What should I do with my LX200??

[philipok]

hi All

I wondered if the 'Lounge could advise on my situation:

I have recently installed a run off shed and pier mount for my 12 -year old 10" LX200GPS.  It's a great location - looks south, has a nice horizon, has a warm room with all the cables run under the floor.. nice.  Even has a radio, heater and whisky supply (Cadenheads small batch Glenrothes, if you're wondering).  I've had some really nice views of Venus, the ISS, some deep sky in Leo etc..  

I'd really like to get into imaging (likely on a fast WO Zenithstar mounted on top) beyond DSLR stuff.. But I had a very long and frustrating night last night - my Meade seems unable to track or maintain enough control for PHD2 to calibrate.  It's also beginning to lose its GOTO capability (not that I really mind, I much prefer manual).  Basically it seems all over the place (although the optics are fine)

But as I was trying at 1:30am to make the PHD drift trendline go down for the umpteenth time, I asked myself - am I wasting my time?  Life is too short..

I'm loathe to take out the Meade and sell/dismantle having build the obsy around it.  

What would members advise on next steps - bin the Meade??  Mount the OTA on something else?  Buy a new one??

I'm just not skilled enough to open up the Meade and conduct open heart surgery on gears and worms..  sadly.

I do love the visual stuff, but I wouldn't mind being able to take a decent widefield image ..

Thanks for any suggestions!

Philip

 

 

[chaxastro]

Hi Philip,

I've never been a Meade fan, so my suggestion would be to bin it! (OK, that's not really helpful)...

If I were to go for a SCT would probably choose a Celestron. But they (as with the Meade equivalent)  are usually long f ratios.

Probably a short refractor would be a better bet. As to which one..... hmmm. Lots to choose from and depends on your budget of course!

Am about to launch into the field of astro imaging myself, now my mount and pier are done.

Hope that helps...

chaxastro

'Humour is reason gone mad!' Groucho Marx

[philipok]

thanks Chaxastro..  

I should have been a bit clearer.. I have a couple of lovely short refractors (ZS66 and ZS61) that I plan to piggy back and shoot through, using the lx200 to guide (with a focal reducer).. 

so i have the refractors.. it's more the control of the mount that's my issue!
Cheers

philip

[chaxastro]

3 minutes ago, philipok said:

'so i have the refractors.. it's more the control of the mount that's my issue!'
 

That's OK Philip

I assume the Meade is on a fork mount?

chaxastro

'Humour is reason gone mad!' Groucho Marx

 

[chaxastro]

30 minutes ago, chaxastro said:

'it's more the control of the mount that's my issue!'

 

 

Back again, have re-read your initial query...

Assuming the Meade is fork mounted(?), then I'd recommend replacing the mount.

A decent GEM such as an AZEQ6GT https://www.tringastro.co.uk/sky-watcher-az-eq6gt-pro-synscan-mount-eq6-539-p.asp

(that's the mount I have, got it last year just before the price increase) or one of the SW EQ6 range. Should easilt take the Meade OTA if you intend keeping it.

Be interested to hear what you think...

chaxastro

'Humour is reason gone mad!' Groucho Marx

[philipok]

now there's an idea.. looks very capable indeed, and could take the weight.  

Also Tring Astro is down the road, so that's easy 

The only mod I'd have to make is to the pier plate 

Thank you for the suggestion..  any idea how easy it is to remove the OTA??

 

Best

Philip

[philipok]

now I've started looking, maybe even the Sky-Watcher EQ8 PRO head... 🤪

 

[chaxastro]

4 minutes ago, philipok said:

'any idea how easy it is to remove the OTA?'

'now I've started looking, maybe even the Sky-Watcher EQ8 PRO head... '

 

Firstly:

As for removing the Meade OTA, suggest you trawl YouTube, chances are someone has done a video about it. Or hopefully someone on here can answer that one. I know it can be done...

Second;

Beware the EQ8!!!, they have issues!

