SGL is becoming irrelevant to me to be honest Dave.

 

I'm guessing the bullseye isn't very bright on purpose. Both the Rigel and the Telrad were deliberately designed for astronomy. One of the problems with the usual 'gunsight' reflex sights is that the LED is often too bright when used in night time. I'm sure I'll find a way lol.

 

Okay, Mak. I'll hold the reports. I just thought you might be amused to hear/read how those idiots are blissfully shooting themselves in the foot (among other anatomical-structures). The only reason I still haunt are that I enjoy helping people in need. And gently protect them from the ravages of the out-of-control you-know-who's.

So now I'm off to 'tweak' the altitude on this Vixen PII. Weird Note Dept: They list the larger of the two Allen-Wrenches as a 4mm, and a 3/16th's one. Why on Earth would they be using a screw, bolt, or anything else measured in imperial-measures? That's like having a chemical-synthesis that says: "Reflux 40mg 'X' in anhydrous Diethylether at 20mm Hg for 6 h. Now add a pinch of Granny's OldTyme Vanilla-Extract!"

BOOM!!

Dave

 

You kind of get used to using the occasional imperial measure here. Everything's more or less metric ... except for measures of beer (pints and half pints). Spirits are metric of course, as is milk and other fluids. Petrol is in litres but geographical distances (and car speedometers) are normally in miles (mph). Yet land areas are usually measured in metric (hectares etc). Virtually all heights and weights are metric but most people refer to their own height in feet and inches and their weight in stones (one stone = fourteen pounds). So it's a bit like astronomy measures!

 

Not many in the US know the metric - only those involved in the sciences. I'm particularily strange - I think in metric. And people occasionally realize this and the questions begin. I quickly (these days) tell them the story of Mr. Fahrenheit and Mssr. Celsius and the thermometer:

Mr. Fahrenheit had noticed that the position of elemental Mercury (Hg), sealed in a glass-tube, moved in response to increasing the heat from a candle, so he decided to investigate this phenomena. Here's what he did:

He took a file and made lines cut horizontally across the sealed glass-tube containing mercury. And he marked his cuts with numbers from 0 up to 250. Then he put his tube into ice-water that was just freezing. Looking at the numbers of his cuts, he saw this put the level of mercury at the cut marked 32. He called these 'degrees.' So water was freezing-up solid at 32° in his sealed glass-tube of mercury. Then he did likewise with boiling-water. "Oh boy!! Water boils at 212°!"

Thus was born the thermometer and the Fahrenheit-Scale of temperatures.

Meanwhile, in Sweden, a Mr. Celsius was also playing with this idea (in a bit more complicated way than I'm writing here - wanting to keep it simple for my fellow countymen/women - who have the attention-span of a gerbil). But Celsius didn't put his numbered scale on it until he put the glass-tube into ice-water. Then, across the extent of the mercury at this point, he scratched in the line and marked it: 0.° Then he did likewise with boiling-water, marking this extent of the mercurys' travel as 100.°

So, in the UK, water froze at 32°Fahrenheit. And boiled at 212°F.

In Sweden, water frooze at 0° Celsius. And boiled at 100°C.

The Fahrenheit scale remains the prevelant measure in the USA, but elsewhere the Celsius scale is used usually. Some Native methods I won't attempt to explain. Suffice to say, The Inuit People in Arctic climates have over 14 different names for ice. Each depending on the sound of the groaning heard from the ice as it freezes more solid, or thaws a bit.

Most of us scientists use 'centigrade' instead of 'Celsius.' As centigrade more accurately reflects the fact that this scale is based on multiples of 1 & 10 & 100 & 1,000 - etc.

THIS CONCLUDES OUR SCIENCE & HISTORY LESSON

Dave & Raul & Mrs. Shelley

 

It's funny you should mention the Celsius/centigrade thing. When I was at school everything was metric and the weather on the radio and the telly was mainly in centigrade. Then they changed the weather from centigrade to 'Celsius'. I blame Auntie Beeb (BBC).

Famous British scientists often end up on the front of banknotes, the Queen being on the back of course, Faraday, Darwin, Newton and others have all had print runs. lol

A quick way to change Celsius to ye olde fashioned scale (aka Fahrenheit) is to double it and add 30.

Thus: 10° C is doubled to 20 and then 30 is added. Making 50° Fahrenheit. You can reverse this process to convert the other way. It's approximate but surprisingly close.

Of course, nobody in their right mind uses Fahrenheit now. I have an old wall mounted thermometer that was my dad's. It's older than me. Apparently it never converted to metric. I still use it lol.

 

Waxing Gibbous Moon, 8/1/2017, 20:30 GMT. 82.3% illumination, 353.6° azimuth, 51.7° altitude, 364,537 km (Aries). Magnifications (approx) 66x, 73.5x, 96x. Telescope: 90mm Maksutov.


Conditions were below average with haze and wispy cloud for about 40 mins then degenerated totally. The highest magnification with any real clarity achieved was 96x. The Moon was very high even past transit though so that helped.



