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Everything posted by syd_malicious

  1. I am not an optical engineer but there are other factors to consider such as the relative curvature of the mirrors; the closer these match the flatter the field but the larger the CO. Here is an interesting article comparing a RC system with and without a flattener. What this also mentions is the curved focal plane too. Paul
  2. Don't forget that when people start eulogising and going gooey about RCs that they are not really talking about true RC scopes. You also cannot compare them, in general, to SC scopes. A true RC scope only has 2 surfaces - a hyperbolic primary and a hyperbolic secondary with no other optical elements. They were designed to elimate coma to allow a larger usable FOV for scientific research. They have a significantly curved field with astigmatism but these can be calculated out of the equation for scientific research. Now as of a few years ago RC scopes were only made by a handful of manufacturers, usually US based, at an eye watering price compared to SC scopes. Part of this price differential is because of their general quality being higher than the standard Meade/Celestron SC but also because the mirrors are more tricky to make. However, especially for larger format camers, the curved field and astigmatism of the RC is not suited to the "pretty pictures" that we generally want. Therefore you almost HAVE to buy a field flattener and corrector to use these scopes. Result is that they are not really a RC anymore but a corrected-RC. Nowadays there is an optical system that is easier to make than hyperbolic mirrors and that is the corrected Dall-Kirkham. These are a standard Dall-Kirkham with an integral corrector; at least these amnufacturers are honest and calling them a corrected-Dall-Kirkham I am not knocking the RC per se and if you have a smallish camera chip they should be fine with no corrector. Just don't get misty eyed at some of the fantastic shots from elsewhere in the world where they have skies that you can actually see through and that use a corrected RC scope. Other people that knock Meade/Celestron SC are comparing a mass produced scope (with some issues such as mirror flop) with a custom made and much better manufactured scope. People seem to draw the conclusion that RC scopes are therefore better. They aren't - they are just different. It's a bit like comparing a Trabant to a Mazda RX8 and concluding that the Wankel engine MUST be better. Just my thoughts as I find all this RC nonsense driven by the US vendors one of the biggest cons ever perpetuated in astronomy. Paul
  3. I know, I know - there is enough rubbish on fleabay but this really made me smile. "listed here i have an unwanded gift that i have never used. an arena newtonian reflector telescope, d=114 f= 500 ali tripod one small scratch on outer case. i know nothing about this instrement , too heavy for me to understand." An "unwanded" gift - did Harry Potter reject this? "too heavy" to understand - er, cool, like this is so heeeeeavy man. If this is an example of our wonderful educashun system I despair.
  4. No answer to your question but AWR has always intrigued me. Looks a very well thought out, proficient, comprehensive system but the website is an awful mess and makes the whole thing look a Heath-Robinson cludge. Such a shame and typifies UK engineering - innovative but lacking any marketing finesse. Not meant to be harsh but just expressing frustration at industry in this country which could be so much more successful. Paul
  5. To quote Scotty "ye cannae change the laws of physics". These are quite cheap and that probably is for a reason - they are built down to a budget. Meade OTAs (particularly the ACFs) are really quite good but they have too long a history of putting out good ideas ruined by poor implementation and penny pinching. I really wouldn't touch with a barge pole; I can't believe these will have either a low or smooth PE if they work for long enough to find out. I would get an OTA from them certainly but n mount it on a separate mount. Paul
  6. This has developed into another UK - US price discussion but that is still a valid discussion. My interpretation is somewhat between the 2 points here (FLO and the others). It seems that US Larger consumer base Higher expectations of customers Different after sales - correct me if wrong but in the US there is a higher likelyhood of being told to deal directly with the manufacturer in the event of an issue most big manufacturesrs based here and don't seem to know there is a whole world beyond North America UK/Europe Usually a single importer (certainly for Planewave, Celestron, Meade) Higher taxes Perceived difficulty in shipping things from the US I can understand a manufacturer only dealing with one company (Hinds for Celestron and Telescope House for Meade) as it means that any issues can be attemopted to be rectified by a trusted single place to avoid shipping back to the US. They really couldn't be bothered by various companies such as FLO etc directly contacting them with warranty repairs etc. It is easier to palm of warranty support to the importer. However this does mean there is essentially a monopoly in the UK with the importer holding retailers to ransom over the