Guiding conversion project for 200p and EQ5

[RikM]

Do you need the barlow in the guide cam for focus? 9x 50mm finders are about f/4 which is perfect for guidescopes, you get nice a nice bright image and a good wide field of view so you don't have to go hunting for guide stars. Adding the barlow dims the image, narrows the field and make it 2x as difficult to focus. If you don't need it to focus I would ditch it.

PHD prefers slightly out of focus stars because it uses the star disc to calculate the exact centre to get sub-pixel guiding, tighter stars give it less to work with.

Edited January 26, 2012 by RikM

[Quatermass]

The problem is this, If you put the LVI camera in your main telescopes focuser to test it out as I did you will first focus on a star with your standard 25m WA lens and once thats done put in the LVI lens to focus on the star again so the camera will pick up the star. However that reguires a fair old turning down of the focus knobs to get the star in the LVIs lens in focus. It is this that makes it hard to work with the finders scope. It can be done but will require a good diy job to insure you can rack it back and forth to get in focus and have enough back and forth movement to do so. I think a proper guide scope will do a better job having tryed it out tonight but I might be wrong other may have done this and be using the LVI guider with it.

Edited January 26, 2012 by Quatermass

[RikM]

I bought a c mount to straight through finderguider adaptor at £28 from Modernastronomy. Guider Cameras @ Modern Astronomy

I just unscrewed the eyepiece bit off the back of the finder, screwed in the adaptor and then the cam and it was as close to focus as I needed. My QHY5 looks much the same as the LVI so should focus at about the same place?

Is the LVI C-mount, T-mount something else?

I would still get rid of the barlow.

[Stagman]

The problem is this, If you put the LVI camera in your main telescopes focuser to test it out as I did you will first focus on a star with your standard 25m WA lens and once thats done put in the LVI lens to focus on the star again so the camera will pick up the star. However that reguires a fair old turning down of the focus knobs to get the star in the LVIs lens in focus. It is this that makes it hard to work with the finders scope. It can be done but will require a good diy job to insure you can rack it back and forth to get in focus and have enough back and forth movement to do so. I think a proper guide scope will do a better job having tryed it out tonight but I might be wrong other may have done this and be using the LVI guider with it.

Thanks!... Now I'm confused Why not use the LVI parfocal EP in the finder to get focus and then insert the camera and check the focus on screen and adjust as required?

Edited January 26, 2012 by Stagman

[Chris]

Quatermass! you've rocketed through this project mate, and what a lovely clear thread you've made for people to follow, Superb stuff, I would be an idiot not to follow! I see Opticstar stock shoestring products so its good to know you don't have to order stuff from to far away Any idea about the guidescope now with your weight critical setup, I see that Scopes n Skies have several 60mm fracs in their bits and bobs section and the cheapest is a tenner this could work and it would be cheap. It will be interesting to see if the eq5 has the same Dec backlash issues as Stan's eq3? any way impressive stuff you must be buzzing!

[Quatermass]

Thanks!... Now I'm confused Why not use the LVI parfocal EP in the finder to get focus and then insert the camera and check the focus on screen and adjust as required?

Your confusing me now the Parfocal EP is tiny and really hard to look through you have to look first through a 25m EP to get the star in the centre then put on the Parfocal EP. When you do that the star is out of focus so you turn the focuser down to focus in on the star and get it sharp. That done you then put in the LVI camera and it searches for a star and finds one. If you try putting the P.EP in you will really find it hard to get a star in the centre so you have to use a 25 m standard EP first. Well I had to it was near impossible otherwise. But once your star is centred your good to go. I may be wrong more exsperinced LVI user may do it another way.

[Quatermass]

Quatermass! you've rocketed through this project mate, and what a lovely clear thread you've made for people to follow, Superb stuff, I would be an idiot not to follow! I see Opticstar stock shoestring products so its good to know you don't have to order stuff from to far away Any idea about the guidescope now with your weight critical setup, I see that Scopes n Skies have several 60mm fracs in their bits and bobs section and the cheapest is a tenner this could work and it would be cheap. It will be interesting to see if the eq5 has the same Dec backlash issues as Stan's eq3? any way impressive stuff you must be buzzing!

