EQ Conundrum

[beren]

Noticed theres a few people going the EQ mount route with DSLR imaging in mind, thought it may be interesting to debate the merits pros and cons .My way of thinking with my scope being a LX200 is that i could have the benefits of Altizmuth mounting for general viewing and with the addition of a wedge be in astrophotography mode .With DSLRs exposures times generally sub 5-10 mins the advantage of a accurate EQ mount would i think be lessened and if the mount has goto capability you would i think still have to go through some polar alignment/home procedure if the setup is a mobile one for viewing . A wedged SCT certainly has its drawbacks especially when imaging towards the SCP but as a all-rounder im surprised its popularity seems less apparent

[h0ughy]

DOn't mention the WAR! :prey:

I have both, and I have to say for visual work you can't go past the alt az setup, but I cringe when I say this for photography work and IMHO the EQ mount (a stable one) is much better for photography. I have a wedge and its a dog to setup. I also have a field derotator and its not much chop either.

I can only speak about other EQ mounts I have seen used or have quickly used myself, I am yet to setup my newly aquired EQ6 with synscan goto. I will fully comment when I get this beasty up and going. :scared:

[gbeal]

Be careful Houghy, I fear that Beren is just trying to get us all involved in an argument here, boy what a can this will opn.
I have only had a very fleeting fling with the fork mount, so am really in favour of the GEM, certainly for imaging.
For visual I prefer the dob base, and to that end I use an MN76 on a Tak EM200 for imaging etc, and when I observe visually with it I put it in a dob base. Best of both worlds that way.

[atalas]

beren I think the EQ is the way to go for imaging,but the fork mount is a lot cheaper platform for a large SCT and a hello to Mr beal !

Louie :jump2:

[cventer]

Wow,
what a can of worms you have cracked open. If have owned both and imaged with both. Here are my thoughts.

The fork mounted SCT are great for Visual Use in ALT/AZ. For imaging you obviously need a wedge. Polar aligning a fork mount has always been harder and taken longer than EQ mounts(at least for me). You need to spend a LOT of money on a quality wedge eg Milburn Wedge etc.. if you want decent imaging results when fork mounted. The cheaper Meade wedges tend to sing like a turning fork. The plus for imaging is that you can image through the meridian and not worry about mounts strikes. The problem is most SCT’s have mirror flop which means when you pass the meridian you get a clunk which = ruined exposure….

Another issue with fork SCT’s in Polar mode is that imaging near South Celestial pole is almost impossible with todays large imaging trains (the new Meade RCX’s get around this problem with longer form arms)

Most of the fork mounted SCT’s aka Meads and Celestrons suffer from high or unpredictable Periodic Error, which makes imaging at native f/10 a VERY difficult task without the use of devices like SBIG AO7. Many imagers are using their SCT’s with wide field piggyback dopes like the ED80. The y image through the ED80 and guide via the SCT with great success. Its all about cost and expectations. To get a 10 inch scope like a Meade LX200 into an affordable package some compromises must be made. These compromises are often in the quality of material, tolerances in bearings, precision in machining etc…. Don’t expect Gendler type pics from a stock form mounted SCT and you wont be disappointed….

A decent EQ mount is miles ahead in stability and damps out vibration much quicker, but then again tends to cost about he same as a complete SCT fork mounted package. The added benefit of EQ’s is that you are not limited to one OTA but can change OTA’s depending on what you are looking at or imaging and the seeing conditions. I don’t own a fork mount anymore as I tend to spend more time staring at computer screens than eyepieces. If I wanted a visual platform I would probably get a good DOB with an Argo Navis.

