choice o fEQ mount considering autoguiding for astrophotography

[spearo (Frank)]

Hello fellow stargazers (and capturers)
My first post !

I have a thousand qustions but I'll start with this:
A bit of background: I've been reading up a fair amount, I own a 100mm spotting scope used for some (bad) astrophotos (planetary) and aim to move up in the world...

I'm still debating internally over which type of scope to get, the pros and cons of each are driving me batty!

I'm beginning to consider one alternative more seriously ie the scope mounted on a good (great) german equatorial mount for astrophotography.

I understand that reviews and opinions place such mounts as the Losmandy and Tak as "up there" amongst the best of the best...they're also a bit pricey...
I understand their worm drives also account for the increased accuracy. But is the praise they receive mainly related to their outstanding performance UNGUIDED?


Question:
I'll keep the question simple and probably add to it later depending on feedback.
If I hooked up an autoguiding system to an "inferior" mount (compared to G11, TAK, etc) (either using a nice CCD such as SBIG or Starlight express or even just a TOUCAM etc) wouldnt the tracking be fine even in long exposures?

I think some mounts can make more frequent corrections per second. I could be way wrong...

Would it be a matter of considering an EQ mount that
1) can take input from auto guiding
2) can obviously handle weights etc of scope/equipement etc
3) isnt outrageously "bad in terms of gears /bearings etc/


Any input will be greatly appreciated.

Sincerely
Spearo

[[1ponders] (Paul)]

Hi Spearo.

Much of it will depend on the type of photography you wish to do, Very wide field (piggyback), wide field (short tube refractor, short fast newt) or deep imaging with long focal lengths. Naturally the smaller the imaging system (wider field) the less demanding on the mount for accuracy and weight bearing capacity. Deep field imaging need to have very accurate tracking.


While Losmandy are good mounts there are much better ones around. It's just that they are considered relative good price for moderately good pec and carrying capacity. This is probably the main reason they get high praise and are so popular. If you want "top" mounts look towards the Astro-physics mounts. But be prepared to pay for them and wait for one.

Unguided accuracy depends on a number of things, low pec, accurate polar alignment, good balance and a mount that is suitable for the weight of your imaging equipment.

Using a poor mount even with the best autoguiding doesn't nessessarily equate to good imaging. The worse the pec the more and great the correcting needs to be. This is not a good option. The idea is to keep the guiding adjustments to a minimum. The mount that is getting the most attention these days is the EQ6 with skyscan. It seems to be doing a good job for a relatively small mount.


You don't have to have autoguiding, but it is important to have some sort of motorised tacking that can be controlled by a hand box while you manually guide through a reticle. However having a mount that is capable of taking autoguiding instructions is certainly a bonus and makes image capture much easier.


Balancing weight and carrying capacit is important for successful imaging. As a guide a mount should only carry between 40 - 60 % of its carrying capacity for imaging. The difference in % depends on the quality of the mount.


As I mentioned above, try to get a mount with as small a pec as you can afford. While autoguiding will certainly help, but it's better to not to have to make any corrections than to continually make corrections.

[JohnG (John)]

Hi Spearo and welcome

I really cannot add much to what Paul has said except to say, if you are looking towards autoguiding I would be inclined to get a mount that has an ST-4 compatable autoguiding port, you will get a wide ranging set of options for guiding then. The only other thing I would say is that even the real top end mounts will suffer from PEC, just that it will be a lot less than cheaper mounts, and, you pay big time for that.

Welcome to the world of spending.

JohnG

[h0ughy (David)]

EQ6 and up !! search the site there is heaps on the topic. paul is a sad Losmandy supporter, I opted for the Eq6, there are Vixen guys and some others that are home made. just ahve a goo search and you will find heaps

[spearo (Frank)]

Thank you Paul, John and Houghty for the very quick replies.
I have been considering the HEQ6 with upgrade. Best price at Andrews?
What do you think of the Meade LXD-75 10 inch F/4 model SN-10AT as a package overall-is the mount good?
I'm obviously starting to think away from fork mounts on wedges...
thanks again
spearo

[[1ponders] (Paul)]

Originally Posted by spearo

I'm obviously starting to think away from fork mounts on wedges...
spearo

They have their place especially if you want to take your scope away and have a quick setup goto scope, yet have one that can be converted to imaging. They aren't an ideal setup for imaging though. If you are serious about imaging then Equatorial mount is the way to go. Yes they can be expensive when compared to some fork/wedge combinations, but IMO it will do the job much more effectively.

There are a couple of members here who image with LXD75s. Hopefully they will pop by and give you their impressions

[JohnG (John)]

You might want to get in touch with Astroboy, Zane is not far from you. You might get a few ideas and directions.

JohnG

[[1ponders] (Paul)]

Also maybe contact Itchy. He uses the 10" SN with LXD75

[h0ughy (David)]

Originally Posted by spearo

Thank you Paul, John and Houghty for the very quick replies.
.............................
thanks again
spearo

Who isthis Houghty character, what mount Does he have probably and EQ1.

Please don't commit your self until you can have a play or a decent look at mounts and scope setups. Best Idea, the SPSP is on in a month, why not turn up for a day or so to check out the competition , and meet some IIsers in the process. You will see all shapes and sizes, and prices

[spearo (Frank)]

Thanks
you guys are great
ill follow up the suggestions tonight (gotta go earn some "scope spending money" now)
what's the spsp ?
spearo
and just aquick one....know if the lx75 accepts autoguiding (looks like it might with AUX port)
cheers
spearo

[xstream (John)]

SPSP:- South Pacific Star Party.

http://www.asnsw.com/spsp/index.html

[Striker (Tony)]

I will just throw in Focal length...from my short experience so far.....it is all relative to Focal length and what you want to image....My EQ6 with Skyscan has backlash and I dont even have to polar align it when imaging with my 20DA on the ED80 at 600mm focal length...it will guide correct enough for that focal length of imaging.

Then to my G11 imaging between 2000-2800mm everything has to be spot on to guide or you get star trails.....so I would be looking at the scope first and what you want to image at what focal length then buy the mount to suit.

For example I dont see the point of a G11 mount or up for say imaging at 600mm with a DSLR....you get just as good job with EQ6 or even a HEQ5.....my opinion.

[spearo (Frank)]

Thanks everyone,
All excellent advice. Itchy's Orion image is stunning!
So it sounds as though perhaps the EQ6 (HEQ6 same?) might be a sturdier mount able to handle a larger payload.

Does anyone know if some mounts make more adjustememnts per second than others in autoguiding?
Is that a factor worth considering?

spearo