Cheers Chris

I will be much happier once I can start doing some imaging with it but the finder scope needs a major DIY job so you can get the focus sorted out first. I am still a bit concerned about the motors and if the auto guider is moving the declination. I watched both motors when it said it was guiding and the display showed corrections on the x and y axis charts but it was a bit odd. The RA drive motor was clearly being guided it would move forward a bit then move backwards a bit but the Dec axis motor seemed to be hardly moving, I guess thats normal but not sure as I have never done this before. Once I get the guide scope sorted out properly and can take a few images then I will be more certain about the outcome. The 60 ml fracs sound like a good idea I will have a gander and see what they have got. Many thanks.

[Stagman]

Your confusing me now the Parfocal EP is tiny and really hard to look through you have to look first through a 25m EP to get the star in the centre then put on the Parfocal EP. When you do that the star is out of focus so you turn the focuser down to focus in on the star and get it sharp. That done you then put in the LVI camera and it searches for a star and finds one. If you try putting the P.EP in you will really find it hard to get a star in the centre so you have to use a 25 m standard EP first. Well I had to it was near impossible otherwise. But once your star is centred your good to go. I may be wrong more exsperinced LVI user may do it another way.

Thanks again Still confused... Hopefully I will get to try out the LVI over the weekend and report back.

edit....

Edited January 27, 2012 by Stagman

[malc-c]

I have a few questions that if you have time to answer would be great :

1. Do many Guide camera's have a st4 port?

2. You talked about being precise, what would this include?

3. I take it the guiding software will adapt to the motor gearing?

Thank you very much for trying the mod, great money saver.

1) - Most of the dedicated astro cameras from the QHY5 upwards have ST4 ports

2) - Not sure in which context this is referring to. Generally it helps to have the polar alignment as precise as possible to minimize tracking errors

3) - the software doesn't know didly squat about the gearing. What you are doing is using software (once calibrated) to measure the drift of a target star captured by the camera. The software then works out how long a pulse is applied to the mounts axis (DEC / RA / or both) to put that star back where it was, and then sends this pulse to the mount. If you have PHD set to On Camera it will use the ST4 port on the camera to communicate this instruction to the mount. Using this conversion the NSEW buttons on the handset receive the correction pulses and thus trigger the response, almost as if you had pressed the buttons momentarily yourself. It then repeats this over and over again, in a basic closed loop - measure deviation - calculate - send pulse(s) - mount moves - back to the beginning

[Quatermass]

Thanks again Still confused... Hopefully I will get to try out the LVI over the weekend and report back.

Are you trying to focus using the scope or the eyepiece? in other words do you focus the camera first and try to match that?

I could not use the finder scope so I put decided to try the LVIs auto guiding camera on that instead. Because it was easy to focus with it found a guide star first thing. In other words the finder scope did not have a way to focus apart from moving it out of the foam a bit. So looking for better guide scope. Be good to hear how you get on with yours.

[Quatermass]

I bought a c mount to straight through finderguider adaptor at £28 from Modernastronomy. Guider Cameras @ Modern Astronomy

I just unscrewed the eyepiece bit off the back of the finder, screwed in the adaptor and then the cam and it was as close to focus as I needed. My QHY5 looks much the same as the LVI so should focus at about the same place?

Is the LVI C-mount, T-mount something else?

I would still get rid of the barlow.

No Rik the LVI is slightly different as I was going to get the adapter myself. The LVI does not have a removable tube so you have a good inch to focus in an out to get it right annoying but there you go live is often like that.

[Quatermass]

This is correct and therefore I should be able to solder the wires on. I have a few questions that if you have time to answer would be great :

1. Do many Guide camera's have a st4 port?

2. You talked about being precise, what would this include?

3. I take it the guiding software will adapt to the motor gearing?

Thank you very much for trying the mod, great money saver.

I think Malc just answered those set of questions better then I could most guide cameras are st4 port compatible but allways check first, By precise I meant the focusing to find the guide star need to be done accuratly once done your fine.

The guiding is done by my LVI control pad Im not using software on a laptop here. But that can be done.