A friend of mine has had a hell of a time trying to get the GOTO to function properly, still isn't working properly after a couple of years. Also, no built it polar finder (mistake in my opinion) As above, look on YouTube, you'll see what I mean...EQ

That's not to say the AZEQ6 isn't perfect. There are glitches (from what I've read on here and elsewhere online).

Despite that, its a darn sight cheaper than the EQ8!

If I were you I'd go for the AZEQ6GT...

Tring Astro is my local supplier (I'm in Aylesbury) Where are you based?

chaxastro

'Humour is reason gone mad!' Groucho Marx

[philipok]

thanks Chaxastro - I'm in Great Missenden.  

The AZEQ6 looks ideal in fact.. only issue is whether the height of the viewing platform would drop compared to the fork mount (and I might lose some horizon..) will need to measure.

 

thanks for the help!

Philip

[chaxastro]

1 hour ago, philipok said:

'I'm in Great Missenden.'

 

Small world! I drive past there most weekdays, I work in Gerrards Cross.

That is, when we're not in lock-down!

So is your LX200 fork mounted? You haven't said either way...

If you have any more question, feel free to message me.... 😉

Regards,

chaxastro

'Humour is reason gone mad!' Groucho Marx

[michael8554]

Hi Philip

What makes anyone think it's the Meade mount that's the problem, not inexperience, and that switching to an AZEQ6GT will miraculously solve the issues?

You'll have exactly the same  learning curve with that mount. 

Look at all the posts here where inexperienced EQ mount owners are struggling with Lat/Long/Date settings, with PA, with worm adjustment, with wrong EQMOD settings ?

It seems the norm on this site is to rubbish Meade and promote Skywatcher.

You'll get proper help if you Itemise your difficulties rather than generalise.

Michael

[dannybgoode]

2 hours ago, michael8554 said:

What makes anyone think it's the Meade mount that's the problem, not inexperience, and that switching to an AZEQ6GT will miraculously solve the issues?

If the OP wants to use it for imaging the Meade fork mount isn't particularly suited and an GEM is the much better option.  The AZEQ6GT is an excellent choice for a 10" Meade - I know, I have that combo  

For pure visual work I would agree with you...

[philipok]

hi Michael/Danny - All very good points - and yes, inexperience is an issue.  I know my way around the sky, but am no expert in imaging.  mainly done easy DSLR stuff to date.  

I'm sure Chaxastro has a valid personal preference for gear (as do we all)..  I'm still fond of the Meade is I've had it so long (and had so many great views)

Michael said be specific - so here I go:

- It's fork-mounted - counterweighted and balanced well in Dec, biased towards the East in RA (with weights on the forks)

- guiding with an old Meade DSI plugged into the LX200, focal reducer of 6.3

- Zenithstar 66 sitting on top in rings

- reasonably good drift align by hand (I think)..  

- Guide rate of .66 (60%) as default

- No PEC, no backlash compensation on handset

What I've noticed is that I get a considerable drift in RA (tends to be more East);

PHD2 throws up an orthogonal error (maybe because of the Periodic error?) and calibration is never good.  And then the RA/DEC is all over the place.

So there's basic problem.  But maybe if I can get it guiding taking 30s-1m subs on a fast refractor won't be too much of a problem - what do you think?

Philip

 

 

[michael8554]

Hi Philip

Most of that sounds okay.

Balance Dec slightly off to take up the Dec Backlash

The RA drift will be Periodic Error.

Worth training and then updating the permanent PE Correction in the mount, something for a moonlit night 🙂

Up the Guide rate to 0.90 to help PHD2 corrections.

Polar Alignment needs to be down to about 5 arcmins.

ST4 or ASCOM guiding ?

If ST4 then run a Calibration every night and every time you change targets.

You mention Calibration is never good. Before Calibrating you must move north at slowest slew until you see the guidestar move, to take up Dec Backlash before you Calibrate.

Then run the Guide Assistant before guiding, accept the recommendations.

Have a read of these Best Practices from the PHD2 Developers:

https://openphdguiding.org/phd2-best-practices/

Post a Guide Log that includes a Calibration and Guide Assistant run, then 10 minutes of guiding without tweaking, at around Dec 0.

