Recommendation for lightweight 70-90mm Refractor (triplet or Quad) under 5kg with rings & Dovetail

[Northernlight]

Hi all,

I'm just getting back into astro imaging after a year away and i'm building a small portable grab and go rig using a Sky watcher Star Adventurer GTI which has a 5kg limit.  So i'm looking for recommendations for a small 70-90mm apo refractor that will fit the 5kg limit, well more like 4.5kg as i need to account for a 500g for the miniguider and my asi585mc 

Any recommendations for a lightweight scope would be greatly appreciated.

Cheers,

Richard.

[bomberbaz]

I use the sw az gti in eq mode with a sw 72ED. It isn't a triplet granted, but it does give a well corrected, flat field when in use with the stellamira FF and is only 2kg. However I have 2kg of counterweight to contend with too. 

The william optics range al;ways seem highly recomended and the 81mm triplet weighs in at 3.3kg. Ttoal weight is 4.5kg. William Optics GT81 WIFD Apochromatic Refractor | First Light Optics

[Elp]

My azgti Z61 setup weighs 6.5kg and images fine. I can likely knock 1kg off, but happy with the current setup. Extra hardware adds a lot of unaccounted for weight (I've added the cat handle, guidescope tube rings, longer dovetail for better Dec balancing).

You'll struggle for weight approaching 80mm maybe before especially for triplets and quads as glass weighs a lot. Borg and the ES carbon range are some of your limited options at size.

[Northernlight]

Elp, i just saw a nice one that is just within the weight limit. FLO does the StellaMria 90mm carbon fibre triplet which comes in at 4.5k with all the rings and dovetail etc, then my 30mm guider and asi 585 camera weight 413g, so i'll be coming in just under the weight capacity limit at 4.9kg but then add 100-300g for a flattener.  I figure if i take off the handle i can get it bang on 5kg. 

With a small camera sensor i might not need to even use a Flattener.

 

[Elp]

I know a lot of people like those scopes. As a general rule you should never go to max load on mounts for AP, I am doing it aware I (may) be causing damage to my unit but the cost of it is such it doesn't concern me much. For better guiding and more consistent guiding I use a heavier duty mount.

The SWGTI is supposed to be better built but I haven't used one so cant comment. You can perhaps shed more weight if you use an OAG, it will also guide better.

[Northernlight]

The guider is only 250g, so no massive weight saving. The 30mm guide scope should be fine as I’m only planning 2-3min exposures at about 500mm FL

[900SL]

GT71 or similar clone triplet, don't forget to allow for field flattener / reducer

[Martthebass]

14 hours ago, Northernlight said:

Elp, i just saw a nice one that is just within the weight limit. FLO does the StellaMria 90mm carbon fibre triplet which comes in at 4.5k with all the rings and dovetail etc, then my 30mm guider and asi 585 camera weight 413g, so i'll be coming in just under the weight capacity limit at 4.9kg but then add 100-300g for a flattener.  I figure if i take off the handle i can get it bang on 5kg. 

With a small camera sensor i might not need to even use a Flattener.

 

I'm using the 90EDF, albeit on a bigger mount and it's a cracking little scope.  I do use the flattener on a asi 533 but I concur you would probably get away with it on the 585