GOTO Mounts.

Vince · Post by **Vince** » Mon Jan 19, 2004 3:34 pm

I'm about to embark on a Celectron Nexstar 130GT purchase (via Web coz Astro Scientific charges ridiculous prices). However, I would like to find out if the GOTO mount is any good. Are there any users here with GOTO mounts? I've tried (albeit unsucessfuly) to polar align my scope for the past 2 weeks (where weather permitted) and am getting rather tired of having to do it all the time. I hope fellow SingAstronomers can give me some form of feedback on this type of mount.

Thanks in advance.

harlequin2902 · Post by **harlequin2902** » Mon Jan 19, 2004 3:57 pm

I used a Nexstar 4 myself in the past, and it was quite fun as a *visual* scope. No need to sweat it out while trying to align it. Just point North and level the scope ! Both the GOTO pointing and object tracking are quite accurate if you align the scope according to the instructions. In a low power eyepiece, the object you enter will almost always appear somewhere near the center of the FOV.

Piggyback wide field exposures of up to 3 minutes (at a dark site, else the sky glow will start messing up your photo) is ok, but not recommended for longer exposures through the scope or eyepiece because it tracks only in alt-az mode - unless you get an equatorial wedge ... which is also not recommended for us in Singapore, because the single fork arm will have to be set almost parallel to the ground...not very good for the mount itself and the motors inside, I heard.

blurblock · Post by **blurblock** » Mon Jan 19, 2004 3:58 pm

I am a newbie, so I might be wrong, but the GOTO mounts need you align your scope to the polaris too ..... once aligned then you the computer inside the scope or on the mount will travel the distances to your object based on your calibration (Depending on what you had bought, but I heard most of Celestron and Meade has the computer insidethe scope, so as to lock you in, but I heard of GOTO mount like Vixen offered by Mcgill too).

However, the GPS GOTO mount is different, it make use of GPS to search for your stars, if I am not wrong, every GPS request you had made will be charged to you........

harlequin2902 · Post by **harlequin2902** » Mon Jan 19, 2004 4:08 pm

I am a newbie, so I might be wrong, but the GOTO mounts need you align your scope to the polaris too ..... once aligned then you the computer inside the scope or on the mount will travel the distances to your object based on your calibration (Depending on what you had bought, but I heard most of Celestron and Meade has the computer insidethe scope, so as to lock you in, but I heard of GOTO mount like Vixen offered by Mcgill too).

Nope, that's not true. If we have to align specifically to Polaris, then none of us here can buy GOTO scopes since we can't really see Polaris in Singapore anyway :roll: .

Ok, maybe I forgot to add this to the above

: For the Nexstar series, after pointing North and levelling the scope, you have to align the scope to at least 2 bright stars in the sky visible from your location before your alignment is complete. It dosen't have to be Polaris. In all, the alignment is still pretty easy. It'll take just a couple of minutes with practice.

I really do miss my Nexstar 4

Post by **VinSnr** » Mon Jan 19, 2004 4:14 pm

blurblock wrote:I am a newbie, so I might be wrong, but the GOTO mounts need you align your scope to the polaris too ..... once aligned then you the computer inside the scope or on the mount will travel the distances to your object based on your calibration (Depending on what you had bought, but I heard most of Celestron and Meade has the computer insidethe scope, so as to lock you in, but I heard of GOTO mount like Vixen offered by Mcgill too).

However, the GPS GOTO mount is different, it make use of GPS to search for your stars, if I am not wrong, every GPS request you had made will be charged to you........

Ok..to set the record straight, there are two type of commercial GOTO mounts. The first type do not require you to polar align, unless you are using a wedge. Such scopes are like the Nexstar 5, LX-90, LX-200. For this kind of scopes, all you have to do is to point it to North (I say North..I didn't say North star. Note the difference here) , make sure the base is flat and off you go for your alignment stars.

The second kind of GOTO mounts are the GOTO EQ mounts. These are like the LXD55 and the recent Celestron Advance CG5 series. These mounts require you to polar align first. It is a little bit more of a hassle at the start, but the good thing is, you don't have to be very accurate at it unless you are doing AP with it. A rough polar alignment is sufficient for visual as the computer will compensate for slight inaccuracy.

So don't get them confused. I believe the original poster got himself confused because the Nexstar series do not require polar aligment

blurblock · Post by **blurblock** » Mon Jan 19, 2004 4:30 pm

Ah ..... I see ..... ok

...... Celestron added to my shopping list in June / December

...... But definately not from Astro Scientific ..... just to think, the owner is the president of Singapore Astronomy Society and he is dissuading people from joining by charging exorbitant prices .... will rather get scope from overseas and risk the shipping or get the scope from other parallel importer ... hint hint ..... to local importer ;)

Vince · Post by **Vince** » Mon Jan 19, 2004 10:38 pm

Thanks for all your replies. It means that the Nexstar 130GT will still be unusable for me coz I kinda intend to do AstroPhotography with it as well as piggyback AP. Darn...that means that if I go for the GOTO EQ mount, I'll still have to manually polar align first...darn..why can't they come up with something that doesn't require polar alignment and is relatively accurate for long exposures at higher magnifications!?!?

Btw, checked with Binoculars.com, the price is US$359/= (shipping was another US$230) compared to S$1350 if I get it locally.

Post by **weixing** » Tue Jan 20, 2004 9:12 am

Hi,
Even you do a very accurate polar alignment, you still need to guide using a scope (guide scope). Anyway, GOTO system alone can only help you to find objects more easily, but does not guarantee to track accurately.

Have a nice day.

blurblock · Post by **blurblock** » Tue Jan 20, 2004 9:58 am

Vince wrote:Thanks for all your replies. It means that the Nexstar 130GT will still be unusable for me coz I kinda intend to do AstroPhotography with it as well as piggyback AP. Darn...that means that if I go for the GOTO EQ mount, I'll still have to manually polar align first...darn..why can't they come up with something that doesn't require polar alignment and is relatively accurate for long exposures at higher magnifications!?!?

Btw, checked with Binoculars.com, the price is US$359/= (shipping was another US$230) compared to S$1350 if I get it locally.

Get from B&H lor Price US$399.95 (make it 400), but shipping only US$173 by UPS express, 3 - 5 days working days delivery

.

http://www.bhphotovideo.com/bnh/control ... sku=296091

Post by **VinSnr** » Tue Jan 20, 2004 6:13 pm

why can't they come up with something that doesn't require polar alignment and is relatively accurate for long exposures at higher magnifications!?!?

They do have this. It's called LX-200GPS with a field derotater.