Sinis Iridum was nicely caught by the terminator shadowing. Delisle and Diophantus were well defined although I forgot what they were called. Fortunately I’d taken my ‘Orion Moon Map 260' out with me. Unfortunately they aren’t named on the Orion map. They are on Sky & Telescope’s Moon Map though lol!



Kepler’s ejecta and ray system were visibly apparent. Gassendi was very nicely dramatic with shadow. Clavius was visible in the south.



I used a 20mm Celestron erecting eyepiece to get an inverted view of the Promontorium Heraclides’ ‘Moon maiden looking over the ocean’ or ‘Moon Goddess’ as I call her. The terminator wasn’t perfectly placed but you got the idea.



Images ~ SN7, VMA & GIMP.

 

Looking good, Mak! One of these days I've got to get all my wires sorted and start-up trying some V-AP up here in Podunk. Got the gear, but need to set-up my location for 3-season usage.

Regards conversion formulae for Centgrade to Fahrenheit, we were taught this - which works both ways:

F = C X 1.8 +32

Works exact.

Back to my rounds...

Dave

 

Yeah, that can work ... it's way easier to double it and add thirty without a calculator though lol.

 

Hey Mak? I've sicced a new guy named Randall, who is from North Carolina, on you for some Barlow-advice. I've been helping him now & again over in "That Which Shall Not Be Named" ( ) - he's a nice guy. His query deals with a good 3X Barlow. He can get a "essentially free X-Cel" or spend some coins on a TeleVue®, and wants some data to help him. Hence - you're IT!

Back to de-populating the Dark Lord's house!

Dave & Raul

 

Well, the TV 3x is probably the best of its kind. It is 13cm long though and heavy, so may be problematical in a diagonal. The X-Cel is aluminium housed, as far as I can tell, so lighter and shorter. High quality though. The TV has a captive set screw, which is useful. The Celestron is probably not far off the TV actually in use although a lighter build quality. The X-Cel, like the TV, has no safety undercut which is a plus in my opinion. I haven't noticed any aberrations in either.

 

9/1/17. Waxing Gibbous Moon, 90.6% illumination, 54.3° altitude. Starting observing 21:30 GMT (Transit 21:45) until about 22:30. Conditions were above average and actually improved slightly after transit.



Telescope: 90mm Orion Maksutov, alt az mount. Magnifications (approx): 42x, 66x, 73.5x, 83x, 96, 104x, 125x, 178.5x.



Nice terminator shadowing on Anaximander and Anaximenes. Schroter’s Valley region was very well defined. Aristarchus was better defined at around 100 ~ 125x but did get a good sharp few minutes at 178.5x on the pyroclastic valley area.



Schickard very dramatically shadowed and good definition on Schiller and the surrounding area, particularly Hainzel and Mee. Wilhelm and Tycho seemed easily discerned. Entire Mare Nubium clear as well.



Lunar images ~ SN7, VMA & GIMP

 

I don't know about the screw sizes Ray. I thought 4mm was a pretty standard size. To be honest, the set screws on the ST80 should be fine if you make sure both are tightened. Often, one of them can loosen during a session, but that applies to all set screw pairs I find. Just check them now and then.

Regarding the TV3x Barlow, I think it could be used on a small scope like the ST80 easily enough if it was kept as vertically upright as possible in the diagonal. It would angle up and down in declination and wouldn't be used in conjunction with a large heavy eyepiece, but a smaller Plossl size type would be OK I reckon. It's only really problematical when rotated to the side and gravity can affect it.

You'd probably only use the TV3x on lunar/planetary anyway as that's where you'd need the magnification. In which case you would be viewing predominantly in the plane of the ecliptic with no real need to rotate the diagonal. I usually set the mount height for a comfortable seated lunar viewing low enough not to have to rotate the diagonal to the side. With an alt-az mount (unlike an EQ) the mount height itself won't vary with the azimuth as it tracks.

I've used a few 3x Barlows, the TeleVue is outstanding, the X-Cel superb. If I could only have one it would be the TV.

 

Yeah, they're probably out there somewhere. It's like smooth chromed brass draw tubes and other accessories; they seem rarer than rocking horse manure lol. I have the website of someone in the US who actually makes and sells 1.25" smooth chromed brass draw tubes somewhere. If I can remember which browser on which computer I bookmarked it on I'll post it as he might have some info. It could take some time though, I have more than one computer, all with different OS's and all have multiple browsers lol.

 

Well, rocking horse shit(e) would probably have been edited by the swear filter lol. One of the great things about US sites is that I can type bollocks, pillock, wanker and other British expressions which the filters would take out on a UK site ROTFL.

 

I had a similar problem with the azimuth on the Vixen, although this was fixed by just attaching it higher. The Agena slo mo cables look like stock Synta cables to me as they all seem to have the same rosettes. Although the Celestron ones had slightly different rosettes from what I can see. Which is a bit odd anyway as they're all Synta lol.

It might be that you need a short cable for the altitude and a longer one for the azimuth. I find that works best for me. EQ mounts are also usually supplied with two cables of varying lengths. It's another one of those great mysteries in amateur astronomy as to which cable goes on which control lol. I normally have the longer cable on the RA control.