Synguider through Finderguider problems...

[AndyUK]

Cheers Sly - I think I was expecting it on a plate (just screw in and off you go), but at under a tenner and a bit of sandpaper, if I do bodge it up, well, it's no more than a bottle of wine. I will wait for the barlow to arrive though (just in case) - I wasn't anticipating attaching the synguider via it's thread though, I was going to use it via nosepiece (so I could parfocalise it). Anyway, after having tried out the 102 (tonight maybe) I'll see if I can try that and if it doesn't work, I'll get the sandpaper and PTFE out.

Good luck with the 12" dob,,, but hope you don't carry it too far...! Visual work for me is very difficult - Even the less fainter DSO's are tricky from the garden - Aside from the obstacles (houses, trees, hedge) I'm directly effected by 3 sodium lights (one 20yds away) and next door's security light which gets set off every 30 mins by one of the plerthora of cats around here. Unfortunately our dog's asleep by then (idle git!) but I'd also fear for my kit if he were up as I seem to be breeding cables as time goes on.

I have added a .22 air rifle to my Astro kit wishlist though - Every garden astronomer should have one...

[MikeWilson]

I have added a .22 air rifle to my Astro kit wishlist though - Every garden astronomer should have one...

Is that the .22 light pollution filter? I hear it's quite effective.

[MikeWilson]

Hi Mike - As you say, there's a lot of similarities between our requirements and constraints... I'm not sure if you've seen this, but checkout this link http://stargazerslounge.com/sponsor-announcements-offers/114910-new-skywatcher-kit-incoming.html

[EDIT - Ah, I see you have seen that link...!]

Have seen

I wonder how much lighter they will be, given how heavy the mirrors and focussers are. There are no set date or prices yet either.

I think my weight concerns are worse than yours as my CG5 max payload is stated as 12.5Kgs whereas the HEQ5 is stated at 18kgs. I'd be seriously pushing the max on mine, and I know that FLO etc note that the bigger reflectors act like a sail and have an uncanny knack of picking up any breeze that might be about, so my future plans for a 200 plans may already be scuppered (maybe in a couple of years time when the EQ7 hits the streets the second hand market will get flooded with unwanted EQ6's? I wish...!)

I didn't realise the HEQ5PRO had a heavier payload than the CG5, thanks for clearing that up. I had presumed that the CG5 was just a noisier equivalent (although my HEQ5 sounds like a coffee grinder at the start and stop of slews).

And I too, like you, are looking forward to all those lovely cut price EQ6's.

I bought my HEQ5PRO second hand from someone downgrading to an EQ3, but there are usually plenty of them on astrobuysell from people upgrading to an EQ6.

However, with your ST80 weighing a whole kilo less and the HEQ5's extra 5.5Kg capacity, I'd reckon you should get away with it (but don't take my word for it!)

If your ST102 is being relegated to guider-duty, might it be worth considering offering it as a swap for a second hand ST80. I'm sure there are ST80 users out there who might want to upgrade their primary scope for "free" - and as part of the trade you'd shave off 1kg of weight and maybe get a few quid in addition to put towards more cables.

Best,

Mike

[AndyUK]

... Yes, and actually even better than a Hutech IDAS LPS as it's 100% effective (and also 100% effective against "security light" bandwidth too).

Unfortunately they are quite expensive... and having learnt from a previous experience (when I was 16), if you shoot from your own garden, they're traceable back to where you live. Lesson learnt - Don't shoot from own back garden...

[AndyUK]

I wonder how much lighter they will be, given how heavy the mirrors and focussers are. There are no set date or prices yet either.

All I saw was summer 2011 - I doubt I'll have the cash saved up by then anyway as I'm sure it'll be more than the £300 odd for the PDS (and then of course there'll be my mount capacity issue). Still, a 200mm/f4 - I've been looking at the Orion version - It'll be interesting to see at what price they pitch it

I had presumed that the CG5 was just a noisier equivalent (although my HEQ5 sounds like a coffee grinder at the start and stop of slews).

