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DevonSkies

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Everything posted by DevonSkies

  1. HI, OK, I bought a Celestron Nexstar 127 SLT Goto Mak about a week ago. Despite following all the setup instructions and carefully checking all the date/time/location data, I am having crazy problems getting the goto to work accurately. I am able to successfully align the mount using either SkyAlign or two-star alignment. The alignment method doesn't seem to make any difference. What happens it, once I have aligned carefully to two well-spaced stars (e.g. Dubhe and Sirius), the scope can successfully be slewed back and forth between those two alignment stars and it hits them pretty much bang on (centred in the 25mm eyepiece). However, if I then try to Go-To to any other object it misses by a significant margin. Usually the scope is about half a degree off target (sometimes its just on the edge of the field of view). Sometimes (especially near zenith) it's even worse. The strange thing is, as I said, it will still slew accurately to the alignment stars. It's just everything else that is off! I've checked and double checked the following: Latitude, Longitude (both taken from a handheld GPS), date (US format), time (Universal Time, Standard TIme (not Daylight saving)), levelled the tripod, I am running from a Powertank, I have aligned using the same direction as the goto approach, etc, etc. I've played with the goto approach direction, I've adjusted the backlash compensation, I've performed a factory reset and I've even updated the firmware. It's driving me crazy! Surely the goto should be accurate enough to get a given target somewhere within a 25mm eyepiece? I don't expect it to be perfect, but if I didn't already know my way around the sky I'd never be able to locate anything with this scope as it stands. How accurate do other 127SLT owners find the goto? Does it usually locate any given object within the FOV of a 25mm eyepiece? I'm starting to suspect my mount is faulty (as it happens my OTA is also faulty, but that's another story...), but I'd like to hear other people's opinions on this before I start to think about returning it. Thanks!
  2. The cluster just below Sirius was probably M41.
  3. I'd say the 150 Dobsonian would be best for a beginner, and by far the best value for money. The AZ4 is a good mount, but doesn't really do anything you can't do with a basic Dobsonian. I have recently got hold of the Nexstar 127SLT as a secondary scope, but personally I find the setup and alignment of the goto mount takes some of the fun out of observing. The simplicity and fast setup of a Dob is unbeatable. Don't be afraid of collimation - my 250PX Dob was reasonably well collimated out of the box, and although I did collimate it when I got it it has only needed the occasional tweak since then. The 150 should be even more forgiving.
  4. just to follow up: in the end I went with the Nexstar SLT on the basis of advice from FLO that the Nexstar had a slight edge in build quality and software. It's certainly a clever piece of kit. Unfortunately I'm having fairly major problems with GoTo accuracy at the moment. Basically, despite careful setup (and double checking all the usual suspects, i.e. time/date/location, etc) it misses every target by about half a degree. FLO have suggested I try a firmware update, so I'll give that a go and see if it fixes it.
  5. If she's interested in planets I would stear clear of the ST102 in favour of one of the other options. It's not that it won't do planets, but the magnification is limited and CA is significant, resulting in small, washed out views. I've just bought the Nexstar 127 SLT (mentioned above) as a dedicated planetary scope. I've yet to try it out though. I agree the 150mm Dob would also be a good option.
  6. Hi, I'm considering buying a small Mak on a budget goto mount. The Celestron Nexstar SLT and the Skywatcher Synscan AZ Goto look very similar, and I've read a few reports that the main difference is in the alignment routine. Is there consensus on the differences between these two mounts? Is there any mechanical difference at all (e.g. accuracy of tracking), or is it more a matter of "toss a coin"? Personally I prefer the "look" of the Skywatcher (purely cosmetically!) and of course it's slightly cheaper. Any thoughts appreciated!
  7. Thanks for all the comments in this thread. I think from what I've heard I can conclude that, although the Mak is a good little scope, the 100ED is worth the extra for the best planetary views. I think, deep down, I knew this all along. If I'm lucky I might find a used 100ED near me; otherwise I'll scrape together the cash for a new one. I don't want to plump for the mak and then wish I'd got the ED all along.
