Captain Scarlet

22 hours ago, JeremyS said:

I’m not so interested in the number of stars in the pan. What really counts is the number in the handle

🤣

the key number regarding the pan is of course the number of sausages

On 25/06/2021 at 19:43, Mr Spock said:

Arrived today just four days after ordering from Astroshop EU - Lacerta dual speed focuser upgrade for my 250mm Newt.

Very very good bit of kit. I loved mine.

10 hours ago, markse68 said:

sorry Magnus for the mixup- no it was just an aside really that i’m getting noticeable flex in my focuser

Mark

Ah now I understand, you were talking about your own tube, not Craig’s, my apologies!

M

Are you referring to the OTA tube material on the “blue-tube” Skywatcher Mark? It’s 1 mm steel, and not very rigid at all. Attached a pic of a hole I drilled out of mine to move the focuser a few cm up:

I love reading your reports: great to read and perfect to subsequently use snd follow.

Magnus

I haven’t applied the tube yet. I’m in the process of moving to Ireland, and the carbon tube was delivered to there just after I last left 3 months ago. So it’s still in its packaging. I’ll be back in 2 weeks though and will install it then. Also I swapped out the SW mirror for an OO one, so it’s a bit Triggers Broom really 🤣.  I didn’t actually need to lose the SW mirror, I think they are rather good, but I got seduced by the OO website. Only the cell and the spider remain SW, and I’ll be building my own cell quite soon.

After I ordered the Klaus tube he got quite ill I think, and everything was seriously delayed. He wrote later that he had suspended taking new orders until maybe late summer, I’m not sure how things stand at the moment.

I have both a 300p just like that and a 200p. They both suffer from flexure, the 300p not too bad but the 200p absolutely terrible. So much so that I resorted to putting an aircon hose-ring , which has helped but not fully cured:

The 300p tube I’ve now ditched and replaced with a Klaus Helmerichs carbon tube.

A handful of things that “are what they are” (or were, not necessarily all good), because of Astronomy:

GPS;

The fact that the Sun is at the same place in the sky at the same date&time every year;

Various Empires, owing to the fact that a principal skill-in-trade of a ship’s captain 2-300 years ago was astronomy and spherical trigonometry;

Winston Churchill’s escape and navigation from PoW camp in Pretoria to the coast - he said he used Orion as a guide;

Of course those things aren’t why I and likely you do astronomy. I do it because it boggles my mind to be able to observe such vast differences in scale, and such huge amounts of “stuff” just hanging out there in “nothing”, so easily with merely some good engineering and curved mirrors*. Such beauty.

Good, thought-provoking question!

Magnus

*some refractors aren’t bad either

Assuming the pairs of vanes are parallel, you’ll get just 4 spikes, but they will be “doubled-up” in intensity over single vanes. If they’re not quite parallel, you’ll get 4 pairs of spikes, with each pair annoyingly close to each other but distinct.

Stu’s point about the single adjustment bolt is fair too: unless you can absolutely guarantee the mirror is perfectly positioned on the holder and square, you do need the extra degree of freedom provided by another bolt. 3 is actually overkill, 2 I’d say is a minimum.

M

6 minutes ago, PeterW said:

Can we change the post title… 😉

 

Peter

… something like “the artist formerly known as …” 🤣

Part of my initial (misguided) motivation for removing the baffle was to reduce the Central Obstruction to an absolute minimum. It was only later that I realised that the CO% was actually defined by the (unnecessarily wide) retaining ring for the primary mirror. So the baffle can be anything up to that value without spoiling things (meniscus-refraction adjusted).

With the baffle completely removed you can see directly from the front of the scope and see light past the visual back, bypassing the secondary-mirror path. That should not be "allowed". In that configuration, looking at a bright object like the Moon will cause all sorts of serious extraneous light problems. Part of the purpose of the wider baffle therefore must be to block off that direct line of view through the VB.

M

I did remove the glass, though I'm not sure if I documented it. I pulled off the baffle because it was seriously off-centre, but that in itself didn't require wholesale removal of the glass plate IIRC. I did eventually decide though to check that the clips retaining the glass in place were not "metal clip directly on glass", and found that that was in fact the case, so I did remove the glass to insert thin pieces of electrical tape under the clips. Recollimation was fine.

