Some of my SeeStar Projects

Project 1 - The Dew Shield

STL file for the Dew Shield (25% fill - 3:13)
STL file for the Short Dew Shield (30% fill - 1:51)

Any exposed glass will want to dew over, at least here in Florida. The S50 has a built-in dew heater and it works well. Dew heaters suck power and I wanted the battery to last as long as possible. Dew shields greatly delay the lens dewing up and draw no power. So it was time to make a dew shield. Attaching it to the s50 uses a standard compression fitting inside the micro built-in mini lens shield. As a bonus this also blocks some stray light.

The short dew shield is about 32mm long and about 1/2 the length of the regular dew shield. Both dew shields use thinner walls and are lighter than other parts.

Project 2 - Modify the Megrez oak tripod to use with the S50

Back in the Y2K year of 2000 I made the weightless oak mount to handle the Megrez 80. The tripod that comes in the SeeStar box is a beautiful thing, especially for traveling light. I wanted a more substantial and taller tripod at home and when it was practical to use it. My first thought was a bigger photo tripod and then I remembered the weightless oak mount project from __ years ago. Since the weightless arms came off of the base tripod all that I needed to do was drill a 3/8" hole in the top plate and urethane the new exposed wood hole to waterproof it.

I had a 3/8" threaded hand clamp bolt. I added a bubble level to the top of the tripod to ballpark it in on the initial setup. A three point leveling base was also add between the tripod and the SeeStar to fine tune the level during the SeeStar setup. A few inch length of glow-in-the-dark tape is on each tripod leg to help prevent anyone from bumping into the tripod in the dark. It's rarely dark enough during public observing to need the glow tape.

During public events the tripod tray holds a tablet in guest mode and extra power supply to show what the SeeStar is imaging. The tablet is strapped to the tripod to help prevent it from being borrowed.

This setup has the SeeStar in equatorial mode. Well, not really. This is the first time that I used EQ mode and the scope needs to be rotated 90 degrees so that the on/off switch is up. I'll update this photo when I remember to take a new one in the correct orientation.

Project 3 - The Dew Shield with a 2" Filter Holder (40% fill - See Below)

The LPR filter built in the S50 helps quite a bit and I've been impress with it's results. I was thinking that If I could use a standard 2" filter I would like to try one of my favorite filters, the Optolong L-Pro, on it. A quick web search turned up a filter holder made by lewisite on Thingiverse (Thank you!). I liked the idea but with the filter glass even more exposed that the original lens this really need a dew shield. The part that attaches to the SeeStar wobbled a tiny bit. I changed the SeeStar coupler with the one from the earlier dew shield and added the dew shield to the other end. The twist lock was angled slightly differently to allow more surface contact. It locks with only a slight twist between the two halves. The filter may rattle a tiny bit if shaked because the size of the frame around the filter varies quite a bit. In practice the scope is angled up and it doesn't move while in use.

STL files for the Dew Shield with a 2" Filter Holder (both parts)
Part A - Filter Tray section (40% fill - 1:23)
Part B - Dew Shield section (40% fill - 4:47)

Project 4 - The Dew Shield with Drawer for the ZWO (Gen 2) Filter Tray (40% fill - 7:31)

STL file for the Dew Shield with Filter Drawer

Here are the parts in TinkerCad

Most of my astrophotography filters are in ZWO Gen 2 filter trays. I really like this system. It allows for quick filter swaps and less chance of touching the filter greasy finger prints on them at 2am. The previous 2" filter holder was made using three sections: SeeStar coupler, 2" filter holder and dew shield. If I replaced the 2" filter holder section with a drawer that fit the ZWO filter tray it would allow easy changing filters on the SeeStar and between telescopes.

I put quite a bit of time into getting this just right. The gaps were tweaked at the 1/100th of a millimeter (decimeter) level. I wanted a smooth fit but no wobble. The magnet placement was critical. Quite a few trimmed models were printed. I removed the coupler and dew shield to speed up the test and use less filament.

This must be printed using supports everywhere.

There will be quite a bit of supports to remove but the results will be worth it. A downside of the supports is that when removed they leave some small roughness on the surface. Where the tray slides in you will need to carefully file off this roughness for the tray to slide in. The bumps need to be smoothed all the way in the back where the thin part of the tray slides in. Make sure that you don't grab the sides of the battery hole with the needle-nose pliers and tear them out when removing the supports.

The magnets (see the note in the box above) for these parts are sold as 5mm wide x 2mm thick. In reality they are 1.78mm thick and the STL files are made for this thickness. I have been using JB Weld 5 minute epoxy to hold the magnets in the holes and have been successful so-far. I use a toothpick to place the epoxy in the hole. Press the magnet in the hole all the way and make sure that it's flat. The magnet will stick out slightly above the hole and this is intended. Wipe off any visible epoxy. I haven't tried these in freezing weather yet.

The filter holder (below) has the same dimensions but since it is printed with the opening vertically there are no supports and the filing is not needed.

Project 5 - Filter Tray Holder for the ZWO (Gen 2) Filter Tray (see below)

This project is independent of any telescope and anyone that uses ZWO Gen 2 filter trays may benefit from it.

