3 star alignment without the handset

[azkaz]

Hi, I've just setup my ED80 on HEQ5pro to run purely off stellarium on my laptop via a Bluetooth adapter and the relevant EQMOD files.
My question is regarding star alignment.
With the synscan hand controller I used to do the 2/3 star alignment to dial in accurate tracking.
Has anyone had experience in doing this without the hand controller and in stellarium?
Your help is much appreciated.

Aaron

[Merlin66]

Aaron,
Using EQmod you just have to locate your stars (using the planetarium program) and sync on them -as many as you like!
Check out the EQMod manual (in the EQMod folder) for more detail.

[kosborn]

A good option is to use Astrotortilla with Stellarium. It is a free plate-solving program that compares where the mount should be pointing with where it is actually pointing. It will accurately centre the mount based on the expected position and sync the mount each time so that each subsequent target selection is more accurate.

[azkaz]

Thanks guys, I will check out both these options!:thumbsup:

[Startrek]

I progressed from the Synscan handcontroller to the laptop 8 months ago using EQMOD with StellariumScope and Stellarium
Extremely accurate in finding objects with sync function and tracking is very good
All free software , just need cables etc

[Startrek]

Aaron
Found the post
Just a few quick questions are you imaging with a DSLR or a CCD camera ?
If your using a DSLR are you running BYEOS for your image capture etc
If you pm me your email address I can send you a procedure on EQMOD , StellariumScope, Stellarium and BYEOS for telescope control , goto and tracking etc...
But remember none of above works accurately unless your mount is polar aligned properly with minimal error ( say to 1 or 2 arc minutes )
Cheers

[Wussell]

I too have just recently moved away from the hand controller and now have my NEQ6 connect via EQMOD. I use Carte du Ciel and also have my PS4 controller connected to it. It took me a bit of fiddling to work it all out but have managed it. I finally got guiding to work with PHD2.

I have a ED80 with a DSLR, and have just ordered a motorized focuser for it. Its all coming together nicely :)

[Wavytone]

Aaron there is a method to do alignment using just a declination circle and a small torch to read it - no handset required (!), and 2 stars of known declination. I learnt this in the days before GOTO mounts with old-school scopes that had a simple RA drive. I still use it always when setting up, as with practice I can do it in 5 minutes - faster than drift aligning, and faster than futzing with GOTO handsets.

This method will give an alignment around +/- half the finest division of the circle and with care you can do better; with my AZEQ6 I regularly get it within half a degree of the celestial pole.

It also pays to use an eyepiece with cross-hairs to centre the stars in the scope, I use a 20mm SWA with a graticule for this. Trying to eye-ball it without cross-hairs invariably results in a worse alignment.

This method assumes the dec circle has been aligned accurately to the optical axis of the scope, so that when reading -90 the scope is parallel to the RA axis and reading 0 means it is indeed perpendicular to the RA axis. Aligning the dec circle can be done in a few minutes using any distant object - with the scope on one side of the mount (a bright star near the meridian will do nicely) read its dec. Now flip the scope over in RA to the opposite side of the mount, centre the same star and read its dec. The correct value is the average of the two readings, adjust the circle accordingly.

The mount alignment procedure is:

1. Set up mount with the polar axis point roughly south (compass will do).

2. Choose two brights stars, ideally one low down near the east/west horizon wand close o the celestial equator (ie declination between +10...-10) and another near the meridian and high up (ie near the zenith).

3. Starting with the star near the east/west horizon, unlock the azimuth adjustment of the mount and set the dec axis to the declination of this star and clamp the dec axis securely. By moving the scope in RA and altering the azimuth of the mount, centre this star in the scope.

By this means you have set the azimuth of the mount, using the star as your compass. Lock the azimuth of the mount.

4. Now for the star near the zenith, set the dec axis to its declination and clamp the axis securely. Unlock the altitude adjustment of the mount. By moving the scope in RA and altering the altitude of the mount, centre this star in the scope.

By this means you have set the altitude of the mount, using the star as your compass. Lock the altitude of the mount.

5. If the adjustments in altitude/azimuth were large (ie >10 degrees) it is advisable to repeat steps 3-4.

6. Check the alignment by aiming the scope at a few stars and read their dec off the dec circle, it should agree with the catalog positions from Stellarium or Sky Safari within a degree.

[sharpiel]

Very elegant and sensible way of aligning Nick. Copied and pasted into Notes on my iPad for future use.

[Wavytone]

Les, FYI Slight correction in step 4.

[sharpiel]

Recopied. Thanks.

[azkaz]

Thanks for all that info!
When you set your mount pointing roughly South, do you set it south east? I mean I get my compass, point the compass south, move the marker rotating dial on the compass to 11 degrees towards east and set my mount to that direction. I believe this is to adjust for magnetic south not being celestial south and adjusting accordingly for where I live.