At last, preparing the dob for action

[Ships and Stars]

After buying a SW Stargate 500p dob in March or April this year, I didn't really get to use it much, only two or three short sessions and never set up the GOTO, so for the first time in my life, I've been waiting for summer to end! 

I did somehow manage to pick up some nice eyepieces since the end of viewing season, a coma corrector and even a rather large GEN2 night vision tube from a Centurion tank sight (yes, seriously) which I'm hoping to use handheld to look through a 55mm TV plossl. More on that soon.

Now that true night sky darkness has now returned to NE Scotland, plus I have some time here and there booked off work soon, I'm seriously itching to load the van and head to the hills.

A few foibles between me and the dob: 

a.) It's very heavy (surprise surprise) to move around. I've discovered my level of personal fitness is slightly lower than I anticipated when purchasing, and my back has duly alerted me to this 🤣

b.) the secondary dews up quickly, but once cleared, tends to stay clear most of the night

c.) unfortunately my pricey Lithium power pack died, so I needed to sort something reliable, and fast

So to address these today I've:

a.) ordered a heavy duty sack truck with pneumatic tyres (NO solid tyres or solid casters) with a 60cm extension plate, so I can hopefully wheel the base and mirror assembly as one up some loading ramps into the back of my van and unload just as fast. This will make life much easier and faster, almost to the point of grab and go territory - I'm optimistically hoping. Splitting the mirror assembly from the base is a pain with the GOTO drive cable and the weight, plus the risk of something falling...if all of that can be kept together, it's quite easy to install the truss rods and top end and be up and running in maybe ten minutes or less. 

b.) Rather than potentially ordering a dew controller and three secondary heating strips for three different scopes (130PDS, 200p and the Stargate), I went with a £15 12v hairdryer that actually received a halfway decent review for clearing secondaries. That way I can grab it for whichever scope I'm using without having to run wires along the spider vanes, etc etc and faff with controllers. If it fails, then I'm not out much. This might be temporary anyway, but the dew controllers and heating strips seem really expensive to me.

c.) I went all out and bought a decent 70Ah Yuasa leisure battery - small and 'light' by leisure battery standards - for half what a dinky 7Ah lithium power pack costs. This should easily run the hairdryer for a bit, my GOTO and any other small future add-ons in the dead of a winter's night.

I also picked up a 3.5m cig socket extension with HD alligator clips, some glow in the dark tape for marking certain bits around the scope, some 32mm bullseye spirit levels and finally, three 80mm 12v computer cooling fans for the primary.

Soon hoping to provide a much better review of this scope/GOTO system that my first initial impression!

 

Clear skies all.

 

 

 

 

 

[A McEwan]

Pictures, or it didn't happen!  

 

[Ships and Stars]

Pieces and bits and bobs and batteries should be winging their way here, hopefully by the weekend.

My poor dob's been sitting in the corner all summer, waiting for some photons to hit the mirror🤣

That reminds me, I need to re-glue the foam pad to the underside of the mirror cover. Not a very well thought out cover for such a pricey mirror.

Still a few tweaks and tuning to do, no doubt, but can't wait for a clear night when I'm set up in advance and not rushing to get back home for a few hours sleep before work. And a crack at using the GOTO! At last.

[Ships and Stars]

24 minutes ago, A McEwan said:

Pictures, or it didn't happen!  

 

Here's a quickie of the NV tube and the 55mm plossl. The NV tube is too chunky to hang off any focusser, so will be handheld up to the plossl to start, or I might use a 50mm camera lens etc and make a handheld viewing device for meteor showers, etc. It certainly works, I ran 6V to it with a cheapie lens recently in a completely dark room, and voila! Could see everything nicely.

[A McEwan]

Excellent! I have always been curious about the TV55 Plossl. So can you explain the NV idea please? I've not heard of this before.

 

[Ships and Stars]

I'm definitely not an expert here, but basically I saw a video about night vision and astronomy, think it was Montana or somewhere in the US West, and he said the 55mm plossl was ideal for pairing up to a night vision tube. The next day, a used 55mm plossl came up for a good price online. The tube he used in the video was a gen3+ NV tube, a mod 3 I think he called it. It screws right onto the plossl with a simple adapter. Insanely expensive though, and not even sure you can bring them into the UK! So a gen2 mullard 1332 tube went on eBay for a cheap enough price. I'll look into adapting it to the plossl. No definite expectations! But should be an interesting experiment, haha. Will definitely let folks here know how I get on.

[A McEwan]

3 minutes ago, Ships and Stars said:

I'm definitely not an expert here, but basically I saw a video about night vision and astronomy, think it was Montana or somewhere in the US West, and he said the 55mm plossl was ideal for pairing up to a night vision tube. The next day, a used 55mm plossl came up for a good price online. The tube he used in the video was a gen3+ NV tube, a mod 3 I think he called it. It screws right onto the plossl with a simple adapter. Insanely expensive though, and not even sure you can bring them into the UK! So a gen2 mullard 1332 tube went on eBay for a cheap enough price. I'll look into adapting it to the plossl. No definite expectations! But should be an interesting experiment, haha. Will definitely let folks here know how I get on.

Cool. And what is the end result of this? Enhanced glowy views of what's in the eyepiece, or something else?

 

[Ships and Stars]

Basically, if this works, I can pair the NV tube up to the plossl and perhaps a 2x or 3x powermate, and just observe faint DSOs etc with ease. Horsehead nebula apparently is a doddle to spot!?

[Ships and Stars]

Supposedly the tube has 70,000 times the light gathering ability of the human eye, and the dob 5500-7000 times the human eye, so very faint objects 'should' jump out with relative ease! In theory!

[A McEwan]

Aha! Interesting...... 😮 

 

[Ships and Stars]

A few pieces starting to come in, mainly the 70Ah L26-70 Yuasa leisure battery from Tanya batteries, £69, 2-year warranty, free next day delivery. That's on the charger topping up. 

Stylish 'Brunner Monsun' 12v hairdryer, £16.99. Designed in sunny Italy, churned out in China. To read reviews, these 12v dryers do nothing for actual hair drying unless you are Jason Stratham, but otherwise get pleasing reviews for cheap and cherful defrosting of secondary mirrors. I've plugged it into my van and ran it for about five minutes. It does draw some serious juice, but feels like ample heat to clear a secondary mirror relatively quickly. Time shall tell. Glad I have a leisure battery for this now, a LiPO pack would drain in short order!

A set of extra long tamper-resistant torx drivers, £15.00, to remove the cover on my Synscan altitude box, there's a squeaky bearing inside that needs inspecting. Delicate surgery as to not alter the encoder settings and belt drive...more details on that to come. Holds breath...

Still waiting on a few more bits, mainly the sack truck, which may fall prey to the angle grinder and MIG welder in short order to make the dob base and mirror assembly as stable as possible when on the loading ramps 😮 I'll see how it fits first before chopping and welding...

 

Edited August 15, 2019 by Ships and Stars
added more info

[Ships and Stars]

Right, so that's the leisure battery, 3.5m long cig lighter extension with alligator clips, 12v hair dryer and today, pack of bullseye levels and no less than five 12v variable speed cooling fans (they were cheap! £2.50 each). Three fans for the rear of the primary and possibly two to clear the boundary layer on the business side of the mirror. One blowing in and one extracting on the other side, or whatever arrangement seems to work. Don't want to blow grit and dust across the mirror either, so will take a little thought...

Still waiting on heavy duty sack truck, then I think it's time to chop up my credit card for the year...🤣

Edited August 19, 2019 by Ships and Stars
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