I'd heard that the Celestron goto's were somewhat noisier, but fortunately I bought the non-Goto model (part of a package with the 100ED) and then added an EQ5 goto upgrade, so the drive is actually Skywatcher... However, regreasing with lithium grease actually made quite a difference, but as you say, sometimes at the start of a goto slew it does sound a bit horrible!. Although I'm very pleased with what I have (and I'm sure it'll last me a couple of years or so), I sometimes do wish I'd manaqed to find the cash to go all-out and get the EQ6 from day one... Still, never mind.

If your ST102 is being relegated to guider-duty, might it be worth considering offering it as a swap for a second hand ST80. I'm sure there are ST80 users out there who might want to upgrade their primary scope for "free" - and as part of the trade you'd shave off 1kg of weight and maybe get a few quid in addition to put towards more cables

That's certainly food for thought - I hadn't thought of that... Thanks!

[simon84]

No carrying involved with the dob, it will be stored in one of my shed approx 4 feet from where it needs to be for using. I'm going to put some nice wheels on it. I've got my best mate helping me out with building the base, so I should be alright.

I see now, I forgot they have a nosepiece, been forgetting alot lately.....it wont take much to get that adapter to fit, hoping mine will be here tomorrow so that I can get on with it, I do love these little sitting down jobs I can do, building a PC to control everything with and decided to strip a few old towers and pillage the best bits from each.

I have a few street lights which are dealt with by using the astronomik cls ccd filter, works really well but I'm itching to try an idas p2 filter. I've also got very high walls as im on the side of a hill which shields everything from direct light, its just the glow to contend with.

I hope you get the adapter sorted though, looking forward to hearing how Peter gets on with his one.

[MikeWilson]

Bigger and heavier than I expected. But it's so cute and the colour is amazing my wife will love this little scope

Smaller and lighter than I expected!

Can't wait to fire this all up later!

[Psychobilly]

Take your time setting up a parafocal EP first use a bright star - vega perhaps although it will be close to the Meridian... early this evening... but gives you a chance to make a start in twilight...

Pity SW just didnt supply a cheapo parafocal EP with it out of the BOX...

Peter...

[MikeWilson]

Take your time setting up a parafocal EP first use a bright star - vega perhaps although it will be close to the Meridian... early this evening... but gives you a chance to make a start in twilight...

Pity SW just didnt supply a cheapo parafocal EP with it out of the BOX...

Peter...

The manual almost alludes to there being a parafocal eyepiece in the box. It does at least include a 1.25" eyepiece extender as well as the parafocal eyepiece ring.

Thanks for your suggestion on getting started at twilight. I will use one of the stock skywatcher eyepieces that came with the ST80 as a semi-permanent parafocal eyepiece. The 20mm LER one will do nicely, I think.

[adamsp123]

An interesting article???

Auto Guiding

[AndyUK]

Sly

I hope you get the adapter sorted though, looking forward to hearing how Peter gets on with his one]

Me too... but my skies are looking a bit naff at the moment - Hope Peter has better luck... And Mike, now that it looks as though christmas has arrived early for him too...! I'll just be playing with the 102 and synguider tonight (trying to set up a parfocal eyepiece and then seeing how easy it is to focus and how long it will track for)... If only these bl**dy clouds disappear!

Mike - Good luck tonight with the new kit - As I don't think I'll be able to get out tonight, perhaps you can let me know how easy it is to focus with the parfocal eyepiece. One think I nearly got caught out on though was the noise setting out of the box - It was set REALLY high and I couldn't see a thing. When I checked the noise setting and brought it down to c. 5 everything then appeared!

[MikeWilson]

Not bad... not bad...

Just a few small clouds for a small telescope.

Peter - sorting out a parfocal eyepiece is the first order of the evening, thanks for the tip. AndyUK - let me know how your 102 works out. I reckon you'll find it easier to get a guide star than me! Thanks for your tip about reducing the noise meter level too.

Fingers crossed I'll be able to see a single small blob on the display tonight!

[Psychobilly]

Had some really heavy squally showers here so everything is soaking wet so might have to abandon plans for the test tonight its supposed to clear up after dark but dont fancy crawling round in the wet grass / mud

[MikeWilson]

No sooner did you write that did the heavy showers start down here too and tonight was looking so promising.

The forecast shows heavy showers for much of the next hour but clearing from 8pm to be totally clear overnight. However with temperatures around freezing, I'm not sure I'm going to be doing much in the way of imaging.

