jetstream

What about distilled water stealing all those ions and causing havoc?

And possibly between these scopes and less expensive but good refractors from other manufactures. My SV90mm provides great high power views for such a small scope and sports as perfect a star test as I can decipher. If seeing limits magnification so much maybe these expensive scopes arent worth the time?

I dont think Gavins was IIRC.

Rumour around the campfire is that the new fluorite TECs are an improvement, but I have never looked through one so I cant verify it.

All I can say is that ES eyepieces are tough. A few years ago I was observing in -30c and had frost and light ice form on my eyepieces, including the ES 18mm 82. I figure I'd test this purging and sealing of ES out...so.. I came in, filled the sink with the cold water tap and threw the 18mm in the water to "warm" it up a few minutes later I removed it, wiped it off, including the glass and no ill effects! No fog inside, no leaks and it was put back in service that night once completely dry. Yeah, their tough and it makes zero difference what its purged with, argon or nitrogen IMHO.

If getting the TEC 140 get the new fluorite version IMHO.

I put reflective bubble wrap insulation on my concrete obs pad to keep the suns heat off- shhhh! 🤫

We have a 6.7mm ES 82 and its a very good eyepiece and unusually sharp for its design.

If possible get an SQM-L and take it to these dark site to confirm the darkness levels. Stu's 16" dob will perform so well under dark skies its not funny, on everything.It will begin to show the dark lane cutting the gulf area in half in the NAN for instance as well as the Pelicans Head. Wait until @Stu gets the dob on the Flame neb, next to Alnitak, under these skies. I was watching a highly detailed view of the Pacman neb the other night in the 15", a view that the TSA120 cannot give because of its aperture. IMHO.

Me too.

I would think that a very stable set up would be needed with a C8 and its narrow TFOV.

How about a tripod mounted Heritage 150P?

Just imagine what an Agema could do with those 2 lenses an inch apart straightening out the photons

Is the back issue stable or other David? Is a permanent set up possible for you?

Perfect, I checked mine and it was the mentioned unit but I had put the stock chrome nosepiece back on. Just to see, I unscrewed it then screwed it back on however not as tight as original. These diagonals sure do work thats for sure.

Which one is that John?

I'm not sure anyone requesting a top mirror looks at a single figure- one requirement of mine is smoothness- Terry O makes very smooth mirrors as do all the other top makers. Lockwood works with JP Astrocraft and their cells and knows what works with his thin mirrors. He tests the mirrors ( for reference, not all of them) in the cell as does Terry O on request. The magnification seen with these scopes is a testament to their optical quality, similar to Taks idea- real performance and not a battle of test results. If a Tak, TEC or LZOS refractor can take ultra high mag, then a bigger quality scope would work well then too. To each their own for sure.

No sense hurting yourself David.

Lockwood makes it simple: "For telescope mirrors made by us to our highest standards, our optics will perform at up to 50 power per inch or beyond of aperture on nights when the atmosphere is steady enough to allow this, so long as the mirrors are properly supported, equilibrated, collimated, and reasonably clean. When you experience a night that allows this type of use of our optics, you will forget all about the numbers." https://www.loptics.com/faq.html Thats pretty good for a, say, 20" newt- 1000x...+...

I think the f ratio should be over f12 for this at 6" aperture? But yes, the likelyhood of getting good 6" f8's and 8" f6's is really high. I guess thats why the 6", long fl newts are called "APO" killers.

SW can make vg optics no doubt!

👍 Or Lockwood. I dont think any would be in business long if they were merely avg optics and duds IMHO.

The wow will be on everything IMHO. A 16" f4 -f4.5 truss dob would be perfect. There is no comparison between an 8" scope and a 16" scope on the Veil for instance- in my own aperture upsizing I try to go at least one magnitude deeper on stars which results in amazing differences on all objects, skies considered IMHO. The difference between the 10" and 15" here on the Veil is staggering... and the Lobster Claw and...galaxies and...

Excellent report Magnus! Out of curiousity what eyepieces were you trying Stephans Quintet with? It actually matters IMHO. Using my VX10 I can get 3 of them, using high transmission eyepieces like orthos. Definitely worth a try as is upping the mag like @mdstuart told me years ago.. We observe under the same skies basically so it will be fun to compare- and yes its now raining here lol!

Yes it works, been doing this for years myself 👍 Its an inherent advantage to truss dobs IMHO. I have no set distance to pull up, sometimes much more than 3" and just let the views be the guide. Doing this and a couple other things has allowed my 15" to go well over 700x on the moon and razor sharp.