View Full Version here: : 508mm Imaging Newt
This is my 1st ATM and I have dived in at the deep end. First a little about my reasons for starting this project. I began this new hobby only a couple of years ago after selling my boat and retiring from target rifle shooting plus at 65 it was time to slow down from my job as an electrician. I had an interest in astronomy so bought a 5" Meade and enjoyed using it for a year before aperture fever grabbed me. I had the opportunity to by a 14" Meade for a reduced price and built a ROR to house it and was very content viewing & taking images with my converted Canon 600D. Then one day I had a phone call from a chap who was planning to visit my area and had heard I had a polar mounted 14" and wondered if he could use it with his camera to take images of planets. NP I replied not knowing what I was letting myself in for. Bird arrived a few weeks later and spent some time collimating and adjusting my badly setup scope. I spent 2 weeks watching with amazement as he created many wonderful images of Mars and got hooked on planetary imaging. Several visits during the next 18 months during which he brought his 16" Newt culminated in Bird buying a block not far from me and starting to build a new observatory. With lots of help from Bird I have had some success with my 14" & although it is good all round scope not ideal for planets so the new build begins.
Gary Mitchell has built the 3 part 600mm tube. Normand Fullum is making the 508mm F3.95 Tech Mirror which is in the polishing phase. The Titan mount has been purchased. Moonlite 2.5" focuser and Atik 9 pos filter wheel will align the ZWO174mm camera. I'll upload photos and update as parts arrive, the observatory is extended and tuning begins getting ready for Mars in 2016.
These images from Normand this morning and he has confirmed the weight as 17.7kg which is just below my anticipated 18kg, figuring tomorrow.
Cheers, Phil.
glend
03-04-2015, 06:37 PM
Wow that is a big tube. Re the three sections, how do you give it the necessary stiffness to carry a 508mm mirror (which is going to be a heavy). Tube rings, dovetail, etc all the components are going to have to be custom made or do you have that sorted already?
Tube rings, Mirror cell, radius blocks, end cap, all made by Gary.
Mirror is a Tech type front and rear 5/8th " supported by piers and a 100mm hole in the base and an estimated weight of below 20kg I'll have exact weight in a couple of days.
My estimated total including focuser, filter wheel, camera, guide scope, 2 x dovetails, cables, spider with 112mm Antares secondary under 40KG.
cheers, Phil.
Nice. I'm doing something very similar but with an 18" f3.3 mirror and an alloy truss scope. I have the mirror done but not coated yet and the scope is just about done. The main use for mine will be planetary imaging and some visual work.
Mines looking so far to be just under 30kg.
Sounds nice, any more details, photos?
DavidTrap
03-04-2015, 09:13 PM
That tube is a work of art itself.
Look forward to the end results.
DT
Here's a shot of mine. The secondary is just a make do setup for now. I'm going to make a spider that holds the camera(asi120) at prime focus so no secondary will be needed.
It ended up being 24.5KG and the CGE mount seems to be able to take it ok.
The mirror is still uncoated as I've made it myself.
180132
that looks awesome, it will be very fast at prime though you will need plenty of mag for planets. Just need to paint those counterweights..lol:lol:
Haha yeah, the paint has been falling off them for a long time but i then used them for weights when I was making the mirror so they are a bit rusty now. The mount is an old spare I have, my main(good) imaging mount is a Tak NJP.
I need to get a 2.5X powermate, I've got a 5x powermate i use with my 10" f4 scope.
If your mirror figure turns out good you are going to have an awesome planetary scope.
sopticals
04-04-2015, 06:22 PM
Nice.:thumbsup:
I hope to have the tube in a few days so I can try it on the Titan mount which I have stripped and serviced. Also the counterweight extension and 25kg weight.
That mirror looks interesting!
I chose this type for it's advanced thermal cooling properties and light weight. Active cooling via an exhaust fan in the cap then passive via the hole in the centre should keep the mirror very close to ambient all night. That is why the tube is so large it is 100 mm larger than the mirror but very light using 1.1mm aluminium sheet. We will see.:thumbsup:
http://www.normandfullumtelescope.com/en/mirrors/large-mirror/
rustigsmed
08-04-2015, 10:49 AM
this is going to be a beast!
what a great undertaking.
can't wait to see your results when its all up and running!
cheers
russ
John K
08-04-2015, 02:20 PM
Phil,
that is looking like a great project - you will end up with a great scope in time for Mars next year so cannot wait to see your results!
Did you consider using a carbon fibre tube instead or would that have created a weight issue?
John K.
