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  #21  
Old 07-10-2019, 09:59 AM
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ChrisV (Chris)
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Unless you are going with another camera lens you are going to have to get a bigger mount that can handle a scope - heq5/6 size depending on the focal length you are after. So bang, you are over budget already

I just can't see the star adventurer handling it. Or have I got something wrong in this discussion ?
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  #22  
Old 08-10-2019, 04:35 AM
poider (Peter)
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Originally Posted by ChrisV View Post
Unless you are going with another camera lens you are going to have to get a bigger mount that can handle a scope - heq5/6 size depending on the focal length you are after. So bang, you are over budget already

I just can't see the star adventurer handling it. Or have I got something wrong in this discussion ?
The ed 100 lens comes in under 4 kg and my camera is under 1kg so the should be ok
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  #23  
Old 08-10-2019, 12:15 PM
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Originally Posted by poider View Post
The ed 100 lens comes in under 4 kg and my camera is under 1kg so the should be ok
There is ok and then there is ......OK. One can never know how good until one tries, but I suppose Chris is pointing out that you are at or beyond the limit, depending I suppose on where you choose to draw the line on load related tracking accuracy, guiding accuracy and its resultant effects on image quality. To get some sort of line in the sand on the differences between mounts have a read of this (in particular see it quantified in tables 1 and 1.1 for the Star Adventurer versus other higher payload mounts, bearing in mind that using your proposed scope, the ED100 with its 900mm focal length will with the Nikon D7200 have an equivalent field of view to a 1350mm focal length optic on full frame. The data in table 1 and 1.1 for the Skywatcher Adventurer are for a 537mm focal length: VERY significantly different.

https://www.darkframeoptics.com/blog...mance-charts-1

As an aside the Manufacturer of the Star adventurer, states that ...
DESCRIPTION
Sky-Watcher Star Adventurer Motorised Mount – Astro Package

The Star Adventurer Astro Package is an ultra portable equatorial mount kit ideal for small telescopes or for astrophotography with camera lenses up to 200-300mm in focal length. It fits on most.....
from here...https://skywatcheraustralia.com.au/p...-fi-kit-black/

but somewhat contradictingly state that the mounting suits a 90mm Mak (whatever)

Perhaps you could try before you buy (your ED 100) or try with a friend's longer focal length scope.

Best
JA

Last edited by JA; 08-10-2019 at 12:38 PM.
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  #24  
Old 08-10-2019, 12:33 PM
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Icearcher (Chris)
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Hi Peter

There has been lots of good advise so far but Ill throw in my 2 cents.

If you wanted to keep using the SA then I would keep using the lens you have and look at getting a guide setup, that would extend your subs out to 5 minutes or more and would get you sorted with polar alignment in a few mins.

Keep in mind that as you get longer focal lengths then your subs will need to be shorter to stop stars trailing in your images, even with autoguiding, you will hit the limit quicker.

Also keep in mind that the ed100 would be pushing the payload of the little SA pretty close to the limit, I know its rated for 5kg and the scope and camera are 5kg but have you factored in all the other bits like the finder and the FF/FR (mine is almost 300+ grams). Plus you have the length of the scope working against you as well adding a twisting force to the mount.

Personally, I went with the Skywatcher Evostar 72ed with a FF/FR and autoguider and its been great, I can get 5 minute subs consistently with very little throw away.

If I had a $1k to spend, I would get autoguiding and get the most out of your SA. Upgrading to a HEQ5 is a great idea but a bit more expensive and you are going to want to get an autoguider eventually anyway.
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  #25  
Old 08-10-2019, 02:35 PM
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My advice would be to extend your lenses and use what you have.
Samyang 135 F2 gets a lot of good shots. Your SA would handle it easily.

A refractor, even a small one is possible with the SA but not easy.

Also when the focal length becomes longer it becomes harder to even find the objects you want to image. A go-to computerised mount then is needed.

I would say that point is around 250mm focal length.

I have a Williams Optics Redcat 51 and a Fornax Lighttrack ii and I find it:

1. Too heavy for the mount.
2. Hard to find the imaging target.

So a refractor is heavier again and I think it will be a challenge.

So either go lens (lots of targets there) or go a HEQ5 mount and continue with lens imaging and then get a small refractor. 70-100mm.

Greg.
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  #26  
Old 08-10-2019, 07:25 PM
poider (Peter)
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Thank you all for your experience and knowledge, I guess I will have to fight the urge that closer is better, I need to learn better stacking, I took a bunch of subs and lights and darks etc but didn't really like the result.
It's hard to think of taking photos of objects so far away and not using every bit of magnification.
I am already starting to think the Star adventurer was a waste with the amount of cloud we have here in Adelaide.
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  #27  
Old 08-10-2019, 07:52 PM
poider (Peter)
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anybody have any luck with micro 4 thirds, I have an Olympus OM-D E-M10 Mark 3 at my disposal with a 14-150mm lens
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  #28  
Old 08-10-2019, 08:17 PM
gb44 (Glenn)
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observations

Peter
My observation is that a range of equipment could be rated and held as a sticky in the forum. I wonder if people are aware of what is available.

More people find it easier to go wide angle - the gear can be less expensive (effective, lower quality etc) or you can go to a RASA or Takahashi Epsilon 160 astrograph.

The more magnification you use the better tracking and seeing and optics and etc need to be, up to the level of Hubble space telescope. It gets harder so at that point forgo acquisition of data and just download the Hubble ST data sets and do the processing and post processing. I am seriously thinking of doing that. Maybe that way of thinking is proportional to time spent playing with telescopes of high magnification ie. f9 and higher?

Cheers
GlennB
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  #29  
Old 09-10-2019, 11:42 AM
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Originally Posted by poider View Post
Thank you all for your experience and knowledge, I guess I will have to fight the urge that closer is better, I need to learn better stacking, I took a bunch of subs and lights and darks etc but didn't really like the result.
It's hard to think of taking photos of objects so far away and not using every bit of magnification.
I am already starting to think the Star adventurer was a waste with the amount of cloud we have here in Adelaide.
The Star Adventurer is ideal for lens imaging. That is what I use my Lighttrack ii for.

So far though the Redcat 51 is too heavy for it and a small refractor would be pushing it.

But its perfect for lens imaging up to say arbitrarily 135mm or so, perhaps 200.

I use mine for nightscapes not for deep sky particularly but I did do one deep image of the Large Magellanic Cloud.

A decent mount is the starting point.

You can get a decent image with a lousy camera and lousy lens on a good performing mount.

You can't get a decent image with a lousy mount even with the best camera and lens.

Astrophotography of deep sky objects tends to start with the ability to get round stars in 10 minute long exposures.
Not entirely true these days with the ASI and ZWO CMOS cameras where 30-90 second exposures are common.

Even then, to get round stars at 90 seconds with optics 300mm or longer is surprisingly difficult.

Greg.
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