#seestars30pro — Public Fediverse posts

Rapid prototyping.

I quickly knocked up v5a of my lens hood/light baffle design (loop for attaching a thread, telescope interface wall 3 perimeters thick instead of 2, but 3 mm long instead of 5, opening half angle increased from 2.3° to 2.4°), printed it on my Prusa Mini+, and put it on the telescope by the time the night was about half over.

I'm pretty happy with the design but it did expose the issues with relying on a push fit. Despite being designed with the exact same outer diameter as my previous lens hoods this one (and only this one) was too loose, and was going to fall out when the telescope moved. An emergency application of a single strip of masking tape on the interface surface to tighten it up may just be enough to keep it in place for tonight, but I'll need to investigate more tomorrow.

I may be partly due to my printer producing a smoother surface than the previous prints that suffered from cold conditions, but I suspect it was actually the shortening by 2 mm that is the main problem. Now that I think about it I recall there being a fine moulding line or seam between parts a few mm inside the aperture. My previous lens hood might have been relying on that for grip, and the new one doesn't quite reach it. I can tweak the dimensions to try to get the perfect fit but I really should find a way to use the magnets instead.

#Seestar #SeestarS30Pro #3Dprinting #FreeCAD #SmartTelescope #TMMT #ThirtyMillimetreTelescope

In other telescope news I am absolutely nailing putting my tripod outside. Twice this week I've taken it into the backyard and attempted to put it down where I had it before just by eyeballing it (no marks on the ground) then levelled it as best I can by adjusting the leg extension while looking at the tiny bubble level on the top of the tripod. Both times I've then put the Seestar onto the equatorial wedge and started the polar alignment process only to find that I didn't need to make adjustments at all, it was already within a couple of tenths of a degree in both axes.

#Seestar #SeestarS30Pro #SmartTelescope #TMMT #ThirtyMillimetreTelescope

Damn. I forgot I broke another of my v5 25° 3D printed Seestar lens hood/light baffles on Tuesday night so tonight the Thirty Millimetre Telescope is wearing the ludicrously large v5 20° design.

These things are getting broken at the end of the night when the Seestar automatically closes the telescope arm, bending the push-fit lens hood out of the aperture and causing it to drop onto the concrete patio below.

The weak point is where the narrow cylindrical section that fits inside the Seestar aperture meets the top of the conical section. The walls are as thin as I can make them at that point because any additional thickness right there intrudes on the telescope beam, losing light. Compounding the issues are the fact that these are printed in matte black PLA which is rather brittle, and they were printed when it was very cold inside the house wasn't doing the layer adhesion any favours.

I don't know whether they're breaking when the telescope is forcing them out of its aperture or when they hit the ground. For now I can reduce the length of the cylindrical section to reduce the moment arm when it gets nudged out and add a loop so I can tie a safety harness to the lens hood to stop it dropping all the way to the ground.

Longer term I can try printing them in tougher filament (I have a spool of PETG-CF I bought for this purpose, but need to swap out my brass nozzle for hardened steel first) and switch to magnetic attachment instead of a push fit.

For tonight I'll just turn off the automatic closing function of the Seestar, I don't think the bigger, heavier 20° hood will survive the fall to the ground. As long as I bring the telescope inside in the morning before the Sun can shine into it that'll be fine.

#Seestar #SeestarS30Pro #3Dprinting #FreeCAD #SmartTelescope #TMMT #ThirtyMillimetreTelescope