Synguider - HELP??!!!!

[rocketandroll]

I've just got back in from the most frustrating night I've had so far in astronomy.

Now I wasn't expecting using a Synguider for the first time to be easy... but nor did I expect it to be impossible.

If anyone who has (successfully) used a Synguider can help... that'd be awesome...

So, here's what happened:

I got everything mounted on my HEQ5, Meg72 with DSLR attached, ST80 next to it. Got it polar aligned and tracking.

So, I follow the instructions and first try to get the ST80 pointed at a star and in focus with an EP in...

Problem 1:

The ST80 can only achieve focus with any EP I have about 1.5" beyond it's maximum outward travel of the focuser tube. Right, why is that? Surely such a scope is designed to actually be able to be focused? I didn't have a diagonal in there, firstly because I don't HAVE a 1.25" diagonal, secondly because the Synguider doesn't work with one so I assumed I should focus it without one in there to get the light path roughly the same length?

Having bodged an extension tube I get a 1.25" 9mm ep to focus, now the next stupid thing...

Problem 2:

The Synguider instructions tell you to 'use the EQ mount's hand controller to slew it until a bright star is in the middle of the field of view'... erm, well, I've just pointed it at the target I want to image... if I move the whole damn rig to point somewhere else, get it guiding on a bright star, then re-point it at the target, surely it'll then not be pointing at the bright guide star and will stop guiding?! This is totally insane and makes no sense... I assumed the sensible thing would be that you used the Synguider handset to scan around the field of view of the chip to find a suitable star?

Anyway, I find a relatively bright star fairly near the target, point it directly at it, swap to the Synguider.

Problem 3:

How on earth do you know if the Synguider is in focus or even seeing anything for that matter? I did as instructed and adjusted the noise level down to just above where it was noisy (about 4 IIRC) and set the exposure to 256ms. I have no idea how frequently the Synguider refreshes, but I tried moving the focuser in and out slowly... nothing, no stars, no nothing. After a minute I left it to re-read the instructions. When I returned it said it had a star, brightness 6 (way too low to guide) but a dot was visible top right.... hooray I thought, at least it's in focus... nope. I then tried focusing it better, in and out... the star (one pixel) stayed the same... no change to anything. I then tried moving the mount to center it... it didn't move. About ten seconds later the screen went blank again.

This was getting stupid, I'd so far wasted about an hour.

I decided to just try and prove if the Synguider was working at all, the moon was coming up so I pointed it at Alkaid... very bright and in almost the opposite direction to the moon.

Again, I got it in focus and dead center of the field of view with the 9mm ep. Switched to the Synguider.... nothing.

I tried focusing in and out... nothing, no stars, no response, zip. Again I went to look at the instructions... came back, lo and behold, the same 'star' was back, exactly the same pixel, same location, same brightness. Clearly it wasn't just chance there was a feint star in the same place, I am guessing it's reading a hot pixel as a star or something?

Anyway, after an hour and a half of messing about, I gave up.

I have no idea why the thing never saw any stars, even when it was pointing at one of the brightest in the sky.

Maybe I was doing something stupid?

If anyone can shed any light on this I'd very much appreciate it... my imaging time is scarce and very valuable to me... I can't waste two hours every time I want to image messing about with this thing only to fail to get it to work at all.

Help... someone... please :-(

Ben

[Stephen]

That's a whole big angry post, it may help to condense it to the simple questions

First up, the ST80 is designed to be used with a diagonal. If you aren't using one, nothing will come to focus. A synguider comes with a t-thread to 1.25' adaptor which means you can use it with a diagonal. If you aren't using a diagonal, you need an extension tube.

Secondly focus. I found it very easy to focus the synguider once I had a star on the chip. When it's as small as possible, it's focused. Also start off with the exposure high (2048ms or 4096ms) then turn it down gradually keeping the brightness (BRI) above 10 (IIRC from memory.)

Thirdly aiming : If you have your main scope pointed at the target, and there isn't a star on the synguider, then you have to adjust the guidescope. This can be done with guide rings for example.

