Exercise in futility

[Demonperformer]

That just about sums up this morning between 1.30 & 3 ... repeatedly could NOT get the system to accept alignment ... finally managed it and got the camera focussed on Antares ... GOTO M62 ... and up it goes towards the zenith ...

Finally gave up, packed up, fed up ...

I know it will all go perfectly next time, and this morning will be 'as a dream on waking', but currently feel I could have done without it.

Moan over.

[cotterless45]

Quite amazed by my GOTO, but it's moody. Some nights it's crack on at x200, other nights it's not playing my game.

I heard from a chap at a StarParty who set up a GOTO for a newbie. When asked what he'd like to see, "Pleiades". With great flourish our man lifted his pointing GOTO finger and said " there it is" before making a sharp exit.

It's still a great pleasure and fun, just to take a Dob or eq mount and hunt the elusive and the obvious,

Nick.

[D4N]

The last issue I had was that I forgot to account for summer time when I set the time on the handset so everything was an hour out. I just corrected for it with the star align and didn't bother to reset the handset time that session.

Personally I think they should abolish summer time but that's a moan for a different thread

Astrotortilla is a wonderful thing when it is working though, just let the computer sort it out

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[ronin]

Sounds like Hampshire is trying to save money by using the 0.8eV electrons not the standard 1.0eV electrons overnight. :grin:

[Demonperformer]

Thanks, guys.

I agree that it can be fun to "just cruise" and see what I can find, but it's not such fun when I am trying to complete a program.

Yes, I checked the usual suspects - date (mm/dd/yy) and dst - but something weird was happening. As for astrotortilla, I have another thread detailing the horror story I had with that (without altering the mount's position, it produced an ever-increasing amount to correct by???).

Basically this morning consisted of:

(1) Solar system align on Saturn - check.

(2) Goto Antares - check.

(3) Align on Antares - ALIGN FAILED.

(4) Repeat steps 1-3 three times (I can be really stubborn when I want to be!)

(5) Solar system align on Saturn - check.

(6) Goto Altair - check.

(7) Align on Altair - check.

(8) Goto Antares - check.

(9) Goto M62 - mount heads north instead of south!!!

(10) GIVE UP.

[Steve Ward]

Do the alignment using stars not planets , the planets move across the sky relative to the stars over time and this cannot avoid introducing errors into the mix ... 

[D4N]

Did you allow the mount to complete its move? It might have just decided that it needed to do a meridian flip to get to where you wanted it.

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[Demonperformer]

Steve, I always (if poss) start with a planet, as that way I can be absolutely sure what I am looking at - alignment always fails if you are pointing at the wrong star - that gives me a basis to get to the right star and then I add two of them. That is the process I usually use, and it almost always works  - except for times like this morning.  But even then it was taking me to the star, just refusing to align on it - except for Altair. And even if there were some minor uncertainties based on the Saturn/Altair alignment, they should not have been enough to make the scope think that north was south.

D4N, it is a celestron mount which is Altaz and so does not do a meridian flip, but yes, it had stopped moving and the star was in the eyepiece.

[Droogie 2001]

Have to agree with Steve Ward on the not using the Planets for alignment though if you have always done this and it has never been an issue then fair enough.

I usually like to go for Mizar on my first or second alignment star as it is clearly a double star and easily identifiable in the Plough asterism.

What power source are you using, a Power Tank? If so charge it for 24 hours and then make sure you charge it after each use. (I realise you probably do this but do give the Tank a full charge if applicable)

I had craziness with my Celestron AVX where it would just start pointing straight down or up upon a alignment slew.

Left the power tank on charge for 24 hours and obviously always fully charge after each use. Since then never had a problem, its also possible it could be getting to end of its life?
I know you are probably going to tell me you are using mains next though..  
 

[Demonperformer]

I know you are probably going to tell me you are using mains next though..  

You must be psychic.

[Droogie 2001]

 

Hope you get the issue resolved.

[Demonperformer]

How obsessive am I? I have been gnawing away at this problem for just over a week and, although I would not be able to prove anything, I have come up with possible explanations for these two problems.

(1) Why did the align work on Saturn-Altair, but not on Saturn-Antares? Firstly, the fact that Saturn was involved in both attempts makes the 'Saturn is a planet and moves' theory extremely suspect. The explanation must lie in some difference between Antares and Altair. Well, the most obvious difference between Altair and Antares (in this context) is their distances from Saturn.  At the time, Antares was 10d23'36.2" from Saturn, while Altair was 62d54'03" from Saturn (figures obtained from CdC). Now, my ep of preference for aligning is my meade 32mm because I stand at least half a chance of finding the object somewhere in the fov. [i know that I would probably get better alignment with the 12mm reticle ep, but that is a subject for another thread.]  Anyway, let's suppose that I can get the object to within 5% of the centre of the fov, that works out at a 7.5' potential error on each point, so upto 15' total error. As a proportion of the Saturn-Antares distance, that is nearly 2.5% of the total distance between them. On the Saturn-Altair distance it is only 0.4% of the distance between them. I don't know what level of flexibility is built into the alignment system, but this seems to me to be a significant enough difference as to explain why it would align with Altair, but not Antares, even though the scope was taking me more or less to Antares after loading Saturn into the system. Moral - DON'T try to align on objects that are too close together [how close is too close is another question!].

(2) But having successfully aligned using Saturn-Altair, and successfully taken me back to Antares with the GOTO, why did the computer suddenly decide that it would find objects further south than Antares by heading north towards the zenith? The only explanation I can suggest is that I mis-typed the '6' as a '9' [they are adjacent on the keypad and it was 3am and I was already feeling 'frazzled' after the align problems I had been having]. If this were to be the case, then the computer would indeed head towards the zenith to find M92, which was sitting at an altitude of 82d at the time. Moral - READ what you have typed before hitting ENTER.

As I said originally, I can offer no proof that either of these explanations were the actual causes of my problems, but (subject to anyone offering any reasons why they are unlikely) I am willing to accept them as probable reasons and stop worrying about it.

Thanks.