However I really do want to play with my new toys, so I will be out if even for an hour or so.

[simon84]

Crystal clear here today and tomorrow by the looks of things but seeing as I have only been up about an hour I dont think I'll be outside playing tonight. I feel like rubbish. lol. Good luck to everyone else though. I hope you get some good results from your guiders.

[AndyUK]

Hi both - Ditto weather-wise here... However, as I'm not imaging but simply trying out the parfocalised synguider on the 102, all I really need is a couple of clear hours. I'm thinking if I leave it another hour or so I might be lucky (although setting up in the dark and in the wet / mud doesn't exactly fill me full of confidence!).

Mike - I'm pretty sure you'll do better than my first time out using the finderguider (although I still haven't QUITE given up on that route yet!)

Clear skies to all - Andy

[Psychobilly]

Will it Rain Today? | Rain radar for the UK | Going to rain? | Meteogroup

[AndyUK]

Hi Sly - I didn't want to seem unfeeling - Our posts crossed over. I'm sorry you're still feeling a bit crook... I have similar forecasts too, but I'm not going to hold my breath - I'm supposed to be clear now, but it's p*ssing down . I suspect it'll be nice and clear about 1 or 2am, by which time I'll either be asleep or polishing off a bottle of wine (I'm on annual leave this week!)

Peter - Thanks for that link... If it's reliable, it looks as though I could set up in about 30 mins (although there's not a star, or moon, visble anywhere at the moment (... how lucky do I feel?)

[simon84]

Dont be daft....lol. I get plenty of that from the wife....*duck* that was close.

Full of cold at the moment, kicked in at about 3am last night whilst I was dreaming of sticky toffee puding

Just stuck my head out of the window and its as miserable as sin. Where do they get these forecasts from. Its just total nonsense and I always thought that metoffice.gov.uk wasnt too bad......

[AndyUK]

I hope you haven't got the one I had - Caught it in Dublin and had it for 2 weeks. The only good thing that came about as a result was that it kicked me over the edge to stop smoking (not counting, but now 24 days...). I've told the wife (who hasn't quit) that I'm going to save the money I would have spent so that I can see a growing incentive and then in a year's time I'll blow it all to reward myself. By my calculation, that should just about cover an NEQ6 Pro (and if I can get it 2nd hand, maybe I can get another OTA as well ). Hope you kick it soon - Night nurse and port is my usual cure (unless I have to work the following day )

[MikeWilson]

A smoking habit costs almost as much as a astronomy habit, you say? Wow I wonder what wine, beer and coffee cost me if I added it all up.

Anyhow - I'm suffering with dry eyes/throat/skin caused by the dry air in the house and the central heating being on most of the time. So I can empathise with not feeling 100% right now. So I went out into the garden - it's 3 degrees celcius out there and the ground is sodden. To cap it all there are clouds in the sky too.

I'm tempted to velcro-fasten a laser pointer to my scope and set up indoors in the dark in order to test the guiding.

EDIT: Needless to say that BBC weather forecast is a lie! It's totally off on cloud, temperature, wind and precipitation.

[AndyUK]

Well, I just had one of THE most frustrating mini-sessions. The clouds appeared to have left the building at 21:00, so I thought I'd have a go at testing the 102. I got everything set up, 3 star aligned and then slewed to Capella. I put the synguider in, set the noise to 0 and the exposure to 2048ms and was rewarded with a big white blob, which I was then able to focus (result 1!)

As "the blob" got smaller on the screen, I lowered the exposure setting which eventually I lowered to 16ms in order to keep the brightness under 100. I then centred (using zoom factor 3) adjusting the focus at the same time [Note: as a comparison when trying to use the finderguider on Aldebaran, the lowest exposure I was able to get was 2048ms, so I was obviously WAY out of focus!]

I then removed the synguider, put it in a 10mm eyepiece and within a minute I had a parfocal eyepiece [Result 2]. So now to try out a lock and guide...

