24 replies to this topic

[xcy]

By comparing the two mounts Star Adventurer seems to have better specifications indluding selectable tracking rates, DSLR and auto-guiding interfaces and better load capacity. However from what I read it seems that the iOptron SkyTracker could be a better mount when doing unguided exposures with longer lenses. What is your opinion?

[ollie31770]

There's a good review of the Star Adventurer here:

 

Part 1: http://orlygoingthir...ortable-eq.html

 

Part 2: http://orlygoingthir...er-part-ii.html

[bobzeq25]

Considered this choice.  The StarAdventurer is capable of better tracking, and has an autoguiding port.  The iOptron is easier to use, with a brilliantly simple and well positioned polar scope.  I'm a lazy guy, and went for easy.  I can do 90 second exposures at 200mm, 75% keepers.  This (modded camera).

 

http://www.astrobin.com/227049/C/

[Raginar]

Polar scope on the star adventurer is simple and easy to use. If you want to use the illuminate you do have to remove the declination assembly.

Works great upwards of 300mm unguided. Wedge is awesome.

Edited by Raginar, 23 November 2015 - 09:29 PM.

[bmhjr]

I only have experience with the Skytracker.  I can put it along with camera gear, tripod, and laptop, hike up on a ridge, and take nice quality exposures.  It all depends on what you are after and reasons for choosing a camera tracker versus an EQ mount.

[xcy]

The Skytracker (and probably most other trackers) does not seem to be well suited for using a long lens. This is because in some angles (for example when pointing south or west in low altitude) a long lens could either hit the mount or the polar scope (if not removed after initial polar alignment). And I suspect that polar alignment needs to be checked every time the camera is moved to a different target as the tracker could move slightly and get out of polar alignment so removing the polar scope could not be practical. A German equatorial mount does not have such limitations but what about the Star Adventurer?

[Hesiod]

The small Skytracker is not very suited to support lenses much longer than >200mm, due to weight and sampling.

 

"Conflicts" may happen with every kind of eq mount/tracker, depending on the size and shape of the payload; however most of times these conflicts may be avoided by mean of accurate planning.

 

Maybe the best thing is to think about your aims: how long is the longest focal you want to employ? What kind of targets you are more interested in (small DSOs? large DSOs?starfields?)? From where (light polluted environment vs "pristine" sky) you want to shot?

 

A tracker is best suited for large DSOs and starfields, hopefully from dark sky, and a DSLR/short tele (or wideangle) are nice way to keep the whole setup light and easy to employ.

If one want to shot from the backyard in a light-polluted town, then a fairly large computerized mount can be a better purchase, because it offers goto (most DSOs will be invisible), enough payload to take advantage of a guiding system, and may eventually allow narrowband AP. Such device is fit for both small DSOs and large ones (but take note that shorter focals will be still easier to employ succesfully).

[bobzeq25]

The Skytracker (and probably most other trackers) does not seem to be well suited for using a long lens. This is because in some angles (for example when pointing south or west in low altitude) a long lens could either hit the mount or the polar scope (if not removed after initial polar alignment). And I suspect that polar alignment needs to be checked every time the camera is moved to a different target as the tracker could move slightly and get out of polar alignment so removing the polar scope could not be practical. A German equatorial mount does not have such limitations but what about the Star Adventurer?

Somewhat repetitive with the above post, somewhat not.  An augmentation.

 

The trackers are indeed not suited for long lenses.  Mostly because they don't track well enough, that's the realm of the true mounts.  Some trackers more expensive than most people want to spend, like the Astrotrac or the SkyGuider, do better.  Autoguiding the StarAdventurer will give it the capability to do better (and it may do slightly better than the StarTracker without), but I can't imagine adding the complexity and expense.

 

In terms of the lens getting in the way, the offset polar scope of the Skytracker is a plus.  If you're shooting at any reasonable altitude for imaging, and willing to modify your framing, you can nearly always be sure it's out of the way.  It's also a plus in that it's very easy to recheck it as often as you like, it remains both accessible and well lit.  With any tracker, checking polar alignment every time between moving the camera and imaging is pretty much an obvious need, especially given the tripod almost certainly being used.

 

Within their capabilities, trackers have 3 big advantages.

 

They're cheap.

They're very easy and fast to set up in your back yard.

They're extremely portable, easy to get to a dark sky site and image with.

 

Trying to make them what they're not is tempting, but somewhat like driving a nail with a wrench.  They are not a cheap substitute for a mount, although you can take very nice images with them.  They're especially useful for 3 groups.

 

Beginners.  Good way to get started in AP.

People who cannot afford a good mount.

People who have a good mount, and want to add a more portable option to their arsenal.

Edited by bobzeq25, 29 November 2015 - 09:47 AM.

[xcy]

Let me write again that Star Adventurer costs about the same as the SkyTracker but has selectable tracking rates, DSLR and auto-guiding interfaces and better load capacity. I am not sure about its tracking accuracy but I would like to be able to use a lens of 300mm focal length at least for short exposures. Anyone that bought Star Adventurer and regretted it?

Edited by xcy, 29 November 2015 - 11:17 AM.