price. To argue that this is the reason for the high price doesn't explain why there is such little variation in prices. If you look at most of the UK suppliers the prices are virtually the same for the big companies; lack of margin does not explain this. Overall I think we have what amounts to a cosy little cartel that is instigated by a few big US companies and in general we have no option but to put up or go grey import and face "no warranty" issues. Afterall in a truly free market we could buy from the US - it would just mean we would have to ship back there for warranty issues but this option is denied to us. The situation is completely different for smaller US companies and I have dealt directly with the following Optec, Bob's knobs, Kendrick, Software Bisque - all with excellent personalised responses that have been a pleasure to deal with. The issue with these has been the ridiculous charges by the highway robbers that are the Royal Mail and customs. Paul
  7. From the title I was expecting you to mean "names" rather than catalogue numbers. Being pedantic for your example most Messier objects would have multiple titles - eg Orion Nebula, M42 etc etc - could even argue that Orion has more (Orion nebula, M42 NGC 1976, M43 NGC 1982, Sword of Orion) etc etc. How about the object with the most proper names as there are multiple catalogues which seems a bit of a cop-out? (And then do we mean deep sky or any object at all ). Paul
  8. Sorry got carried away talking about direct comparisons. As olly said if the DSI works fine then you wouldn't get much benefit and if I was you I would stick with the DSI. If I was looking to buy and had nothing I'd recommend the Lodestar if you could afford it. Paul
  9. Not sure where I saw it (so slightly useless answer) but may have been ansomething like S@N mag. There was a comparison of the cameras with the same chip and the Lodestar was more sensitive, albeit slightly. Electronics are important for sensitivity too not just cooling. Paul
  10. From 2 years ago until last month I had both. I satrted with the DSI and had so many problems I switched to the Lodestar. The problems are 2 fold. First power requirements - they are both powered directly by USB and as such can be very temperamental unless there is enough power. If you use a hub it has to be powered externally. However the DSI was still far too unreliable with regards to power even with a powered hub. I moved to the Lodestar and never had any further problems. The second problem is drivers. Whilst Starlight don't have the best approach to drivers (they rely on 3rd party ones written by hobbyists sometimes) there are at least separate drivers available. As for Meade you cannot get specific drivers and have to fight through installing their horrid software first to find the drivers. Even then I don't think they have 64bit ones available. The Lodestar is also much smaller and gives a slightly better SNR. Overall, as usual, the Meade is a good idea poorly implemented. Having said thatpeople use the Meade quite happily and if (IF) it all plays nicley it will be fine. You did ask for reasons to get the Lodestar though and it is better but you pay handsomely for that privilege.
  11. As mentioned above I don't think this will work either. The USB-ethernet hub just allows you to use network cable as a "replacement" for a USB cable, it doesn't convert USB into a standard network protocol. Also the hub you have a link to is only USB 1.1 compliant - meaning sloooooooooooooooooow. Nice idea but I think you are wasting your money. I have a powerline network adapter but only use it to connect my house pc to the observatory pc; it is (just) adequate for this but the thought of all the copmplex timing that usb needs with it being fickle enough as it is would put me off. Paul
  12. Just for a laugh I did ask where they were in the UK and as before it's..................."in Shetland Isle. where u based?". Much as I am English I always thought there was more than one "Shetland Isle". Anyone live in the Shetlands and can call the seller's bluff? Paul
  13. Olly, With sub-pixel guiding now the norm I can't see the astroart option being much use, but I've never used astroart though . The Lodestar works fine with Maxim the way I have it set now. Paul
  14. I have a Lodestar (and am happy with it) but just to mention a couple of things you need a decent voltage/current to run it adequately. A single cable from your computer should be fine but anything longer and you would be best with a powered hub. MaximDL works fine with it but some settings are a bit cryptic - don't know if it applies to the latest version of Maxim but on some older ones (even earlier v5 releases) the stars could look really bizarre as you need to check the "swap even and odd rows". Paul
  15. I have now ordered stuff direct from Optec direct from the US. I have always had a quick response to questions and they don't ignore non-US customers like the majority of US companies. The last item was received 1 week from order at a p&p cost of $15. This is quicker than I have had from some UK and European suppliers of astro equipment. As the actual postage cost on the front of the parcel was $13.95 I think this is fantastic service and they do not go in for rip-off p&p either. Highly recommended.