M45 wasn't far away so I slewed to it with a 32mm, centred it and then put in the parfocalised 10mm and refocused. Then I replaced the 10mm with the synguider... and 3 or 4 stars immediately appeared on the screen [Result 3]. I centred one of them and zoomed in on it to centre further (raising the noise level on the way, and lowering the exposure to 256 in order to lower brightness to below 100 - done). I then locked it and went to guiding and selected auto calibrate... after c. 30s the scope synnguider went into guide mode [Result 4]

It stayed guiding for about 10s and then lost the star (). The screen displayed no stars (), so I decided to put the synguider back into preview mode and try and refind/centre a star... Unfortunately I then found that the mount was locked out and I couldn't use the EQ5 handset (), which was somewhat annoying, but of equal concern was that where there had been stars before, now there were none - I lowered the noise to 0 and raised the exposure to 2028, but still nothing... and then I look up to where M45 should be - THE BL**DY CLOUDS HAD MOVED BACK IN!

Looking around at the sky, the clouds were scudding over from the North West but I thought I'd try again. However, as the mount was still locked out, I first unplugged the synguider (still locked out) so then unplugged the synguider from the ST4 port (still locked out). The only solution was to switch off the EQ5 goto and realign again... With clouds still scudding over, I decided not to bother and called it a night.

It took about 15 mins to pack away, and just as I was bringing in the mount... The skies were crystal clear again .

I couldn't be bothered to set up all over again (I was sure there were probably clouds just waiting for me to set up), but aside from the fact that the last (and arguably most important) aspect of my test wasn't run, it certainly proved that, for me, it's FAR easier to focus using a parfocal eyepiece than guessing on the focus using the synguider screen and also the addditional aperture (50mm to 102mm) makes it MUCH easier to pick not only a star but I can see will enable the selection of smaller stars (thus allowing for longer exposures so not chasing the seeing...)

I'll obviously still need to have another go tomorrow night to complete the test (weather permitting of course!), and possibly there are some objects which may be fine guided with a stand-alone through a finderguider (ie horsehead nebula with Alnitak as guide?), but I think I now know that I need to buy some guiderings and a dual plate (or rings/dovetail) in order to guide with the synguider.

[MikeWilson]

Thanks for the report, Andy! I almost feel like I've lived through your experiences with you.

I managed to read the manual [result 1] and install the ST80 finderscope to the main OTA scope rings [result 2] and after removing the ST80 and attaching the synguider, I went into the garden and by hand I pointed the scope wildly around the sky - at Jupiter and the moon mostly. I saw that the synguider could detect light and even where it was coming from. However I couldn't hold the scope still enough to try it out on a star.

Regarding focussing - my understanding is that you do have to focus the synguider with the scope first and then establish the parafocal eyepiece after? Therefore there's no way to be absolutely sure that you're in optimal focus.

Andy, can I ask you a question about the field of view for guiding with respect to your main OTA? Do you have to have a star at or near the centre of the field of view in order to lock it or will a bright dot off centre or near the edge of the field be sufficient?

Did you pick the guide stars yourself or did you allow the synguider to automatically select a guide star within the field of view and guide off that? (This is what I'm hoping I can do).

In any case, I will have a shot myself tomorrow night (weather permitting) and will let you know my own experiences then!

[MikeWilson]

The ST80 is mounted sturdily although I can't really move it at all. I accept that I may be limited to guiding on stars near the centre of the ST80s field of view which might limit image composition a tad.

I'm also not quite sure about the orientation of the Synguider. I've read the manual which suggests a method of calibrating the horizontal travel with the RA axis (or was it dec?) and I suppose once I know for sure I'll probably just tighten everything up and semi permanently leave the Synguider attached.

I'm also wondering if this would work better without the diagonal, too (although that may make the display harder to see when pointed anywhere above the horizon).

[AndyUK]

Hi Mike - I thought I'd stay awake just in case, but it looks like it was fruitless (the clouds have fully rolled in)... The ST80 on the reflector looks great by the way (colour co-ordinated too!)

Regarding focussing - my understanding is that you do have to focus the synguider with the scope first and then establish the parafocal eyepiece after? Therefore there's no way to be absolutely sure that you're in optimal focus.

1. Bringing the Synguider to Focus

During setup, I aligned the finder scope with the guidescope and then 3-star aligned. The 1st thing to do is select a bright star (choice is yours - I went for Capella this time, although last time went for Aldebaran) and slew to it using an eyepiece (I used a 12mm illuminated reticle but I guess any eyepiece will do as long as it's more or less centred )

Remove the eyepiece and insert the Synguider - I used it with the included extension tube and used the diagonal (as it made it easier to see the screen - It may also mean less of the focus tube is extended(?))

