Guiding, guiding and more guiding...

[swlloyd3]

...questions

I have a number of questions with regards to guiding that I hope some people may be able to help me with! I am looking to get up to roughly 3 minute exposures.

1) How critical is polar alignment? (currently setting Polaris onto the circle in the polar scope based on its location at current time in stellarium... this seems to work ok for upto 45 sec exposures with my canon eos 1000D and Megrez 72 unguided)

2)Does the finder/guide scope need to be aligned perfectly with the imaging scope?

3)Do I need to set EQMOD/ASCOM interface to 'tracking' or leave PHD to deal with that? (The reason I ask this is because I attempted to guide last night but found that when PHD said it was 'guiding' the mount didn't seem to be making much noise and the image produced had very elongated stars, indicating no guiding. So I click on 'sidereal rate' in the tracking options on the interface and it seemed track better but still off and this was only 1minute exposures.)

Upon my second attempt (PHD froze first time:mad:) the mount seemed to be making lots of little sounds like mice running around BUT I had put 'sidereal' tracking on in the interface and as a result the images had weird movement on the stars, not perfectly elongated but in strange directions. I can only assume that PHD worked this time but was conflicting with the interface option I had selected (couldn't turn off to check because the laptop crashed!)

I think my main issue is the crappy laptop that freezes on me when I use PHD time to get a very long USB lead and sit in the comfort of my house!

Ste.

[Merlin66]

More info needed....which mount? which guide scope? which guide camera?

Answers:

1. The better the polar alignment, the easier the guiding becomes....

2. Doesn't matter, as long as you can find a suitable star to guide on....

3. Can't answer without more info...

[swlloyd3]

Sorry here is the equipment details:

Mount: HEQ-5 PRO

Scope: WO Megrez 72

Guide Cam: Phillips Webcam SPC900NC

Guide Scope: Finderscope 9x50

Ste.

[Merlin66]

OK

using the webcam as a guide obviously needs the computer to "talk" to the mount - which cabling do you use? I can help if its a shoestring adaptor to the ST-4 port on the mount.....if you're using a EQDIR module and EQMOD - sorry no experience...

[themos]

(currently setting Polaris onto the circle in the polar scope based on its location at current time in stellarium.

You are taking into account the fact that the polarscope view is inverted, right? So, if Stellarium shows you Polaris being west of (left of) NCP, the polarscope would show it to the right of NCP?

[mark7331]

To answer point 3) - yes and sidereal rate should be selected by default. If it isn't select it. I've switched it off by accident before and PHD says it's guiding but it's not.

[swlloyd3]

@mark7331 - Excellent will make sure it is selected next time

@themos - my god I am stupid I had not taken that into account!!! Damn I feel stupid!

@Merlin66 - Yes it is EQDirect/EQmod - But like I said I don't think the problem is in the connection with the mount as it seems to track/slew fine through stellarium and I get no error messages in PHD to suggest it has not connected properly.... It is most probably a Mixture of bad Polar alignment, computer performance and inexperience! Will take into account all of the mentioned next time I can get out with the set-up!

Thanks to all!

Ste.

[themos]

If it's EQMOD, there is a pop-up that helps you align the polarscope and shows you what you should expect to see in the polarscope.

http://eq-mod.sourceforge.net/docs/PolarScopeAlignment.pdf