RolandKol Posted April 6, 2019 Share Posted April 6, 2019 43 minutes ago, Thalestris24 said: Anthony - try an artificial star: Edit: Actually, what I would do is make a small cluster so that would show up the distortion pattern better, I think. Louise you need quite a space for that.... I saw calcs somewhere, 130PDS+ASI1600 needed at least 20m distance... his setup will probably need more or less the same.... Link to comment Share on other sites More sharing options...
ollypenrice Posted April 6, 2019 Share Posted April 6, 2019 1 minute ago, RolandKol said: you need quite a space for that.... I saw calcs somewhere, 130PDS+ASI1600 needed at least 20m distance... his setup will probably need more or less the same.... A driveway will often be long enough. If it ends in a garage you could put the ballbearing at the closed end of the garage for better contrast but I've done it outside. The first time I did this test was in a condom warehouse. Don't ask!!! Olly Link to comment Share on other sites More sharing options...
Thalestris24 Posted April 6, 2019 Share Posted April 6, 2019 1 minute ago, RolandKol said: you need quite a space for that.... I saw calcs somewhere, 130PDS+ASI1600 needed at least 20m distance... his setup will probably need more or less the same.... Yeah, something like that - shouldn't be too difficult to arrange something... I wish I could but I live in a 2nd floor flat which is severely limiting on many accounts. Anthony has an ed80 + dslr, so similar, I think. I reckon it would make life a lot easier for anyone trying to set flattener spacing. Louise Link to comment Share on other sites More sharing options...
Thalestris24 Posted April 6, 2019 Share Posted April 6, 2019 1 minute ago, ollypenrice said: A driveway will often be long enough. If it ends in a garage you could put the ballbearing at the closed end of the garage for better contrast but I've done it outside. The first time I did this test was in a condom warehouse. Don't ask!!! Olly ? Link to comment Share on other sites More sharing options...
ollypenrice Posted April 6, 2019 Share Posted April 6, 2019 29 minutes ago, Thalestris24 said: ? Well I had this friend, you see, called Captain Condom - at least this was his business name - and he had a long warehouse. But once when my car was stolen he loaned me his van to go to school in. This made me a superhero amongst the kids... Olly Link to comment Share on other sites More sharing options...
Thalestris24 Posted April 6, 2019 Share Posted April 6, 2019 1 minute ago, ollypenrice said: Well I had this friend, you see, called Captain Condom - at least this was his business name - and he had a long warehouse. But once when my car was stolen he loaned me his van to go to school in. This made me a superhero amongst the kids... Olly Clearly, size is important Link to comment Share on other sites More sharing options...
gorann Posted April 6, 2019 Share Posted April 6, 2019 On 03/04/2019 at 19:51, Anthonyexmouth said: No, I've got this one https://www.altairastro.com/lightwave-0.8x-reducer.html Just be aware that the ideal distance to the chip may vary with the focal length of your telescope, as seen on the info for this reducer from TS (which is likely to be similar to yours from Altair): https://www.teleskop-express.de/shop/product_info.php/info/p5965_TS-Optics-PHOTOLINE-2--0-79x-Reducer-4-element-for-Astrophotography.html Link to comment Share on other sites More sharing options...
Thalestris24 Posted April 6, 2019 Share Posted April 6, 2019 This is an interesting read (80ed + lightwave 0.8x towards the bottom) though he doesn't mention adjusting the spacing at all: https://astro.ecuadors.net/refractor-reducers-televue-trf-2008-vs-altair-lightwave-0-8x-on-sw-evostar-80ed-equinox-80-ed/ I might be wrong, but I've always assumed spacing is 55mm unless otherwise mentioned - as with TS. But there is always the +/- (0.5 - 1mm) fiddling! Louise Link to comment Share on other sites More sharing options...
Anthonyexmouth Posted April 7, 2019 Author Share Posted April 7, 2019 Ok, can someone with a more experienced eye comment on this please Link to comment Share on other sites More sharing options...
vlaiv Posted April 7, 2019 Share Posted April 7, 2019 Almost perfect? I think that correction is about as good as you will get with that FF/FR. I think I still see a trace of tilt, but it's so minor that I'm not sure if it's worth pursuing. You should stack multiple subs - any slight distortion in the corners will probably be masked by the seeing after stacking multiple subs. Link to comment Share on other sites More sharing options...
Anthonyexmouth Posted April 7, 2019 Author Share Posted April 7, 2019 Just now, vlaiv said: Almost perfect? I think that correction is about as good as you will get with that FF/FR. I think I still see a trace of tilt, but it's so minor that I'm not sure if it's worth pursuing. You should stack multiple subs - any slight distortion in the corners will probably be masked by the seeing after stacking multiple subs. thats made me happy and given me the confidence in this FF to look for a cooled camera... unfortunately for my credit card.. lol. still annoyed that i followed the image chart on AA website that said it was too far away. i spent money on a low profile t ring, almost bought a load of extension tubes i didnt need. i'm glad i saw the baader t ring on amazon and with their easy returns gave it a go. Link to comment Share on other sites More sharing options...
Thalestris24 Posted April 7, 2019 Share Posted April 7, 2019 56 minutes ago, Anthonyexmouth said: thats made me happy and given me the confidence in this FF to look for a cooled camera... unfortunately for my credit card.. lol. still annoyed that i followed the image chart on AA website that said it was too far away. i spent money on a low profile t ring, almost bought a load of extension tubes i didnt need. i'm glad i saw the baader t ring on amazon and with their easy returns gave it a go. Measuring the distance from the sensor line to the front of your original t ring would have shown you something was amiss straightaway but - live and learn! Never assume things are what you believe them to be... Louise Link to comment Share on other sites More sharing options...
carastro Posted April 7, 2019 Share Posted April 7, 2019 Really glad you have got this sorted. Any chance of getting a refund/exchange on the wrong items. Also out of interest, (got a bit lost on this thread), were those distance diagrams, the wrong way around for what spacing you needed? Carole Link to comment Share on other sites More sharing options...
Anthonyexmouth Posted April 7, 2019 Author Share Posted April 7, 2019 3 minutes ago, carastro said: Really glad you have got this sorted. Any chance of getting a refund/exchange on the wrong items. Also out of interest, (got a bit lost on this thread), were those distance diagrams, the wrong way around for what spacing you needed? Carole yeah completely wrong. I was too close, the baader was a little thicker and that sorted it. i'll keep the bits i bought. just in case. Link to comment Share on other sites More sharing options...
carastro Posted April 7, 2019 Share Posted April 7, 2019 Quote I was too close, So that is the same as I found. Strange these diagrams have been published the wrong way round, and very misleading. Carole Link to comment Share on other sites More sharing options...
Anthonyexmouth Posted April 7, 2019 Author Share Posted April 7, 2019 4 minutes ago, carastro said: So that is the same as I found. Strange these diagrams have been published the wrong way round, and very misleading. Carole especially as its one of the pictures on the AA web page for this flattener. misleading and very disappointing. Link to comment Share on other sites More sharing options...
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