[Hesiod]

Selectable tracking rate is an almost useless feature (except half-sidereal speed, maybe useful for starlapse shots).

DSLR control is useful, but can be done through a rather inexpensive intervalometer.

I give the autoguiding interface little value too*; however if you plan to shot at 300mm, it may be quite helpful ot get consistent results. Still, you have to get a stand-alone autoguider** and try to keep all the guiding rig as light as possible due to the limited payload, and get a sturdy (=expensive) tripod, so beware of the "operative price".

Better load capacity is always a nice feature, at worst it makes your life easier if the same payload is employed.

 

Take note that the devices (Star Adventurer and Skytracker) follow different "philosophies" and address to different issues.

Skytracker offers supreme portability: you do not have to worry about adding it to your hand luggage because of size or weight, nor to put in your backpack for a trekking (and of course the payload should be similarly lightweighted, so it is perfectly reasonable to limit its tracking accuracy to very short focals).

Star Adventurer instead is halway between the Skytracker and a light mount, stronger but more cumbersome than the former, more transportable than the latter (low weight, modular structure, low energy consumption).

It can manage larger lenses (be them teles or small OTAs), but as focal grows, likewise grows the difficulty.

Autoguiding may solve the mechanical tracking error, but you have still to find and frame manually your (maybe invisible) target, and perform a very good polar alignement.

 

Last, the price does not include a tripod; while the Skytracker may employ light and cheap ones, to take full advantage of Star Adventurer greater payload you have to purchase either a strong, lightweighted photographic tripod (and pay a good amount of money) or get a cheap, quite strong, but heavy and cumbersome astronomical tripod (e.g. those sold with Eq3 or Eq5 and the like)

 

 

*my tracker may be autoguided, has enough payload to bear the guiding rig, and I have a stand-alone autoguider: however I found that it is an unnecessary intricacy for widefields (<400mm), while shooting with longer focals is extremely hard.

 

**if you have to employ a laptop, then I suggest to forget trackers and look for a proper mount (zeq25, AVX, Sirius, GP2/AP, etc...)

[Raginar]

The new firmware for the Sky Adventurer opens up quite a bit of time lapse options.

I disagree that the SA is any bigger than the ST, and no, I don't regret buying it. It's a solid little mount. I think 300mm is probably right on the cusp of its capabilities though. My next lens will be a 180mm f/2.8 and I think it will be just right.

Good luck,

[bobzeq25]

I disagree that the SA is any bigger than the ST,

"Any" is incorrect.  I respect the StarAdventurer, it's a better choice for some, but, with the wedge and the dec bracket, it is bulkier than the SkyTracker, which, with integrated "wedge" and a ballhead for dec, packs into an amazingly small volume.  The included padded case makes things very easy, it's smooth and flat.

 

Is the difference "significant"?  Matter of opinion, but there is a difference.

Edited by bobzeq25, 29 November 2015 - 01:40 PM.

[Raginar]

 

I disagree that the SA is any bigger than the ST,

"Any" is incorrect.  I respect the StarAdventurer, it's a better choice for some, but, with the wedge and the dec bracket, it is bulkier than the SkyTracker, which, with integrated "wedge" and a ballhead for dec, packs into an amazingly small volume.  The included padded case makes things very easy, it's smooth and flat.

 

Is the difference "significant"?  Matter of opinion, but there is a difference.

 

Fair enough Bob, I went and looked it up.  The Ioptron is 2.4 lbs, the Sky Adventurer is 2.2 lbs.  Dimensions the SA is 7x4.5x4 inches, ST is 6x4x2.4 inches.  So, it's actually smaller in weight, very close in demensions, and has a larger capacity.

 

 

Chris

[xcy]

The new firmware for the Sky Adventurer opens up quite a bit of time lapse options.

I disagree that the SA is any bigger than the ST, and no, I don't regret buying it. It's a solid little mount. I think 300mm is probably right on the cusp of its capabilities though. My next lens will be a 180mm f/2.8 and I think it will be just right.

Good luck,

How can the firmware be updated on the Sky Adventurer?

[Raginar]

You plug into it via USB. If you go to the sky watcher website, they have directions. The new firmware is pretty complex and really improves its ability to act as an intervalometer and it's time lapse capabilities.

[Raginar]

https://groups.yahoo...ions/messages/5

Took me awhile to find it. Hope this helps!

[bobzeq25]

 

 

I disagree that the SA is any bigger than the ST,

"Any" is incorrect.  I respect the StarAdventurer, it's a better choice for some, but, with the wedge and the dec bracket, it is bulkier than the SkyTracker, which, with integrated "wedge" and a ballhead for dec, packs into an amazingly small volume.  The included padded case makes things very easy, it's smooth and flat.

 

Is the difference "significant"?  Matter of opinion, but there is a difference.

 

Fair enough Bob, I went and looked it up.  The Ioptron is 2.4 lbs, the Sky Adventurer is 2.2 lbs.  Dimensions the SA is 7x4.5x4 inches, ST is 6x4x2.4 inches.  So, it's actually smaller in weight, very close in demensions, and has a larger capacity.

