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Ricochet

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About Ricochet

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    Brown Dwarf

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    Hertfordshire

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  1. If you tighten all the secondary screws equally the collimation should remain the same. The trick is to tighten the screws whilst looking through your Cheshire so that you can make sure the tightening locks the secondary in the correct position. Alternatively, you can just tighten the central screw which will pull the mirror stalk up against the collimation screws. Edit: Beaten to it by quite some time. When I opened the thread there were no visible posts about the secondary, when I hit reply lots loaded.
  2. I always used to have to collimate my dob at the start of my session, but the last time I collimated the telescope I tightened the collimation/lock screws more tightly. Since that time I've not had to recollimate my telescope. I took a photo of the collimation at the time and recently I wanted to post that photo. When I had scrolled back far enough to find it, I discovered it was taken in something like April 2019. So my advice of you are collimating at every session is to tighten everything up more securely and see if that helps the telescope hold collimation.
  3. I've not used either of these mounts so I can't say which one is the most stable over the other, which is probably the most important factor in choosing. You don't put it on a tripod. You find some raised surface that you can place the base on so that the telescope is at a reasonable height. You can buy an alt-az astronomical tripod with a vixen dovetail clamp, like the skywatcher az4 or az5, and fit the telescope straight to that, but then you will probably exceed your budget.
  4. You don't need a reducer to change the focal ratio for visual astronomy, you instead change eyepieces to alter the exit pupil size and/or field of view depending on what object you are looking at. A "standard" 1200mm 6/8/10" dob is a good all round telescope choice and a good alternative instrument to your binoculars. I have both 16x70 binoculars and an 8" dob and think it is a good pairing.
  5. Only in so much as the field of view is limited by the focal length of the telescope and maximum field stop for the size eyepieces it will take. For the 90/900 with a 32mm Plossl the maximum field of view is roughly the same as for my 8" dob, so I would not be particularly worried. Getting to a dark site will be far more important for nebulae and galaxies. If you click resources (top of the page on desktop, in the menu on mobile) > astronomy tools > FoV calculator you can simulate the field of view for a telescope as different eyepieces, then click through the various Messier objects to
  6. Which 130 do you have? If it is a 130p with rings and a dovetail you could just buy an AZ4 mount and put your current telescope on it.
  7. This one is possibly the best option you have found so far. In astronomical terms the mount is still a bit on the lightweight side but it is use able and light years ahead of the mounts supplied with the telescopes you were originally looking at. The other already suggested option now you have increased your budget is the Bresser 80/640 which is a slightly smaller and more portable option on an alt/az mount whereas the skywatcher is on an equatorial mount. These two are OTA items, which means Optical Tube Assembly, i.e. just the telescope and no mount. A suitable mount for either of t
  8. Ok, so what I mean by fittings is how the telescope connects to the mount and also how the finder scope connects to the telescope. Have a look at the picture below, by @Highburymark of a telescope attached to a mount. You can see a long silver bar attached to the telescope, which is a "Vixen" dovetail, and on the mount you can see a silver clamp that is holding onto the dovetail. These items are a standard size so that telescope with its standard dovetail can be fitted onto any mount that has a Vixen dovetail clamp, so you can have more than one telescope and mount and interchange th
  9. I think this is a bit of an extravagance for a 5 and 10 year old. An 80mm carbon fibre triplet is a premium small scope mostly aimed at astrophotography. For visual a doublet is going to be lighter and will cool quicker, both of which are probably key considerations if you want to use the telescope as a grab and go instrument.
  10. Do you have a link to the shop you are looking at? Do they list all the out of stock telescopes too? If they only list in stock telescopes there is a chance they might have something suitable once deliveries from china start coming in more regularly (and more cheaply).
  11. The normal ST80. Optically they may be the same telescope, but the Levenhuk has the same problems with an inadequate mount and non-standard fittings as the first one. Bear in mind that the normal ST80 can be bought as an OTA only package so check the one you are looking at comes with a mount.
  12. Probably not. On face value it looks like a typical 80mm f5 achromat, which is a fairly standard scope, sold for instance as the skywatcher skytravel (ST) 80. However, the one you've linked to appears to have an even cheaper focuser than normal, with no standard finder shoe for you to easily swap finder as with the normal one. In terms of mounting, the mount itself looks extremely weak and flimsy, and the connection between telescope and mount looks like some odd concoction instead of the standard vixen dovetail/clamp so you can't easily mount the telescope on a decent mount later. Finally, it
  13. If another user can focus the 6mm eyepiece near the 15mm eyepiece focus position, perhaps there is a fault with your eyepiece. I would try some other eyepieces and see if those focus properly.
  14. Well then really it is down to how desperate you are to have a telescope now. If you absolutely have to have a telescope now then the 6" is a good choice and will be a good performer. If you can bear to save for a few more months then the 8" will be just a little bit better on DSOs due to the additional apperture and is worth saving for. Of course the 10" is then a little bit better again than the 8" and the same again for a 12" over the 10". You have to draw the line somewhere and where you draw that line is up to you.
  15. When you arrive at the location, how far will you need to carry the telescope from the car? Can it be done safely in more than one trip? (i.e. can you carry the base to the location and then go and get the OTA?) If you are only going to observe a short distance from the car so that you can carry the telescope in a couple of trips, or if the ground is flat and even so that you can safely carry in one piece I would definitely go for the 8". If you need to carry the telescope quite far or the ground is uneven and difficult to walk over, a smaller, more transportable telescope is going to be
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