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Woohoo!!! guiding with the EQ3-2 !!

stan26

By stan26
in Imaging - Discussion

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stan26

stan26

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Just had my first ever guiding experience, and to be honest it all went pretty smoothly considering.....:)

Its almost a completely DIY approach. Mount as per sig EQ3-2 with dual axis motors, ST4 port added as per shoestring astronomy, guiding using PHD on my PC with GPINT-PT serial interface. Guide scope is home made from an old cut down F13 refractor, guide rings/mount home made from steel canisters, guide camera is an un-modded logitech quick cam pro 4000 CCD webcam. Plus about 15 meters of cables running everywhere :(:o

Total extra cost to go from unguided AP to guided AP......approx £60 ;)

and the results from tonight's test using betelgeuse as an easy start guide star.....I present to you a 5min guided sub picture from the EQ3-2 !!!!!

Well chuffed, now to fine tune everything.....

stan:)

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stan26

stan26

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A slightly better quick PS edit closer crop centre FOV. Its not perfect buts its a start and if anything this 5min sub has more round stars then my usual unguided 30sec subs..!! Obviously pin point stars are going to be a problem with a fast achro as well.

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stan26

stan26

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Thanks guys. Btw just noticed that star below and to the right of betelgeuse which looks like a huge RA tracking error, on inspection of the original size sub its actualy two stars next to each other. Like I said its not perfect, there is a small amount of error but what can I really expect from this setup!....

:)

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stan26

stan26

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Thanks peter, I hope that my progress will inspire people in a similar situation (skint with kids and decide to take up the most exspensive hobby on the planet:D:rolleyes:) so that they to can enjoy AP on a sensible budget. If/when I get round to it I may post up the project in the DIY section in detail.

Although last nights initial testing went ok it did highlight some issues with the setup the main one being the DEC backlash, its horrendous! even though I thought I had tuned it. Some of the first attempts lasted for only 30/40secs before star would just run off up the screen whilst the DEC motor was taking up the slack playing catch up which resulted in a lost guide star. This was helped by tightening the worm gear mesh but its now quite stiff to turn. Got to get my head around how to offset the weight of the scope toward the backlash. Also a few mods to help prevent flex between guide/imaging scope, i.e shim out the guide scope draw tube, make a clamping device to take the cable weight etc etc.

Also one question if anyone can help, With the EQ dual axis controller ST4 mod, when its guiding the little LED light in the centre flickers red/orange/green....Is this normal..??

Thanks

Stan:)

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stan26

stan26

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Thanks guys, Steve it was in your excellent book where I first read about the EQ controller mod and from that moment on the project was on the cards...

Hi ags, thanks, yes it will be interesting to see how faint I can go with the unmodded webcam. Although it's not quite as sensitive as the phillips toucam it has got the better of the two sensors fitted to these models the sony ccd sensor. I ended last night by taking a 5min sub of M42. For this I use the central star on orions belt and it was very bright on the pc screen with no adjustment needed with default cam settings. I could "just" get the brightest stars to show in the sword area but whether or not I could guide with them is another matter. I will update my findings on here when i get a chance to get out under some clear skys again :(

stan :o

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Psychobilly

Psychobilly

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If your using PHD pop up the star profile window and it will show the intensity profile cross section of the currently selected guide star... Guidestars can be too bright although I don't suspect you'll come across this very often with an un-modified webcam...

if its flat topped it's too bright...

Peter...

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angusb1

angusb1

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I was originally planning to use an unmodded webcam for guiding. If you can't guide with PHD due to not being able to find a bright enough guide star you could try using Metaguide. I would stick with PHD if possible as there is so much more support for it and in guiding I've found the best approach to be to try not to introduce any unknowns. If you can't get a guide star in PHD, metaguide may be able to use fainter stars because it does integration in software to increase the effective sensitivity of your camera.

Congratulations on getting your guiding working. Its a very satisfying moment when it finally goes right for the first time, and all the more satisfying when you know your DIY kit is doing the job.:(

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RikM

RikM

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Also one question if anyone can help, With the EQ dual axis controller ST4 mod, when its guiding the little LED light in the centre flickers red/orange/green....Is this normal..??

I suspect that the LED is showing the response to the guide commands in the same way as if you were manually pressing the direction buttons. If so, yes, this is normal.

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stan26

stan26

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Thanks guys. Hey Chris/Quatermass, just imagine what you could do with your EQ5's........:p

Toward the end of the test session the wind started getting up again with some real strong gusts, the problem was amplified on the guide screen with some fairly wobbly moments, poor old PHD was working its nuts off :o But just before I gave up I swung the scope onto M42 and line up the guide scope with Alinam the central star on the belt with an apparent mag of 1.68, this was very bright on the screen with the un-modded QC pro 4000 even though the heavens were awash with moonlight, so I set the 500D to take one single 5min exposure (it would have been rude not to)

A quick tweak in PS to remove a bit of CA and a little stretch/levels. No darks/flats just a single 5min sub. The gradients have been left alone, no serious editing here, just to show the guiding really.

I can't wait to start stacking guided subs!:(

Stan

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Quatermass

Quatermass

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Wow Stan that is very impressive! you have totally convinced me to get my guiding set up sorted this month. I wont be needing a laptop as I have got the LVI smart guider passed on to me by a good friend. I will need to get the dual axis kit and the st4 port modded on but that all seems pretty straight forward. I have a mate who can make me a guide scope holder but can use my finder scope at a push. So going to sell my single RA drive battery pack and controll pad for 40quid if any one needs one just pm me. Let me get this right though, you modded a dual axis kit for the eq3? is that like the eq5 dual axis kit? and was the fitting of the st4 port easy to do?

Heres a picture of the smart guider Its been in the box for over a year now about time it got put to work me thinks ;-)

Cant wait to see what your going to come up with next :(

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Sent from my GT-S5670 using Tapatalk

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stan26

stan26

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Let me get this right though, you modded a dual axis kit for the eq3? is that like the eq5 dual axis kit? and was the fitting of the st4 port easy to do?

Yes I modded my EQ3 hand controller, and yes its exactly the same mod on the EQ5 dual axis controller. The hand controllers are essentially the same, its the mechanical motor side of things where the kits differ. The important bit is - you are adding an ST4 port. ST4 is a particular layout (cable configuration) of RJ12 (network cable) that is widely recognised by astronomers and now manufactures across the globe. A quick read on the LVI site confirms that it use's ST4 so you'll be fine. The important thing is when you make the mod you do to st4 configuration as per the shoe string instructions. All you are doing is adding a port that will in theory take the inputs from the LVI or PC and "press the buttons" for you, like a form of automated manual guiding if that makes sense. Yes it is really easy to do. Theres a nice pretty picture on the Shoestring pdf instructions thats shows you where to solder the wires, i.e Red wire solder to here, Blue wire solder to here etc etc. I didn't even need any solder wire, I heated the existing solder on the back of the circuit board and simply dipped the wire in and let it set!

HTH

Stan :(

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Quatermass

Quatermass

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Ahh I see thanks for that Stan will be putting in my order this week for the bits needed. Do you think I can get away with using my guide scope as a finder scope? Not sure what sort of scope to be using for my skywatcher 200p as a guide scope and if the finder scope will work I could use that I guess. The LVI has a standard fitting for the normal lens hole but my finder scope is much smaller then that. I'm all excited now been wanting to do this for ages just never got round to it but seeing the results you got from just one 5 minute sub of the Orion Nebula was enough to change my mind. Hoping you get a good clear night soon so we can see some more guided goodness from you.

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