My Journey So Far

[PhilPassmore]

Mods, if you think this would be better placed in one of the other sections, by all means move. It is just my first proper posting, and an intro. 

 

Hi everyone, I thought that I would introduce myself, and tell you a little about my short progression into the hobby.

 

I'm possibly average in age for stargazing, at sixty one, and I so wish I had got into astronomy when I was younger. What I have been seeing and learning is just so much fun. 

 

I bought a really cheap 4 1/2 inch reflector a while ago (though with a discount from Ebay, it effectively cost me nothing). It came mounted on a cheap equatorial mount which I took the time to learn how to use, which definitely helped a lot. It came supplied with some cheap and nasty 0.95 inch eyepieces, which were almost bad enough to put anyone off astronomy in their own right. But with that scope, I actually saw Saturn and her rings. Ok, so it was actually a pretty small elongated blob, but you could tell what it was. I was so chuffed. 

 

About a year ago, I picked up a humungous home made 10 1/2" Dobsonian, all wood construction, and pretty rickety. No finderscope, but a full size focuser for which I bought a couple of mid range eyepieces. Now I know saying this will probably have all you die hards yelling at me, but I struggled to get that piece of furniture pointing at very much at all, other than the moon, which I must say, was utterly spectacular. I had never seen it with such clarity and detail. So this has prompted me to start thinking about building a goto system for the mighty Dob. Arduino based, driving some stepper motors, and at the same time seriously thinking about getting the mirror re-silvered, as it is significantly hazy. 

 

So, I tend to be a bit slow getting projects underway, as I put a lot into the planning phase. Therefore, I thought it would be nice to have a stop gap. Facebook marketplace found me the complete opposite of the Dob in the shape of a 60mm Meade refractor in its own little dedicated goto mount. This proved to be a great little scope (to my eyes at least) and portable enough to get dragged out in my campervan to darker skies. The camper incidentally was my Lockdown I build project. Six months of solid graft, but that's a story for another day. 

 

While playing with the Meade, I read up loads, learned tons, and actually got the scope to point at things I wanted, and TRACK them. This was a revelation. Not having to continually manually shift the mount made life so much easier and enjoyable. At this point, being a dedicated AliExpress follower, I decided to have a go at building my own refractor, and following the maxim of 'go big or go home', bought an achromat airspaced doublet from the said AliExpress, and the cell to hold it. I went mad, and got the 150mm x 1300 version. 

 

Construction is based around a section of underground drainpipe for the objective end, and some carbon fibre tube of smaller diameter for the eyepiece end. The objective cell is a perfect fit on the drainpipe. The coupling between the two sections is machined from 20mm thick plastic sheet, turned on my Myford lathe into two rings, retained with machine screws. The focuser, another AliExpress buy is quite a nice dual speed unit that required a 94mm x 1mm pitch thread ring to screw into the rear of the scope. This was made out of aluminium. Most of the other hardware was off the shelf from the same well known Chinese source, together with a star diagonal (2 inch being retained). Although I haven't yet baffled the scope, I have flocked the entire length, which was quite fiddly. I am not sure if baffles are completely necessary now, as the flocking really kills internal reflections of stray light. 

 

It's all set up on a Skywatcher EQ 5 Synscan mount, and when I recently got to point it at Saturn, I was absolutely gobsmacked! Yes, there is significant chromatic fringing, but what do you expect with a 150mm refractor, that only cost about £300 for the OTA?  But seeing such detail as I could, especially through my recently acquired (off a Stargazer Lounge seller) Takahashi eyepiece was beyond what I was expecting. It is truly beautiful. I have been viewing both it and Jupiter every clear night for the last month, and every time it makes me gasp! Incidentally, the goto system on my little Meade died, so with a bit of hacking about, and making a mount, it's now been pressed into service as a finder scope. 

 

I am a bit restricted in my viewing, as my house blocks views to the north, so I am waiting for my first views of M31 as it creeps round from the east. I recently built a deck on the back of my slightly raised house, accessed from some French windows, and about a meter off the ground. Conscious that such a wooden structure is going to wobble like mad when the scope is on it, from the slightest footstep, I used another piece of the 150mm drainpipe from the scope build, as the former for a steel reinforced concrete pier that comes up to just below deck level, and is accesed through a section of removable decking. The pier is completely isolated from the deck, and the scope will mount on an extension of the pier, made up of left over bits of aluminium from the van conversion, TIG welded together, and retained to the pier proper with hand nuts. In the interim, I have aligned the tripod pretty well, then put brass marker studs into the deck in the location for each of the legs, meaning that as long as I don't disturb the head of the tripod, I can get pretty good polar alignment in a matter of moments. The pier should be even more accurate with some planned indexing pins. 

 

So,that's where I am. I love the tinkering aspect, and I adore seeing things that relatively few people have looked at. Stargazers is a great resource, and I thank you all. Phil. 

[Astro Noodles]

That's some excellent tinkering and DIY you've done there. Thanks for sharing it with us.

Welcome to SGL

[banjaxed]

Hi Phil, welcome to SGL. I think it must me in astronomers blood to tinker with our gear.

[barbulo]

Hi and welcome to SGL

[Nigella Bryant]

Welcome to SGL, brilliant bit of engineering and so fulfilling to see the results of your own work. 

[Floater]

Welcome. Hope you continue to have lots of fun. 🙂

[Luke]

Welcome to SGL, Phil!

Sweet looking scope!

When I looked at your last image, I initially read the brand name on the diagonal as "AliExpress"! 

[RT65CB-SWL]

Hi @PhilPassmore and welcome to SGL ... from another Phil or Philip. 

[Starwatcher2001]

Welcome aboard SGL Phil. Good to have you with us.

Love the projects that you've done. Well played.

I motorised my own homebuilt dob about 20 years ago. The driving software was MSDOS based, provided free by a very helpful American chap called Mel Bartels, who's well know in ATM circles. This communicated using the parallel printer port of an ancient laptop to a home-built driver circuit cobbled together on vero-board. The bipolar steppers came from an old mini-computer printer. The hardest part was the physical connection between the steppers and the mount. I'm no engineer and don't have a lot of facilities, so used threaded nylon rod around both the alt and az wheels, driven with a worm drive. The main problems were accuracy and getting a decent slewing speed. I never overcame the accuracy issue but managed to get "goto" within 2-3 degrees or so of the intended targets. The tracking worked well enough for visual (microstepping the motors). Slewing problems were solved with a combination of ramping up and down the stepper speeds, and adding flywheels to the motors keep the momentum. Oh, the whole thing ran on two car batteries, which weren't exactly light to move around.

It was a fun project and I learned a lot, but the whole apparatus was unwieldy and needed a lot of babysitting. Having realised I'd spent 18 months messing with tech rather than doing much observing, I gave up and reverted the dob to manual.

Things have moved on a lot since then, and you look to have a lot more engineering skills. Looking forward to seeing what you create Phil.

All the best,

Mark

[Dave Lloyd]

Hi Phil, welcome. 

[Pete Presland]

Hi welcome to SGL from Pete in Bedfordshire 🙂