Basic goto help please

[BenP]

Hi All,

Newbie here looking for some advice. I have a Skywatcher Skyhawk 1145P SynScan AZ GOTO. My knowledge of telescopes is limited so any help or tips would be great.

I am having trouble setting the goto up. Using the 2 star set up I have been trying to use Betelgeuse as my number 1 and Polaris as number 2.

When the goto looks for Polaris it is quite some way off. I then find it difficult to locate as, well, there are loads of stars up there!

I have taken my co-ordinates from Stellarium so maybe I need to be more precise?

Are there any better stars to use? I live in Essex, England.

Thanks,

Ben

[rwilkey]

Hi Ben, no better stars to use in my opinion, though Sirius might be a good alternative if it's not too low.  However, three things to mention:

1) have you input your location and date information correctly

2) is the mount and telescope absolutely level (bubble-levelled?)

3) Have you aligned your finder scope correctly and accurately (best done during the day on something like a distant church spire or pylon etc)

See if this helps, good luck!

[Oddsocks]

Hello Ben,

It is generally not a good idea to use Polaris for calibrating GOTO as it is too close to the RA axis for the GOTO software to calculate its sky model accurately.

I normally choose something at around 45 deg altitude in the south for the first star and then either something 90 degrees east or west, wherever a bright star is convenient at the time, but hardly ever try for anything to the North.

In Stellarium, go to the "View Settings" window and tick the box "Stars" under limit magnitudes, now adjust the limit magnitude to 1 or 2, this will remove from the display most of the dimmer stars and just leave you with the easier to find bright stars, now you will be able choose your alignment stars more easily from whats available at the time

When out with the telescope a simple plastic Planisiphere, which only cost a few pounds, is a lot simpler to use as an aid to finding suitable guide stars.

When aligning on your first and second bright stars begin by using the finder, or Telrad if you have one, and centre as accurately as you can before finalising the centring by looking through the telescope eyepiece, that way you will have more confidence that what you see through the eyepiece is really the alignment star and not something else almost as bright nearby.

[Oddsocks]

Sorry Ben, didn't read properly that your scope is an AZ mount in which case Polaris would be ok although still rather dim, quite a few brighter stars to use.

[ronin]

To repeat bits, level the mount then more or less for the hell of it aim the thing North and also for the hell of it level the scope tube. Not I think nexessary but you have to start somewhere and it looks good.

Next what data are you giving the mount?

Every bit of it and in what order.

Do not say it was the right values, supply them.

Essex is too big to supply you accurate Long+Lat so where in Essex, and what did you input

Don't use Polaris, Polaris is close to a 0 degree direction and if there is a division in the software it can go nuts. Try Betelgeuse and Deneb, you could try Vega if it is not too low but Deneb should be good.

Question:

Are you setting DST = Off ?

What timezone did you input, should be 0.

Your Longitude will be +ve, or E.

Does the handset want Longitude first ? Easy to enter Lat and Long when it should be Long and Lat.

[NGC 1502]

Hi Ben, if we are not too far away, the folks here http://www.cpac.org.uk/  maybe can help.

We are there most Weds at 8.00 pm, or there's our public event on March 8th, details in the link.

Hope you get sorted.

Regards, Ed.

[stevend]

In addition to the good advice already given;

- Make sure you have a good power supply, if using batteries make sure they are new (note: as they run down it can make the GOTO play up, an external power supply is a good idea),

- Make sure all your data is accurate; you can get your position from eg google earth, then input date, time & zone (US style, mm/dd/yyyy) etc correctly

Pick your stars; apps like Stellarium and Google Sky for mobiles can help. A planisphere is a good idea. Like ronin I avoid using Polaris. Betelguise , Regel and Castor are ones I have used recently. Though if mainly going out to eg look at Jupiter and/or the Moon I will use Solar System align instead.

[lethbridgeryan]

Thanks for asking this question Ben, Im in the same boat as you.

[lethbridgeryan]

Sorry and thanks guy's for the sound advise.

A little bit of trail and error at first but Im hoping it will get easier with time!!

[BenP]

Wow, I come back hoping for 1 reply and find all this! Thanks!

When I get home from work I will go through this thread and put your advise into practise.

Ronin - thanks for your help, the answer to your questions is that I don't really know. I will have a look tonight although I know timezone is 0.

I live in Boreham outside Chelmsford.  I will try Google to see if I can get a different co-ordinate reading.

Lethbridgeyan - You and me both!

[ronin]

Well Boreham from google is:

Longitude in decimal is: +0.55 or 0.55E

Longitude in degrees is: + 000 33, or 000 33E

Latitude in decimal is: +51.76 or 52.76N

Latitude in degrees is: +51 45, or 51 45N

As said the timezone is 0, you have to supply this.

DST is off, it will ask that when you start the scope up to use it, so not part of the actual setup data.

Sorry about 4 options each for the Long/Lat they are the same but no idea which format the scope wants.

One possible error is that the scope if wanting degrees and minutes (and I think it may) could need all the 0's supplied for longitude degrees, then it goes to the minutes value. Someone a few weeks ago fell foul of this.