Sure is a beast Russ, glad I have Bird building so close as I will need his help to tune this monster.
Cheers, John. I considered carbon as well as truss construction and both would have been too heavy for the Titan. Plus aluminium has very good ambient properties. I am starting to design a cable pre-stress system to prevent tube sag with resultant and constant collimation changes.
cheers, Phil
John K
08-04-2015, 10:22 PM
Thanks Phil,
Makes sense.
One more question, how are you planning to mount your mirror, and are you going to be using some edge support brackets as well on the mirror cell?
Also - gather there is no need to peltier cool a mirror like this and fan cooling is more than sufficient?
Hi John,
I'll use 2 flexible steel wires which will be supported by old antenna parts as in this image, they are sikaflex'd to the bottom only.
Yes no need of a Peltier as the Observatory is air conditioned and the top cover fitted extractor fan will be run prior to the roof opening and natural convection through the mirror central hole will work continually during use.
Cheers, Phil
Is that vivid around the edge. Did the edge end up turned?
It'll be interesting to see how well it holds collimation with that cell setup, is it sitting on bubble wrap?
This is not my mirror just an image I found. I understand many mirrors used for high definition imaging are blacked out along 5mm of the outside edge to improved image quality and nothing to do with bad edges.
Yep sitting on bubble wrap which is what I'll do initially to see how well it works and a number of other options including an 18 pointer.
I've made an 18 point cell for mine but I've found its the edge supports that needs to be done really right. My first effort caused a little pinching and produce a slightly triangle star. With a mirror that tall i would say the edge support is going to be very important.
If you're going to mask the edge of yours then i would recommend making a ring rather than vivid as in that image. There should only be a need to mask a 1mm off the edge unless the edge is rolled.
Even my Royce mirror works better with the last .5-1mm masked off with a ring i made in my lathe.
Good info thanks, what did you make your ring from?
I'm sure there will be very little edge roll from Normand but 1mm is what I'll start with, any more than that and it will be costing me lots of wasted $.:(
The edge support will be a work in progress for some while unless I get lucky, I will start with 2 wires and 12 supports both anchored E & W.
John K
10-04-2015, 03:36 PM
Gents,
Very interesting discussion - and another example of amateurs pushing some boundaries.
An interesting thread below FYI as well on edge support for sandwich style mirrors:
http://www.cloudynights.com/topic/485328-looking-for-sandwich-mirror-edge-support-ideas/
And some additional info here as well:
http://www.jpastrocraft.com/cells.htm
and a very interesting article here:
http://www.loptics.com/articles/mirrorsupport/mirrorsupport.html
Interesting John, though many refer to Dob support the idea that edge can have more effect on the mirror than cell needs more thought. My top and bottom mirror plates are the same shape and size 508mm x 16mm.
After fusion of the pillars to both plates the second fusion is done with the mirror inverted over a mould allowing the mirror to slump to the correct shape F3.95 in my case which gives a FL 2008mm.
Update on my mirror from Normand, figuring is going well and now at 1 wave another week it will be ready.
Satchmo
11-04-2015, 08:19 AM
Phil , did you talk to Bird about the test results I got on his three 16" F4 mirrors including one a Fullham sandwich mirror ? PM me if you need any clarification .
dave brock
11-04-2015, 12:32 PM
Hmmm...
Can you explain the logic of this?
I can see only one reason to do this and it has everything to do with bad edges.
Dave
You can ignore the blackout around the edge of the mirror Phil showed earlier -that's my 16" Fullum mirror, and it was blacked out while I was chasing the source of overcorrection I was seeing in my images, but blacking out the edge made no difference. In the end the problem was the barlow and nothing to do with the mirror.
The mirror does have a slight turned edge so I keep an edge mask on there that's a few mm wide, for planetary work you don't want any scattered light from a turned edge, no matter how small.
cheers, Bird
dave brock
12-04-2015, 09:09 AM
I've got a Televue 1.8x barlow that adds a small amount of correction as well.
Dave
Yes, it seems that pretty much all barlows add some over-correction, even if their marketing department says otherwise... probably due in large part to my f/4 mirror being right at the edge of the design criteria and using the barlow for more magnification than intended.
It was very handy to have 3 different mirrors on hand for the testing - all of them gave the same over-corrected images which helped to isolate the problem, but for a while there I wondered if they all had turned edges so I asked Mark to check them out. There is a very slight turned edge on all of them that can be covered by a mask a few mm wide, so now I do that always as a matter of course. Kills off stray reflections too from the edge of the glass.
