Which Autoguiding Package?

[beastmaster]

Hellooo all the masters and guru...

Im stepping in astrophotography (my main motive of getting my first setup - C8)

As per my subject, I am looking to get Autoguiding. Am not sure which to get and what is needed or available out there.

Did some reading and research on my own. One of the most popular is Orion ST80mm with SSAG. This particular setup has many good review.

The other setup is the much newer package, the Celestron 80mm Guidescope Package with NexGuide. This setup has very few reviews and quite a number of negative or rather disadvantages.

Which one to get? Should I pair Orion SSAG (with sub-pixel) with Celestron 80mm Guidescope (600mm FL)? Will they work well? Any masters and guru here have experience with either?

[shirox]

if you want a light weight auto guider set up, you may wanna source for a mini borg 50mm with a qhy5 or if you are planning for planetary, an Imaging source DMK/DFK CCD cam.
Works well for me and a few guys here.

[beastmaster]

Thanks bro... not very familiar with those items. Shall head back to the research room...

Meanwhile if there is any review, comments or advice... please drop them in

brb...

[beastmaster]

Shirox... where did you purchase the QHY5 (Monochrome) and MiniBorg 50mm? How much?

My research...

Pricing - Individual
QHY5 (Monochrome) = RM799 (+/- USD245)
Mini Borg 50Ach F5 Basic Set (drawtube version) for any t-threaded cameras = USD320.00
Mini Borg 50Ach F5 Basic Set (helical focuser version) for any t-threaded cameras. Back focus less than 13mm = USD370.00
Total separate purchase cost = USD565 - USD615 (excluding shipping)

Pricing - Package
Mini Borg 50Ach F5 & Orion StarShoot AG Complete set, including AG50B & SSAG = $599 (excluding shipping)

I believe the package or setup above does not include the piggy back system - dovetail or whatever as compared to below Orion's Package that comes with everything.

Orion's package
Orion Magnificent Mini AutoGuider Package = USD349.99 + USD62.70 (Shipping) = USD412.69
Awesome Autoguider Refractor Package = USD399.99 + USD94.32 (Shipping) = USD494.31

Since QHY5 is the same as SSAG, now the crucial point is the scope. Which scope have better optics?

Celestron 80mm Guidescope Package with NexGuide seems to be abit lost now...

[MooEy]

The smaller package is better due to the lighter weight. Less load on the mount, less flexure on the system.

The one I'm using is as follow
http://www.kwtelescope.com/KWT_KWIQ.htm
I somehow prefer this over the rest since there is nothing to flex and the focus can be locked in place. You may want to get a proper UV/IR Cut filter for the camera.

I'm using the Stellarvue finder brackets instead
http://www.stellarvue.com/f50.html
This bracket was suggested by Meng Lee and works pretty well. The 6 points ensure proper lock down, and Stellarvue offers a wide range of mounting base.

The small 50mm scopes guides pretty well. Assuming the focal length to be roughly 180mm, calculations as below
Arcsecond/pixel = 206.265/focal length * pixel size = 206.265/180*5.2 = 5.96 arcsecond/pixel

Given subpixel guiding, you can shoot at somewhere 1.5 arcsecond/pixel and still get reasonably round stars.

And if you can afford it, go for the mini borg. Those have slightly more focal length and better optics. And makes for a fun scope in the future.

~MooEy~

[orly_andico]

Mooey, I don't think you can reasonably expect to shoot at 1.5" / pixel and get round stars unless your mount is also up to it - even if autoguiding.

To give an example, somebody on CN reported that his iEQ45 has a fast 5" amplitude, 6.2-second periodic error from the gearbox. That is un-guidable and would impose a limit on the pixel scale at which stars remain round.

[MooEy]

Orly,

While i agree with you a good mount is required, the original post only asked about autoguiders, we should stick to the topic and not discuss any other stuff so as to stay focused on the topic.

There are so many other thing that we can discuss, eg. mount, scope, cameras, adapters, filters, skies, location etc etc etc

Regarding your example, I have to remind you and all other forumers. Do not bad mouth vendors or products that you do not own or have ever used. Such comments only unfairly devalue the product and may cause the vendor/dealer of the product to come after you.

Astro being a science related hobby should be somehow approached "scientificly". We should approach with evidence and not just based on assumptions and imagination.

2nd handed smoke should be avoided, we should only comment on equipment that we own or have 1st hand experience. Did you actually test the same mount and come to the same conclusion?

Reposting someone's comments from other forums without first verifying the source doesn't add alot of value and will cause other newcomers to follow in suit. We wouldn't want a forum that is full of 2nd handed smoke, inaccurate assumptions and false information.