My 2 cents worth….
Best regards
Chris venter

[mick pinner]

having had both an SCT and a 10" newtonian on an EQ6 which l recently sold to Houghy l can see the merits of both systems, they are both mounted in a way that is dictated by their size, to produce an EQ mount capable of carrying a 12" and over SCT given that a mount should only carry about 80% of it's capacity if being used for photography it would not be possible in a mass produced market, this is why generally they don't make a 12" newtonian available on an EQ mount.
there are of course the high end EQ mounts but then price plays it's part, for large aperture scopes with good go-to capability and the ability for photography a fork mounted SCT is the cheaper option although after having had both l now see the combination of an SCT on a newtonian mount as the best of both worlds if you ignore the financial aspect that is.

[ving]

i use a dob...

[beren]

:D no cans to open fellas , just curious , ill admit ive fleeted with the notion of a EQ mount and it would become reality if i decided {and could afford :whistle: }imaging with a CCD camera was my major interest.I guess the thing that amazes me is the work people do with DSLRs {check the Cloudy Nights DSLR forum} at relatively short exposure times which would maybe somewhat negate the disadvantages of a fork mount.Practice makes the wedge easier to use Houghy, it took me awhile but with a few mods and and a few practice runs its a cinch , just wish my images reflected the effort :rolleyes:

[ballaratdragons]

and a lovely dob it is, David.

[Striker]

I know the answer Stuart.

Have both.....lol

The main reason why I swapped from the Fork mount to EQ mount was for all the photographic equipment....I didn't see the room and ballance that I would need on a fork mount compared to virtualy unlimited on the EQ mount.

[h0ughy]

I must be a Capitalist, I have both

[beren]

Interesting Cloudy night thread

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/628028/page/0/view/collapsed/sb/5/o/all/fpart/1/vc/1

[rumples riot]

Hehehehehe,

Well I have owned both and both have issues. To be honest I like the fork mount over an EQ. Reasons being many but some are small physical size of the scope (I have limited space to work with), you can put a DSLR and pass it through the pole on the fork (despite what others may argue), with a good weights system (3D not 2D) there are no balance issues with the Fork and you don't walk into the counter weight system of the Fork. Not to mention polar aligning an EQ is really painful. Moreso than a fork.

With EQ mounts you can have massive problems with weight. Particular on a Newtonian. Once you place a camera on a newtonian errant problems occur all over different points of the sky. The cost of a good EQ mount is another factor that worries me. A G11 mount costs a small fortune. Sure there is the EQ6, but there has been problems with these mounts not having consistent drives.

On the downside of forks though, flexure is a major problem with the tines. Meade have done a lot to address this, but despite this there still exists a problem on very long exposure (40 minutes plus). Also if you have a flip mirror and Sbig on the scope imaging around the pole is impossible (although there is not much really there). And: the super wedge is a little finicky and needs work to bring it up to par.

On top of all this is that there are lots of guys mainly in the US using forkmounts and producing some beautiful images. One person of note is Gary (TeamGS) on cloudy nights. He has a 8" LX200 and is producing lovely images.

I think really two things matter most. First, what your budget will allow and second what you prefer to work with. If I had the money and space I would like a 300 mewlon on a G11. Since I don't I will stick with the forks.

[robinsm]

Have a 12 inch GS dob, mounted it on an EQ6 on a pier. Dob great for transportable (have kept base) and EQ great for observatory work. Both great mounts, horses for courses.

Just my 2c worth
robinsm

[h0ughy]

Can you add some pictures with your 2c worth, i am interested to see this!

[Stu]

I was just about to ask what Houghy's opinion would be on the same subject!
LX90 8" SCT or LXD75 8" SCT. Luckly I read this thread before posting as you guys just answered my question for me! I think I might get the EQ mount now...

[Stu]

Nup, just changed my mind again. I was speaking with the Guy from Astro Optical about the two mount types and he said the fork is much more accurate with tracking and the LNT makes the fork much quicker to set up. It does mean that I would be stuck with having to buy the DSI to adjust for field rotation though, as the wedge is a pain in the...;)

My wife keeps laughing at me because I change my mind so much...
Only two weeks worth of mind changes to go before I get my scope!!!