[Quatermass]

1) - Most of the dedicated astro cameras from the QHY5 upwards have ST4 ports

2) - Not sure in which context this is referring to. Generally it helps to have the polar alignment as precise as possible to minimize tracking errors

3) - the software doesn't know didly squat about the gearing. What you are doing is using software (once calibrated) to measure the drift of a target star captured by the camera. The software then works out how long a pulse is applied to the mounts axis (DEC / RA / or both) to put that star back where it was, and then sends this pulse to the mount. If you have PHD set to On Camera it will use the ST4 port on the camera to communicate this instruction to the mount. Using this conversion the NSEW buttons on the handset receive the correction pulses and thus trigger the response, almost as if you had pressed the buttons momentarily yourself. It then repeats this over and over again, in a basic closed loop - measure deviation - calculate - send pulse(s) - mount moves - back to the beginning

Very intresting Malc so when I was watching the RA motor gears move forward and then back slightly then doing it again and again that was the pulse your talking about being sent by the guide camera as it tracked the star. SO that must mean all was well and it was guiding as it said it was on the display.

You see after it had told me it had found the star it then moved on to the calibrating screen when I pressed calibrate it started to adjust the motors first the RA but then it would stop and say motors not moving! eek. But if when it had found the star and showed me the star and where it was in the cameras view as it was pretty much in the middle I just pressed load and it loaded got ready and said wait. It then told me it was ready so I pressed start and it started guiding with both x and y axis showing clearly on the graph that it was adjusting them both. SO I assume that all is well and it is doing what its supposed to do.

With out being able to put the guide camera onto the diy finder scope come guide scope I could not do any imaging but just wanted to see it guiding. Do you think it was working when it showed this on the screen and the RA motor gears were going forward and backward or am I going slightly paranoid here now..

[malc-c]

The basis of guiding as I understand it (and I'm still a novice) is that regardless of using an autoguider or PC software the system has to calibrate the mount / camera system. It does this by sending a pulse to the mount based on the settings in the software / firmware and measuring the pixels the star moved. If the settings result in a pulse that doesn't move the mount enough to detect movement then this is why the software reports this as an error. Often it's a case of changing some of the guide parameters in the software or re-running he auto-calibration settings again until it starts guiding.

I'm not familiar with your motors used but on my HEQ5 I can't see the motors moving but the mount does sing as the pulses are applied. I can only assume that as you saw both RA and DEC motors moving and the system told you it was guiding then all must of been well ?

Like I said, I'm still a novice and still learning how to tweak setting in the software and getting decent results... but hope that helps

[Quatermass]

Hi Malcolm and all following this thread,

Thanks for that information very helpful. I double checked my pin connection with the recommended setting for the Lvi auto-guider and they are correct. It states in the troubleshooting section on there website the following

(Motor not moving)

The following message is displayed during calibration if:

1. The SmartGuider camera cannot communicate

with your mount;

2. The guiding speed is either too high or too low;

3. The guide star has been lost;

Case #1 - Check your mount compatibility on the chart that can be found in the inner face of the SmartGuider case lid. (DONE THAT ITS FINE)

Case #2 – Carefully take note of when this message is displayed. If it happens

within about a dozen seconds since the start of step 1/6 Moving RA-, the guiding speed must be lowered through your mount control box.

If it happens in a couple of minutes, the guiding speed must be increased.

Suggested values range from 0.10x (10% of the sidereal rate) up to 0.50x (50% of the sidereal rate). (THIS IS THE MOST LIKELY PROBLEM I AM HAVING)

Case #3 - See error message “1.1.1 STAR LOST”.

Case #4 – Adjust your mount as to minimize the backlash between the worm and the gear. Such an error could be displayed during 3/6 Moving DEC+ calibration step.

In my case I think what is happing is the motor is not moving because of the guide speed as the pin connection are all correct. So once I get my guide scope sorted out I should be able to sort out these small issues.

The main thing is I now have set up that I can auto guide with after doing with out one for over a year

Its hard to get used to another way of doing things when you get set in your ways and the extra time needed to adjust those setting makes me wonder how on earth people can sit out there in the freezing cold messing about with a laptop, I just could not do it myself as the lvi auto-guiders control pad is nice and chunky I can keep my gloves on.

