Skywatcher goto/synscan dob

[Quopaz (Nick)]

Thinking about maybe getting the upgrade kit that converts a standard dob to one with goto/synscan, but not sure if it's a good idea or not. Have heard that the tracking probably isn't suited to deep sky, but it might be OK for planets? Mine's the 10" solid tube, so it weighs a bit and I don't think any of the cheaper eq mounts would take the weight. Would be interested to hear from anyone who has a dob with goto/synscan what their opinion of it is, especially the tracking. Haven't found any videos yet that really show how it tracks. Cheers.

[carneb (Barry)]

I had a Skywatcher 14" goto dob. Tracking was OK for goto and general visual use. For planetary when using a barlow and a small chip (ASI290MM) then the planet would still drift across the frame even when tracking. And every 30 seconds or so you would have to re-center the planet.

I also tried some deep sky with a DSLR and could only manage 20s exposures or you would get tracking errors showing in the photos.

[Allan_L (Allan)]

Did you try doing a search here on IIS.
This has been discussed numerous times.

For example here is a recent discussion:
http://www.iceinspace.com.au/forum/s...kywatcher+goto

I previously had a 12" Skywatcher (collapsible) GoTo.
It was pretty good, with accurate levelling and careful alignment making the goto better.

FYI I found the goto and tracking even better for DSO's than planets.

But I found the weight a bit much and swapped to a 10 SW Dob currently with the argo navis system which is Aussie and although still "push to" and not tracking, I find a better solution for me.

Also note you can't generally use an alt/az mount (like the SW goto) for long exposure photography due to image rotation. The EQ mount does not suffer from image rotation. (as I understand it)

Good luck with your progression.
Feel free to ask more (specific) questions
cheers

[Outcast (Carlton)]

In general terms, Alt/Az Goto/tracking mounts in any form are only suitable for short exposure shots when imaging deep sky objects.

You will need to experiment with your exposure lengths to see how far you can push before you get star trails. 20 seconds would be around the upper limit from my experience.

With respect to planetary/lunar imaging, Alt/Az Goto/tracking mounts are fine, generally one captures around 30 seconds of video which results in over a 1000 frames for quality selection & subsequent stacking. Since you are entirely focused on the planet & not the surrounding stars, this method provides adequate tracking to capture some stunning planetary & lunar images.

For long exposure AP you will need an Equatorial mount, this is because an equatorial mount is setup to take into account the earth axis tilt; ie: your mount will track perfectly (well, depending on how well setup it is & how good the mount is) in line with the earth's rotation axis. Some Alt/Az setups allow for the addition of an Equatorial Wedge, this essentially converts your Alt/Az setup to an EQ setup with the wedge being setup to an angle that corresponds with the earth's equatorial axis, ie: your latitude.

Even with an Equatorial mount, exposures are generally limited to around 2 minutes or under unless you add guiding into the mix. There are exceptions to this but, you will pay a lot of money to purchase a mount capable of doing over 2 minutes unguided & it will still depend on how well you set it up to achieve this.

To accomodate your 10" f5 tube you would be looking at an EQ6 as a minimum.

Hope this helps with your decision making process

[Startrek (Martin)]

I wouldn't recommend using a goto synscan dob for DSO astrophotography



I have a 12' goto dob which is unbelievable for visual but for astrophotography the moon and maybe larger planets are about your limit ( up to 15 or 20 sec exposures )


I also have an 8" f5 Newtonian reflector for astrophotography which sits on a new EQ6-R mount and is fantastic for all types of imaging , Planetary and DSO


However my EQ6-R mount is at its limit with this 8" scope and all the other ancillary gear imaging outdoors



I would not consider sitting a 10" f5 OTA on this mount if you want + 5 minute quality subs in various conditions outdoors. Maybe ok in an observatory out of the wind



The 10" and 12" f4 and f5 OTA's ( +18KG ) would be more suited for a larger capacity mount like an EQ8-R Pro or similar



My 2 cents.............

[Quopaz (Nick)]

Thanks guys, sorry if it's been discussed before, just doing some research before I spend the money. Don't think I'll get it just yet, although I nearly did. Got an illuminated reticle finderscope and a dual speed focuser instead, which should be an improvement. I'll see how that goes first. Very hard using the drift method on planets when you can't see the cross in the dark. Jupiter looked so good this morning drifting through, just wish I could keep it on the screen longer.