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Review of new SBIG SG-4 with AP160 + DSLR

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#1 Aquatone

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Posted 19 July 2009 - 01:47 AM

As I am testing the new SBIG SG-4 standalone auto-guider with a Canon 40D DSLR I will post a quick review here.

I received one of the first new SBIG SG-4 auto-guiders last week. I have been looking for a compact standalone guider for some time and I ordered the SG-4 in advance largely on the basis of SBIG's reputation and previous positive experiences with other SBIG cameras. At $995 this is the most expensive of the new standalone guiders coming on market and I have not tested the cheaper alternatives from Orion and LVI (The same instrument) to make any valid comparisons.

Full details of the SG-4, essentially the successor to the STV can be found here.

http://www.sbig.com/..._autoguider.htm

This is a completely standalone auto-guider and especially well suited for a "grab and go" DSLR imaging rig - no computers, almost no cables. You just need a 12V power supply. The guider is initially focused and set up connected to a laptop, but is completely standalone after setup is done.

My first setup using my laptop to initially focus the SG-4 with my guide scope (A Borg 77) was reasonably straight forwards. The least satisfactory aspect was the lengthy time taken to download each image (through a RS232 link) when manually focusing my guide scope in "continuous" mode, but there is a fast focus option that zooms into a small focus box that updated the images more quickly. I also did the initial mount calibration attached to my laptop (It took about 10 minutes connected to a AP1200 and only 4 minutes the second time) and it is pretty cool seeing the SG-4 report on what it is doing in the text box. All in all the setup took about an hour but everything worked as per the instruction manual. Since then I have not used my laptop at all and I have used the SG-4 purely in standalone mode.

So far all stars in my DSLR 10 to 15 minute test exposures are perfectly round. The SG-4 is very easy to operate - I just press the main Guide On/Off button for 5 seconds to calibrate the SG-4 to the mount, push it again to start guiding, and everything else is automatic. It locates a star on its own and adjusts exposure time automatically if it does not find a star bright enough. I have not needed to worry about anything else at all. So far I have not pointed the SG-4 to anywhere on the sky where it can't find a guide star. Stars are perfectly round and guiding is very precise when tested at different declinations. It certainly seems as accurate as my existing Starlight Express Lodestar and PHD combination. (With laptop)

Every time the camera sends a correction to the mount it beeps quite noticeably - at first I thought this was irritating, but actually it is quite reassuring to hear everything is working while I am doing something else.

The SG-4 itself is not bulky or super heavy but it is not small or light weight either. I think it needs a very substantial and solidly mounted guide-scope to avoid any flexure problems. I believe the LVI (also marketed by Orion) is a lot lighter though I believe the SG-4 is more sensitive and the general setup and onboard software appears pretty well thought out. After 2 hours of guiding last night I noticed some slight trailing in my later exposures. I tightened my guide-scope within its clamps as much as I could tonight and the problem went away. The picture below shows the size of the SG-4 hanging off the end of the Borg 77 and clamped to my AP160. I also want to try the SG-4 with my OAG though the documentation says that the SG-4 is not primarily intended for use in that mode.

In general the SG-4 worked straight out of the box and to a high degree of precision. From my limited experience so far it is performing well.

Chris

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#2 Aquatone

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Posted 19 July 2009 - 01:58 AM

Another view of the SG-4... Almost no cables!

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#3 Psyire

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Posted 19 July 2009 - 09:30 AM

Thanks Chris for posting this review! I was also looking at this stand-alone unit.. my biggest problem is that it dosen't have a parafocal eyepeice. I'm not sure why SBIG would't include one as it would help so much in focusing without the laptop connected. Perhaps though some trial and error a person could find a parafocal EP that you could use.. Great to hear it's working out for you, more than I can say about the Solitaire guider I'm trying out. (but I shoud resolve the issue soon I hope)

#4 Mike Clemens

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Posted 19 July 2009 - 03:15 PM

Thanks for the review. I am disappointed to see the massive size and construction style. I rather like the little "puck" looking Orion units. This unit would definitely be too much for my ancient guiding achromats construction to withstand.

