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Ricochet

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Everything posted by Ricochet

  1. You are understanding correctly. However, I don't think it is as simple as painting the edge as I tried that first and still ended up with a mask. I'm not sure where exactly the bloat comes from, but suspect it might actually be where the coating right at the edge isn't quite as smooth or the vertex at the edge of the coating rather than the uncoated chamfered section.
  2. The 24mm ES68 is too big for binoviewers. 24 Panoptics work because they are significantly smaller.
  3. It could increase the strength of the diffraction spike associated with that vane, but if you consider that the light being reflected is only in the central 8" of the tube, you may find that the twist is far enough over that it doesn't matter. However, as it is twisted it could have potentially been weakened so I would contact your supplier and see what solution they propose.
  4. If it is still available there is a 24mm ES68 going for all of £60 on ABS. Not quite a 24 Panoptic, but most of the difference is in the size and weight of the eyepiece rather than the optical quality.
  5. It depends what you are observing. For double stars you can probably push to 400x, but for planetary the optimum for the scope is more like 200-250x, for star clusters up to 200x (if it fits in the fov), galaxies 100x, filtered nebulae less than that. All of that is assuming the atmosphere allows you to push that high. In the UK once you hit 150x you can start to hit atmospheric limits and they will override anything your scope may or may not be capable of under perfect conditions. I didn't mean it was literally a 1.25" set of lenses inside a large barrel. The glass can still be 2" but the eyepiece can be stopped down internally.
  6. Do you have a picture of this telescope? William Optics are a Taiwanese company and as far as I know they have always used the Taiwanese manufacturer Long Perng to produce their telescopes. There may be slightly different optical designs in different editions of the same scope line but you would have to hunt down comparison reviews to find out if that makes any difference that can be seen. If you were looking to buy a Celestron SCT then you could have the old built in USA vs new built in China scenario. I suspect the two histories have been confused.
  7. Probably not. It looks like a 26mm plossl unnecessarily put into a 2" fitting for marketing purposes. As someone with an 8" dob I would suggest that at some stage you will need one 2" eyepiece for your telescope, but it needs to be one that shows a wider field of view than a 1.25" eyepiece can show, and it needs to be one of decent quality so that it is reasonably well corrected to the edge. If the eyepiece isn't well corrected you might find that the usable field is actually less than in your widest 1.25" eyepiece. For your initial upgrades, I suggest that something shorter than your 25mm is probably the way to go in order to give you a range of options to try on different objects. I would start by picking something in the 12-14mm range and then dividing whatever focal length you choose by 1.4 to find your next focal length.
  8. There are three possibilities I can think of: You haven't got your IPD set correctly and/or your eyes positioned correctly over the two eyepieces. The eyepieces are not being held correctly in the clamps, either they are offset or they are tilted. If you have some eyepieces with smooth sided barrels try those, have both dioptres screwed fully in, make sure that the eyepieces are seated flush with the top of the eyepiece clamps and try tightening only one screw on each clamp. The binoviewers are out of collimation. Of these possibilities 1 is quite likely given that you're new to binoviewers and 2 is a known issue with this model of binoviewer.
  9. Thanks, Mark. I meant to order one ages ago and never got around to it.
  10. Did you buy the standard one or the solar version? Is there any reason to buy both?
  11. I've not seen one before but it looks like a JMI EV 1N. I often think that the sign of a good retailer is not the service they provide when everything goes right, but the service supplied when something goes wrong. In this case it looks like they've really stepped up to the mark.
  12. Is the camera not centred over the Cheshire properly? In the photo everything is offset from the cross hairs. If the cross hairs line up when you look down the Cheshire with your eye then the collimation might be ok.
  13. I've got the Altair Astro branded version on a Manfrotto 190c and I'm surprised it copes with a 102s. How long do vibrations take to settle?
  14. Its difficult to assess as you really need to take the photo through a Cheshire or collimation cap to make sure the camera is properly centred, however I would say that the photo you have posted does look out.
  15. The first thing that I would do is to check the collimation using a Cheshire. I'm not really a fan of lasers and generally speaking think a Cheshire will give an more reliable result. When it comes to poor images most problems are usually due to atmospheric thermals. The first and most important are those in the scope itself so make sure that you give it a good amounting time to cool. I would suggest at least an hour as you are trying to assess the image quality. Secondly, be careful about what you are looking over when you observe. Man made structures (buildings, roads) tend to hold and release heat much later into the night than fields and forests. If possible try to avoid observing over houses. Even waiting for an object to pass over the gap between two houses can have a dramatic difference if you're in an urban location. The amount of atmosphere you look through will also have a big effect, and larger telescopes suffer more from this than smaller ones. Observing an object when it is at its highest will minimise the amount of atmosphere you are looking through and hopefully improve the views. Beyond that, I would advise trying to contact your local astronomy group and see if there is any possibility that one of their experienced members could have a look at your scope and give their opinion.
  16. You can use just the Cheshire for all steps of collimation, which will save on costs. However, I would advise spending your money on a good quality device rather than a cheap one, either the FLO premium Cheshire or a concentre would be my choices.
  17. Usually the mirror cell is fixed to the tube via screws and should not just come loose. It would probably be a good idea to post a photo or two of the rear of the scope so that we can see what damage has occurred. This just means that you were out of focus and does not mean that there is anything wrong with the telescope. You just need to wind the focuser in or out to make the image as small as possible to focus it.
  18. For monoviewing I'd go for a 7XW. You might not "need" it for planetary, but the 70° field is a bit of a sweet spot.
  19. In my experience, I don't think so. Maybe carefully examining a photo you might be able to spot something but close enough is probably fine. If you want something really accurate I think I've seen commercial masks for Skywatcher scopes somewhere, Telescope Express perhaps.
  20. You've answered it in your question. Bigger things are easier to see. I can't give a direct quote/link but the idea that the brain picks out bigger things better than smaller things is a constant idea in texts on observational astronomy.
  21. Ok, perhaps a picture will help. Look at the image below. The left hand star shows what your stars currently look like, with both mirror edge diffraction spikes and clip shadows. The middle star shows what your stars will look like if you get rid of the clips. The right hand star shows what your stars will look like if you mask the mirror edge. It's not the shadows that are the problem, it is all the excess spikes. I'm a solely visual, but even then masking the mirror edge is the single best upgrade that I have made. It's also the cheapest, as my mask is just made from black card.
  22. That is my point. The mirror clips are not causing the issue, they are preventing the issue at three points. If you take them off the problem becomes worse.
  23. You don't mask the edge of the mirror to prevent shadows from the mirror clips. You mask the edge of the mirror to remove the scatter/diffraction spikes from the mirror edge. If you have shadows corresponding to the mirror clips, those shadows are the only places where you don't have a problem and you need to mask the rest of the edge.
  24. I'm sure Solarscope can help you. You want double stacked 100mm etalons, a blocking filter and a custom adaptor to fit the etalons to the front of your Tak. https://solarscope.co.uk/filter-systems/ I've no idea how much that all costs though.
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