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DevonSkies

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Everything posted by DevonSkies

  1. 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.
  2. I already have a 250 Dob, so I don't really want another dob cluttering up the garage!
  3. 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.
  4. Thanks for that - I hear what you're saying about contrast. I agree the ED100 is great value for an ED refractor.
  5. 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.
  6. 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.
  7. Aside from the goto issue, do you find the mount tracks well enough when it's aligned with the target?
  8. 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?
  9. Yes, I saw that one. Local collection only though, and Cambridgeshire is too far for me!
  10. 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?
  11. 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
  12. Yes, the Starwave 102 f11 does look like a good alternative (maybe even better). I notice Astroboot have a TAL 125 Apo in their Bargain Zone at the moment - out of my price range though! Optical Vision (the importers) still list the 125 on their website, but maybe they are just clearing out remaining stock.
  13. I contacted a couple of dealers today (Rother Valley Optics and Harrison Telescopes) who recently listed the TAL 100RS on their websites. Both told me that the TAL is no longer being imported! Sounds like bad news for anyone looking for one of these highly-regarded achromats. Guess I'll have to save my pennies for a SW 100ED instead.
  14. Thanks, that's good info. I have this padded bag for my ST102: http://www.rothervalleyoptics.co.uk/geoptik-padded-case-for-100mm-refractors-f750.html and it's actually oversized for the scope - in fact I'm sure an ST120 would fit. I'm wondering if I'm taking that bag on holiday anyway, I might as well fill it up and put an ST120 in it!
  15. Looks good. How do you find the size/weight compared to the ST102? Does it still make a good grab-and-go?
  16. I do wonder whether I actually should have got the ST120 in the first place. I was undecided between the two when I made the purchase, and decided on the 102 because I thought it would be more portable. But in the end the ST120 is only 10cm longer and 2cm wider, and for DSOs one needs all the aperture one can get! I'd be interested to hear how you think it compares to the 102 when you get it. Will you have the chance to compare side by side?
  17. Good idea, I might try something like that. Also a good point about the aperture mask for moon and planets. I've found it virtually eliminates CA, but it does cause some loss of resolution. I forgot to add that I have also tried the Baader Contrast Booster filter, which is supposed to be the most aggressive of the CA-reducing filters. Although it did noticeably reduce the CA, it left a yellow cast which I found unpleasant and also noticeably reduced the sharpness of the view at high magnification. In the end I decided I preferred the unfiltered view! At some point I will probably buy a dedicated grab-n-go for lunar/planetary work (maybe a Mak or an f/10-ish refractor).
  18. mmmm.... 150mm f/8... now there's a thought! Not sure I could justify it alongside the 10" Dob though!
  19. I have been using a Skywatcher Startravel 102 for about a month now as a grab-and-go scope. I also intend to use it as a travel scope for holidays, but I've yet to try it in that capacity. So I thought I'd record some of my thoughts about this scope. Initially I purchased the ST102 with an AZ3 alt-azimuth mount, but I quickly found I didn't get on with the AZ3. On the plus side, it is very compact and lightweight and would make an excellent travel mount. However, I found the friction bolt arrangement for setting the altitude tension to be unreliable, and the mount was difficult to use near zenith. So, I changed the mount to a Vixen Porta II, which is much more comfortable to use. The Porta II tripod does seem to vibrate a bit more than the AZ3 though (especially on concrete), so maybe I will change the legs for something more substantial one day. Onto the telescope itself. The optical tube feels very solid and substantial. There is a large dew shield fitted, which is held on with a simple push fitting held in place by a felt band. Removing the dew shield reduces the OTA length significantly, but unfortunately the supplied lens cap won't fit over the front cell without the dew shield in place. This is a pity, as removing the dew shield would make the scope very compact for travel. The 102mm doublet objective has a blueish-looking coating, that seems