lets focus on Ha

[Ewan]

Evening everyone.

Just a quickie, as Ha is very faint whats the best/easiest way to gain good focus ?

I Artemis i would normally do a 4 sec looped sub but with Ha it is not so easy & seems to take ages.

Any thoughts or tips please.

[RobH]

Focus on a mag 4 or 5 star, then shift to your target.

[carastro]

Agree with Rob.

Carole

[gingergeek]

Yep, I do it the same way as Carole and Rob. On my last alignment star I do my focusing (tighten up and recheck) and then slew to the target remembering to remove focus mask of course (not that I' not remembered of course) and then image away. 

[Ewan]

Thanks for the replies, what i should have added, my fault, is that if i want to do L & Ha on the same night i normally do L first & then Ha, but changing the filter wheel selection to Ha after the L really means i don't want to be moving the scope to a brighter star just to focus as it would then mean re framing again, i guess it makes sense to shoot Ha 1st instead.

[RobH]

Reframing only takes a minute, and making sure that your focus is perfect is critical. I have to reframe, but will still check focus on a nearby star when changing between broadband and NB filters. There's nothing worse than having a run of subs that are all slightly out of focus.

[ollypenrice]

If you re-synch your mount (whether planetarium or handset) on your target as framed, over-writing the original 'correct' synch) it should go back to pretty much the same space after a short slew to and from a star.

We have this on the Astrodon 3Nm. Anything much less than Sirius tends to be darned nearly invisible!!! I'd try to focus on a star at a similar elevation to the target, ideally.

Olly

[Ewan]

Nice one Olly exactly what i was after, so when i frame the target i can select Synch on the HC & it stores that info, then if i slew away then select the same target again it will goto the 'newly synched' target & position (just so i am clear).

Didn't even think about using that feature, learn something new every day.

[ollypenrice]

Nice one Olly exactly what i was after, so when i frame the target i can select Synch on the HC & it stores that info, then if i slew away then select the same target again it will goto the 'newly synched' target & position (just so i am clear).

Didn't even think about using that feature, learn something new every day.

You have it, I think.

Olly

[kirkster501]

If you use AstroTortilla and SAVE an image from that location you can slew away and do what you need to with focusing and return to exactly the same place, within a few pixels.  Just don't rotate the camera, which you should not need to do anyway.

Seriously, I would check out AT if I were you.  I don't know what I would do without it.

[Ewan]

Thanks Kirkster i have just downloaded it.

[kirkster501]

It's the best thing astro wise since the invention of the telescope mate! I swear it!!!!!