The next eshine telescope

I am printing this: https://wiki.openastrotech.com/en/OpenAstroTracker

Hans worked on getting various bits of the system to move without having to use LabView, and has managed to get the FW moving using the LV system as is, to turn on power for the FW, and then using ThorLabs software and a USB cable to move the FWs from a laptop. Recall that when we use the LV software to move the filters they move – but switch to ‘something else’ right after. Hans goes on to summqrize a plan for the way forward:

Slutsatsen är att filter-hjulen fungerar att köra från Windows.
Man måste bara kunna slå på reläet i boxen. Jag vet nu
HUR man slår på strömmen, även om jag inte förstår helt
VARFÖR det fungerar.

Förr eller senare måste vi göra oss av med skåpet. Jag tror att det
är klokt att starta nu och långsamt, steg för steg, flytta över funktioner
till en PC.

—

Jag har tänkt genom varför vi överhuvudtaget har en PXI
istället för en vanlig dator. LabView kan ju köra på en vanlig PC,
så det är inte det som är skälet. Jag tror att den enda anledningen
är att köra motorerna till kniv- och fokus-mekanismerna, och att
kunna få tillbaka signaler om positioner. Man har valt motorer
från National Aperture Inc. som drivs av en servo-förstärkare, som
i sin tur drivs av PXI-kortet som heter “Motion Control”.

Allt annat borde fungera från en vanlig PC. Jag tror t.o.m. att vi
kan installera LabView på en vanlig PC och kunna använda många
av funktionerna i Engineering Mode. Allt utom det som är relaterat
till motorerna går ju via helt vanliga COM-portar.

This software to ‘automatically’ control a whole observatory exists: ACP link
It costs about $1000 and you need Maxim DL (at $200). You get support.

Here is someone who has used an Arduino to control a telescope. His idea is to replace stepper motors and use ‘good’ DC motors. He still uses LX200 commands from planetarium software. The software talks to the Arduino which talks to the motors.

Perhaps these ideas can be used to make a system that uses cameras to find the target (Moon) and track it – in a way simpler than this mans system: No GOTO commands – just a small PC or Arduino controlling motors until some target distance is minimized. Using an equatorial mount allows easier tracking once the target is acquired – just one motor spinning.

This guy’s mount has to do meridian flips – probably has code in the Arduino for that. If a fork EQ-mount was used (like on a Celestron or Meade) MFs could be avoided.

The pointing of the telescope was not perfect. We set the pointing by calibrating the mount on a target field of stars the position of which we found using image-analysis software (see astrometry.net). The centre of field was then added, by hand, to a setup menu, and the telescope would centre well for a while. After a meridian flip, or after a few days, the centring was not so good any more.

We tested polar alignment by the drift method, but results were not clear. We are thus unsure why the pointing of the mount would deteriorate.

GOTO telescopes have calibration modes where a sequence of observations at different parts of the sky are made so that a pointing model can be calculated and used. We could not do this – we did one pointing and updated the model based on that – we needed a way to access the ‘build a pointing model’ system by software. Even to do this automatically.

We had the basic ingredients of a system to take pictures of the Moon and centre accordingly, but it was not functioning robustly.

The dream solution would be something like this: the system is lost and does not know where it points – so it takes a picture of the sky and gets an astrometric solution – then it gets more – if one solution does not work it gets more pictures, at random
above-horizon, places – and keeps going until a solution is found. Then it goes about its work. Sigh.

We needed to focus the system now and then – but it turned out that this was when the wrong filter had been selected. In view of this, there may never have been a focus problem – as long as the filter was correctly selected the system would proceed to set focus to that filter.

There was never an automatic ‘set the focus’ operation, but perhaps this was not needed? It would have been required if we had gotten the NDs up and running as a known laboratory-tested focus point for these may not have been at hand, and then it would have been necessary to find it by hand and setting a fixed value.