Peter Drew

"And now for something completely different", I'm using a 60mm F700mm fitted with a SM60 Coronado Ha etalon and BF15 for grab and go solar observation. Excellent images with a zoom eyepiece.

My Mk4 already has a AWR Technology stepper drive system, it just needs the worm brackets upgrading. I have started from scratch with the OTA, it is now a truss tube assembly with primary mirror focusing. I will eventually have the choice between the Mk4 or a fork mount that I originally made for a 12" Maksutov. I have a keen interest in telescope performance and have been looking forward to comparing it to my long focus 12" Newtonian and 12" LX200.

I'm currently rebuilding one from an optical set I purchased a few years ago. It is a F5-F20 set by David Hinds, the alternative set that he made was F4-F16. Have a look at the back of the mirror, if it has a number followed by an A or just an A then I doubt anyone would refigure it to a better standard. I also have a Mk4 mount which carries either a 8" f8.5 Newtonian or 11.75" F8.5 Newtonian, hard to find a beefier mount at low cost.

Things I've found out through experience. 1) Always buy good quality keys. 2) The ball ends are not as strong as the plain end. 3) Avoid sets packed in flimsy plastic holders, the keys never go back in unless you are either a Swiss watchmaker or a bomb disposal expert.

Human hair is a good source of crosshair material. I have a bald patch as proof! :smiley:

Producing a sphere initially is the traditional path to further work for parabolizing.

Good point Nigel.

With a curve that deep it would be back heavy.

In reality, secondary mirrors in Newtonians should be pear shape rather than ellipses as the lower edge of the mirror intercepts a wider part of the light cone than the top edge.

Place a washer or a coin in the centre of the secondary holder then add 3 blobs of silicone at 120 degrees somewhat thicker than the washer/coin. Then press the secondary gently on to the silicone until it touches the washer/coin. This ensures the mirror seats squarely and gives a gap to facilitate eventual removal.

I have a good 40mm Coronado PST and a good Coronado SM60, the SM60 is noticeably better than the PST, I would expect the Lunt 60mm to be proportionately better than the Lunt 50mm.

You might be better served by purchasing a Quark and fit it to a 80mm-100mm achromat around F5-F7. Double stacking is of great benefit to imaging the Sun.

I currently have a visitors 76mm F700mm Tasco Luminova reflector. It was brought in to me as a bag of bits, literally right down to the smallest screws, fortunately nothing missing. The tube seems to be the same one as Tasco use for the 114mm version which was helpful as I needed to get my arm up inside to attach the side bearing plates for the alt azimuth fork. I cleaned the very dusty primary mirror which came up like new and collimated the optics. The scope came with three quite nice looking 1.24" fit eyepieces, a H25mm, H12mm and SR5, not the most suitable for a reflector but at around F9.5 at least useable. I have only had chance as yet to try it out terrestrially but encouraged by the views through the rather narrow field supplied eyepieces I popped in my Nagler 3mm_6mm zoom. At the maximum 3mm setting giving a massive 233X it still gave a well focused view of fine writing on a distant transformer that we often use for testing. I'm hoping to get an astro view in before the owner collects it, I'll report back if I do.

Hello John. Come along and visit us sometime, I'm sure we can be of help to progress your astronomical interest.

+1 for Keith's suggestion, I've used a similar approach for up and over shutters on domed observatories.

The main problem usually with refractors is that you are financially stuck with a small telescope.

Yes, scrap the mount and make a Dobsonian version if you are into DIY. Almost anything is better than the supplied mount.

Of historical interest, the 26mm Vixen Plossl was the reason for the founding of Astro Promotions Luton. A large number of this eyepiece was made available to Astro Systems Luton and they were offered as a promotion to the general public at a very reasonable price. The promotion was so successful that other items were bought in quantity and sold on the same principle. Astro promotions ran in parallel with Astro Systems and eventually superceded it, the latter fading away until it was wound up.

These eyepieces were well thought of in their day, the 35, 40 and 45mm focal lengths had rather long eye relief. The 17mm, 22mm and 26mm were the best of the range.

You would have to change the the title.

I'll raise you one thumbscrew. I use 4 for heavy components, works like a 4 jaw.