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No south views what to do

bendiddley

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bendiddley

bendiddley

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Hi all. I've recently become interested in ap and having spent a good few weeks looking into it, reading loads and finding about how to get started I have come to a bit of dead end. Today I discovered that to get precise polar alignment one needs to drift align, and to do that one also needs a view of the southern celestial equator for the southern star alignment. Well unfortunately I don't have that from my garden. I can see Polaris well and have ok views north, East and west, but no south at all because my house is in the way, not even higher up than the equator. So is that the end of the road for me? Or is there another way of getting round this problem?

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Leveye

Leveye

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My Ioptron ZEQ25GT's handset has an alignment routine that requires no direct view of the pole star. If you autoguide you'll need to get close with your basic alignment using your true north/south position not magnetic, alt and of course balance and you might be alright. All you need to do is use a computer with the camera's view to "nudge" the mount to point basically where you want it to be and then use a guidescope with a camera and PHD to autoguide while locked onto a guide star.

.

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bendiddley

bendiddley

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But he has a 200P Dobson!

Am I wrong in thinking that unless there is a field de-rotator for the alt/az mount then no amount of drift aligning will even work?

Thanks all so far. Forget the Dobson though. I'm planning on selling that to help fund the ap expenses. The plan was to start with a dslr and eq5 mount because that's all I can afford, then get a 130pds and continue with unguided ap, then later down the line upgrade the mount get a lap top and guider and start guiding and seeing where that takes me. Not sure the first reply is going to work as I can't afford a go to mount. In response to the second. I had thought about wide field but if I get the bug I'm going to be shtuck if I want to take it further. I will be doing wide field though to start so that's good to know it will work but what happens after that?

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PorkyB

PorkyB

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A good polar alignment will get you exposures of 1-2 minutes with a 130PDS on an EQ5, a very careful alignment will give 2-3 minutes.  There is a lot you can image with that.  I have never felt the need to try drift aligning.

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bendiddley

bendiddley

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A good polar alignment will get you exposures of 1-2 minutes with a 130PDS on an EQ5, a very careful alignment will give 2-3 minutes.  There is a lot you can image with that.  I have never felt the need to try drift aligning.

That's good to know but lots of people say you'll eventually want longer exposures and need to guide, which is when I would need to drift align. I am interested to know what you have achieved without drift aligning, have you got any photos?

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RichM63

RichM63

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Got it Ben, we are on a similar path. My final bit of kit at this stage will be the DSLR due to arrive in September.

Apart from the DSLR and AstroEQ all of my kit is S/H, quite a bit bought from members of SGL. It has taken me all of this year to get to this point, save, search, save, search.....

Regards the South view problem, when I look into the DIY Observatory section I see that most people have them in a back garden and thus have a house or trees in the way at some point, which leads me to conclude that something is possible.

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ollypenrice

ollypenrice

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There are lots of alternatives to drift alignment. Not having a view to the south is not a major problem. As stated, get a polarscope and be very careful to get it correctly aligned within you mount. (Point its crosshair at a distant tip of a spire or whatever and watch it as you rotate in RA. The crosshair must stay in the same place. If it describes a circle simply adjust it till it doesn't.  Then find the polaris position for your location, time and date http://www.trutek-uk.com/takahashi/polarisfinder1-2en.htm  and put the star in the right place.

I do drift align because I have an excellent site but if you ask on here about software polar alignment packages (I'd put it on the imaging discussion boards) you'll get lots of answers.

Olly

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Tinker1947

Tinker1947

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A HEQ5 would be the right mount to start PA with starting with a EQ5 will just lead to upgrading, a second hand EQ5 would be better there will be little loss of money should you decide AP is not for you or if the bug bites you want to upgrade, a second hand HEQ5 would of course be ideal, on the NEQ6 built into the handset firmware it has the ability to Polar Align on and star in any part of the sky, i don't know if the HEQ5 has the same option somebody on here will come along and say yes or no.

