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The Ultimate Travel Rig
I bought my Tak FS60cb second hand and paired with a no longer produced and relatively cheap Borg x0.7 super reducer. New the Tak FS60cb with it's dedicated reducer costs £1173. A great scope but not budgety - also this set up works best with a mono camera which means you need to buy a filter wheel and filters too.
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Telescope:Takahashi FS60cb with reducer
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Mount: Skywatcher AZ GTI
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Camera: ZWO ASI178mm
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Filters: Mini filter wheel and Baader LRGB filters
Inspired in part by Stellina and refined through experimentation the ultimate biscuit travel rig is powerful and relatively cheap but to get this set up singing calls for a high level of geekery. Before I guide you through the theory of what makes this rig good, lets lay out the blue prints so you can see what she's made of.
The Telescope
Takahashi FS60cb
Dedicated FS60cb 0.72 reducer
The Tak FS60CB has a fluorite crystal front lens which reduces colour fringing making this scope 'tak' sharp. If you combine it with the dedicated reducer you get a fast (F4.2) sharp scope capable of resolutions of about 2 arc seconds which just happens to be the resolution of the mount (we measure mount wobble in arc seconds too) its all part of what makes this such a good little astrophotography set up. Everything is in balance. You might want to spend a bit less money on the scope though. Below are what I've heard are good although I've not actually used them.
Alternative scopes
I think the Evostar 72ed is probably the best value scope for this rig. Although tbh any small apo refractor would do it.
Don't be fooled by the size of these little beauties, as you'll see they're gonna pack quite a punch.
The little 61mm Zenith stars (above) look super fun but I've not actually used them.
The Mount
I LOVE the sky watcher Az-GTI mount (I talk about this mount here). You can control gti via wifi through an app on your phone (just like Stellina!) or on your laptop (recommended) .To really make this mount sing you have to align it with the rotation of the earth. That means buying some kind of wedge and counterweights and installing a firmware update which allowsit to work in eq mode.
You find the same shafts and counterweights on the old eq1 mounts
Skywatcher has a little adjustable wedge which isn't very precise but with a bit patience it does work
The Skywatcher AZ GTI mount doesn’t have a polar scope, so after an initial rough alignment - simply by angling the mount to 52 degrees( which is my latitude in London) and pointing it North - I then use sharpcap software's polar alignment tool along with an adjustable wedge or tripod of some kind to align the mount to the rotation of the earth to with an accuracy of less than 1 minute. Having a good quality adjustable wedge really helps you get excellent polar alignment... I actually use an old Meade deluxe field tripod instead.
William Optic's wedge is pricey but it is better than Skywatcher's offering.
Skywatcher AZ-GTI Summary
PROs
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Cheap
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Surprisingly good at tracking especially in eq mode (less than 2 arc seconds wobble when guiding).
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Super Portable
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Has GOTO function via phone app
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Can connect to a computer via wifi allowing the use of serious and powerful astrophotography software like Nina
CONS
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Is intended as an ALT AZ Mount. In order to make it work in EQ mode you need to install firmware and cobble together a suitable mount which can be polar aligned. Brief description here
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No polarscope
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Need to acquire counterwieght and counterweight shaft.
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Complicated
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Can only carry small scopes
STOP PRESS !!!
Skywatcher have just brought out the Star Adventurer GTI which I am confident will be even better than the modified AZ-GTI above. I'd get this if you can afford it.
The Camera
The final and most important part is the camera. I reccomend the ZWO’s asi178mc or asi178mm. This is a very fine lunar, solar and planetary camera (see here) can also be used for deep space astrophotography. To be honest the credit for choosing this camera really goes to the roboscope Stellina although I had run a few tests on the imx178 sensor a few years before. The colour version is fantastic but for extra flexibility and performance you'll need the mono version with zwo's mini filter wheel (see here).
Bodes Nebula and the Cigar Galaxy shot with a sony imx178 sensor in a point grey camera back in 2016 through an old televue NP101
The tiny 2.4um pixels in the imx 178 sensor reveal a tremendous amount of detail. This is key for the travel scope design because it means that you can shoot through a small telescope and still get tremendous detail - enough detail to reveal galaxies 30million light years away. Amazing isn't it.
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Evolution of theTravel Rig
In February 2021 the biscuit man decided to take on the awesome but expensive robotic scope known as Stellina. You can watch the video of this astrobiscuit adventure here. I wanted to replicate Stellina's power without the 3 grand price tag. To match Stellina's 80ed optics I borrowed youtuber Astrofarsography's skywatcher 80ed telescope. I mimicked Stellina's alt-az fork mount with my Skywatcher AZ-GTI (in the standard alt-az mode) and I borrowed from FLO a camera with the same Sony imx178 sensor that I though Stellina was hiding under her bonnet (the ZWO asi178mc)
VS
The optolong L extreme filter performs as well as filters I own which cost 3 times the price.
As we were in lockdown the test was done from light polluted London which was a bit annoying but there you go. Stellina has an inbuilt light pollution filter. To match her I plumped for an Optolong L extreme.
Thing is the Skywatcher 80ed is too long. Or another way of putting it is that it is too slow. In fact at f7.5 I’d say the Evostar 80ed is disappointingly slow At f5 Stellina's scope is really fast and gathers light really quickly. For the Evostar to catch up we need to reduce its focal length to about 500mm. I used an old borg 0.7x super reducer. You can’t buy these anymore. I got mine for about £200 second hand and to make the reducer fit into the scope I needed an adapter supplied by Beat from Switzerland (if you buy from him please tell him the biscuit sent you!)
