SW 200P / EQ5 goto users.....

[Aenima]

Hi folks,

I know the EQ5 is not the most versatile and stable mounts for a 8" newt, especially if you venture into astrophotography.

It is universally recognised as insufficient for long exposure imaging unless you have a much lighter OTA on it.

Yet many people have this set-up, and some are getting good, but hard earned, results from it.

Rather than focusing on what equipment would work better, i'm hoping to hear from those who have found ways to improve and utilise their 200p/EQ5 set-up - the compromises and concessions made in the struggle to achieve pleasing images (or any images at all given the mount's status as unusable for AP in general).

What tweaks and mods have been useful? Are there any ideas regarding the weight issue or balancing that make the most out of the gears and tracking?

There are bound to be limitations, many of them unavoidable, but there are also ways to get around certain issues - a lot of genius diy solutions exist, and determined astronomers on a tight budget can make a big difference.

If anyone with the above set-up can share anything of use I'd be eternally grateful if they could post here or discuss their ideas on the thread.

Every little helps

Any and all replies much appreciated.

Regards

Aenima

[Aenima]

For example,

I have been able to get images of 30sec exposure by using the basic goto 2 star alignment and only rough polar alignment with very little star trailing - though this is without a barlow - and with better polar alignment maybe longer exp. but I'm not sure if using a guidescope/finderscope will make more improvement than fitting a polarscope . . .

Also the counterweights can be shifted depending on which side they are on to help the motors run easier.

Aside from Quartermass there must be some people who have gone this route - possibly before upgrading to the eq6 - and can shed some light on better techniques for using the EQ5/200P for imaging.?

Regards

Aenima

[Uhwaz]

I have that set up too i got 10mins subs with it with about 50% succes rate

recently i bought http://www.teleskop-express.de/shop/product_info.php/info/p229_Mount-for-Cameras-and-Accessories-to-the-Counterweight-Shaft.html

Havent had time yet to try it out properly as i am in middle of buying new house.

Tried just mount guide scope ( ST80 ) inside and it seems much more stable

here is example of m51 i got http://stargazerslounge.com/topic/147320-m51/

hope that helps

on side note, as soon as i have house sorted i am building obsy and getting new mount EQ5 is rly not enough for AP

[cantharis]

Currently I have to carry my gear up a spiral staircase to my observing area. My largest mount is myEQ5 - my poor back couldn´t handle anything more massive - strikes me it weighs quite enough as it is.

[Aenima]

Currently I have to carry my gear up a spiral staircase to my observing area. My largest mount is myEQ5 - my poor back couldn´t handle anything more massive - strikes me it weighs quite enough as it is.

Ouch! thats quite a task. !

Its a good point, the amount of carrying needed to set your stuff up. I really thought the EQ5 was tipping the scales for my size and strength and I assumed the difference between that and the NEQ6 would be one of stability and rigidity, but now I know they are also much heavier as well, its possibly a good thing I stayed with the EQ5 - I have to at least get it out of the flat and through the front door which kills me already, I wouldn't like to try it with anything bigger.

Uhwaz,

That sounds pretty impressive - 10mins - how did you get that long without startrails? I was hoping to get closer to 3mins with strict polar alignment and careful balancing but 10mins is a ridiculously long exp time - even with a 50/50 success rate! - would you be able to describe a little more of what you did to extend your exposure times whilst avoiding trailing of stars?

I'm about to check out your links, thanks for posting - much appreciated.

Regards

Aenima

[Uhwaz]

its all down to polar align , leveling and guiding

i use ST80 as guide scope with MS life cam as guide cam ... then PHD for guiding

thats it rly then just gotta pray for no wind

[Rustmonkey]

I believe you can buy new tripod legs for it too that are stronger and more stable.

[malc-c]

its all down to polar align , leveling and guiding

i use ST80 as guide scope with MS life cam as guide cam ... then PHD for guiding

thats it rly then just gotta pray for no wind

The 200P + ST80 is quite a weight for an HEQ5 let alone EQ5. You must have the thing really finely balanced, and as you say, only able to get results in absolute calm conditions.

[Aenima]

The 200P + ST80 is quite a weight for an HEQ5 let alone EQ5. You must have the thing really finely balanced, and as you say, only able to get results in absolute calm conditions.

Yeah, in all honesty, and not meaning to sound sceptical either - but my scope and finder, with the dslr, seem to be very much at the weight limit, if not over the limit, in my case.

I have heard of people guiding using a 'finder/guider' made from the supplied 9x50 finder and a webcam, which seems to me the way to go with this particular set-up.

Does anyone know how it works, or how best to explain it rather, and how much it affects say, tracking and whether the results might justify the extra bit of work to make it and use it ?

