Guide Scope

[bladekeeper]

I have been eyeballing this guide scope for a while: https://agenaastro.com/agena-precision- ... -60mm.html

And it has been "out of stock" for a while too.

But, over on Ebay, I see what appears to be the very same guide scope direct from China for half the price: https://www.ebay.com/itm/60mm-CCD-Imagi ... 3028905104

I have ordered astro stuff from China on a couple of occasions. It takes a little longer to get here, but it gets here, and China Post always kindly provides a tracking number.

So is there any reason why I do not want to order this direct from the folks that make them?

[Gordon]

If you don't have a mounting issue. These work really well.

https://optcorp.com/products/or-8891-mi ... gLN7fD_BwE And it's in stock and ships from the US.

[ARock]

I bought the 50mm version of the guidescope on ebay for about $60.
Still think it is too expensive compared to my $90 OTA

[JayTee]

My only reservation is that it is suspended in a 3-point ring mount. This is typically a "differential flexure" source of frustration. Go with the Chinese version because it's cheaper and is only being used as a guide scope, which means I'd do a little surgery to it and afix a dovetail foot to it instead of the rings.

So, go cheap so the surgery will be less painful. Remember that I use a $10 70mm f/5.7 frac from Craigslist. So going cheap doesn't necessarily hinder your guiding.

Cheers,
JT

[Aidi]

I used the very same 60mm scope for a year before switching to OAG. Mine was branded Orion. Very good scope and did an excellent job guiding. If it were me, I’d go with the eBay option

[helicon]

It seems like you can't really go wrong with either option, though I'd probably go with the new one.

[bladekeeper]

Thanks for the great input, friends!

I think I may go with Gordon's suggestion of the Orion Mini.

As for flexure, this seems to be one of those things that have pros/cons for varying styles. I've read that the plunger style bracket with the Mini can have movement due to the spring pin not being strong enough, so go for the three-point rings. And then I have also read comments similar to JT's. So it sounds like things can go either way and really may depend also on how well a specific piece behaves.

Another concern, of course, is overall weight and how much of that a component will add to the setup as a whole. Seems like the Orion Mini would be better in that regard at less than half the weight of the other.

[Aidi]

Does this guidescope get used on all of your scopes or a particular one? Ever considered off axis guiding?

[bladekeeper]

Does this guidescope get used on all of your scopes or a particular one? Ever considered off axis guiding?

While I use multiple scopes for imaging, I use only one for long exposure deep sky. The others would be employed for lunar/planetary and no need to guide there.

As for OAG, I have not considered that overly long. Not being a dedicated astrophotography (I am a visual observer who is dabbling) it seems a bit more complicated than I need for my present circumstance.

[ARock]

There is also the

which looks like a clone of the Orion mini.

The 3 point ring is a bit of a pain to adjust, compared to my RACI. But I don't know if the 3 point ring is more stable than the RACI like adjustment of the Orion mini.

[UlteriorModem]

Don't you have an old ST80 laying around? They make pretty good guide scopes. You will need a looooong extension tube though

[bladekeeper]

Thanks, AR and Tom!

Yeah, the Meoptex does appear to be the same. There are several on Amazon labeled with different names. All appear to be the exact same scope.

Tom, yes indeed I do have an ST80, though I would likely have to put the OEM focuser back on there to save weight. The GSO Crayford on there is quite weighty.

Not so sure I'd need an extension tube. I have imaged the full Moon several times with my ASI120MM (what I plan to use for the guide cam) and have no issues reaching focus. That was with the GSO Crayford though. The stock Synta focuser may be a different matter.

I've also got a spare ES 50mm straight through finder that would be great if I could find a way to mount the cam on the end of it.

[UlteriorModem]

I thought I had a picture of when I tried an ST80 as a guide scope with some guide camera in it. Could not find it.

But I distinctly remember needing like a 2" extension tube (stock focuser).

[OhNo]

Your ST80 would work with the ZWO ASI120 IF you use a diagonal. I built a guide scope out of a old finder scope, but I have a machine shop full of old junk that is always looking for a new purpose in life.....

From the other forum there was a thread about the ratio of scope to guide scope, might want to insure your getting the one with the proper ratio!

[bladekeeper]

I thought I had a picture of when I tried an ST80 as a guide scope with some guide camera in it. Could not find it.

But I distinctly remember needing like a 2" extension tube (stock focuser).

Your ST80 would work with the ZWO ASI120 IF you use a diagonal. I built a guide scope out of a old finder scope, but I have a machine shop full of old junk that is always looking for a new purpose in life.....

From the other forum there was a thread about the ratio of scope to guide scope, might want to insure your getting the one with the proper ratio!

I reading Tom's reply and I had a face-palm moment! Yeah I was indeed using a diagonal! Apologies for that, Tom! And thanks for the validation, Brent!

I'll need to see if I can locate that AF thread...thanks, Brent!

[OhNo]

Let me know where that thread is if/when ya find it. I believe Kathy was instrumental in it.

[Gordon]

Hey Bryan.

Try this and see if it helps: http://astronomy.tools/calculators/guid ... uitability

[JayTee]

When using a guide scope you want to compare Imaging scales between your Imaging scope and your guide scope. in the olden days we didn't like our Imaging scale to be greater than 4 to 1. Nowadays, with PHD2s sub-pixel guiding ability you could actually get away with up to 8 to 1.

Keep in mind that your best guiding occurs as those Imaging scales get closer and closer to 1 to 1.

Cheers
JT

[bladekeeper]

Holy cow.

Since it is completely socked in cloudy for the next decade, I've been playing with the guide scope and guide cam. I've got the whole rig set up in my living room. Added a USB 3.0 hub yesterday.

Anyway, everything is talking nicely. Even tried out NINA and all works like a charm. Just need some stars showing so I can try actual guiding.

Trying to help a feller out over on AF, I just hooked up mount and guide cam to the PC. Pointed the scope out of the back living room window. There is a travel trailer parked about 3/4 of a mile away. And we are in deep twilight now. Anyway, I could clearly see two gentlemen working on an ATV there in front of the travel trailer.

While I was fiddling with exposure, one of the guys stood up walked a bit in my direction, looked around, assumed "the stance", whipped it out and began urinating right there in PHD2.

I started laughing my head off and my wife and the boys came running. Fortunately, not much detail to be had but you could see the flash of the stream in the rapidly fading light. That was terrible but humorous timing.

[JayTee]

Okay, I tried to reply, but I got nothing.

JT