Which Autoguiding Package?

[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... which DMK21 got so many model with different resolution. I guess you referring to the one with 1600 x 1200 pixel res?

Where to get the Miniborg cheap?

[MooEy]

For those who are interested in sub pixel guiding, the following article might be a good read
http://www.stark-labs.com/help/blog/fil ... curacy.php

Somehow the author suggest accuracy of roughly 1/5 pixel.

~MooEy~

[beastmaster]

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~

Hi Mooey

Indeed Miniborg focal length is 250mm and Orion mini 50 is 162mm. Weighs better than ST80.

Think I will consider the Miniborg. Which package to get and what else is needed to? Where to get? Direct?
Ref - http://www.sciencecenter.net/hutech/prices/guide.htm
Pic - http://www.sciencecenter.net/hutech/bor ... /index.htm

[orly_andico]

Being able to detect drift with 1/5 or even 1/10 pixel accuracy is one thing, but the mount being able to correct these differences is quite another. Craig says so right at the end of the article linked: "Odds are, your mount, the wind, flex, etc. will be causing more trouble than even this error unless you're using a very wide FOV guide setup."

I in no way questioned the idea that subpixel star positioning is possible, I simply pointed out that guiding to that level is not achievable unless the mount is up to it. Now as to the iEQ45 "bashing" - as I stated, it's one report from one person, but a person whose methodology I respect. Besides, all the China mounts in this price class suffer from similar issues, it's not a criticism of the mount but merely an acknowledgement that at this price, you get what you pay for.

To the OP - my personal experience has been, even with a 0.63 reducer and guiding off-axis (meaning I am not using a guide scope but guiding at 1:1) getting round stars on my C9.25 is very hard.

As Kevin said - you probably should not try to image with your C8 given the mount that you have. Or at the very least, please get the f6.3 reducer which will help a lot by lowering the focal length of the C8 and increasing its photographic speed by almost 2 stops as well.

[orly_andico]

oh, and Kevin

1) I'm not annoyed just a bit puzzled that my post would elicit such a vigorous reaction

2) my PE issues are not that "severe" - but yes they do make life pretty hard. I can only wonder how much of an issue PE and gear noise would be on a CG-5..

[beastmaster]

Dear masters and gurus...

Thank you so much for all the inputs... they are priceless to me.

So what will work well for C8 with CG-5 mount and Canon 60D?

When are you guys doing sidewalk? I stay in Tamp, i dun mind helping you guys carry

Can buy a drink or two too

[cloud_cover]

In terms of guiding: Probably the best setup is an off-axis guider with a sensitive camera. Having said that, this is also the most difficult setup to use as finding guide stars is generally not easy. But it will eliminate the issues of flexure, focal length difference and mirror flop all at the same time. Note that it will not decrease the effects of mount vibration and stability.
In terms of AP though, your best bet is to get a focal reducer or a shorter (and smaller) scope

[beastmaster]

In terms of guiding: Probably the best setup is an off-axis guider with a sensitive camera. Having said that, this is also the most difficult setup to use as finding guide stars is generally not easy. But it will eliminate the issues of flexure, focal length difference and mirror flop all at the same time. Note that it will not decrease the effects of mount vibration and stability.
In terms of AP though, your best bet is to get a focal reducer or a shorter (and smaller) scope

Wont be changing to a shorter scope. Will be getting a focal reducer. But which focal reducer?

So my shopping list is?
Scope - http://www.sciencecenter.net/hutech/prices/guide.htm
A Mini Borg 50Ach F5 Basic Set (drawtube version) for any t-threaded cameras

Cam - Which to get?
http://www.astronomycameras.com/product ... k21au04as/
The Imaging Source DMK 21AU04.AS
OR
QHY5 - where to get it cheap?

Mount/Bracket
http://admaccessories.com/MDS_guidescope_kit.htm

Reducer
Which one to get?

And what else is needed?

[orly_andico]

Are you using a C8 standard or an EDGE?

If the standard, use the ordinary 0.63 reducer from Celestron.

If an EDGE, you can use the Optec 0.7X or the new Celestron one.

Since you're determined to use your C8, I'd say pay very close attention to balancing and polar alignment. And of course the longer the guide scope the better. They "say" the Lacerta MGEN stand-alone guider is the most sensitive one, but I have not used it personally. Might be worth looking in to so you don't need a laptop.

Between the QHY5 and the DMK/DBK... I have seen lots of folks using the DMK/DBK cameras for high resolution planetary imaging. Plus you can use it with Metaguide if you want to try that route. I am not sure if the QHY5 has a Directshow driver to use with Metaguide.

But then I'm using an absolutely ancient Meade DSI (first version) as an autoguider, and it works fine. I believe your choice of guide camera is not that critical, either the DMK/DBK or the QHY5 would work. I would go with whichever is cheaper.

There's a guy "oldstargazer" on the CN forums (oops.. here I go again.. ) who claims to get 2 minutes unguided with a C8 on a CG-5. So it's probably possible.

Good luck!

oh. If you intend to image in Malaysia going forward, do get a dew heater for your C8 as well.
That Schmidt corrector dews up alarmingly fast over there.

[beastmaster]

Are you using a C8 standard or an EDGE?

If the standard, use the ordinary 0.63 reducer from Celestron.

If an EDGE, you can use the Optec 0.7X or the new Celestron one.

Since you're determined to use your C8, I'd say pay very close attention to balancing and polar alignment. And of course the longer the guide scope the better. They "say" the Lacerta MGEN stand-alone guider is the most sensitive one, but I have not used it personally. Might be worth looking in to so you don't need a laptop.

Between the QHY5 and the DMK/DBK... I have seen lots of folks using the DMK/DBK cameras for high resolution planetary imaging. Plus you can use it with Metaguide if you want to try that route. I am not sure if the QHY5 has a Directshow driver to use with Metaguide.

But then I'm using an absolutely ancient Meade DSI (first version) as an autoguider, and it works fine. I believe your choice of guide camera is not that critical, either the DMK/DBK or the QHY5 would work. I would go with whichever is cheaper.

There's a guy "oldstargazer" on the CN forums (oops.. here I go again.. ) who claims to get 2 minutes unguided with a C8 on a CG-5. So it's probably possible.

Good luck!

oh. If you intend to image in Malaysia going forward, do get a dew heater for your C8 as well.
That Schmidt corrector dews up alarmingly fast over there.

hmmm... something new again.

This one has Canon EOS control... a direct control to Canon DSLR... pretty neat