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Fogagen

Fogagen

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A HEQ5 would be the right mount to start PA with starting with a EQ5 will just lead to upgrading, a second hand EQ5 would be better there will be little loss of money should you decide AP is not for you or if the bug bites you want to upgrade, a second hand HEQ5 would of course be ideal, on the NEQ6 built into the handset firmware it has the ability to Polar Align on and star in any part of the sky, i don't know if the HEQ5 has the same option somebody on here will come along and say yes or no.

+1 for this.

At £250 difference new, it may take you ages to be able to upgrade, but overall the expense will be worth the wait. Even 2nd hand, the HEQ5 will serve you better, I reckon. I have struggled with my EQ5 for 2.5 years, backlash in DEC is a major problem, and I'm finding drift alignment is the only way I can get to 3min exposures and above - the reason being that PHD is unable to cope with the amount of backlash I'm getting in DEC and shuts down N-S guiding.

However, polar re-align from the handset CAN work very well, and is present in the EQ5 Pro, but I was finding it rather random in whether the results were any good or not.

How high above the southern horizon can you see?

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bendiddley

bendiddley

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Cheers guys. Blue straggler I see you use a guider, do you get away with not drift aligning then? I thought you needed to if you were guiding as well because of the longer exposures, also you say 1 - 5 mins, is that a typical amount then for suburban skies, so even if I was to drift align or start guiding that's all I would get regardless? Tinker, thanks, I was thinking of second hand to start with and then a second hand heq5, but I appreciate Fogagens point about the eq5, I have heard mixed views about it, however I thought that because my kit would be under 5kg, it wouldn't be a problem, didn't know about the dec backlash thing though, that's a bit off putting, useful hearing about that though. The view of the south I get if I am to keep polaris in view is about 65-70˚, below that is my house/neighbours house, big tree etc. Ollypen rice, can you enlighten me on an alternative to drift alignment? Also anyone got any pics of stuff taken that wasn't drift aligned?

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AndyKeogh

AndyKeogh

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Cheers guys. Blue straggler I see you use a guider, do you get away with not drift aligning then?

I am currently testing some guiding configurations on an eq6 but the same principles apply. I am not using drift alignment.  I do check the mount alignment at the start and end of each session and tweak the polar alignment. I am using a zenithstar 70 with a lodestar and achieving 4 arc seconds peak to peak.

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AndyKeogh

AndyKeogh

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 Also anyone got any pics of stuff taken that wasn't drift aligned?

Here is one of my test shots at 60s exposure with guiding but no drift alignment.  The moon had not yet risen  so I guess my light pollution is pretty bad.   ISO 1600.  Guiding used 2.5 second images with PHD2 and pulse guiding via EQMOD.

Note the attached picture has been reduced by a factor of 7 on each axis so detail is  limited. I have attached a full resolution crop of the centre so you can see there is no trailing

post-3505-0-54421600-1408184421.jpg

post-3505-0-52359200-1408185248_thumb.jp

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PorkyB

PorkyB

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have you got any photos?

I don't normally need an excuse, but since you ask my good photos are on my Flickr page, see the link in my signature.

I agree with the advice above, buy second hand if you can.  That way you get to use the kit for as long as you want and then sell it for to close to what you paid for it.  I bought my 200P and EQ5 for £300, planning to sell it when I upgraded. Two years later I still haven't found the need to upgrade, but I have bought a couple of additional scopes. 

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Tinker1947

Tinker1947

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This is Vega single 600 second image, the NEQ6 Polar Scope aligned to Polaris then adjusted to put Polaris in the bubble, the Polar Scope its self has never been aligned, guiding by way of  PHD, ST-80 and a Lodestar, Mount NEQ6, Scope 10" Newt.....taken some time back prior to having a permanent set-up  in  Obby, so the alignment need to be good but not perfect.....

IMG_1377.jpg

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ollypenrice

ollypenrice

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This is Vega single 600 second image, the NEQ6 Polar Scope aligned to Polaris then adjusted to put Polaris in the bubble, the Polar Scope its self has never been aligned, guiding by way of  PHD, ST-80 and a Lodestar, Mount NEQ6, Scope 10" Newt.....taken some time back prior to having a permanent set-up  in  Obby, so the alignment need to be good but not perfect.....

IMG_1377.jpg

Split diffraction spikes say you're a bit out of focus there.

Olly

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