Some questions

[dpastern]

OK - I'm new to a EQ mount scope, but not to astronomy. I've just invested in a SkyWatcher Equinox ED100 and a EQ6PRO setup. My main interest is astro imaging, which I'm completely new to also. Since I'm new to an EQ mount, that means polar aligning is alien to me.

1) Balancing the scope in the RA axis is straight forward. In theory, it's also straight forward on the DEC axis. But - due to the scope etc, it doesn't balance very well. I really need to move the OTA further forward etc. That means loosening the tube rings etc, and moving the scope. Sound easy? Yes. Was it easy? No. I've basically loosened the large knurled bolts on the opposite side to where the hinges are. The hinges simply will NOT open. I loosened a few other screws, which I didn't think would make a difference, but there's no harm in trying. Nothing. I know these suckers should open up, but how to do so, is beyond me. There must be some very illogical, non-obvious trick to it. SkyWatcher's user guides are, well, pathetic imho.

2) the other thing that is catching me out is aligning South. Here's my understanding. Get mount. Align due (not Magnetic) South. Set latitude on the mount. Level mount. Attach OTA. Balance mount in box axises. The basics are fine - it's doing them where I'm coming undone.

a) I have a cheap compass - how do I use it to find due South not magnetic South?

b) I don't have a southern polar reticule unit unfortunately, it seems that it shipped with a northern one. I have asked Andrews about this, and Lee has said that they'll follow it up, but I haven't heard back from them and it'll probably get forgotten as not being important. Apparently, Andrews is not an official distributor for SkyWatcher, hence the cheaper prices. Tasco Australia has confirmed this. They will not help whatsoever. A product is a product, no matter where you bought it from, and a customer should receive the same service & support irrespectively.

Is it totally necessary to have a southern reticule, view through it, align it with the southern celestial pole etc? Or...

c) just ignore b) and do a basic 3 point alignment after the initial setup of the scope/mount, then do a drift alignment for further refinement?

I want to really get more info astro imaging, and that means an accurate polar alignment.

At the moment, I do not have a guide scope, nor autoguider, nor am I using PHDguide. Eventually, I'll invest in that sort of gear, as well as a CCD imager (probably a cheapie Orion to start and learn with). For the moment, I'm imaging using my DSLR (Canon EOS 1D Mark IIn), no guiding, limiting shots to 30 seconds. Obviously I'm getting star trailing etc. I had my first run last night with the scope, and had a lot of fun. Took a few images, this was the best:

http://www.macro-images.com/web/_DN_1977.jpg

Any help would be appreciated.

Cheers,

Dave

[darrellx]

Hi David

I like the shot of M42. Quite good.

Having walked the same path, this is what I did to overcome these problems.

I balanced the OTA in the tube rings, then on the mount (I have an EQ5), I simply move the whole assembly forward or back at the dovetail. Seems to work fine. Depending on what I have on the scope, it moves forward or back by maybe an inch either way.

On the issue of finding the SCP, I tried the compass thing and compensated for the magnetic variation, but I had trouble lining up on something. If you want to use the compass, you will need to find the magnetic variation for your location, then either add or subtract the value from you compass reading. So anyway, I used the Sun. I got a straight pole 2 meters long; found the centre point of where I wanted to place the EQ5, then at midday held the pole vertical using a spirit level and marked out the shadow. You will need to compensate by around 12 minutes because you are not in the middle of the timezone. This got me very close. I refined the placement over a month or two to confirm the calculations. Then I drift align. I have since maked the spots on the lawn where the tripods legs must sit.

I have a southern reticle, but I don't use it.

Hope this helps.
Darrell

[acropolite]

You can save the guesswork by determining solar noon as described in this post (http://www.iceinspace.com.au/forum/showpost.php?p=66749&postcount=1).

[dpastern]

Darrell - yeah, I tried sliding the dovetail, but it still doesn't balance properly, hence wanting to move the OTA forward inside the tube rings.

Thanks for the advice on South etc, much appreciated. At least I was thinking along the right lines ;-)

Dave

[barx1963]

Thats a very fine first effort, certainly compared to mine!
Did you do any processing?

I can't offer any advice as I am a raw beginnmer in the imaging game as well, just very impressed ith the shot!

Malcolm

[troypiggo]

G'day Dave,

As you know, I'm no pro, but I might offer some words here.



Silly question, but when you loosened the knobs opposite the hinges, did you swing them out of the ring slots? Say you have the scope sitting across your lap with the hinges on the opposite side of the scope to you, the knobs are closest to you. You loosen them up and swing them towards you. The knobs themselves are hinged and only fixed to one half of the tube rings. Hard to explain, hope you get what I mean.



I'd change the order a little. Align South, level mount, then set latitude etc.

In Brisbane, magnetic deviation is about 11 degrees east. So with your compass you want to stand behind your mount (facing roughly south), and align your scope 11 degrees left/east of where the compass needle is pointing south.



You don't need it. In the city it's too hard to make out Octans with all the light pollution anyway. Just do the above rough alignment, then do a drift alignment.



No.





Drift align first, then 3 star alignment. Drift aligning is to get your mount aligned with SCP. You need this before you worry about 3 star alignment.

[dpastern]

I did a basic levels/curves adjustment, and some smart sharpen, but that was it. Very basic. I did another take on the image last night, but there's so much noise in the shot, and not really enough data to work with, that bringing out any of the fainter nebulae isn't really possible, not without killing the black point in the image, and introducing lots of noise. Pity.

At the moment, I'm limited to short exposures, in reality, probably no more than 15 seconds, due to innacurate polar alignment, no drift alignment to cure it, no autoguider etc. Current gear will be paid off in 4-6 weeks time, which will leave me money to then get a guide scope, autoguider unit, and then play with phdguide. EQMOD will come later.

Troy - I've tried what you said with regards to the tube rings, they simply won't budge. I surely must be doing something wrong :( it's too late tonight, but I'll try and grab a shot tomorrow night of the tube rings and what I've done, so people can see.

Thanks again to all that replied.

Dave

[dpastern]

Troy, thanks for the info on the offset of the south pole vs magnetic south pole. I couldn't remember how many degrees it was. Aligning via solar noon should hopefully fix things though :-)

I've read that the latitude adjustment on the SkyWatcher mounts is not that accurate. I've seen a photo of a spirit level that electronically measures this, but cannot find one online to buy :( Since I'm still using the scope at home, and I've already set the latitude, I presume I don't have to reset it everytime I go out observing ;-)

I would have thought the better order would be:

rough polar alignment
3 star alignment
drift alignment

Dave

[troypiggo]

No, drift align first. Gets the mount axes in the right direction first, then 3 star align to tell the computer where the stars are. If you 3 star first, then drift align you'll stuff up the computer's star locations.

[dpastern]

Will do.

Dave

[darrellx]

Dave

Just on the accuracy of the mounts (latitude), my EQ5 was just over 10 degrees out on the scale. I was really confused when I couldn't get it to track properly. I read here somewhere about the inaccuracy. The solution which I used was to get an A4 piece of heavy paper and mark out the 28 degree angle; cut it so it was obvious; then held it up against the mount and scope aligning the bottom edge to horizontal. An easy and cheap way to check. But you are right - once set you don't (shouldn't) need to do it again. I check mine every month or two just to make sure.

Darrell