jetstream

M101, the Pinwheel galaxy can be tough- I'd stick with what @SuburbanMak recommended. After a while youll get to know what makes some things easier or harder to see such as the surface brightness of extended objects etc. Congrats for getting out! Gerry

Maybe you could take that box and ship me one

I think realistic expectations are in order and what is really needed for good views. Knowing what optical qualities and parameters really degrade these views are a great tid bit of information to know. As an example my 15" tests vg but know where near some of these sky high test reports show. It has an accurately tested .92 Strehl or so IIRC 1/6 PV and very smooth. The IF picture shows all the lines nice and sharp and straight. It might be good for us to read Peachs vg example of what different levels of optics can really show... perfection is not needed but good average numbers are across the spectrum IMHO https://www.damianpeach.com/simulation.htm

Brand new, high spec flats are not cheap. Thankfully there appears to be some latitude in the actual specs needed.

Having read a pile of test reports over the years I'm a bit skeptical when every single optic-from whoever- tests with an almost perfect Strehl ratio. It would be nice to see their Focault tests and their shadowgrams -which DPAC can also show I believe. Also an actual IF fringe picture is vg- not just the synthetic image produced from the fringe pictures through a program. I do realize one actual fringe picture does not tell the whole tale, but it goes a long way IMHO.... I really and truly dislike test reports that could potentially be misleading. There is nothing but good to come out of our enlightenment with respect to DPAC testing I believe.Many thanks to those who brought the test to the forefront through the forums.

I wonder if I could use a DM 6 on a SW AZEQ6 tripod? any adapters out there?

This looks like what @Rainmaker - might do 👍 You have very nice stuff! I might get a Planet, we'll see whats available.

Nice nice set up!! Ok I not only want the mount but your pairs of the superb TSA's!!!

One point for me is to compare what I see through the eyepiece as "sharpness" for example to what the fringes indicate. Another point is to compare manufacturer supplied test reports ie Zygo, whatever to the DPAC fringes. Many people using low to mid mag might think they have a good optic... and may have paid a hefty price for those optics. Sure be nice to know we are getting our moneys worth and base purchasing decisions on things other than word of mouth or manufacturer supplied tests, IMHO Any reason to DPAC test is up to the individual.

Thank you very much for the info- years ago I looked into these mounts and just missed them because of Charles unfortunate passing. Rumour around that time was a family member would continue on but I guess that never happened. I would love one of these mounts...

Thanks I just looked them up, will call later.

I normally dont care if my threads wander but I dont want it to wander in the direction of criticizing a moderator on another forum and I also dont want this thread to be the focus of the 180mm SV tested, or SV in general. What I hope to get here is interest in DPAC and some banter about its methodolgy so that I (we) can get on board and do some proper testing, should anyone choose to do so. Thanks, Gerry

Me too- the test results do the talking so to speak and its hard to refute the DPAC method of testing. Ive talked to opticians and they confirmed the validity of the test. What Im still not sure about is the specs of the flat and possibly testing vertical vs horizontal ie edge distortion in the flat. My feeling is a flat of 1/10 on the wave front would be great for tworeasons- one for the obvious optical quality and two to add validity to the test ie one less thing for naysayers to pick apart. The edge distortion is most likely not an issue either but I was just thinking out loud really. Btw, you are doing a great job under difficult circumstances, my hats off to you.👍

Me neither! But hey this could be my last chance to manage one

Yes, I read the results and I too find this fascinating. I can say this- DPAC catching on will force scope makers and vendors into providing more consistent optics.

Rohr seems to be a resource many quote eventhough some question his results as is bound to happen espc the interferometer results. Apparently interferometer results are hard to duplicate between units and the conditions they test in ie horizontal vs vertical, atmospheric concerns and type of interferometer used. DPAC appears to be an easy and accurate test to use and can be easily repeatable. Good opticians use many tests to evaluate optics as they are being made including testing in multiple wavelengths of light. I think the future will bring many many test results for us to view and this will tell the tale.IMHO.

@John Do you think or have you heard if the AZ100 would hold the likes of a TEC 160 steadily?

I have a funny feeling there are going to be many samples of one tested as DPAC really catches on...

@Space Hopper Thank you Rob! You have very good equipment, great info on all this- now comes decision time...

Yeah no kidding- I'm still bummed out about my SW120ED- for a tiny fraction of the price- which was touted as an excellent quality refractor- DPAC will tell me. It was rumoured to have been tested (all the scopes) from a vendor...

This was one of my questions ie how much weight imbalance will the 6" bearings hold- thanks Louis!

What I have a hard time understanding is how a company, trying to establish itself in the high end refractor business would allow a scope with those (alleged) issues out for sale - makes no sense to me. I might assume- with no evidence or experience- that the smaller the aperture the less off in the green and blue they will be. I'll tell you this- every refractor I buy from here on in will be run through DPAC... and maybe a knife edge if I can figure it out. First on my list is my SW120ED.

👍👍 Same here, they are very good for sure.

Theres the difference, I still have the factory grease in there and bearings. I'm still looking for soft silicone rubber cables.

Congrats for a fine session! Yes, NGC 3628 can be a ghost, actually listed as "bright" but its surface area makes it hard. Bang on using the 12.5mm Morph on it- the only thing left to try is an ortho, or something like a 14mm Delos- these eyepieces are extremely good for this kind of thing IMHO. They have ortho like contrast and transmission. Upping eye illumination a squeak might help ie 14mm.