Again a good use of moonlit nights

Michael

Edited May 8, 2020 by michael8554

[Davey-T]

Is it on a wedge of some sort ? I've been imaging with mine for years, the main problem is balancing the thing especially if you piggy back stuff on it.

What are you guiding with ?

Dave

Edited May 8, 2020 by Davey-T

[philipok]

hi Michael - this is a really good checklist to go through - thanks for your input.  I will report back

Dave - it's on an astro engineering mega wedge, on a rock solid pier.  Bubble shows level.  Have ADM counterweights under the OTA.  It 'feels' well balanced (ie. I can put it in any position and keep it still - aside from the intentional east RA bias)

The intention is to guide with the LX200 (with a focal reducer), and image with the ZS61 and something like a ZWO 183c (one shot colour).. nothing too complex, just wide field.

Philip

[Davey-T]

Still using PHD1 with mine, got it set up so it only does north corrections.

Dave

[Nemo9]

https://www.cloudynights.com/topic/631350-how-to-remove-8inch-ota-from-lx200gps-fork-mount/

My lx90 came apart very easy and it's surprisingly light on its own

[michael8554]

4 hours ago, philipok said:

it's on an astro engineering mega wedge

Me too - built like the proverbial brick outhouse....... 🙂

Michael

[philipok]

On 08/05/2020 at 23:22, michael8554 said:

Me too - built like the proverbial brick outhouse....... 🙂

Michael

Well - since that post I used a moonlit night to hit the drift alignment and PHD2...  the scope was heavy south, biased east RA

Did two runs of PEC training with PHD2 in charge

Managed to get PE down to 0.8 arc min, with peak to peak RMS/PE of 13.81" (according to the Guiding Assistant over 120 seconds).  I guess that's not unusual for a Meade

by 1am.. Guiding RMS was about 1.52" (not great I know, but at least I've got a decent guiding graph)..  Dec line is now dead flat.  Increasing RA aggr to 85% seemed to help

My only confession is that I instructed PHD to ignore the orthogonality error and assume the axis were perpendicular

work in progress...  any other suggestions on tweaking the PHD settings? or more PEC training?

Philip

[philipok]

I meant of course - Polar alignment error down to 0.8 arc mins..

attached is a picture of my last graph ( i know people usually post logs)

[michael8554]

Hi Philip

Good to see you're getting there.

Afraid your tiny image is not much help, a guide log would.

The image shows two RA spikes, then it settles down.

The RMS figures only report on the section of guiding in the window, so if you'd carried on guiding until those spike had left the window, you may well have seen much better RA RMS.

Was this guiding based on Guide Assistant recommendations ?

6 hours ago, philipok said:

My only confession is that I instructed PHD to ignore the orthogonality error and assume the axis were perpendicular

Depends on how much it was out, which the guide log will show. After Calibrating you could go to Tools / Review Calibration data and make a judgement before guiding, often that warning can be ignored.

4 Seconds exposure is a bit slow.

Michael

 

[philipok]

hi Michael - thanks for the reply - yes it was based in GA, with me also tweaking the RA aggr up a bit.  I'm chuffed the Dec I can leave alone now (switched off guiding Dec at one point).  So you recommend shorter exposures.. ok - will try that - maybe 2 secs?

Might also update the PEC if I get a nice smooth guiding graph

philip

[philipok]

btw - have you used Pempro?  I downloaded it and pulled the PEC  curve from the lx200 - it looked terrible - 100" deviations. But I guess that's the curve that resulted from the 2x training I did ?

[spillage]

Hi @philipok,

If you want to do long exposure imaging then the meade mount will restrict you. If you are thinking of an eq8 then I would go down this route. The new ones now have a belt on RA and DEC so the dreaded DEC backlash should be sorted and as you would be connecting the mount to your pc the mention above about goto issues will be eliminated. It should also manage the meade and wo scope without much effort.

If I could afford the eq8 then I would have one.