I also heard that a recent version of synscan firmware has a feature that allows for rough polar alignment to be sufficient enough to give longer and better tracking - by 3 star aligning an extra few times (a bit like PAE but for polar) ....... Again, any thoughts on this? Has anybody used it? Its a beta Ver. 3.32 soon to be officially released.

Thanks again to those posted above, apprreciate the input... ta.

Regards

Aenima

[Digz]

Finder guiders work great and are a good way to keep the weight down without the expense of going down the OAG route.

Guiding will essentially mean your subs can be as long as you want (within the limits of your imaging camera, seeing conditions and local light pollution levels). However to make the most of guiding you shouldn't sacrifice good polar alignment, or overload your mount.

[Aenima]

Nice one digz,

This seems definitely a good plan, there probably is a tutorial somewhere - does it have to be an spc900nc?, as i have only one which is in use as a planetary cam, but i also have an xbox, ps3 eye, and a couple others - mostly cheap ones, can it work with a bog standard webcam? Logitech c310 for example?

Thanks again..

Regards

Aenima

[Uranium235]

Finderguiders are a must if trying to guide a mount like the eq5 (very similar to my old cg5). It also pays to have a go a tuning the dec axis to remove any play as once you go 5min+ backlash will be the enemy.

If you have a polarscope, use it. Especially if you have polarfinder.exe (search google for it), that will get you remarkably close PA in a short space of time. Certainly good enough to guide off. Avoid OAG like the plague with this type of mount too, I tried it and it was a long trip to failtown.

Trouble is, with something as heavy as the 200P, one gust of wind would send your PHD graph into the stratosphere.

[Aenima]

Cheers for the pointer, Uranium.

Still very new to dso imaging, and any kind of guiding/tracking so not sure what PHD does, though I know what wind will do to a long exposure, I have actually seen my own pulse beating through my feet on garden decking bobbing jupiter in time with my heart beat ! So with long exposure wind would be like bumping into it. I will be happy not trying it in windy weather.

So, what is backlash exactly and how do I set the handset so its accounted for? I understand PAE but backlash eludes me so far. Is it easy to program goto to allow for backlash, and while I think about it the handset has periodic error correction - another concept I'm wanting to learn about.

Any ideas highly welcome.

Regards

Aenima

[Digz]

Ah yes, wind is not your friend. The slightest gust and it acts like a sail. I need very still conditions to use my 250.

As for the web cam, I'm afraid I'm no help here. I think as long as its a sensitive camera it should work. If you search the forum there are plenty of posts. One thing to consider is also ensuring you have a sturdy way of connecting the webcam to the finder that allows adjustment for focus whilst being secure.

[malc-c]

Cheers for the pointer, Uranium.

Still very new to dso imaging, and any kind of guiding/tracking so not sure what PHD does, though I know what wind will do to a long exposure, I have actually seen my own pulse beating through my feet on garden decking bobbing jupiter in time with my heart beat ! So with long exposure wind would be like bumping into it. I will be happy not trying it in windy weather.

So, what is backlash exactly and how do I set the handset so its accounted for? I understand PAE but backlash eludes me so far. Is it easy to program goto to allow for backlash, and while I think about it the handset has periodic error correction - another concept I'm wanting to learn about.

Any ideas highly welcome.

Regards

Aenima

I think you're discovering the reasons why it was suggested that you invest your money in an HEQ5 rather than the Synscan upgrade.

Firstly you need a sturdy base, this is why most of us who opt for a fixed pier in the garden or observatory place it in or on a cubic meter of concrete. Decking is no the ideal base, unless it's been fitted with extra bracing. If yours is flexing as you claim then you are making imaging hard for your self given the equipment you have.

Backlash is the free movement of the gear train. There will be free movement between the worm and main axis, then between intermittent gears from the worm to the motor. You can train your handset to control the Periodic Error that Backlash produces, or try and mesh the gears better to reduce the slop between them, however you then run the risk of binding if they are too tight. I've never used the PE correction on the handset, but basically it is used to try and calculate the free play in the drive train and the will use the result to provide better goto and tracking.

Finder guiders using webcams are a way of keeping the weight down but really only give good results with bright stars. Modern astronomy do a range of adapters to fit a Philips 900 to a standard SW 50mm finder body. They also do a nice adapter to use the QHY5 CCD camera which is better at picking out fain stars for guiding on. These are £180 new, but can often be picked up for around half that price second-hand.

PHD works by sending pulses to the mount (NSEW) and reading how many pixels the star moved by to calibrate the software. Then it will start tracking on the selected guide star by sending pulses based on the calibration to the mount to counteract the error. Obviously it will have problem calibrating and guiding if the backlash in the mount is excessive

[Aenima]

I think you're discovering the reasons why it was suggested that you invest your money in an HEQ5 rather than the Synscan upgrade.