Bird
The Titan does indeed look small compared to this monster, it will just have to grin and bear it. I will however make sure it is near perfectly balanced so I don't break it's back.:lol:
strongmanmike
12-04-2015, 05:14 PM
Wow, that looks awesome :thumbsup:
Mike
mswhin63
12-04-2015, 06:36 PM
I don't think it will be a case of breaking it's back, instead will it break your back getting it on there! :D
What do all the tube components weigh?
weighing myself and holding individual components on the bathroom scales is not really very accurate but it works out to about 30kg
and good news my mirror is going in for coating and will be sent in a few days time,
Test results from Normand
Assembled on mount
The mirror from Normand arrives today, as expected it was packaged very well and looks wonderful. Manufacture of cell support and secondary holder with spider will commence soon.
rustigsmed
29-04-2015, 09:55 AM
awesome, super excited to see the images you produce from this!
do you anticipate to have it up and running by Saturn's opposition?
I doubt it as I haven't extended the observatory yet and her indoors wants the bedrooms re decorated. :sadeyes:lol
rustigsmed
29-04-2015, 10:00 AM
haha oh well, you have the aperture to make up for it ;)
the big one will be Mars, so plenty of time :thumbsup:
Satchmo
29-04-2015, 11:24 AM
I couldn't help noticing the 7 zone foucault test claiming an 0.99 Strehl ratio. Such tests are useful for small slower mirrors but in larger fast mirrors are often idealized in relation to the reality as measuring the all important edge zones edge zones is much harder this way and of course complex figure distortions ( not just simple astigmatism ) more common with large fast and laminated mirrors are pretty much invisible to the maker using these methods. Do trust your eyes and star test diligently before making decisions on the optical quality.
I found the 16" F4 Fullham sandwich mirror I tested that was mentioned earlier in this thread , looked at with sensitive null interferometry to have results nothing like the documents presented here though I didn't see original foucault test results it was supplied with . I do wish you the best results with your new optics and as always trust your eyes.
Yes nothing is caste in stone until I star and planet test it. I never take much notice of tests other than actual usage, fingers crossed it will be of a high standard we will see in the next month or two. It will be very close to a 14" Meade and Bird's 16" so a direct comparison should be easy enough. I did a comparison between Bird's 16" and my 14" Meade the other night on Jupiter which we were imaging at the same time and with the same cameras, the contrast was much better on the 16" as expected but I was impressed also with the finer detail apparent nr the GRS.
cheers, Phil.
The external main mirror adjusters with extensions installed and also the 5 internal tensioners. Work has commenced on the experimental mk1.1 mirror support system which leaves me with 9 alterations before I start the mk2. lol:rofl:
It'll be interesting to see how it all turns out. For me it's hard to go past a simple truss design, light, stiff, cheap and easy to make.
Satchmo
29-05-2015, 10:46 AM
( EDIT )
Hi Phil
I will take that as a complement then as its not often I hear feedback :) A good mark for Australian manufacturing I hope.
Mark Suchting
Logieberra
29-05-2015, 11:04 AM
Mark, the view of Saturn through Stringscope's (refigured by you) 16" (a Meade mirror I think) at IISAC 2014 was tops. There you go :)
strongmanmike
29-05-2015, 01:50 PM
Looking pretty impressive so far Phil :thumbsup:
Mike
SpaceNoob
29-05-2015, 02:45 PM
Far out, that thing is a weapon!
I've seen similar looking pods hanging off the sides of Russian warships in the Persian Gulf, big nasty SS-N-22's (Sunburn Missiles) sitting inside of them. The resemblance is uncanny :lol:
First mirror cell completed this will be an interesting project with so many different ideas whirling around.:question:
Now awaiting custom spider and secondary support so that can be fitted.
Observatory addition commences this week.
50:1 gearboxes and new Maxon high res motor for RA on the Titan to be purchased.
FlashDrive
30-05-2015, 02:50 PM
:eyepop:..... What a piece of ' kit ' this is going to be.....let alone what will be ' seen ' with it. :atom:
Awesome.....:jawdrop:
Progress is being made, thanks to Bird who knows his collimation 1st light in poor seeing showed a clear image of Saturn. Much still to do re wiring etc.
rustigsmed
04-08-2015, 09:11 AM
awesome!!! getting there - can't wait to see the images this thing produces - lovely setup :thumbsup:
sopticals
04-08-2015, 03:43 PM
Very nice.:thumbsup:
clive milne
04-08-2015, 03:48 PM
Phil... by what mechanism is the force applied by the mirror support pads (on the back of the mirror blank) equalised?
