Upgrading the guide scope, will it be worth it?

[bomberbaz]

I have recently upgraded some of my imaging gear, the new mount (when it arrives) will be a HEM15 holding a 150 quattro (previously an AZ Gti & a 72ED) and I was thinking that as it is capable of taking a little more weight comfortably, should I bother.

I have a F4 svbony 60mm guide scope that I had forgot about, it would be a direct replacement of my F3.75 WO 32mm Uniguide if I wanted to take this route.

Aside of the increased aperture and slightly longer FL, what else would this potentially offer in return in imaging guiding terms?

cheers

steve

 

 

[WolfieGlos]

When I upgraded from my Evostar 72ed to the SF 102ed, I had similar thoughts.

My scope is slower than the Quattro but with a little more reach (720 native FL compared to your 600). I asked FLO and they said my current ZWO 30mm guidescope with the asi120mm would be fine. And it is 🙂

I’m sure others can give technical reasons one way or the other, but just thought I’d drop some real world usage in. I’d be interested in seeing what benefit there could be though.

[Elp]

Not sure on actual numbers but the first thing you'll notice is being able to see more stars (better resolved) when looking at the live view through the larger guidescope. I did the same for another reason, changed from an SVbony 30mm to a 50mm guidescope. The 30mm was freed up to go onto another setup.

Edited November 12, 2023 by Elp

[Astroscot2]

If it were I, I would go down the OAG route with a Newtonian.

 

Mark

[bomberbaz]

11 hours ago, Astroscot2 said:

If it were I, I would go down the OAG route with a Newtonian.

 

Mark

What is the benefit of an oag over a standard guide scope other than a little less weight?

[tooth_dr]

2 hours ago, bomberbaz said:

What is the benefit of an oag over a standard guide scope other than a little less weight?

The main mirror in a reflector can move a bit. Using an oag means you are also guiding through the same mirror, and therefore follow all the same movements. A guidescope doesn’t and you can end up with issues when even though your tracking is good, you still have poorly shaped stars.

[Elp]

Also the guiding RMS may improve slightly but if you're not imaging at such a resolution the gain is pointless. OAG also is better if imaging at long focal lengths, but sometimes you struggle to find stars which is why they usually have rotators built into them.

 

[bomberbaz]

3 hours ago, tooth_dr said:

The main mirror in a reflector can move a bit. Using an oag means you are also guiding through the same mirror, and therefore follow all the same movements. A guidescope doesn’t and you can end up with issues when even though your tracking is good, you still have poorly shaped stars.

Yes makes sense and can see how that would work.

2 hours ago, Elp said:

Also the guiding RMS may improve slightly but if you're not imaging at such a resolution the gain is pointless. OAG also is better if imaging at long focal lengths, but sometimes you struggle to find stars which is why they usually have rotators built into them.

 

Ok so would be imaging at F4 or F3.45 depending on if I use of CC or not. Not would be during spectroscopy. So maybe the OAG benefits are likely to not be quite so pronounced if indeed there are any!

Based upon the fact I already have the two guidescopes but no OAG, once my other gear arrives I think some starfield rich practice images with the two guidescopes as a shootout to check star shapes and compare RNS would be the most sensible approach.  I have learned over time not to open the wallet in haste to avoid impulse buys wasting ones funds. This last action has only taken me 60 years to achieve too, quite proud really 👍😂

[Elp]

If you don't need it you don't need it. I too was curious and didn't think it affected my images much (it was also a pain to setup but partly because I setup from scratch each time). But if I image F6.3 with my C6 (1000mm+ FL) it's essential.

[bomberbaz]

7 minutes ago, Elp said:

If you don't need it you don't need it. I too was curious and didn't think it affected my images much (it was also a pain to setup but partly because I setup from scratch each time). But if I image F6.3 with my C6 (1000mm+ FL) it's essential.

Ah now there we are at an all different ball game. Also some scopes of that design are known for having a little mirror movement and as you say at that FL, a little can make a lot.