I think all the surfaces at that end are spherical, and there is very little scope (apols for pun) for lateral movement of the glass, so the process of glass-removal and replacement is pretty forgiving. The thing you should take care of, if you are concerned, is to ensure the central reflective spot goes back in properly centred. I'm not actually sure how much care they took in ensuring that at the factory anyway, given how badly my baffle had been placed.

All in all, you should be fine I think. The glass is coated with SiO2 (i.e. Quartz crystal, very hard indeed) so will be extremely scratch-resistant. I re-glued and removed my baffle (using Acetone) about 4 times I think before I was totally happy. Use superglue, it's totally soluble in Acetone.

Good luck and keepus informed!

Cheers, Magnus

I guess taking a hack-saw to the back of the tube would be out of the question for such a rare and valuable beauty 🤣 ?

2 hours ago, A McEwan said:

Skytee 2 mount is a great bit of kit. I'm on my second (and last, hopefully) now!

Ant   

… and I’m on your first! 😁😉

Here’s my 200p on a skytee2 … the saddles are upgraded to the ADM ones, though it is on the original Vixen-type dovetail on standard SW rings

This I am looking forward to...

I recently bought as a present for a helpful neighbour a pair of Nikon Prostaff 3s 8x42. I specifically chose them for their wide FoV and when I tried them out I could use them easily: I require long eye relief and use specs when using them. I’m used to Leicas, having 3 pairs, and these were not disappointing at all in comparison.

M

4 hours ago, Stu said:

 

Are you going to market your new solution?

Magnus’ Magnificent Fluid perhaps?

Haha I’d have to add something, all I’ve done so far is find ROR’s regulatory filing and more or less copied that recipe. Perhaps an extra drop or two of “Eau de Magnus” to make it uniquely mine. Yuck.

I've just got around to finding out the IDs of the stars in the field: I'd made a note of what it seemed to be its match in brightness. Through my 8" and Nag 31, it seemed the same as HD 175919, which is mag 8.54 according to SIMBAD. This would've been around 0130 0100 this morning, 14th June.

Quite fascinated to have witnessed something unusual.

Cheers, Magnus

Amazingly different from last night. Barely detectable with my 15x56 bins. Whereas last night it was in a par with the 3-star asterism to the North. 

I got my 62mm spotting scope out today during the day and put a baader solar filter on the front, which I’ve had for a year but never used, until now. That feature you point out was amazingly clear this afternoon, had rotated into view, and had real depth to the “hole”. Amazing, actually. Is it a sunspot?

36 minutes ago, Stu said:

I thought everyone knew that Magnus?

🤣🤣🤣

More seriously, that is very handy to know and will make for slightly easier star hopping. I can picture you now with your setup, working it out 😀👍

What else is there to do on a lousy weekend like this 🤣☀️

After spending my observing session last night trying to navigate from the Coathanger to the Nova in Hercules (/Aquila) with my Skytee2 carrying a SW 8" newtonian, and eventually succeeding, I thought I might share a number that I wish I'd known last night.

I was able to find the Nova very quickly using 8x binoculars plus @JeremyS's chart of the locale. Knowing that it was a bit over 7 degrees "mostly right and up a bit" from the Coathanger, I simply panned right just over a full binocular FoV and there it was. Through the eyepiece of the Newt, it was more difficult. First I had to note which direction the slo-mo knobs turned the mount, and I also had to judge how far to go. At higher magnification than the bins, with stars racing across the view and with one axis "reversed", it was quite tricky. Knowing the angular distance between the objects, if I'd known the "angular distance per full turn" of the slo-mo knobs, I would've been able to "fly blind" to the general vicinity with some confidence and pan around from that point.

I did find it eventually, but knowing that number would've saved me some time. It should really be stamped or printed on the mount somewhere.

I spent a pleasurable part of this afternoon with my collimation laser measuring distances between laser-spots on my living room wall.

Any way, the Magic Number is ... ... ... 2.5 degrees per full turn on both the az and the alt axis. (perhaps this is well-known?)

Cheers, Magnus

Just got it myself. Started at the Coathanger then one full viewfinder right in my 8x56 bins gets me more or less there.

M

I’ll have a go at it myself tonight, just setting up for a session anyway