Peter Drew Posted November 22, 2018 Share Posted November 22, 2018 The other day we were bequeathed a number of astronomical items. One of them was a mint Skywatcher 90mm Mak. We already had the 102mm version so I was interested in a comparison. Terrestrially I was surprised to find considerable field glare which washed out the image unless the eye was placed perfectly on axis, this would no doubt also be obvious with lunar viewing. Close inspection revealed that the interior surface of the baffle tube, although black, was high gloss finish. The baffle tube itself is pretty small and would not easily be a candidate for flocking. As an experiment I lightly scored the surface in rifling fashion with a pointed needle file, the improvement, perhaps unsurprisingly, was dramatic. Anyone else noticed this issue with the 90mm? ? Link to comment Share on other sites More sharing options...
Stub Mandrel Posted November 22, 2018 Share Posted November 22, 2018 Hmm. Must take a look at my C90 to see if it shares the same issue. I wonder how much they have in common? They don't appear identical. Link to comment Share on other sites More sharing options...
jkwhinfrey Posted November 22, 2018 Share Posted November 22, 2018 Yup, my C90 has the same shiny baffle tube. I used some thin non-adhesive flock paper from Edmund Optics to fix this. Cut a piece to length, rolled it into a tube, and inserted inside the baffle. It doesn’t interfere with this view and, as Peter says, it’s much improved ? James Link to comment Share on other sites More sharing options...
happy-kat Posted November 22, 2018 Share Posted November 22, 2018 Interesting the needle scratching had same effect as my C70 baffle tube is even smaller! Link to comment Share on other sites More sharing options...
Alien 13 Posted November 22, 2018 Share Posted November 22, 2018 This has me thinking about my C90 now, maybe I should get some of that blacker than black nano tube stuff but other thoughts welcome. Alan Link to comment Share on other sites More sharing options...
Mr niall Posted November 22, 2018 Share Posted November 22, 2018 15 minutes ago, Alien 13 said: This has me thinking about my C90 now, maybe I should get some of that blacker than black nano tube stuff but other thoughts welcome. Alan Your C90 is the same I think - I stumbled across a YouTube video of some guy that showed how to flock the tube of a c90 a while back. Reckoned it made a huge difference Link to comment Share on other sites More sharing options...
happy-kat Posted November 22, 2018 Share Posted November 22, 2018 2 hours ago, jkwhinfrey said: I used some thin non-adhesive flock paper from Edmund Optics to fix this. Cut a piece to length, rolled it into a tube, and inserted inside the baffle. It doesn’t interfere with this view and, as Peter says, it’s much improved ? James Hi, did you use the 0.01 or 0.02 paper they stock please? Link to comment Share on other sites More sharing options...
Alien 13 Posted November 22, 2018 Share Posted November 22, 2018 I wonder if this simple improvement will turn my Mak into a poor mans Questar Alan Link to comment Share on other sites More sharing options...
jkwhinfrey Posted November 22, 2018 Share Posted November 22, 2018 1 hour ago, happy-kat said: Hi, did you use the 0.01 or 0.02 paper they stock please? Hi happy-kat, it was the #40 non-adhesive flock paper that’s 0.01” thick. Once rolled into the baffle tube it doesn’t seem to move much. James Link to comment Share on other sites More sharing options...
Alien 13 Posted November 23, 2018 Share Posted November 23, 2018 13 hours ago, Mr niall said: Your C90 is the same I think - I stumbled across a YouTube video of some guy that showed how to flock the tube of a c90 a while back. Reckoned it made a huge difference Thanks, was this the video as the difference with flocking is quite dramatic in the daytime. Alan Link to comment Share on other sites More sharing options...
Mr niall Posted November 23, 2018 Share Posted November 23, 2018 58 minutes ago, Alien 13 said: Thanks, was this the video as the difference with flocking is quite dramatic in the daytime. Alan Yep that was it - sorry should have dug it out for you was stuck on a train at the time. Yes it's quite a big difference isnt it? Link to comment Share on other sites More sharing options...
happy-kat Posted November 23, 2018 Share Posted November 23, 2018 There is also a thread on here on flocking a C6 but the thread from memory goes on to include a C90 before and after images. Link to comment Share on other sites More sharing options...
Stub Mandrel Posted November 23, 2018 Share Posted November 23, 2018 Hmm. Wonder where my C90 has gone... the trouble with such a small scope! Link to comment Share on other sites More sharing options...
happy-kat Posted November 23, 2018 Share Posted November 23, 2018 Found the thread, 5 pages to read but plenty of pictures added from page 2 on wards but page 6 has the flocked C90. link here Link to comment Share on other sites More sharing options...
Stub Mandrel Posted November 23, 2018 Share Posted November 23, 2018 Cripes, the tube is thinner than a thin thing! Link to comment Share on other sites More sharing options...
Stub Mandrel Posted November 23, 2018 Share Posted November 23, 2018 The video is great but no advice on how to actually do the flocking! My tube has a texture to it on the inside and doesn't seem as bad as the one in the video, I guess Celestron responded to criticism. I think I may try heat resistant paint but I will trial on a random bit of thin, long tube first! Link to comment Share on other sites More sharing options...
Alien 13 Posted November 23, 2018 Share Posted November 23, 2018 12 minutes ago, Stub Mandrel said: The video is great but no advice on how to actually do the flocking! My tube has a texture to it on the inside and doesn't seem as bad as the one in the video, I guess Celestron responded to criticism. I think I may try heat resistant paint but I will trial on a random bit of thin, long tube first! I think my C90 is the same. the baffle tube internal seems to be a matt finish and has a texture. I will certainly try a piece of rolled up flocking (non sticky) to see if there is a difference though. I noticed from the link supplied by Happy-kat that the dimensions of the material required to flock the C90 was 53x190 mm. Alan Link to comment Share on other sites More sharing options...
happy-kat Posted November 23, 2018 Share Posted November 23, 2018 From re reading the post flocking the tube looks pretty but the real improvement comes from flocking the baffle, the inner thinner then a thin thing. Link to comment Share on other sites More sharing options...
Alien 13 Posted November 23, 2018 Share Posted November 23, 2018 2 minutes ago, happy-kat said: From re reading the post flocking the tube looks pretty but the real improvement comes from flocking the baffle, the inner thinner then a thin thing. Thanks just corrected my previous post. Alan Link to comment Share on other sites More sharing options...
Merlin Posted November 23, 2018 Share Posted November 23, 2018 It's surprising that the manufacturer would overlook such a basic necessity as glare reduction. I used some self-adhesive, matt-black, material from WILKO for my SKYMAX 90 baffle tube. Link to comment Share on other sites More sharing options...
Stub Mandrel Posted November 23, 2018 Share Posted November 23, 2018 It was surprisingly easy to put a bit of self adhesive flock inside the tube. 50mm by 130mm for the record, but about 2mm too long so slight overlap, about 5mm short at each end of the tube. I rolled it around a pencil and carefully worked it until it stuck to itself, once in the tube it stuck to the tube more than itself and I was able to 'wind' it off and into position. Having see the vids and looking down the tube the difference is very big, more than enough to make up for 1-2% of lost light. Link to comment Share on other sites More sharing options...
nightfisher Posted November 25, 2018 Share Posted November 25, 2018 this has got me wanting to see if the 127 mak has same issue Link to comment Share on other sites More sharing options...
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