Firstly you need a sturdy base, this is why most of us who opt for a fixed pier in the garden or observatory place it in or on a cubic meter of concrete. Decking is no the ideal base, unless it's been fitted with extra bracing. If yours is flexing as you claim then you are making imaging hard for your self given the equipment you have.

Nice1

Oh yes, I am definitely seeing why the bigger more stable mount is the right one for imaging, very much so. Though I luckily have a few other options of where to set-up than that decking - which is ridiculously flexible, and so only used for observing - cos just outside my door is a handy concrete area, not the best expanse of sky but enough to sweep for a variety of objects and an ocasional planet or two.

I still feel a little unsure of the practical setting of backlash, though the theory is not hard it isnt the same as knowing what numbers to punch in to the handset, or how to simplify the working out of these things.

Many thanks for the well meant advice, malc, even though I didn't get my stuff together and ended up doing slightly different things, I appreciate your advice, spoken from much experience, and wouldn't hesitate to now suggest that same imaging solution to anyone in a position to make use of it. Also my search for more stable set-up might be delayed but wont be forgotten..

Regards

Aenima

[Uranium235]

Maybe you should refrain from using the handset anti-backlash settings for now. In my experience it usually tends to overcorrect, thats why I concentrated on the mechanical aspect of tightening the whole dec axis up. But try not to attempt that until youve had a good read about it first

[Aenima]

OK. Will do.

The short answer is .. I wouldn't know where to start, ! so regarding those type of adjustments, waiting till I do learn how -- it can definitely wait.

Thanks though, these are new techniques for me, so everything is a great help, however simple it may seem.

Star trail is stopping me getting more than 30secs at a time so until I can overcome this i'm focusing on the basic dso's for now - practicing and experimenting etc.

Still trying to work out flats and bias - for example, as well as deepskystacker, not as easy as it seems.

Anyway, clear sky for a bit at the moment so gonna try another few shots, remembering darks this time

Thanks Uranium.

Regards

Aenima

[malc-c]

Star trail is stopping me getting more than 30secs at a time so until I can overcome this i'm focusing on the basic dso's for now - practicing and experimenting etc.

Regards

Aenima

To be honest, without spot on polar alignment, minimal backlash and guiding, I wouldn't expect more than 30-40 s unguided. Even with the aforementioned, 60s unguided would be amazing !

Let me have a rummage in my accessory box as I think I still have the Modern Astronomy adapter (could be wrong as I had a clear out a while back), if I can find it I'll drop you a PM and we can sort out a deal if your are interested. It might help with the guiding, allowing you to get past that 30 second barrier.

As far as backlash, there are lots of info on the web, but basically it's simply using some allen keys and setting the mesh using a thin piece of paper. It's also worth getting some lithium grease (small tube from cycle shops cost around £4) and apply this to the gears.

[Aenima]

Yeah nice one malc, i'd be interested in turning my 9x50 into a guidescope, as i'm totally positive that my weight issue wont stretch any further. I'm lucky, I think, to be getting away with short exposures yet still having fun and results that arent amazing but pleasing all the same.

Still, from my experience so far I wont be using the EQ5 forever, I kinda got the bug and truth is I would prefer a dob base for visual - and the EQ mount just for capturing images. The equatorial design hurts my bones after a while.

A nice chair and a cup of tea

Regards

Aenima

ps. thanks for the helpful input.

[malc-c]

:sad: - Sorry to say that I can't find it... I sold off a load of bits and bobs a while back and it must of been included in that... but they are only £29 from MA and well worth a punt

[IanSX200]

Hi Aenima

I have the same set up as you, 200p and eq5 pro. I am going to use the 9x50 finder as a guide scope. You can still use your spc900 for planetary, but also for guiding, all you need to do is swap the 1.25 nose piece to the above mentioned adapter for guiding, then swap it back for planetary. I bought one from Bernard at modern astronomy, it just screws straight into the eyepiece end of the finder. Hope that helps

Take care

Ian

[Aenima]

That does sound good.

Cmpared to other ways of guiding, or not guiding at all, its worth looking into. Don't worry about the adapter, Malc, plus you've already been a big source of help and a welcome voice of reason. Once I have the basics figured out - polar alignment, proper capture (remembering darks etc.) and processing, balancing in favour of the RA motor to assist it in moving the heavy scope during tracking etc. then by that time I'll have got some funds for the finder conversion and hopefully have learned how to make use of it.

Ian, thanks its great that the webcam will do both jobs, as it really is a good imaging camera which i'd prefer not to change too much if I can help it.

Regards

Aenima