More cold weather on the way so the weather man tells me so if you read in the East Anglian daily times about an astronomer being found frozen solid in his back garden it will most likely be me

[malc-c]

More cold weather on the way so the weather man tells me so if you read in the East Anglian daily times about an astronomer being found frozen solid in his back garden it will most likely be me

LOL - I have the luxury of either using the warm room in the observatory, or if it's that cold, can remote into the Observatory PC and do everything from the comfort of the living room, only having to pop out to close the roof up when its time for bed

[Quatermass]

Now thats just taking it easy Malcolm lol still I cant blame you one bit its very chilly out there past 9am.

Any way I have been looking for an alternitve guide scope rather then messing around with the finder scope and came across this one the Orion Mini 50mm Guide scope

Orion Mini 50mm Guide Scope - SCS Astro

It looks like a very tidy solution for a small light weight guide scope which is just what I want for my set up as need to keep the weight down.

What do you think?

[Quatermass]

Dear dear dear... just rang them and the chap was very helpful but the lvi autoguider wont work with it as it wont come to focus. He said his friend makes an adapter for it for 40 quid. I cant afford that so will have to look for a way to alter my finder scope so I can adjust focus. If its not one problem its another sigh.

[malc-c]

Looks good - and not too over priced... If you priced up a SW 9 x 50 finder and bracket from Bern at Modern Astronomy it would only be a fiver less, and you wouldn't get all the fixing hardware that comes with the Orion scope.

To be honest, I might get one for that money and use it on the Mak127 or even substitute it for the ST80

Nice find

[malc-c]

Noo - that's a shame...

But their guider shown in the video doesn't look much different from your camera.

Check out Modern astronomy's website for adapters - I use one to connect a phillips web cam to the SW finder - £29 - a lot cheaper than the £40 you've been quoted http://www.modernastronomy.com/accessories.html

Edited January 27, 2012 by malc-c

[malc-c]

Dear dear dear... just rang them and the chap was very helpful but the lvi autoguider wont work with it as it wont come to focus.

So much for their statement

The Orion-designed Mini 50mm Guide Scope is a complete and compact guide scope solution designed for use with the Orion StarShoot AutoGuider (sold separately) or similar small-chip CCD autoguider devices.

[Quatermass]

There is a problem to be solved with my lvi guider which is the adapter sold by modern astronomy will not fit the lvi guider. The lvi guider has a fixed 1.25 barrel it cant be unscrewed if it could be then it would have fitting that would screw into this adapter. What I have found is there is about a 40mm space needed between the end of my finder scope before it will focus on a star with the lvi parfocal eye piece.

This eye piece once you have found focus on a star with it, provides the correct focus distance for the lvi camera when you insert it. This means I have to have a focuser on the end or at very least a way to move it back and forward by an inch or so to focus. I just love the way everything is so awkward and tedious to solve when it comes to astrophography give you a real sense of accomplishment when you over come all the problems.

[malc-c]

I'm confused (easily done to be honest ) The Orion guider has a nosepiece - 1.25" diameter including filter thread Connectors

The LVI also has a 1.25" nose piece and the ccd doesn't seem 40mm further back in the housing

Both also look like a QHY5

And no eyepiece is used for that, it just bolts onto the end of the finder (OK the nose cone on the QHY5 unscrews) but the focus of the optics fall direct on the CCD. The finder is basically a 162mm focal length (f/3.2) achromatic refractor, so provided the CCD can be placed at or within a range either side of the focal length it should in theory focus ?

[Quatermass]

The adapter wont fit the lvi because the barrel wont unscrew however I have good news. Tonight I got my first guided image by piggy backing my camera to the telesope and focusing the guide camera through the main telescope. 5 min with nice round stars. I then used a loo roll diy effort to try to get the lvi camera on the finder scope this time it worked. But the dam clouds rolled in just as it started to guide dam dam dam

So im sat out here in my shed waiting but getting nice round stars on my piggy backed shot has really made my day I will post the images I get later for you all

Now just need a clear patch of sky ooooh so close now

Sent from my GT-S5670 using Tapatalk

[malc-c]

Glad to hear you're having some success...