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Guiding scope and camera recommendation for newbie

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#1 Waterobert

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Posted 19 September 2019 - 10:17 PM

Few days ago I got my stellarvue 80mm, 480mm focal length, F6. If ups delivers T-adapter and  weather permits, this weekend I may get my first pictures using Nikon D810 !!!

Scope and camera will be mounted on Mach 1, hopefully I can get some short 30-60 seconds subs without guiding.

Anyway, my next purchase should be guide camera. I read that 50mm guide scope and ZWO ASI 120MM mini are good enough for wide field AP. Is getting 60mm guide scope a better option ? Are there better cameras at similar price point? 

 



#2 durak

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Posted 19 September 2019 - 11:05 PM

There aren't better cameras than the asi120mm mini at the $150 price point. The next step would be the asi290 at about $300. It is a significant improvement but costs twice as much.
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#3 bobzeq25

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Posted 19 September 2019 - 11:08 PM

Either the 50 or the 60 will do fine.  That camera is a good bargain choice.

 

The _crucial_ thing is to mount the autoguiding system _very_ rigidly.  Nothing will degrade results like getting that wrong.  And it's devilishly hard to diagnose.  Your guiding looks fine because the guidescope is tracking, but the main scope isn't following perfectly, which messes up your stars.

 

Scroll down this page for good examples.

 

https://www.cloudyni...ardrails/page-4

 

Do not use a finder shoe.


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#4 Waterobert

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Posted 20 September 2019 - 06:24 AM

There aren't better cameras than the asi120mm mini at the $150 price point. The next step would be the asi290 at about $300. It is a significant improvement but costs twice as much.

So, instead of spending more on 60mm guide scope I would be better off with asi 290 in the long run, right?



#5 bobzeq25

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Posted 20 September 2019 - 09:02 AM

So, instead of spending more on 60mm guide scope I would be better off with asi 290 in the long run, right?

The difference is this.  The 120 works fine with a guidescope.  The 290 will also work with an off axis guider.

 

But depending on the OAG you (eventually) get, and your position on imaging DSOs at the time, you might like something other than a 290 for that.  I used a 120 with a couple of different guidescopes with no issues.  I got a 174 for my Celestron OAG (because that OAG has a large prism, which can use the 174 well, and I also wanted to do some lunar with it), now use it with my guidescope (I don't use the OAG on my short focal length scopes), also.

 

A complicated business, this.  Nothing will help you make future purchase decisions like some experience.  In the meantime, just be aware that others concerns may not be yours.  You need to understand _why_ people are recommending this and that.  I recommended the 120 to you because it's cheap and it works.  The one you want is the 120MM-mini you listed, the form factor is flexible, and the chip/drivers seem to be compatible with most hardware/software.

 

The 290 would also work fine, and might be more useful in the future.  Might not.

 

General rules.  Knowing _why_ in AP of DSOs is important.  The reason for _that_ is that this complicated business is often also unintuitive.  Short posts here like "this is better" often don't tell the whole story, for you.


Edited by bobzeq25, 20 September 2019 - 09:09 AM.


#6 Waterobert

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Posted 20 September 2019 - 08:12 PM

Nothing is simple in AP, lol !!!

 

My grand plan for my AP future is to get  fast  5 inch refractor with 900-1000 mm focal length. That may or may not happen in 2-3 years time, however all my AP purchases are with that scope in mind. If 50mm guide scope with asi 120mini would still work at 1000mm focal length, than no need for spending extra money.  At what focal length OAG is more practical?  



#7 Stelios

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Posted 20 September 2019 - 08:41 PM

Nothing is simple in AP, lol !!!

 

My grand plan for my AP future is to get  fast  5 inch refractor with 900-1000 mm focal length. That may or may not happen in 2-3 years time, however all my AP purchases are with that scope in mind. If 50mm guide scope with asi 120mini would still work at 1000mm focal length, than no need for spending extra money.  At what focal length OAG is more practical?  

At 1000mm focal length, and depending on imaging camera, the 50mm guide scope may not be best (it will guide fine, but it may not be best). 

 

At 1000mm F/L, I would use an OAG (I would use an OAG even at 480mm F/L, but I can understand avoiding the expense and the complexity when it's not needed).

 

With what you have now, almost everything will work (assuming you mount your guidescope well, as Bob said, and, I might add, even if you don't :)). 

 

But as you increase F/L, and especially if you are working with smaller pixel imaging cameras, you will want your guiding to be more accurate, and *that* will be the time to switch to OAG.

 

As long as you have a guide scope, you need nothing more than the ASI120MM-mini (assuming you don't use a C11 or something as the guidescope :)).

 

Getting an ASI290MM-mini won't benefit the guide scope, but it means that you have a good camera for both a guidescope and an OAG. *However*, whether it's best choice for an OAG will depend on OAG. If you get an OAG with a large prism, then the ASI174MM-mini would be a better (and more expensive) choice. If you get the ubiquitous ZWO OAG, the ASI290MM-mini will be fine.

 

Why get an OAG with a larger prism? To give you access to more stars for guiding.



#8 bobzeq25

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Posted 20 September 2019 - 09:35 PM

Nothing is simple in AP, lol !!!

 

My grand plan for my AP future is to get  fast  5 inch refractor with 900-1000 mm focal length. That may or may not happen in 2-3 years time, however all my AP purchases are with that scope in mind. If 50mm guide scope with asi 120mini would still work at 1000mm focal length, than no need for spending extra money.  At what focal length OAG is more practical?  

It's a judgment/personal call.  I use the OAG at 910mm, the guidescope at 580.  I'd say most people would use one at 1000mm. 



#9 Waterobert

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Posted 21 September 2019 - 06:59 AM

I am getting ASI 290mm-mini. This will give me option of OAG in the future and according to ZWO "this camera can enhance guiding precision over ASI 120 by 30%". On the grand scale of AP of things $150 more for 30% better sounds like a good deal, lol. I definitely can't spend $500 for ASI 174mm-mini.


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