Finally true focus. If you got the 9mm EP to focus, I highly doubt it's the same focus for the synguider. When I use mine, I have an 80mm t-thread extension tube AND the focus racked out about 3/4 the way. Was yours anywhere near that far out?

[rocketandroll]

That's a whole big angry post, it may help to condense it to the simple questions

First up, the ST80 is designed to be used with a diagonal. If you aren't using one, nothing will come to focus. A synguider comes with a t-thread to 1.25' adaptor which means you can use it with a diagonal. If you aren't using a diagonal, you need an extension tube.

Secondly focus. I found it very easy to focus the synguider once I had a star on the chip. When it's as small as possible, it's focused. Also start off with the exposure high (2048ms or 4096ms) then turn it down gradually keeping the brightness (BRI) above 10 (IIRC from memory.)

Thirdly aiming : If you have your main scope pointed at the target, and there isn't a star on the synguider, then you have to adjust the guidescope. This can be done with guide rings for example.

Finally true focus. If you got the 9mm EP to focus, I highly doubt it's the same focus for the synguider. When I use mine, I have an 80mm t-thread extension tube AND the focus racked out about 3/4 the way. Was yours anywhere near that far out?

Sorry, it was a little 'angry', only because after a wasted evening, I was a bit :-)

My confusion about the diagonal was simply that A: no one had mentioned needing one, or an extension for the Synguider, B: the Synguider, I assumed, would be somewhat confused by looking through a diagonal, and C: the instructions tell you how to make a parfocal EP to always get focus right... which will only work if the only thing you're changing between the EP and the guider is the EP itself, ie: if you took an EP out once focus was set, then took the diagonal out too, it'd clearly have been pointless, so I assumed you could switch between the two. Anyway... no probs, I'll get an extension tube or diagonal asap.

As for the focus... my worry was not being able to see ANY stars in focus or not on the Synguider at any point in the focus range.

I will definitely try upping the exposure length, that may help.

Is the screen showing the chip in real time? My concern was, if it refreshes once a second or something, as I focus in and out I may well pass the focus point between refreshes and it never show the star. Isn't 2000ms two seconds?

The home-made extension tube I made was about 50mm+ long, certainly with that, plus the focuser at full reach, it never seemed to reach focus (apart from the hot pixel it thought was a star).

I will get an 80mm extension and that may help... maybe it never reached out far enough?

I only have a small amount of movement in the ST80 because a number of people said the Synguider chip was so sensitive it really didn't need to be in guide rings as they'd never NOT found a guide star with it pointing straight ahead at the target.

Ok, well, many thanks for the help.... I'll grab myself a big ol' extension tube, whack the exposure time up and see how we get on... fingers crossed!

Ben

[Psychobilly]

I feel your pain...

You can use a diagonal with the Synguider - the orientation all gets sorted out durign the claibration process - Infact It makes using it a bit easier as it saves crawling round on the floor to look at that pathetic display...

You just want to make nothing moves.. I tape the connections once it's all together...

I use a 12mm reticule EP for the parafocal EP.. The center 50% circle is very roughly the same FOV as the Synguider... but you have the advantage of a wider fOV for guide star location.

Peter...

[shaunster]

Good luck with a synguider, horrible things...

[Psychobilly]

Here's mine on the ST80...

By removing the lens from thhe barlow that came with the scope you can use it as an extension - I get the Synguider focused with the drawtube racked out about 55mm ...

Peter...

[rocketandroll]

Ok... so, I'm still really worried that there is something wrong having failed to see anything even pointing straight at Alkaid and having definitely gone through the point at which it should focus.

What should I do or expect to see when it does get to, or near, focus?

If it's set to 2000ms+ exposure then it can only be refreshing every 2 seconds, if I scroll through the focus range too fast I'll miss it being in focus easily as it refreshes, won't I?

All I've ever seen is a blank screen... what should I see? What should it do?

Still concerned I'm gonna waste another whole night trying to get it to work!