  16. If you do consider trying to contact AstroEngineering then don't bother. In my experience they don't give any support (even advice) if a product is bought second hand. From my experiences with them I'll never buy even a new AE product. Paul
  17. I can only give rather generic advice but it is based on struggling with them in the past. It may not be applicable to your setup though. There are generally 2 chipsets used in these things - FTDI and Prolific. The Prolific ones are cheaper but that's not to say that expensive ones don't use that chipset. I would steer clear of the Prolific chipsets as these tend to have more compatibility problems and each device does not have a unique identifier (unlike FTDI). This means that whichever port you plug the FTDI into it will still keep the same com port number. If you put a Prolific one into a different port it will take a new com port number. You can use multiple USB adapters in the same PC (of both sorts) but I would simply download the latest driver direct from either Prolific or FTDI. If you are limited by available USB ports then just a fairly standard USB hub would help too. The main problem is that you don't necessarily know which chipset a particular adapter is using. Some places will tell you and I would lean towards going with them. Just search "ftdi serial usb" on Ebay and there are a few available such as this one. Paul
  18. I did my own trial accidentally. I stirred as the tin said (ie not too much) and had the same problem as you. I ended up taking the tine back to B&Q demanding a refund - after much kicking and screaming from them I got a new tin. I stripped off the previous coat and stirred the paint very well and it worked fine. Conclusion - ignore the tin and stir properly. Paul
  19. Olly, The think was in italics as I think they do . I really haven't had a problem though. Doing a quick Google search turned up some pages such as this, this and this . Quoting the penultimate paragraph from the last link "In summary, if the mount is well made, PEC reduces the strain on the autoguiding and ultimately produces better SNR, but if the PE is unpredictable, or the guiding system poor (flexure, seeing etc) then the two will fight and cause a problem." The CloudyNights link does also discuss the difference between using a no-cables option (such as MaximDL direct guide) versus using n ST4 compatible cable and mount relays. Ultimately I suppose it's whatever works best for an individual setup and it would be difficult to knock the results you get! I'll continue with PEC and autoguiding as they work for me though. Paul
  20. Agreed that for visual PEC is not an issue. I don't agree about guiding. I know that some people feel that you need to turn PEC off but I have never done that and have not had an issue. Still that has mainly been with the Paramount that has a smooth PEC curve and most Paramounts can be trained to less than 1 arc-sec. In my setup this means minimal guider corrections and works very well; I think virtually all Paramount users keep PEC on whilst guiding. I am not knocking the MESU as such as I think it is a very good piece of lateral thinking and has bags of potential. Perhaps offering it with a choice of controllers (the SiTech one seems very comprehensive and is what Planewave uses on the rather spiffy CDK700 mount) would be good. It comes down to personal choice and I'd be very interested to see how the MESU mounts progress. Paul
  21. I've looked at these with interest, particularly the fork type one. It seems very interesting but having researched as much as possible it seems to have a few short comings. no PEC. I may be wrong as I have never used Argo-Navis but cannot find it mentioned anywhere on the site. I know the MESU mount site (correctly) that the main issue is of a smooth PEC that can be guided out but this still seems to be an oversight. From what I believe Tak mounts do not have PEC and people seem really happy with these but it would put me off getting a MESU mount. the "permanent" mount seems really cumbersome. there seems to be no facility to home the mount. This is a very promising mount but the above shortcomings would put it into the "no" category for me. A shame as the actual mechanical and ergonomic design look very good, especially for a dual scope setup. Paul
  22. This is a rather subjective answer. In theory you can't have enough subs AS LONG AS they are decent ones, have been calibrated, and are of the correct length. In particular the last point is important (see here for more help); essentially they need to be as long as possible without increasing the background signal. The background signal can be compromised by things like light pollution, light skies etc. Practically though I have been like you and tried to maximiaze the targets I can shoot in the limited time we have in this country. What I have tended to do is take as many as possible in one session (I am now on mono so take 4 as LRGB per cycle) and then process them. If the shot is "good enough" (again subjective) then I've done enough; if I feel the result would benefit from more (lacking faint detail, poor S/N ratio) then I simply do more subs. there is a point where more subs would help but there will be a law of diminishing returns and that is for you to decide. Unfortunately in this country the weather really hurts spending loads of time on one subject. Having said all that 50 subs of 3mins seems more than reasonable but why not have a go at processing? Paul
  23. It seems like a good idea to do this (I do) but bots are so sophisticated nowadays that this will do nothing to stop them. the only way to truly stop it would be to post a picture of your address as this would likely need a human operator to decipher. Astrobuysell have a much better contact/messaging system now anyway that circumvents the need to publish email addresses online. paul
  24. After nearly giving up trying to buy Kendrick items from the UK I approached them directly in Canada. I got quick (quicker than most UK suppliers) emails and they were prepared to help me as much as possible with postage issues etc. The quoted postage was not hughely more than UK prices either. In the end I sourced a UK stock just before buying from Canada but in future I would actually approach them directly. Overall a very positive experience and highly recommended. Paul
  25. I bought a second-hand item that came without instructions. I have contacted AE twice asking if there is an electronic version etc I could have but have been ignored. I accept they do not have to support a second-hand item but most astro retailers would at least have the courtesy to reply; just feels like downright rude at best. I was going to buy some other items but will go to German suppliers that offer similar. Paul
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