder with the telescope. Take the telescope outside in the daytime and point it at the furthest thing that you can see. Start with the eyepiece with the highest focal length as this will give you the widest field of view and once you have the telescope aimed correctly switch to the shortest focal length and centre the object. Now tighten up any clutches you might have on the mount so that the telescope cannot change position. After tightening check that the telescope is still pointing exactly where you left it. You can now adjust the red dot finder so that it is pointing at the exact same object. The RDF has a thumbscrew on the side that moves it left to right and a thumbscrew underneath that moves it up and down. Adjust these so that the red dot is on the same object you are looking at through the scope. After adjusting look though the eyepiece again and check that the telescope hasn't moved. If both telescope and finder haven't moved then they should be aligned and you are ready to take the telescope out at night. When you take it out at night the first thing to do is to check/tweak the alignment using a bright star. If you can identify it Polaris is the best option as it will not move (assuming you are in the northern hemisphere). Sorting out the alignment in daytime will also give you a chance to check that you are getting an image through the telescope. It is made for astronomy so it won't be able to focus on close objects but distant objects will probably be OK. At night you will probably need the focuser wound in a little bit from the point at which it focuses on distant terrestrial objects. The blackness that you saw last night might just have been a result of not being focused properly. If it happens again try winding the focuser from one extreme to the other until the stars come into focus.
  11. In terms of brightness a 7mm is the right call, having twice the brightness of the 5mm and half the brightness of the 10mm. However, you may still see floaters with the small exit pupil. I guess the only way for you to find out is to try it.
  12. Except that it seems to me that it isn't. There are two things to consider that your eye can detect. The first is the image formed by the telescope/eyepiece. This is a circular image defined by the field stop of the eyepiece and the central area is not "blocked" by the shadow of the secondary mirror. Light from an object directly in the centre of the field of view passes the secondary mirror on all sides and is reflected back by the parabolic primary mirror to a point directly in the centre of the image. Light from a point offset from the centre also passes the secondary on all sides and is reflected back to a point offset from the centre of the image. All points in the field of view are affected equally by the secondary/spider in two ways: The central obstruction causes extra diffraction compared to the unobstructed view of a refractor. This extra diffraction reduces contrast across the entire image, not just in the centre. The spider veins cause diffraction spikes on bright objects perpendicular to the directions of the veins. Again this effect is seen across the entire image. The second thing that you can potentially detect is the shape of the exit pupil. This is the exact same shape as the aperture entrance and will appear like a circular ring in a telescope with a central obstruction. However, to detect this size of the obstruction has to be more significant with respect to the circle of light entering your eye which requires the exit pupil produced by the eyepiece to be larger than the dilation of your pupil. When you describe "viewing the moon as a whole" with a 12mm setting on the zoom I assume that you mean that the moon fills the entire view and that you also have the barlow lens fixed to the zoom? With this combination the exit pupil will only be 1mm, and there is no way that your pupil will be smaller than this. If you are not using the barlow then the exit pupil will be 2.4mm, which is a typical daytime pupil size and so I would think unlikely to be larger than your pupil. The other thing that makes me doubt that you are seeing the shadow of the central obstruction is that you describe the central degradation in terms of sharpness. If you were seeing the shadow superimposed over the image then I would expect the centre to be darker but still just as sharply focused as the edge.It still sounds to me like your issue is either that you haven't quite got your eye the right distance from the eyepiece or that the telescope/eyepiece combination has significant field curvature in which case you should be able to refocus to get the centre sharp and the edge blurry. Also, as a last thing can you confirm that the end cap supplied with the 130mm Astromaster still looks like this: and not this: If they have changed things and the end cap now looks like the one in the second picture make sure that you are removing the entire end cap, not just the central part. If you remove just the central part then the obstruction would certainly be significant with respect to the much reduced aperture the telescope will be working at.
  13. I don't like the way that mirror is hanging over the edge there