What guiding rate are you using on the mount? I have been using .5x on my own 1200.

#5 nickatnight

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Posted 19 July 2009 - 05:06 PM

Nice review. That does look like a beast of an autoguider, but it looks really good with that beast of a telescope. :grin:

#6 Aquatone

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Posted 19 July 2009 - 11:59 PM

Thanks for the review. I am disappointed to see the massive size and construction style. I rather like the little "puck" looking Orion units. This unit would definitely be too much for my ancient guiding achromats construction to withstand. What guiding rate are you using on the mount? I have been using .5x on my own 1200.


I was using a guiding rate of 0.25 last night but increased to 0.5 tonight. One reason i did so was that apparently the beeping each (1 second) exposure is a sign that the mount is up against its maximum correction per guide exposure. I also increased the Max Move Limit and it now guides perfectly and no longer beeps regularly.

The constructional style is definitely industrial strength to be sure. Its built like a brick and looks like one. (Thankfully at 1 lb in weight it is not as heavy as one) This is not a "little puck", but if this unit is properly mounted it is as solid as you can imagine. The SG-4 also has a full shutter mechanism for remote or automatic dark frame subtraction and even blue tooth capability if you don't want to connect your laptop for setup physically. The more I become familiar with the SG-4, it is becoming clearer that it is a typical somewhat over-engineered SBIG product with a lot of quality, options, and overall sophistication. At the same time once set up you just push a button and it works. Here is a closer picture of the back-end.

Chris

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#7 Mike Clemens

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Posted 20 July 2009 - 12:41 AM

It looks beautifully built. Can you go up to 5 or 10 second exposures?

#8 Aquatone

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Posted 20 July 2009 - 01:05 AM

It looks beautifully built. Can you go up to 5 or 10 second exposures?


Yes - you can go up to 10 second exposures in stand-alone mode, and up to 10 minute exposures when connected to your computer.

Chris

#9 Yedgy

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Posted 21 July 2009 - 12:54 AM

Is it possible to dither with this unit? I know that with my DSLR dithering between exposures is critical to a good finished image.

#10 Aquatone

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Posted 21 July 2009 - 02:26 AM

Is it possible to dither with this unit? I know that with my DSLR dithering between exposures is critical to a good finished image.


No, I cannot immediately see any option to dither. Would be pretty easy to implement I would imagine. Perhaps thats for v2.0!

Chris

#11 Arcturus

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Posted 20 September 2009 - 10:27 PM

Expect soon see use SG - 4 guide star images.

-------------------------
TeleVue NP101
Takahashi EM200
SBIG ST-2000MX
Canon 450D Modify
Canon 5D-Mark2

#12 Gus_Smedstad

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Posted 20 September 2009 - 11:45 PM

Dithering requires good communication between the guider and image capture software. Otherwise, the guide camera has no idea when to shift aim, and the image capture software doesn't know when it's safe to start another image.

I'm not really sure how you'd implement dithering in a guide camera that's meant for standalone use. There's just no way to talk to the imaging camera.

I'm very surprised in this day and age that SBIG is still using RS232. USB is superior in just about every way, and almost anyone using the camera will end up having to buy a RS232-to-USB adapter.

- Gus

#13 Lawrence Lopez

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Posted 13 December 2009 - 06:59 AM

Wouldn't this simple scheme work to dither:

stop the guider.
move the scope.
start the quider.

#14 guyroch

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Posted 13 December 2009 - 11:10 AM

I'm very surprised in this day and age that SBIG is still using RS232. USB is superior in just about every way, and almost anyone using the camera will end up having to buy a RS232-to-USB adapter.


Ahhh... they probably have invested in the RS232-USB industry long ago and they trying to capitalize there as well :) Just kidding... I have no clue... but it could be true because the price of those adapters are way to high for what they do.

