Deadlake

I think that’s another thread…

The point is SV are the only manufacturer I can think of that tests in red, green is as far as I can see an industry standard. No hindsight then, a red flag. Ho ho ho.

In some ways the CN thread has run it’s course. I do not see any thing more to add once the scope got taken back, unless Vic decide’s to use green wavelength to null the lens too. It’s not the end of the discussion, it they could be on other threads and maybe less pruning for you. I see you have your work cut out with the NVD forum as well. 😃

Well if you knew SV was testing red you might. The colour band was not on SV’s site until this blew up and you would of only got a hint if you looked at SV’s Facebook page.

True, but some tube materials will give less thermal currents than others. Polymers of most kinds are self-insulating, as is phenolic/paper, and so is fiberglass. Carbon fiber tubes are not self-insulating. All metal tubes need insulation of some kind. Hence using a phenolic tube gives less chance of tube currents running the view. Yes, there is no free lunch in hoping once scope will behave in a particular way, all a function of environment the scope is being used in...

I think there are many factors making up when a scope lens reaches null. If you are really keeping track of it you would be testing the lens against green light, but how many of us do that? The environment is not just temperature difference, it also includes cooling factors, change in pressure, how much latent heat is stored in the tote systems (lens tube, ground etc) from the day before all play a part. How much the lens is over corrected to start with will be a factor of height and air pressure and hence how long to get to null. Too much over correction at the start is a way to a decrease in contrast as the lens changes shape. I think this conversation has been done to death on CN with the simple conclusion that to many factors to give a simple answer of it's 30 mins for this scope and 60 mins for another scope, etc..

So far we've had three tubes types mentioned. aluminium, phenolic and Carbon. Gerry do you know if carbon has tube currents like aluminium? Also we looked at lens being pinched, the LZOS is good to -30 oC so I imagine at more normal temperature it can compensate better then other designs.

Doing a Google around this there is a huge range of cooling times for the same scopes, and even then if nighttime temperature is changing this has a large effect too. The other item to remember is the phenolic tube thermal expansion will result in better focus compensation than using an aluminium tube. Also apparently zero tube currents. Back to the OP, I was going to suggest a 115 mm triplet is the best compromise between weight and performance, it has just that little more aperture and keeps the weight around 6-7 kg so no expensive mount.

It’s coming from a garage, not quite same temperature as outside. For instance metal of an AZ100 will be cold to the touch as will metal handle of scope and FT focuser. So still some acclimation but not much. The only time the scope spends in the house from the garage is to put on a finder scope, so not much time for it to warm up. The phenolic tube is not a great conductor of heat. The night I took it out was also not relatively cold, i.e no frost in the tube like this Still on that night maybe 25 minutes for it to settle down. Again a phenolic tube. The phenolic tube is a very good insulator making it maybe harder for a thermal gradient to form. Might help???

The 105 mm takes 5 minutes from a warmish garage to freezing to acclimate the 130 mm longer maybe 30 minutes. As far as seeing, recently moved house. It’s 75 meters higher then last house and hidden behind a large hill, one of the highest in the southern downs. Maybe the lower boundary layer turbulence does not effect so much when I view from the new house as much or maybe I’ve not been out as much, I’m picky on nights to view. Although the new house is only five minutes from the old house it’s a noticeable step up in ‘seeing’ quality…

Triplets give better colour but at the expense of weight, which is the trade off you need to make. Also they can take a little while more to accilimate, but the 105 mm I have takes around 5 minutes and then is razor sharp. Much has been made of the TSA-120, and like many Japanese scope you get a very compact scope that is lightweight which I think cannot be over looked. Same time the ‘seeing’ does not make much of a difference between a 105 and 130 I have, but for a larger scope like the 10” then for sure that’s going to be a point. I’d work out how you are going to mount the scope, once you go above 6-7 kg the options you have are going to be a step up in cost and also will remove flexibility. You might need to move the scope around the garden to dodge trees for instance.

I notice a difference in looking thru a Vixen HR and a Takahashi TOE when looking at Jupiter. The TOE colour is more saturated then the HR that does not add any saturation. tHard to put into words, but I think with the HR my eye can see more detail then the TOE, note its 4 mm vs 3.6 for the HR. On the moon the HR and LZOS looks like a ultra high resolution black and weight photograph taken thru a Zeiss lens, whereas my Vixen looked like a high end Canon lens. Maybe the TOE would suite a slower scope…

A one way journey, no mirror, no clock synchronisation. The is called a light ring around a black hole, I leave the expert to it

I’ve not read the whole post, however ways of measuring the velocity of light are 1) Reflection, where a mirror is used to return the light. 2) Synchronised clocks reporting the velocity of light between two points? And the aim is to measure the velocity of light one way? Well one way (no pun) of measuring the one way velocity is to have light bend back on itself, just need a black hole to bend time/space and light will loop around and come back. The astrophysics are using this technique to find out new physics around the photon rings around back holes….

What do you do when kit is not replaceable. I have some LZOS scopes and the supply of those lens cells (even without the war) is no longer financially viable. The only scope I’d change is the 130/f6 for a AP130GTX and that’s because it’s a little more svelte and compact. However I do have gaps, a scope with more focal length. Do I go with a C11 or a 12” Dob? The main reason for holding off is just moved house and I’m getting to use to observing from a different garden. I need to move the scope to avoid the hedge/tree line. I suspect the dob is better however not as moveable as the C11. Wheels on the dob would help however the C11 keeps it collimation quite well. A harmonic mount would also lighten the load when moving. Trying to avoid kit churn which the ultimate money vampire….

I’m tempted by the AP110GTX, the light weight of it and portability is attractive https://www.astro-physics.com/110gtx Thanks for the scope, I’ve added some lightweight printed rings so it fits in a Stellarvue case. the small size of the scope grows on me, handy for moving around the garden. As far as dream scopes, tempted by a Doc Telecope 12.5” dob running at F3, would show some deep rich field views. http://www.doctelescope.com

Your 24” is not in the list, the 15” is easier to get out while the larger scope stays in the seacan? With the dark skies you observer under you do it need more then the TSAto see some DSO’s.

prism or mirror?

Also Jerry the diagonal used, I find the red colours of Jupiter and Saturn come out more using a BBHS coated diagonal over say a max bright. Makes a real difference IMHO.

From what @Dek Rowan Astro has said the joystick connects to the AZ100. This means when using sky safari and the mount is moved using the joystick sky safari will follow. I quite like this approach, however does mean coupled to joysticks Rowan supports.

I have a 105 mm and to fit the scope inside a smaller StellarVue case I use a TS handle (£35). This way no need to take the handle off or on. Just a thought.

Apart from the 12 month wait for the part it add quite a lot of wait to the EP end of the scope. I've thought of going with the manufactures focuser for that reason... But yes FT's are very smooth...

Has anyone got the latest software version that supports joy sticks/pads at all? @Dek Rowan AstroHave you got a list of what joy sticks/pads you've tested with the motor kit?

Knowing the dimensions of the bag and the LZOS I have is 130 mm will your 140 mm scope plus handle with rail fit in the bag??? Mine just sneaks in the bag with a low profile handle attached, no rail is attached to the 130 mm I have.

Well if you could buy one this year. That aside I'd like to know how they compare, the StellarVue and FT focuser's.