~MooEy~

[shirox]

Hi Beastmaster,

I bought my QHY5 and Mini-borg (Used to own it but sold it) 2nd hand from a bro here.
But I think you can get them at acceptable prices at astromart or cloudynights.
The reason because there's a bigger pool of astronomers there as compared to singapore so, you can find alot of goodies and good deals if you know what and where to find.
all of my images were autoguided with either QHY5+mini borg 50 or DMK21+miniborg 50.
I do find using the DMK21, the stars are tigher and resolution is much better, which is important for guiding as well.

Shirox... where did you purchase the QHY5 (Monochrome) and MiniBorg 50mm? How much?

My research...

Pricing - Individual
QHY5 (Monochrome) = RM799 (+/- USD245)
Mini Borg 50Ach F5 Basic Set (drawtube version) for any t-threaded cameras = USD320.00
Mini Borg 50Ach F5 Basic Set (helical focuser version) for any t-threaded cameras. Back focus less than 13mm = USD370.00
Total separate purchase cost = USD565 - USD615 (excluding shipping)

Pricing - Package
Mini Borg 50Ach F5 & Orion StarShoot AG Complete set, including AG50B & SSAG = $599 (excluding shipping)

I believe the package or setup above does not include the piggy back system - dovetail or whatever as compared to below Orion's Package that comes with everything.

Orion's package
Orion Magnificent Mini AutoGuider Package = USD349.99 + USD62.70 (Shipping) = USD412.69
Awesome Autoguider Refractor Package = USD399.99 + USD94.32 (Shipping) = USD494.31

Since QHY5 is the same as SSAG, now the crucial point is the scope. Which scope have better optics?

Celestron 80mm Guidescope Package with NexGuide seems to be abit lost now...

[orly_andico]

Hi Mooey,

Agreed with your points. I thought of the iEQ45 because the guy on CN actually measured its periodic error with a high resolution Renishaw encoder. Was it my first hand experience? No, but I see no reason to doubt the guy's report.

In any case I did not "bad mouth" the ieQ45, I said ONE guy REPORTED... so its pretty clear its one report from one guy and not my first hand experience. Still I consider it reliable because of the guy's methodology. Attribution is very common in scientific writing. Another issue, is that many people can't measure these things accurately. So if I had an iEQ45 and said "it can do 2" unguided" and I show a PHD graph would you believe me? (a common mistake is not to "disable guide output" when using PHD to measure PE.. a mistake I have made myself)

But that is neither here nor there. While the topic is auto guiding, the mount is relevant, because 1.5" with round stars requires much more than just the AG. Perhaps if you had stated that ".. imaging at a pixel scale of 1.5" with this setup should give you round stars if your mount is up to it and you can control differential flexure."

[cloud_cover]

Oh dear.... I'm sad to see two forum friends get annoyed at each other.
I'd like to weigh in on this with my thoughts:

Mooey, that's fantastic advice you've given. In fact I was wondering which guiding setup myself and am toying with using a 50mm guider (someone loaned me his SSAG/50mm). I'm using a Vixen type holder, so no issues with flexure there.
Thanks for pointing out that its good for down to 1.5arcsec/pix. That's pretty useful information!

As an aside, the cheapest kwik-adapter is found at WWW.MODERNASTRONOMY.COM which will ship to Singapore for 28GBP. You will need your own 50mm finderscope though.

Personally I'm not a fan of the Nexguide/80mm. Nexguide sounds like a good idea and it is, if you don't want to bring a laptop into the field. Unfortunately its sensitivity is so poor I had issues locking onto a dimmer than Mag 4 star in the darkish skies of Sedili using an Orion ST 80mm with 2 secs exposure. That's poor performance. On the other hand, the SSAG found plenty of guidable stars with a simple 50mm finderscope in the bright skies of Singapore at 0.5sec.

I'd like to point out though, that because you're using a C8 with a FL of 2000mm, even a camera with largish pixels of 8.4um (my D700. Most APS-C sized cameras are about 5+um), that works about to 0.8+ arcsec/pix, which is well below the minimum resolution suggested by Mooey. Thus in your situation I'm not so sure how well the SSAG/50 will work.

On the issue of mounts, I think Orly has brought up a very valuable point.He's recently had to troubleshoot his mount for severe PE issues hence he's keenly aware of the complications of mounting issues, but its a very valid point. I noticed you're using a C8 on a CG-5 mount, which while a decent mount, is also probably overloaded for photography when you're plonking a C8, guidescope, camera and etc on it, so its also true that your mount may let you down even if you solve your guiding issues.
I would strongly urge you to consider getting a shorter scope (be it a smaller newt or a refractor) and go down in focal length if you're starting out. This would obviate most mount issues and also allow you to use the much lighter and convenient SSAG(or QHY5)/50mm guider.
Also, most objects will be well framed in a shorter refractor while a C8 is generally good for small objects. Its FOV with a cmera is pretty small!

Just my 2c