#15 groz

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Posted 13 December 2009 - 12:47 PM

USB is superior in just about every way, and almost anyone using the camera will end up having to buy a RS232-to-USB adapter.


Yep, usb is superior, unless ofc you want to locate the computers farther than 16 feet from the camera. For most of us with our little / portable setups, that's not an issue. for fixed installations, it can become quite an issue.

RS-232 can run over basically any kind of copper pair, and on distances in the hundreds of feet.

It's easy/cheap to adapt an rs-232 connection for a usb attach on the other end. It's very expensive to adapt a usb connection over distances greater than 16 feet.

usb -> rs232 adapters run about 5 bucks these days. There is a processor board inside that box, and, virtually all processor boards come with rs-232 connections on them already. By using the existing rs-232 connection, the box itself saved significantly on internal parts, because upgrading it to a processor board that includes usb would likely be at least a 20 or 30 dollar increase in just the cost of the internal cpu board, and if they just buried the 5 dollar rs-232->usb connector inside, makes life easy for one segment of the customer base, makes it impossible for the others.

Usb may be more convenient for hobby users doing rapid setup/teardown most of the time, but, for fixed installations with computers set apart in warm rooms, the rs-232 is far less expensive to deal with, and likely still ends up with the 5 dollar connector on the other end, but, leaves the ability to use inexpensive cabling over the longer run.

#16 guyroch

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Posted 13 December 2009 - 01:59 PM

usb -> rs232 adapters run about 5 bucks these days.


They go for about 40 buckaroos in my neck of the wood. I bought one recently and I shopped around to get the cheapest one. I could have bought one for about $10 on the net, but shipping and/or duty fees brought the price to about the same range as local shops in Ottawa Canada.

#17 justabob

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Posted 13 December 2009 - 04:05 PM

Yep, usb is superior, unless ofc you want to locate the computers farther than 16 feet from the camera.


Yep this is why they do it. Can eliminate the need for a second remote computer,"this is what I do, and I think many others." But in a fixed observatory with a warm room that is father than 15 feet from the camera I guess it makes sense.

#18 groz

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Posted 13 December 2009 - 04:47 PM

usb -> rs232 adapters run about 5 bucks these days.


They go for about 40 buckaroos in my neck of the wood. I bought one recently and I shopped around to get the cheapest one. I could have bought one for about $10 on the net, but shipping and/or duty fees brought the price to about the same range as local shops in Ottawa Canada.



Link Check it out. 4 bucks canadian, canadian source, be delivered in a few days to you out in ottawa.

The last time I needed another one, and needed it _now_, cost close to 50 bucks at staples. Learned my lesson, now have a few spares, that I bought online and they are there when I need em. Can have a considerable number of spares at that price, for less than one at the spendy places.

#19 guyroch

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Posted 13 December 2009 - 11:45 PM

usb -> rs232 adapters run about 5 bucks these days.


They go for about 40 buckaroos in my neck of the wood. I bought one recently and I shopped around to get the cheapest one. I could have bought one for about $10 on the net, but shipping and/or duty fees brought the price to about the same range as local shops in Ottawa Canada.



Link Check it out. 4 bucks canadian, canadian source, be delivered in a few days to you out in ottawa.

The last time I needed another one, and needed it _now_, cost close to 50 bucks at staples. Learned my lesson, now have a few spares, that I bought online and they are there when I need em. Can have a considerable number of spares at that price, for less than one at the spendy places.


*BLEEP*! *BLEEP*! *BLEEP*! :foreheadslap: I searched everywhere 2 months ago and ended up paying $42 + tax at a local shop in town. Thanks anyway, I know where to go next time.

#20 bardo

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Posted 14 December 2009 - 04:18 AM

^^ you aint the only one

#21 Alfort9

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Posted 21 June 2010 - 08:03 PM

I know this is a rather large gap in time from the last post, but I am considering buying the sg-4/Borg 50 combo from Hutech and I note the comment above about getting a substantial guider to avoid flexure...does the Borg 50 qualify?


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