Thoughts from Starlight Cascade

Imaging Jupiter last night during the Perseids, waiting for midnight to come for hopefully better and more meteor displays.

These are before and after Registax v6 wavelet processing, to show the power behind wavelets, and the fact that I still do not have what I consider ideal settings 🙁

Seeing was average

Transparency was good but got worse

Sky Quality Meter reading: 21.48 mag/arcsec^2

Meade LXD55 mount tracking below average

Meade 102mm SC F10 FL=1000mm plus a x1.5x barlow, effective FL=1500mm
No dew shield or dew heater on the Meade 102.
North is down (I normally do up)
Thesee are the best 50% of the images.

	Start of run 02:48UTC	End of run 03:14 UTC
Before wavelets
After wavelets

And from this morning, Tuesday 2020 July 21st, just after midnight.
Very low to the horizon and soon to disappear behind the trees.
Catch it if you can after sunset once it gets dark enough.
Awesome comet. again, first naked eye comet in a generation.
It does seemed to have peaked in brightness and is just starting to fade a bit.

Greetings!

I have been looking forward to the opposition of Jupiter for *ages*. Unfortunately I do not yet have my dream setup and am cobbling together anything that will capture photons.

Last night was 1st light with an old Meade LXD55 tripod and mount, an old Meade 102mm F10 1000mm FL, a newer asi 290mc camera.

I do not have the cables to talk to the mount yet (its a serial 4 wire cable with a narrow RJ9 jack, not the “regular RJ11” standard phone style jack). It would have been nice to be able to command the mount from inside the house as the mozzies were insane last night. We were decked out in bug jackets along with long clothing and still they were biting through.

Attached is the processed (pipp, autostakkert!, registax wavelets) image of Jupiter at 02:37 UTC today (22:37 EDT) that shows not too abd detail using Christopher Go’s wavelet settings.. a little overblown but it does show the surface features well.

For comparison, also attached is the stacked but not yet processed in registax for wavelets.

These are 120 second exposure runs at 21ms/frame and these are the stacked best 25% of the frames.

Some time ago I had asked if anyone had done an elementary physics experiment in friction.

Does adding more wheels to a rolloffroof observatory reduce the static (starting) friction and the rolling friction?

All else being equal, more wheels would be a lower PSI on each wheel and the support surface under it, but there would also be more axles then before, generating more friction.

Well, things came to a head here at SCGO and I had the opportunity to get four more wheels of the exact same type.

The existing structure is an 8 foot long mounting surface with 5 wheels, approx 14″ apart with the first and last wheels also being 14″ from the end of the support.

start-space-wheel-space…..wheel-space-end

| 14 W 14 W 14 W 14 W 14 W 14 | (1st image)

when in the closed position, all 5 wheels were in contact with the bottom surface (an upright 2×8).

Interesting discovery when the roof went into the open position… only the two end wheels were in contact, with the middle three free wheeling! That meant that when moving the roof, at some point, all of the weight was on only those two wheels! They may not be rated for that much, and the PSI is certainly much higher than thought and that is tearing up the surface of the bottom 2×8. Aha!

Either the 16′ of track (made from two 2″x8″x8′ sections) had issues, or the roof changed its shape or a combination of both.

strange. when the roof is fully closed, it is completely on a single 8′ board. the same when fully open, only on one board. So even if the 16′ were not completely level, it is still not straddling two boards.

Its like most of the roof mass/force was mostly coming down on the ends of the 8′ supports.

So I added an extra wheel at each end, approx 9″ from the previous end wheels. So before the roof support overhung the last wheel by 14″, now it is 14-9=5″.

start-space-wheel-space…..wheel-space-end

|5 W 9 W 14 W 14 W 14 W 14 W 9 W 5 | (2nd image)

So far so good. It *seems* to be behaving better but it may take the wooden structure some time to change its shape and force loads, especially in the hot weather.

This of course required moving the end stops so the roof could properly come to rest in the correct position to connect the holddowns. hmm… now that I think of it, I only replaced the closed position stops… forgot to do the open stops!

Lastly, the final touch to help reduce the force needed to move the roof, some kind of hard cladding to cap the weakened 2″x8″x8′ top surface.

I know many of you said, go get some angleiron! But is is never that simple. local supplier? limited hours of operation? transport issues (only have tiny car now, no minivan), cost of materials, will they fit the existing wheels without binding?…

In any event, I am confident that now with at least *4* wheels in contact on each side, it will be an easier roof to move. Hopefully with the extra wheels on the end, the middle wheels will come down into contact as well.