Captain Scarlet

1 hour ago, Fraunhoffer said:

... PS - loving the posts on here for some great ideas of things to look at....

Back at you on that - I'm going to use exactly your list for First Light on my new 2nd-hand 200p, once I've re-built it - it's currently completely dis-assembled into almost all its component parts.

Enjoyed your report, Cheers, Magnus

On 13/10/2019 at 17:42, bendiddley said:

Nothing like opening the box of a new telescope! Looks like the cats enjoyed it as much as you!

The combination of cats and large cardboard boxes is a match made in heaven  hell  heaven  hell  heaven!

Arrived yesterday, courtesy of @bendiddley, my new (for me) 8" reflector. Needless to say, I was incapable of unpacking it all on my own, so I got lots of help, as you can see...

the error circle was a bit noisy, so I imagine my 24 arcseconds also included the mounting instability error of my cobbled-together set-up

Even 24 arcsecs though only represents 0.3-0.4mm of error over 2x focal length of a 1500mm reflector...

2 hours ago, jambouk said:

“It would be much lighter if they could just put a reflective aluminium layer on a lighter material!”

They've done just this for the James Webb I believe: a reflective aluminium gold layer on Beryllium...

I recenty acquired, courtesy of a fellow forumite, a Howie Glatter laser collimator, the combination 2"/1.25" 625nm one. It's a real lump.

Having read that one needs to be very sure that any such collimator needs to be itself well-collimated, I decided to test mine out over the weekend.

I set up my SkyTee2 mount with one of the ADM saddles at a slightly tilted-over angle to form a reasonably solid "V" for the collimator barrel to rest in. I then set up a target A4 piece of paper taped to a wheelie bin around 25-30 metres away up the garden. I rotated the collimator around and made a series of marks where mid-beam struck the paper. I ended up walking up and down the garden a good few times!

The result: a non-collimation radius of around 3mm at, say, 26 metres distance, giving a self-collimation error of around 24 arcseconds.

I reckon that should be good enough for scope collimation? Has anyone done anything similar for any other brands?

Cheers, Magnus

I think the chart is off by a few years; the book was published in 1869, and besides I think at midnight on 15 Dec that year the Moon was bright and up. Not that it makes any difference to the stars’ placement, they’re in basically the same place every year at a given date and time.

The actual time looks reasonable to me though when I look it up, of course whatever projection Stellarium is using and whatever implied projection was used to draw the chart will have a major bearing (pun intended) on the relative angles etc of the asterisms.

Magnus

What were you trying to stack with, software-wise (ugh horrid expression)...

On 04/10/2019 at 22:26, DaveS said:

Frost Fairs

Not as often as I thought and the latest was in 1814 according to the article.

I well remember the winter of '62-'63 when the Thames froze above Teddington, and the sea froze out from the land. Brr..

Early 1990s the Thames froze over at Molesey/Sunbury ... before it completely froze over and rowing was stopped I sculled into the ice behind Tagg’s Island.

and I’ve just bought the book mentioned in the OP ... "The Midnight Sky: Familiar Notes on Stars & Planets" by Edwin Dunkin

... also very recently in our very own for sale section ...

Very nice indeed. Starting with the Pleiades and ending with the Moon, with a lovely dark grey-black sky, Orion and Taurus leap out.

M

... oops should’ve been in imaging section not observing. By all means  move it there if necessary ...

... and Antares bonus extra

7 minutes ago, johninderby said:

This adapter from FLO is a good solution.

https://www.firstlightoptics.com/adapters/flo-compression-ring-adapter-for-skywatcher-newtonians-m54.html

Thanks John. That's very like what the SW Quattros get supplied with these days I think, and a friend lent me just such an adapter to screw into the focus-tube of mine before my last trip to Ireland. Unfortunately my 2" didn't quite reach focus using that adapter on its own, I'd need a modest extension tube in addition.

18 minutes ago, PlanetGazer said:

I have a similar thing on the 10inch SW, i thought that if you remove the 1.25 inch adaptor, you are left with the 2 inch default opening.

That's what I thought too at first, but the opening thus revealed is bigger than 2". A 2" eyepiece will go in, but gets pushed to the side off-centre by the grubscrews. The pic above from @tooth_dr shows exactly how it is, the 1.25" adapter (also shown in my own pic) needs to be removed and replaced with the 2" one shown to allow 2" eyepices to fit properly. It's the style of SW newts from a good few years back, they've changed the design since.

M

Edit:  @John answered first, far more eloquently too!

Brilliant, thanks all.

M

... this is the sort of bevel my existing 1.25" has - although this pic is a 2" adapter - perhaps this is precisely what I need...

26 minutes ago, kev100 said:

Ah, okay. He'll probably need a 2in adaptor in any case, though ...  

 

Thanks - that looks like the same/very similar problem, but IIRC the bevel on the shown adapters looks less than what I remember mine to be. Trouble is, the scope is in Ireland and I'm in London.

10 minutes ago, tooth_dr said:

I know the problem you mean! I've encountered it.   If you arent sorted, I'll send you a photo of the part when I get home from work, that might help you?

that would be good, thank you.

9 minutes ago, tooth_dr said:

As far as I can remember, I think he needs a bit screws onto the drawtube itself.

either a bit that screws onto the drawtube, or a bit that replaces the bit that "flanges in" to the existing bit that screws into the drawtube...

6 minutes ago, kev100 said:

Hiya. If I understand you rightly, you want one of these (or similar): https://www.telescopehouse.com/accessories/eyepiece-adaptors-and-extension-tubes/revelation-80mm-extension-tube-2.html

Thanks. Funnily enough I do actually have that exact 80mm Revelation extender (bought from David Hardie's collection), but the problem with it is that its male end is 2", so it won't fit into the mewt's focuser.

A year or so ago I bought a 12" SW newt from a fellow SGL-er. To say I am very happy with it would be an understatement.

However, take a look at the picture. The 1.25” eyepiece shown (TV DeLite 18.2) is slotted into an adapter which fits, via its circular angled-flange plate, onto the main drawtube-end-adapter, tightened in place with thumbscrews. If I remove the 1.25" adapter, the exposed recess is too big for a 2” eyepiece.

In other words, this scope as it is will not accept 2” eyepieces. I understand they now get supplied with an adapter which allows one to fit 2” units and achieve focus. My problem is that I don’t know what it’s called nor would I likely recognize it from a picture

Could some kind soul point me to a link which shows what I need please?

Thanks, Magnus

I'm no AP-er but this sort of thing is nearly enough to tempt me over to the dark side. Superb.

Judging by his avatar it would be right up  @Stu’s street 😂

7 minutes ago, sophiecentaur said:

... Do I need to get out my large Stilsons?

Well that’s exactly what I had to do to remove and fix (parallax and reticule alignment) the polar scope in my then-new AZ-EQ6 a year or so ago. Took a lot of courage, but it worked. Everything had been cemented together.

M

I would imagine the plates in which the eyepieces sit rotate about their centres so that you can effectively change eyepieces. Think filter wheel for eyepieces...

M