evenly applied. The OTA assembly is supplied with decent tube rings and a dovetail. If you buy the scope in a kit with the AZ3 mount it comes without a dovetail, and the tube rings bolt straight onto the mount. The focuser felt quite smooth but a little tight straight out of the box. Initially there was no play in the focuser and the drawtube was well aligned. However, the focuser does prove to be a weak point on these scopes and I will return to this later. Now on to the important bit - performance! The OTA came supplied with the usual 25mm and 10mm MA eyepieces. The 25mm is quite a good budget eyepiece, but the 10mm could be better. However, since I already have a set of reasonably good eyepieces I put the supplied EPs to one side. Also supplied with the OTA and AZ3 kits is a 45-degree erecting prism. This is useful for terrestrial observation, but not really of sufficient quality for astronomical work (although it is OK at low magnifications). I replaced this with the excellent Revelation 2" Quartz Dielectric diagonal. This scope excels at wide-field views of open clusters and brighter DSOs. With a 25mm X-Cel LX eyepiece the whole of the Pleiades can fit in the field of view, which is a stunning sight. I also have a 32mm Panaview 2" eyepiece, which offers a whopping 4.4 degree field of view, framing the Pleiades beautifully within the surrounding sky. Under a dark sky the view is quite breathtaking. Other open clusters such as the Beehive also look superb with such a wide field. Best of all, this scope gives me the best view I've had of the Double Cluster in Perseus, with both parts of the cluster beautifully framed within the FOV. Large DSOs are also a strong point for this scope. M31 (Andromeda) looks fantastic under a dark sky, and dust lanes are visible. Dimmer DSOs are quite within the reach of this instrument, with M1 (Crab Nebula), M33 and M51 all visible under dark skies. Globular clusters also make good targets, although perhaps a little more aperture would be useful here to see them at their best. Working at high magnification, the ST102 is quite capable of splitting the "easier" double stars such as Castor and Sigma Orionis. A 5mm EP works well here, and a Barlow can help to increase the separation on brighter doubles. The dim companion to Rigel can just about be made out under good seeing conditions. You may notice that I haven't mentioned CA (chromatic aberration) yet. That's because, for clusters, DSOs and most double stars it simply isn't an issue. For planets and lunar observation, however, it's a different matter. Yes, the dreaded purple haze is there, especially noticable on the limb of the moon and on bright planets such as Jupiter. In fact, the ST102 is quite capable for casual lunar and planetary observing, but if the solar system is a primary interest for you then you might look elsewhere. Although the optics are pretty sharp at high magnification, I really feel that the CA damages the contrast for planetary and lunar observation. This is my first refractor (my other scope is a 10" Dob). I have to say I'm now a refractor fan! There's something about the ease of setup and the contrasty, pinpoint stars that appeals to me. I also like the short-tube concept from a portability point of view, and these scopes are very capable deep sky instruments. Yes, CA is a problem on bright objects at high magnification, so it's not an all-rounder like an APO, but for the price it's fantastic value for money. I mentioned the focuser earlier. After some use, the focus tube developed some vertical play. There are two grub screws on the top of the focuser which are used to tension the drawtube. I needed to tighten the front (i.e. closest to the objective) screw to take up the slop, and also tighten the rear screw to remove any remaining image shift. After this adjustment the focuser worked fine again. I have now had to do this twice, so it seems that periodic adjustment is required. After the second adjustment cycle the focuser was very stiff, which I resolved by slackening off the screws that tension the spring in the focus pinion assembly. Now the focuser is nice and light and smooth, but I anticipate further adjustments will be necessary in future. We shall see! This is really a faff and the only real annoyance with this scope. There is a dual-speed Crayford focuser available which is a drop-in-replacement for the original R&P focuser, but at around £129 I'm not sure it's worth it on an OTA costing £169! All in all, I really like this scope, apart from the cheap focuser. In fact, I like it so much I'm wondering what the 6-inch ST150 would be like on DSOs and clusters! Ed
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