Chubster Posted February 27, 2007 Share Posted February 27, 2007 Following on from Geoff_K excellent saturn image and not wanting to hijack his post thought Id ask this on a new topic.This imagemate thingy then....is it basically a 4x barlow. Just been looking on Astro Engineering site and it says it is primarily for use with modern webcam...bit confused ? I find it nearly impossible to focus with a 2x barlow....hate to think what it would be like at x4Cheers Chubs Link to comment Share on other sites More sharing options...
blinky Posted February 27, 2007 Share Posted February 27, 2007 As far as I can see you are correct. Looks like a 4X Barlow, I can get my 3X barlow to focus with my webcam so a 4X should be OK as well. Link to comment Share on other sites More sharing options...
geoff_k Posted February 27, 2007 Share Posted February 27, 2007 Thanks for the kind words re my Saturn image.The Imagemate is really a way of increasing the effective focal length of a 'fast' Newtonian.You could also use one of the Televue Powermates which are probably superior, but they cost a lot more.No problem with focusing but rather that prevailing conditions where I live don't allow it to be used to its best advantage. I often find that a 3x Barlow is the most that conditions will allow.As regards focusing, the basic rack and pinion focusers that come with many scopes are poor and the inherent image shift makes focusing very difficult. The other thing I also find very useful is the cheap reticle eyepiece I bought a while back.The Imagemate is a worthwhile addition to your eyepiece collection (I am not on commision from the manufacturers!) Link to comment Share on other sites More sharing options...
FLO Posted February 27, 2007 Share Posted February 27, 2007 Info here http://www.firstlightoptics.com/proddetail.php?prod=ae4ximagemate Link to comment Share on other sites More sharing options...
Chubster Posted February 27, 2007 Author Share Posted February 27, 2007 Cheers Geoff/Blinky/SteveSo can anyone explain why and when I would use this and what does it achieve? Is it a similar principle to the image mate ?http://tinyurl.com/2xk5cySorry.... going over old things I sort of learnt awhile back but have forgotten cos I havent been out for ages !Chub Link to comment Share on other sites More sharing options...
FLO Posted February 27, 2007 Share Posted February 27, 2007 The AC412 is a simple adapter tube used for eyepiece projection whereas the imagemate is used alone, without an eyepiece. Link to comment Share on other sites More sharing options...
blinky Posted February 27, 2007 Share Posted February 27, 2007 I could not get my webcam to focus when using EP Projection. Link to comment Share on other sites More sharing options...
Kaptain Klevtsov Posted February 27, 2007 Share Posted February 27, 2007 Eyepiece projection when I've played with it gives huge magnification. It would be great for filling a DSLR frame with a planet for example, so it's rather too much for a webcam unless its a really long FL eyepiece. It might have other uses, I don't know, or it could be that it seemed like a good idea to make it kind of thing.WRT focusing with the Imagemate thingy, what you have to get is an electric focuser from the usual suspects. FLO and Modern Astronomy definitely sell them and they are the best thing you can get for imaging with the 200mm SW Newt. It lets you turn the focuser without wobbling the 'scopeso the blur on the screen is caused by out of focus rather than you having your hand on the focus knob. Essential piece of kit in my opinion. It also lets you turn the focuser slower than you could possibly do by hand when its set on slow. That way you don't fly past in both directions until you convince yourself that it's run away and hid off the screen.Captain Chaos Link to comment Share on other sites More sharing options...
Chubster Posted February 27, 2007 Author Share Posted February 27, 2007 Cheers CC. So a 5x imagemate would make my scope have a fl of 5000mm ? arghhhh....thought i learned all this ages ago Link to comment Share on other sites More sharing options...
Kaptain Klevtsov Posted February 27, 2007 Share Posted February 27, 2007 yes indeedy, 5X the "native" focal length (which is 200mm (aperture) X the f/ number, so 200 X 5 = 1000).Captain Chaos Link to comment Share on other sites More sharing options...
Chubster Posted February 27, 2007 Author Share Posted February 27, 2007 Cheers again one last one honest Electronic focuser's....are they pretty much all the same or are there good uns and bad uns and once installed do you have to use them or can you still use the manual focussing Oh that was two ! Link to comment Share on other sites More sharing options...
GazOC Posted February 27, 2007 Share Posted February 27, 2007 You do get what you pay for with electronc focusers. The more expensive ones are more accurate than the cheaper ones and have clutches so you can disengage them an use the focuser manually. Link to comment Share on other sites More sharing options...
Chubster Posted February 28, 2007 Author Share Posted February 28, 2007 any particular brands spring too mind ? Link to comment Share on other sites More sharing options...
geoff_k Posted February 28, 2007 Share Posted February 28, 2007 Not sure if they were electric but the Williams Optics focusers I saw at Astrofest were rather neat and looked as though they moved pretty well.A word of caution, however. The friend who went to the Astrofest with me bought a Revelation dual-speed Crayford focuser for his Skywatcher Newt. Not quite the same fit as the incumbent focuser so he is having to get an extra bit machined to make it all fit. Make sure you measure everything carefully.Another aid to focusing is a Hartman Mask. They are quite easy to make and a link for a design can be found here http://billyard.servehttp.com/Hartmann.htmlGeoff Link to comment Share on other sites More sharing options...
GazOC Posted February 28, 2007 Share Posted February 28, 2007 any particular brands spring too mind ?I've got a JMI motofocuser on my ED100 and its really accurate. Link to comment Share on other sites More sharing options...
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