Summary

Designed this Bahtinov mask for out astronomy department to fit a Borg 77 EDII Apochromat telescope.

The ID of the mask is 88mm and is a loose fit to the end of the refractor.

If you wanted to make it tighter just add a strip of duct tape or something to the mask.

Print Settings

Printer Brand:

MakerBot

                                            <p class="detail-setting printer"><strong>Printer: </strong>                     <div><p>MakerBot Replicator+</p></div></p>                                                                                <p class="detail-setting rafts"><strong>Rafts: </strong>                     <div><p>Doesn't Matter</p></div></p>                                                                                <p class="detail-setting supports"><strong>Supports: </strong>                     <div><p>No</p></div></p>                                                                                <p class="detail-setting resolution"><strong>Resolution: </strong>                     <div><p>0.2mm</p></div></p>                                                                                <p class="detail-setting infill"><strong>Infill: </strong>                     <div><p>10%</p></div></p>                                                        <br>                        <p class="detail-setting notes"><strong>Notes: </strong>                    </p><div><p>2 Shells.<br>I print it with the front face on the build plate.</p></div>

How I Designed This

The spec from Astronomy

            <div><p>I’ve attached a PDF and the .svg file output for the Bahtinov mask for the 77mm Borg refractor.<br>I also have the scope here on campus so you could get whatever measurements are needed directly from it.<br>The attachments are not necessarily to scale - I still am not sure how the generator scales these files, and they never seem to be the right size in Illustrator when I open them.   Anyway, based on the measurements of the scope itself you can possibly fit as needed? (I think this is what you did for the previous ones, right?)  </p><p>Here is the generator; scope is 510 mm focal length, 77 mm aperture.  Let me know if/when you want to measure.  </p><p><a rel="nofollow" href="http://astrojargon.net/MaskGenerator.aspx">http://astrojargon.net/MaskGenerator.aspx</a>  </p><hr><p>I basically just printed the pdf and eyeballed it from there. :)  </p><p>From previous experience I know the measurements are not critical.  </p><p>I haven't got to try the thing myself yet because I am an ex-South African with an aversion to cold Canadian nights, but I have it on good authority that it works well.<br>This is the third mask I have made for our astronomy department.  </p></div>

Borg 77 EDII Apochromat Bahtinov Mask