dawson Posted May 7, 2013 Share Posted May 7, 2013 Is there any advantage of using a 2" diagonal in my 180 Mak when the 'fundamental hole' in the back of the OTA is 1.25". Either for visual, or imaging? The crayford style focuser which screws onto the OTA can take either a 1.25" or a 2" so that is where the 2" diagonal could sit; I got a generic 2" diagonal with the OTA which is why I'm asking. Thanks for any replies. James Link to comment Share on other sites More sharing options...
Guest CodnorPaul Posted May 7, 2013 Share Posted May 7, 2013 Has the OTA got a visual back on it which unscrews - my SCT has so I took that off and put a 2" diagonal straight onto the OTA. Advantaged for visual are you can use 2" EPs so you can get a wider FOV - as for AP I will leave that to the experts! Link to comment Share on other sites More sharing options...
dawson Posted May 7, 2013 Author Share Posted May 7, 2013 Here is the nearest I can seem to get to the mirror from the back; I can't unscrew any more bits, and the hole is less than 1.25" as I can't even stuff an eye piece in this hole! JD Link to comment Share on other sites More sharing options...
Guest CodnorPaul Posted May 7, 2013 Share Posted May 7, 2013 In that case James I don't see that there can be a benefit - if the exit hole doesn't open up more than 1.25" then that is all the light it will let through regardless of diagonal, and if your focuser accepts 2" barrels also then that gets rid of the problem of attached camera etc. Obviously stand to be corrected by someone that really knows what they are talking about! Link to comment Share on other sites More sharing options...
dawson Posted May 7, 2013 Author Share Posted May 7, 2013 I was thinking the same as you, that I couldn't see a direct reason to use a 2" diagonal, but it will be interesting to see if anyone else has any other ideas. We missed you on Saturday night. James Link to comment Share on other sites More sharing options...
Guest CodnorPaul Posted May 7, 2013 Share Posted May 7, 2013 I missed it too James - back garden doesn't do it anymore, not after being at a dark site - hopefully be out next time, but think my kit is lagging behind now! Link to comment Share on other sites More sharing options...
dawson Posted May 7, 2013 Author Share Posted May 7, 2013 Your kit is by no means lagging behind. I do hope you were joking. You've got a lot of aperture and the images I saw of Saturn through your kit were top notch. The dark site is great, but lugging kit around isn't. I'm still toying with the home observatory idea; I've got a company working out a quote for me for a roll off roof obsy, but I suspect it will be £2000, and that won't include the foundations for it or the pier, or the things like electricity, running water, central heating.... If I was good with wood it would be another matter. JD Link to comment Share on other sites More sharing options...
catman161 Posted May 7, 2013 Share Posted May 7, 2013 That kind of money James you should check out the Skyshed POD they are a cool little alternative to RO roof obsy. It's want i want to get eventually. Link to comment Share on other sites More sharing options...
Guest Eddy Posted May 7, 2013 Share Posted May 7, 2013 Your kit is by no means lagging behind. I do hope you were joking. You've got a lot of aperture and the images I saw of Saturn through your kit were top notch. The dark site is great, but lugging kit around isn't. I'm still toying with the home observatory idea; I've got a company working out a quote for me for a roll off roof obsy, but I suspect it will be £2000, and that won't include the foundations for it or the pier, or the things like electricity, running water, central heating.... If I was good with wood it would be another matter. JD Just get a shed that's what a lot of people do Link to comment Share on other sites More sharing options...
Guest Meteoriot Posted May 7, 2013 Share Posted May 7, 2013 Has the OTA got a visual back on it which unscrews - my SCT has so I took that off and put a 2" diagonal straight onto the OTA. Advantaged for visual are you can use 2" EPs so you can get a wider FOV - as for AP I will leave that to the experts! Hi. What SCT do you have please? I'm looking at upgrading my nexstar8 to a 2 " diagonal. I was hoping I can just screw it on but i may need an adapter. Richard Link to comment Share on other sites More sharing options...
Guest Kheldar Posted May 7, 2013 Share Posted May 7, 2013 (edited) You buy dedicated SCT diagonals I think? Screw fit Edited May 7, 2013 by Kheldar Link to comment Share on other sites More sharing options...
Guest CodnorPaul Posted May 8, 2013 Share Posted May 8, 2013 Hi Meteoriot Same scope as you 8se - got the celestron xlt diagonal and yes just remove visual back and it screws direct onto OTA. There are cheaper ones available as Stephen says get an sct screw fit. That said the xlt diagonal is nice. Do a search on here for 2†diagonal as I asked questions on here when I was buying and got some great info. When you put a 2" EP in it makes it worthwhile Link to comment Share on other sites More sharing options...
Guest Meteoriot Posted May 8, 2013 Share Posted May 8, 2013 Hi Meteoriot Same scope as you 8se - got the celestron xlt diagonal and yes just remove visual back and it screws direct onto OTA. There are cheaper ones available as Stephen says get an sct screw fit. That said the xlt diagonal is nice. Do a search on here for 2†diagonal as I asked questions on here when I was buying and got some great info. When you put a 2" EP in it makes it worthwhile Thank you. I can't afford to buy a new diagonal such as that. Especially after forking out for new eyepieces. I have however been offered a good quality 2" diagonal and eyepiece though at a good price so I have bought an adapter to accommodate those. I am trying to raise the funds by selling off some binoculars and plossl eyepieces Link to comment Share on other sites More sharing options...
Guest CodnorPaul Posted May 9, 2013 Share Posted May 9, 2013 Great! You will enjoy it - if the cloud ever clears... Link to comment Share on other sites More sharing options...
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