I then followed the directions in the manual (using the main EQ5 goto handset to centre the star in the crosshairs on the Synguider whilst setting a long(ish) exposure (I chose 2048) with 0 noise). Note: You may need to turn the crosshairs on using the Synguider menu.

This is where a "blob" appears on the screen which may well nearly fill the screen. By playing with the guidescope focuser, not only does the blob get smaller, but you'll also see the brightness figure get higher. If / when the brightness gets higher than 100, I found it helped to lower the exposure (that way the refresh is less and you don't have to wait so long between adjustments). Eventually you'll get to the stage where adjusting the focus makes the star slightly bigger going either way and also the brightness amount drops either way. You can then zoom in and make further focus adjustments (although you may need to use your goto handset to re-centre the star at this stage). When at zoom level 3, you'll again get to the stage where adjusting the focus makes the star slightly bigger going either way and also the brightness amount drops either way.

This is when the Synguider is considered to have achieved optimum focus. I screwed down the focuser on the guidescope and then moved to the next stage.

2. Creating a parfocal eyepiece

Carefully remove the Synguider, attach the parfocal ring around your eyepiece and insert the eyepieceinto the diagonal. Using 2 hands (one holding the parfocal screw on the ring and the other to raise the eyepiece) you can get to the position where the eyepiece is in best visible focus (which you then lockdown with the parfocal screw on the ring).

Andy, can I ask you a question about the field of view for guiding with respect to your main OTA? Do you have to have a star at or near the centre of the field of view in order to lock it or will a bright dot off centre or near the edge of the field be sufficient?

Well, the manual notes that it's best to have the guide star as close as possible to the centre of the crosshairs, and I must admit I've been following it more or less to the letter and not tried seeing if it will lock onto one that's on the edge of the screen (although being honest, I can't say that the stars I've locked on have been absolutely bang dead centre... ). However, when it starts guiding, the screen automatically goes to zoom level 4 (a 64x64 screen), so I'd imaging that the guidestar must be pretty close to the centre when zoomed out otherwise when it zooms in, it won't be in that FOV...

The first time out, when I'd slewed to the target and then framed the subject on the main imaging scope with the goto handset, I then used the finderscope adjusters to centre a guidestar (as obviously you can't keep using the main mount goto handset to find the star else you're image framing would be off!). However, the manual does mention you needing to raise the noise adjustment level to minimise the number of stars in your field of view on the screen (otherwise the synguider may get confused and lock onto a different star), which would seem to imply that it doesn't have to be absolutely bang centre...

This is the reason though why I'm going to buy some guiderings so I can choose a star potentially a fair way off from my chosen imaging subject (ie maybe outside the zoom level 1's 512x512 pixels)

Did you pick the guide stars yourself or did you allow the synguider to automatically select a guide star within the field of view and guide off that? (This is what I'm hoping I can do).

There's nothing mentioned in the manual about auto-guidestar selection, and I suspect if it were possible, it would have said as that would be an incredibly useful feature! However,all I can say is that it's not something I've tried - Again I've been following the manual to the letter and manually choosing my own guidestar from the first preview screen (noise 0, zoom level 1, exposure (say) 1024 to start with) and then centering it... Once I've managed to finish this test with the 102 guiding itself, I'll give it a whirl to see if it will lockdown on a star firstly somewhere in the inner quarter of the screen and then again further towards the edge (both as only star in view and also where multiple stars are visible).

I've read the manual which suggests a method of calibrating the horizontal travel with the RA axis (or was it dec?) and I suppose once I know for sure I'll probably just tighten everything up and semi permanently leave the Synguider attached.

I haven't done this yet, but that's only due to laziness - It's very simple... All you have to do is rotate the Synguider in the eyepiece holder so that when using the mount handset the star moves E-W and N-S as opposed to NE-SW and NW-SE. Unfortunately this would need to be an "every time" adjustment as you'll need to swapout the Synguider with your parfocal eyepiece when initially finding your guidestar... (although Having said that, I think centring a guidestar will be much easier with guiderings)

Well, that's it for me - Still cloudy, so a bit of shut-eye (maybe tomorrow night will be kinder)