 

 

Chris

 

Does that include both the wedge, and the DEC bracket, which was a big part of my point?  I'd be surprised.  I'd also be surprised if your dimensions for the SkyTracker include the ballhead, but that's substantially smaller.  Those things actually make the difference larger than I thought it was. 

Edited by bobzeq25, 29 November 2015 - 04:57 PM.

[cruling]

my experience below based on the use of a 300mm lens, if you use 50mm lens, everything is fine.

 

First, be aware that the tracking performance of both SA and ST are not constantly good, it varies a lot for different samples! 

 

i am looking to buy a better tracker recently, and i exchanged 2 SA and 5 ST from B&H, all of them disappointing!  PE of two SA are +/- 30" and +/- 41". PE of the 5 ST are pretty consistent, all around +/- 30". i think the sample they send to S&T for review was specially tuned.  And i don't see a large number of good reviews on either product, and the good reviews are always from the same user. 

 

personally, i like the ST over the SA.  looks to me, SA is a working-in-progress product, many good ideas, but bad implementation. the wedge is a good idea, but it's not strong enough; DEC bracket is good, but blocks the polar scope illuminator; and every time when you move RA axis, polar alignment is almost guaranteed to be off.

 

For ST, you may need to do some calibration on the polar scope reticle, but once you have done that, it's easy to use. one issue with the ST is the very dim polar scope illuminator, i have opened one and found that they used a 30K Ohm resistor to limit the current, and i replaced with a 4.7K Ohm resistor, everything work just fine and the polar scope illuminator is much brighter. 

[Raginar]

You realize you've exceeded the SA's weight with any camera and a 300mm lens.

I didn't have any problems with proper exposures at 300mm with sufficient counterweight.

My guess is you expect too much from both these mounts. It's a common theme with people who are looking to buy them.

[bobzeq25]

"

 

 

i am looking to buy a better tracker recently, and i exchanged 2 SA and 5 ST from B&H, all of them disappointing!  PE of two SA are +/- 30" and +/- 41". PE of the 5 ST are pretty consistent, all around +/- 30". i think the sample they send to S&T for review was specially tuned.  And i don't see a large number of good reviews on either product, and the good reviews are always from the same user.

 

Wow.  Great data.  That's far more consistency than I expected.   You do realize inexpensive real mounts tend to have PEs about +/- 15", or more?  The trackers cited are about where they should be.

 

There are plenty of good reviews about both from a variety of users here.  Also, many excellent images fom both, from a variety of users, on Astrobin.  They're different, and appeal to different users (the ST is smaller, simpler, and cheaper, the SA capable of higher performance, but a bit more work to get there), but they're both fine trackers.  If someone wants a tracker that performs like a low end mount, there's the AstroTrac (maybe also the iOptron Skyguider), and its various accessories (a pier?).  Of course the cost and size approaches that of a low end mount, when fully loaded.  Then there's the question of whether the lenses one uses are good enough to justify that.

 

This is all a good example of the general principle, in mounts, you get what you pay for.

Edited by bobzeq25, 05 December 2015 - 11:26 AM.

[Raginar]

I'd like to know how he's measuring it.  Through the ST4 port?

[cruling]

You realize you've exceeded the SA's weight with any camera and a 300mm lens.

I didn't have any problems with proper exposures at 300mm with sufficient counterweight.

My guess is you expect too much from both these mounts. It's a common theme with people who are looking to buy them.

my expectation is 300mm 2min with 80-90% keeper(round stars at 100% crop), is it too much for those two tracker? 

 

I'd like to know how he's measuring it.  Through the ST4 port?

same method described here: http://www.cloudynig...periodic-error/

but I point the camera due south and at the end of the exposure i will turn off the power for 1min, so that i can see the direction of RA and i measure the error only along RA.

[bobzeq25]

my expectation is 300mm 2min with 80-90% keeper(round stars at 100% crop), is it too much for those two tracker?

 

My limit (SkyTracker) is 2 min, 200mm, 75% keepers.  The stars are slightly oval on each sub, they stack well, and I'm satisfied.

[cruling]

 

my expectation is 300mm 2min with 80-90% keeper(round stars at 100% crop), is it too much for those two tracker?

 

My limit (SkyTracker) is 2 min, 200mm, 75% keepers.  The stars are slightly oval on each sub, they stack well, and I'm satisfied.

 

the best one of the SkyTracker i tested can only do 180mm 90s 70% keepers. total of 7 images, 5 keepers, all with oval stars, about 4X6 pixels.

[Raginar]

 

You realize you've exceeded the SA's weight with any camera and a 300mm lens.

I didn't have any problems with proper exposures at 300mm with sufficient counterweight.

My guess is you expect too much from both these mounts. It's a common theme with people who are looking to buy them.

my expectation is 300mm 2min with 80-90% keeper(round stars at 100% crop), is it too much for those two tracker? 

 

I'd like to know how he's measuring it.  Through the ST4 port?

same method described here: http://www.cloudynig...periodic-error/

but I point the camera due south and at the end of the exposure i will turn off the power for 1min, so that i can see the direction of RA and i measure the error only along RA.

 

Yes, you are exceeding the design limitations.  So holding it to standards it wasn't designed for is probably poor form.