It'll be interesting to see how it performs. One would think an 18 point cell would be the go.
But if it works and the stars are round that is the main thing.
The mirror edge was supported above the cell at 3 points whilst the support glide bases were built up with a type of silicon inside hollow felt pads as the bottom plate of the mirror is curved the same as the top. It was a slow process but when completed the 18kg mirror contacts all glides and can be easily rotated with my little finger. I decided to do this to keep the profile as low as possible and add little extra weight. Not until I start processing planetary images in good seeing will I know if it was worth the effort or successful.
How's this project going?
The best judge of the mirror support system will be visible the first time you defocus a star a small amount - is it round.
Kunama
30-08-2015, 09:33 PM
Beautiful project, looking forward to seeing the output from this beast.
When the good seeing returns I'll know if it was worth doing, until then here are some details of the completed build. The MK2 secondary cell is in design mode and should be complete before November.
Regards, Phil.
Somnium
31-08-2015, 09:02 PM
wow, what a magnificent Newt. that must weigh a lot, is the Titan up to the challenge ?
That was one of the main things I thought may be a problem but it turns out the Titan handles it easily. The original 25/1 gearboxes have been upgraded to 50/1 and the motors have never even been warm. The counter weight shaft is carrying 60kg and I estimate the scope weight at 65kg. Tracking is excellent with a good polar alignment showing a minor drift after 10 minutes. For deep sky I would spend some time on the alignment but for planetary it's no so important. The seeing is not good at the moment although brief moments show the optics look 1st class. The only Saturn image I have processed so far although in poor seeing l am happy with. When the seeing improves I shall find out how good it really is.
mswhin63
01-09-2015, 10:38 AM
If that is poor seeing, then good seeing.. looking forward to it.
I can easily see Saturn's hexagonal pole in your image as well. great stuff :thumbsup:
Observatory is completed, just need some good seeing now that Jupiter has started to show.
Cheers, Phil
batema
02-11-2015, 08:17 PM
10 out of 10 for your effort. Saturn looks amazing. Fantastic project. Well done and great to follow your journey.
thomqos
02-11-2015, 09:32 PM
Hey Phil,
Who made your tube please?
I want to get rid of my 15 y.o. cardboard tube in favour of aluminium..
Russ
Thanks very much, I've had a great time building it.
I can highly recommend Gary Mitchell who made this one for me. He is in Sydney
gnmitch@ozemail.com.au
thomqos
03-11-2015, 09:31 AM
Thanks
I'll check him out..
thomqos
04-11-2015, 06:21 PM
I spoke to Gary today. Seems obliging & has a 10" himself.
He suggested using 1mm thick/guage aluminium... Is this what you used on your tube? If so, is it resilient enough to denting?
Yes mine is 1mm, anything will dent if you try. I'm not all that worried about small dents more concerned with it's thermal properties. The only small dents I have is because I was careless. If you permanently mount it then no problems, if you are going to transport it often then you will either not worry about it or build a couple of boxes.
The mirror has proved very successful and here is an image of Neptune using Bird's IMX252 mono camera.
traveller
14-11-2015, 12:50 PM
Excellent resolution. A great project.
Bo
Here is my latest Mars image in 685nm. This shows details as small as 0.5 arc seconds, also I had another 2 day visit from NASA engineer Padma Yanamandra-Fisher who runs their amateur collaboration section.
My imaging train now includes a non rotating helical focuser inside is a HD12mm Ortho lens which allows me to change my image sampling from my default setting of 10 to between 5-15 pixels per arc second. I hope to be able to use a higher setting if and when the seeing is excellent.
Atmos
19-04-2016, 05:18 PM
It is certainly a performer Phil! Churning out some truly amazingly detailed images.
Thanks Colin, I've had a great time building this beast and a real delight to use.
Due to the quality of my images deteriorating slowly over several months I started looking for the cause. It appeared to be a mirror problem although I was unable to find anything that looked wrong. I removed the mirror to check the supports however everything looked okay. When I reassembled it the images looked even worse so I had found the problem but how to fix it I was unsure. After trying several things including removing the numerous supports underneath and replacing them with s/s the problem was still apparent. Thinking it was perhaps the wire edge supports I renewed them with no success. The only solution was to replace everything with an 18 point whiffletree design and a new designed edge support. I am pleased to say it has performed perfectly since the upgrade has been completed .
Regards, Phil
vBulletin® v3.8.7, Copyright ©2000-2025, vBulletin Solutions, Inc.