Ben

[malc-c]

I went through similar pain last night with a QHY5, and had USB connectivity issues to boot... however, with help from the guys here, and perseverance I finally got the thing focused. Keep at it and I'm sure you'll nail it soon

[philj]

As has already been said the ST80 needs a diagonal, I actually use a SW barlow body as an extension, works a treat.

By all means slew the scope to your target for imaging but you must then shift your guide scope to a bright star for the synguider to work on. If you cant adjust your guide scope independantly of your imaging scope then your taking a chance on having a guide star in the fov. You need adjustable guide scope rings or similar.

The synguider chip is small, you may think the guidestar is centred in a 9mm ep but it wont necessarilly be on the chip when you swap, also there are alot of things that can move when you swap from ep to synguider. I used an illuminated reticule 12mm ep and eliminated any play in the focuser.

Next..... I sold the synguider because it was such a pain and faff and went the QHY5 route which was up and running and imaging within 10 minutes on the 1st light

Sorry but I found the synguider a faff and autoguiding should be and is alot easier than this.

Philj

[Psychobilly]

Ben,

Try the connection method I have suggested with the focuser racked out to the same distance... start on Vega if the exposure setting is too long and the sky not properly dark you may end up saturating the sensor... Adjust focus for the min size on screen then drop the exposure and tweak again...

Like Phil I use a 12mm reticule EP the reticule's inner circle closely matches the FOV of the Synguider...

Perhaps I need to revisit the review and put a caveat on it seeing as so many people give up on the Synguider - I don't use mine as much as I should but bought it for computer free guiding of a EQ3-pro - which as it turns out suffers from guide port problems anyway - Skywatcher are working on a fix but have given up on seeing it any time soon... If they ever fix it I might get to use the Synguider a bit more...

Camera based guiding on a lappy is so much easier and the guide star can be anywhere in the FOV so you don't have the faff of moving the guide scope to centralise the guide star or slewing and compromising your main subject framing - I could live with that as the setup was for wide field work at short FL's...

Peter...

[rocketandroll]

Cheers all, and thanks Peter for your ongoing help :-)

I'm gonna give it one more stab the next clear night we get, see if I can get it working and actually take a long exposure... that'll be the eureka moment.

If I still can't get it to work, or I find I do have to physically move the scope or the mount to find a guide star... I will be giving up on it too.

I only got it because a couple of people both stated that it was sensitive enough that they had never had to physically move the guide scope to find a guide star, which I assumed meant I could frame my target, then worry about picking a guide star within the FOV of the Synguider...

I'm pretty **** about framing stuff so I'm not gonna be happy having to move the mount to find a guide star.

I'll start a new thread about plan B now.... :-)

Ben

[planetdnb]

i had all the same problems when i got mine and ended up just as angry/frustrated as you.

I needed a 4" extension tube to get focus and keep things rigid.

My biggest issue was that i wasnt actually centering the star properly. After i bought an illuminated centering eyepeice the job became easy.

anyway, another thing to adjust is the noise setting.

bring all the way down to 0 and the screen goes black. Then raise it up 1 at a time until the blackness goes. (Usually between 6 and 10 for me). You will see some black specs which are more likely noise than stars but a star like vega will be obvious if its on the chip.

[rocketandroll]

Cheers all

Well, I have a diagonal for it now, hoping that's enough to get it to focus.

I did try dropping the noise as low as it'd go... about 3 or 4 for me was where the noise dissapeared, so that's where I left it to keep maximum sensitivity.

Looking like we may get a couple of clear nights Friday onwards over the bank holiday so I'm gonna go out and give it another go then, see if I can get it working.

Ben

[planetdnb]

concentrate on centering the star, that's where I really went wrong!

[rocketandroll]

concentrate on centering the star, that's where I really went wrong!

Hmmm... With next to no movement in the scope and needing to keep my target well framed (not wanting to have to slew the mount around) thats my big worry.

Ah well... Lets see how it goes!!

Ben

Sent from my GT-I9100 using Tapatalk

[daneinsane]

Hi,

Any update on this....having the same problems...did you succeed.