7 replies to this topic

[dylann]

Hi,

 

I have a skywatcher GTI and I am wondering what a good all around setup would be to complement my Sony DSLR with a 135mm Rokinon lens and another 24mm lens. 

 

I live full time in a vehicle so space is an issue for me, for that reason I was thinking about pairing a ZWO ASI2600MC air with maybe a Redcat51/61 or SQA55. 

 

I think have the guide camera, the computer, and the camera all in one would save space and weight, and it seems like the petzval designs require fewer accessories and seem to be generally preferred. 

 

I would like to have a few lenses as well but I don't think I could fit a lens wheel in this setup.

 

I have watched a lot of videos but would like to know if anyone here has loaded the Skywatcher GTI to its 11lb payload limit?

 

My thinking is to get the longest focal length I can and stay safely under the 11lb limit. 

 

Am i overlooking any components that would add significant weight? 

 

I also have a questions about transporting equipment. I sometimes spend 3 or 4 hours driving down some really bad dirt roads, with some very severe washboarding. My vehicle is not an off road vehicle and shakes and vibrates like crazy. I throw my mount and camera and lens on the bed to damped any vibrations, but I was wondering if anyone here has other solutions? 

 

Thanks for any advice or recommendations. 

[soojooko]

Both the telescopes you mentioned are a good weight for the GTI. I used to run a 360mm refractor on my old StarAdventurer 2i, which worked quite well for 60-120s subs. But that's pushing the limit. The 250mm range would perform better I think.

 

As far as any accessories that may add weight - you may want to add an electronic focuser and filter drawer at some point which will add another 400-500g.

 

I don't have any advice regards the bumpy road problem, other that what you have suggested.

[watfiv]

I definitely had more problems guiding with a 75mm/400mm FL scope and rig that were just over 10lbs (including guide scope and focuser) than I had with my FMA180Pro-based rig that weighed a little over 5 pounds.  So keeping it light, simple, and <= 300mm FL seems right.  I’d agree, too, that 120s is probably the limit on exposure times with longer focal lengths on a GTi before sub quality starts to decline.

 

Then again, there are people here who shoot with Sigma 600mm lenses on star trackers, so it all depends on how much pain is fun for you…

[DeepSky Di]

My RedCat 51 + camera, filter wheel etc altogether weights 9lb 2 oz. It does not balance. I got an extra counterweight bar, and that by itself makes the difference without moving the counterweights onto it. 

 

The other issue with this optical train is that the filter wheel hangs down below the dovetail and can crash into the mount head. I'd suggest using a filter drawer instead if possible.

[matt_astro_tx]

I run an AT60ED on my SA2i (the GTIs little brother, which also has an 11lb capacity). My entire rig, scope, camera, guide scope, guide cam, EAF, and ASIAir, together weigh 7.7lbs. Works fine.

I second your mention of a redcat. I’d love to have one and it would perform great on my mount.

[Zambiadarkskies]

I would go for the SQA55 having seen a few reviews of it.  It looks outstanding.  I actually have a SA GTi incoming for ultra wide DSLR imaging next to my main rig. I do have an iOptron skyguider pro which is also an 11lb limit and in the past I have run it with an 80mm doublet, ZWO 533, and air and 120mm and mini guide scope.  I cannot recall the total weight, but I can tell you it was pushing the limits.  

 

Your suggestion of the 2600 air is one of the actual use cases for it that makes a lot of sense.  It will keep weight and cables (which can also cause big guiding issues) to a minimum.  

 

With the Gti, my intention is to keep things really light and simple.  I will try the 80mm doublet on it, but my real intent is 180mm focal length lens and a DSLR or 533mc.  

[JF1960]

My RedCat 51 + camera, filter wheel etc altogether weights 9lb 2 oz. It does not balance. I got an extra counterweight bar, and that by itself makes the difference without moving the counterweights onto it. 

 

The other issue with this optical train is that the filter wheel hangs down below the dovetail and can crash into the mount head. I'd suggest using a filter drawer instead if possible.

Can’t you just loosen the rotator on the RedCat51 and rotate the filter wheel out of the way?

[DeepSky Di]

It’s bolted together with an OAG and moves around different OTAs. RedCat 51 doesn’t need an OAG but once it’s set up you just keep using it. So either EFW or OAG is at risk unless the dovetail is pulled back in the saddle.