Haven't seen any suppliers over here for CF. I actually enjoy the build process of this type of construction, the challenge of doing something a bit different. This one has been a real exercise in design and execution to much more accurate specs than I have achieved in the past. Hopefully, optically it should perform as good as an APO and with a 2" 2 x Barlow be a bit useful on planetary targets using the ZWO ASI 120mc.
Trouble is I didn't figure on how many clouds (and rain) it was going to generate. This lousy weather is predicted to continue till next weekend at least.
Wet lacquer drying in the winter shade. Then mirror cell with retainers and the velcroed mount pads. Mirror in place and light shield then the styro lid to keep it safe.
Not shown is the secondary attached to the spider all ready to go. Did a simple collimation and it looks good. Can't do a full 'on-axis' collimation till the silicon sets in the side retainers. Fun twiddling the machine heads to move it round. I centred it first with a ruler.
I've had some eyes raised in the past about the Velcro mirror mount system but I did a simple test with this one. Once the mirror was bedded down I held the sides of it and lifted the whole scope up ! There is about 6 sq inches of Velcro surface ( industrial strength ) and it is rated as being capable of supporting a minimum of 2 lbs per square inch. ( USA supplier ) so between that and the silicon side buttons I feel quite confident with the system.
First imaging test, no, the clouds HAVEN'T gone away. In fact it is raining cats and dogs. So this is bench mounted in the back of the garage pointing outside through the gaps in the neighbours deck rails at a couple of Norfolk Pines about 4 km away in steady rain. ( It was the only distant target I had in the circumstances ) The 'vignetting' is actually the upper most rail on their deck intruding into the frame.
If you look closely at the top of the leftmost tree ( jpg compression and size of file allowing of course ) you can make out the pine branches and the leaf extensions individually ..
I hereby declare this build a success
Now where did I put my cloud sucker upper ??
Single speed focuser? Was that by choice or what you had on hand? BTW i'd love to see a detail photo of the guitar string arrangement and tensioners. Did you use guitar string keys to control the tension and how are they mounted? Looking at that for my next scope. Looks great, but you will now have cloud and rain for months because of it.
GlenD> yeah, the focusser was what I had available from my 10" upgrade ages ago. I'll upgrade if necessary although I think I would go for motorised maybe, another project for DIY ? . This thing is quite long and the focusser is going to be a reach.
I'll do you some Guitar Machine Head pix and post them up but nothing to them really. I just drilled holes through the rings and mounted them as per usual fittings would allow. I faced them outwards for three reasons, 1, to maximise the angle to the centre, 2. to stop the string winding off by being pulled over the end and 3. to protect the knobs from bumping as much as possible. Rolf uses a swivelling block to keep them straight but in my case they just come off the spindle to the centre and float clear of the rings. That works for guitars, works for me. Simple and lightweight.
Spider details. I had to add a brass spacer under the machine head nut to make it tighten up but other than that all the hardware for it comes in the packet. Wee screw at the back to stop it turning, black washer and nut. Got it all ( 3 sets of 6 ) plus I think 5 packs of 'E' strings for about $40. I have enough hardware to modify the 10" later if I want.
Excuse the garage mess but there is the whole scope as tested.
EDIT: Each 'pair' of machine heads, top and bottom ring are aligned and by using the left\right sets ( 3 of each in each pack ) all the knobs turn the same way to wind off or wind on and the strings also align off the same side so stay parallel and hopefully (within tolerances ) also vertically aligned so minimal diffraction or added thickness. Strings also blackened with permanent marker pen, very little additional thickness added.
8.6 kg ! half the weight of the 10" ( I just whizzed downstairs with the bathroom scales, thanks for reminding me )
That is slightly better than I'd hoped, 10 kg was my expected result.
Overall it's nearly 1.6 meters long, max width is 350mm. Still to get finder and guide scope attached.
Weather is a bit better tomorrow supposedly, I'll try and do a few more imaging tests under better conditions.
Siliconed the secondary in place last night. Hoping for first light over the weekend.
You guys, buy something !! Keep the clouds preoccupied so they don't notice anything ...
Well the weather has been EXTREMELY uncooperative this weekend so First Light is delayed. I pulled the dovetail off the 10" and mounted that onto the scope. I have a guide scope idea coming along. Planetaries are all very well but I want more from this than just that. Hopefully later in the week the weather is looking a bit more promising.
It's up on the EQ6 finally and did some photo tests and a realignment of the mirrors. She is a bit tetchy to fiddle with, requires very little tweaking to make a big movement. Finally got it right and took some pix with the SONY. It has a focus aid highlighter on the back screen. It's looking good so far. Two shots of houses, the same house not centred in the second shot but with a 2 x Barlow. Distance is about 3.5 km. The crane boom shot is about 2 km away.
Sorry, no 'First Light' yet, weather is NOT cooperating. No sharpening done on any pic.
First light for the RN 8F8 scope. Downright freezing out there (4* !!).
This is a single frame ISO 6400 15 secs in the SONY SLT A77v DSLR unguided and basic processing. LP is high so red shifted downa lot and noisy at ISO 6400 so I ran Noiseware over it to calm it down a bit. No darks, no flats no stacking.
I have some more of K Cru and another small cluster in Carina but I need to play with them a bit. I should be able to stack a group of frames on Eta C later but it's way past my bedtime. Just happy that the field looks quite flat.
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