HEQ5 Pro 2/3 star alignment - choice of stars

[astroboyz]

Hi,

just got my mount, can I please ask for some advice on the stars I should be using (I live in Melbourne, but any choice from other places are also helpful)

Can you please give me your choice for 2 and 3-star alignment? Very much appreciate it.

[astroboyz]

By the way, my viewing session is between 8 - 12pm, still need to go to work the next day :-)

[astroboyz]

sorry by bad, 8pm - midnight, you know what I meant :-)

[raymo]

Don't bother with 3 star alignment seems to be the general consensus
on IIS; I certainly don't find any improvement over 2 star.
Whilst getting used to your new mount it doesn't matter much which
of the offered stars you use, as long, obviously, as they are not hidden by
obstructions, or going to be in the next hour or so. Later you can choose
particular stars to optimise the Go To capabilities of your mount.
Happy aligning
raymo

[pfitzgerald (Paul)]

Alpha Crucis, Alpha Centaurus, Sirius, Canopus & Archenar are all stars that I've used for a 2Star Alignment. This has worked well for visual and imaging with a DSLR using an Orion 80 mm guidescope and PHD for guiding.

Hope that helps.

I think (but I'm not completely certain) that the 3Star alignment is to help overcome cone error.

Paul

[Astro_Bot]

I usually do 3-star alignment. Compared to 2-star alignment, I find accuracy improved, particularly in the quadrant where there were no alignment stars.

As mentioned, 3-star alignment corrects for "cone error", which is a summary term for a range of mechanical and optical misaligmments (small ones), not that I'm an expert.

I obviously have some cone error in my setup that others may not have.

My advice is to try both and see whether you get any noticeable improvement from 3-star alignment.

[Steffen]

If you use 1- or 2-star alignment you should pick your alignment stars on the same side of the meridian as the the objects you want to observe. Since you will have no cone error correction pointing accuracy can be reduced after a meridian flip.

Alignment stars should preferably have low declination (be close to the equator) in order to maximise resolution in RA. They should be between 3 and 9 hours apart in RA and between 10 and 30 degrees apart in declination.

Section 3.7 of the SynScan manual (v.3.35) explains the rules for choosing alignment stars.

Cheers
Steffen.

[raymo]

Everybody goes on and on about collimation, but for some reason, fixing
one's cone error rarely gets a mention. Everyone should check theirs; it's
not like it's hard to do.
raymo

[astroboyz]

Thank you all for your generous advice :-)