  8. I already have a 250 Dob, so I don't really want another dob cluttering up the garage!
  9. Plenty of food for thought. I've also been considering the Altair 102mm f/11 achromat as an other option. It's a lot cheaper than the 100ED, but obviously will exhibit a certain amount of CA on bright targets. Whether the CA would be bad enough to justify spending the extra on ED glass is not clear to me. The longer tube of the f11 scope also makes mounting more of a problem.
  10. Thanks for that - I hear what you're saying about contrast. I agree the ED100 is great value for an ED refractor.
  11. I can keep it in an unheated garage. It's still a bit warmer than outside this time of year though. My 10" Dob takes at least an hour to cool, maybe two hours before the star test really settles down.
  12. Thanks, that's really useful information. It's a tough choice. I can afford the Mak 127 right now, but I'd have to save a bit longer to buy the 100ED. I've also got a feeling I would eventually need to upgrade my mount for the 100ED, as the Porta II suffers from the wobbles at high magnifications, which will only get worse with a longer tube. On the other hand, cool-down is a concern with the Mak, as I tend to have limited opportunities to observe, except on those rare clear, still nights.
  13. Do you really need to use a 45 degree prism (e.g. for terrestrial viewing)? If you're only using the scope for astronomy, personally I would return the 2" 45deg prism and just use the 2" mirror diagonal. The reversed image is not a problem for astro use.
  14. Aside from the goto issue, do you find the mount tracks well enough when it's aligned with the target?
  15. Thanks for that. The Mak appeals both for the price and because it should behave better on my Porta II mount than an f/9 refractor. I have some decent EPs already, so that shouldn't be a problem. Does it take a 'normal' (i.e. push fit) 1.25" diagonal?
  16. Just came in from looking at it myself. Seeing is poor here at the moment, but the GRS looks a dark red and separation from the cloud belt can be seen when the seeing allows. Well worth a look! I found a Baader Neodynium helped with the contrast in my 10" Dob.
  17. Yes, I saw that one. Local collection only though, and Cambridgeshire is too far for me!
  18. If tightening the handle doesn't work, perhaps you could find some way of attaching a counterweight to the bottom end? You probably wouldn't need to add much to balance it out.
  19. Thanks, it's good to hear from someone who has had both. In what ways was the 100ED better specifically? And do you feel it was £300 better?
  20. I'm still on the lookout for a relatively lightweight scope for lunar, planetary and double star observations. I have a 10" Dob which will obviously wipe the floor with most small scopes, but I often can't be bothered with lugging it out to the garden for a quick look at the moon or Jupiter. It sounds like the SW Evostar 100ED would be a nice scope for this purpose. But at over £600 for the OTA it would be a major investment for me. So, I wonder whether the Skymax 127 Maksutov would be a worthy alternative, given the much lower cost (around £350 including a goto mount). I understand the Mak will have a narrower field of view, but that's OK as I already have an ST102 for wide field. What I'm looking for is nice sharp, contrasty views of planets and the moon, as well as good performance on double stars. Any thoughts? How different will the view be between these two scopes? Thanks, Ed
  21. Welcome. Plenty of Devonshire folk on here it seems! Ed
  22. I wouldn't draw any conclusions until you've tested the scope outdoors. Viewing through glass can cause all kinds of problems, especially if it's double glazed.
  23. I've not been in this game very long, but I've noticed quite a few people referring to the sun and moon in observation reports as "Sol" and "Luna". Yes, I know it's Latin, but is there any particular reason for using this terminology? Historical maybe?
  24. That video looks pretty close to what I see visually in my 10" Dob under average conditions, to be honest. Except of course the view in the eyepiece is a lot smaller than it looks in the video.
  25. That looks like simple dew spotting. Best left well alone if you ask me! It won't affect the view in the slightest.
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