Having the commonly used filters in filter trays begs for a safe way to store and transport them. While not SeeStar specific I added the holder here since the other parts are here.

Now that I had a properly fitting filter drawer I should be able to remove the coupling and dew shield, rotate it 90 degrees so that the opening is facing up, add a base to it and have a filter holder. Butting these together would make multiple filter holders in theory as wide as the 3D printer can handle. It would use more magnets but I have a box of more than 200 so that's not an issue. Sweet!

The filter holders use the same magnets as the dew shield with filter tray.

STL files for the Filter Tray Holders (1-5 trays)
One Tray Filter Holder (40% fill - 3:53)
Two Tray Filter Holder (40% fill - 6:27)
Three Tray Filter Holder (40% fill - 9:25)
Four Tray Filter Holder (40% fill - 12:10)
Five Tray Filter Holder (40% fill - 15:01)

Here are the parts in TinkerCad

Project 6 - Gen 2 Filter Trays & Dust Caps

This project is independent of any telescope and anyone that uses ZWO Gen 2 filter trays may benefit from it. None of these parts should be used during solar imaging or viewing

These trays work although I recommend using the official machined ZWO trays to protect your valuable filers.

Now that I had a save way to store and transport the filters in their respective trays I decided to make a dust cap. This, in turn, lead to the Dust Plug and then a 2" filter tray and, finally, a 1.25" filter tray.

Each tray needs two attachment points for the drawer magnets. I chose #4-40 x 1/4" hex cap head bolts, alternatively, Metric M3 x 6mm hex cap head bolts may be used. Each part should be threaded with the appropriate tap for the bolts chosen. I have been using the #4s. Note that these parts must be magnetic so stainless steel does not work well.

The Drawer dust cap only covers the opening (they all cover the opening). The dust plug has a plate that covers the entire interior of the drawer for better dust blocking. The Dust Plug, if printed in matte black, should be usable for dark frames also. Do not use it as a block during solar imaging. I print the cap and plug in red so that they are easily distinguishable from actual filter trays. The magnets in the drawers are slightly offset and the bolts in the trays match that offset, except for the dust cap. The cap bolts are centered so that the cap may be inserted either way.

The filter holders come in 2" and 1.25" sizes. These are printed vertically for minimal supports. Use supports everywhere when printing. The threads print better, at least on my printer, when the part is lying down instead of standing up. The trade-off is that you'll need to file off the rough parts from the supports across the face of the filter holder. I cheated and found a cheap (for its size) 48mm X 0.75mm tap to clean up the 2" threads. The filter holders should be printed in matte black. The red 2" tray shown here was made to see the parts better.

The next photo shows the Dust Cap on the test (blue) drawer and the Dust Plug. The test drawer is on the TinkerCad page (link below).

The last photo shows the huge 48mm (2") x 0.75mm tap working on the threads.

⚠️ These parts have not been tested in hot or cold environments yet.

STL files for the Drawer Dust Cap (30% fill - 1:00)
STL files for the Drawer Dust Plug (30% fill - 1:57)
STL files for the 1.25" Filter Tray (50% fill - 1:51)
STL files for the 2" Filter Tray (50% fill - 1:37)

Here are the parts in TinkerCad

Recommended - External Battery Holder (25% fill - see below)
This isn't my design but it's worthy of using

An external battery holder allows the S50 to add hours to its usable time. I have been using this one for a while: Mike Steffek's S50 Power bank holder. The small holder handles power banks up to 20mm thick and the larger one up to 32mm. This fits on the S50 nicely and works well. I use a couple of 10,000mAh battery packs (one at a time) with the smaller holder. The battery pack drains before the internal battery starts to drop so they may be swapped out. This allows you to monitor the S50's battery power in the SeeStar app and you'll know when the external pack is empty when the S50's battery starts to go down.

In the new equatorial mode the external battery slides around a bit. The quick fix was to wedge a bit of foam in between the holder and the battery. One of the other astronomers (thanks Ron!) suggested adding screws to put pressure against the battery and prevent it from moving. The next day I added a few of #10 x 32 nylon thumb screws through the outer shell and dense foam rubber pads inside. This will allow the battery pack to be lightly pressed against the foam pads by the nylon screws and should stop any motion of the external battery pack, especially when in equatorial mode.

The small battery holder is shown in these photos. After printing a few for friends I decided to make a monogramed blue version to identify my SeeStar from the others.

Small Battery Holder (25% fill - 11:36)
Large Battery Holder (25% fill - 12:23)

Mostly Recommended - Equatorial Head

There are many equatorial head options out there and some sites have reviewed all of them. Read the reviews. The one that I chose was the 'AKTUHRASHID Latitude EQ Base Equatorial Mount Accessory'. It also needed the 'NEEWER 3.15" Rail Bar Vixen Style Dovetail Plate'. I left the leveling base on the tripod and added the EQ head to the top of the tripod. It handles my 28° latitude and just clears the altitude screw knob that is conveniently near horizontal. The Neewer bar clamps in well but sometimes the clamp doesn't easily release it when the clamping knob is released. I'm keeping it.