John

PS: You might find this website useful: https://www.nexstarsite.com/ There are lots of tips and guides on there on the range of Nexstar scopes and versions.

Sounds like you may have the original Celestron Nexstar 8 which looks like this: I used to have the 5 inch version and the opitcal tubes were fixed to the mount arm - no dovetail bar, annoyingly. I think the handset was hard wired in as well. They became the "i" version (more GOTO items in the memory and a steel tube tripod) and then the SE version and the colour scheme changed and they used a dovetail connection with the tripod. There is a chap who services SCT telescopes but I forget his name now. He used to work with BF&F and Astro Engineering.

Nice report I have the 130mm refractor out this evening. Poor transparency and seeing earlier but it got better and better as the hours passed. Really good out there now but I'm too tired to enjoy it Following a rather prolonged galaxy session (wrong scope really) in Leo, I finished my session in Hercules with Messier 13 and the other lovely globular there, Messier 92. Glad you enjoyed your night as well

I find them about the same re: ease of use, convenience etc. Both types really easy to set up and use. I have 1 dob, a 12 inch and 4 refractors from 100mm to 130mm which I use on alt-az mounts. I stand while observing. Tonight I chose a 130mm refractor and it's been a lot of fun chasing galaxies and double stars plus a few globular clusters. It was a rather milky sky earlier (hence the refractor choice) but the transparency has improved a lot over the past hour. If I want to go as "deep" as I can though, the 12 inch dob gets the nod every time of course. For double stars I prefer refractor views although the 12 inch can out resolve them of course. I enjoy using both types of scope

B is about as far from A now as it ever gets. In 2250 or thereabouts it will be less than 1 arc second from A. I won't bother trying for it then

I've annotated John Nansen's diagram to show the A, B, C and D stars. This is a 5 inch refractor view at 229x as it says. B and C are in the same general direction from A.

If you are talking about Theta Aurigae, the position of B does change over time, but slowly. The red numbers are years, the grey spot is "now":

I started this thread late last year which may be of use:

It's far from easy Rob. There are many experienced observers around who have not managed it yet. Like so many astronomical observing challenges, when you have done it once, it gets somewhat easier the next time because you know what to look out for

I have a scope with a focuser just like that and I have just the same problem. Those little screws are not good at holding weight / gripping and are so small that applying any real tension to them is difficult, plus the screws mark up the diagonal barrel. Ideally the visual back (the black part that the diagonal fits into) would be replaced by one with a compression ring fitting. but I'm not sure that these are made for these smaller focusers A simpler alternative would be to replace the two tiny set screws with larger ones that have more for the fingers to grip and which have more contact with the diagonal barrel. This would entail re-drilling and re-threading the two holes in the visual back and fitting larger and more robust set screws. It is an annoying problem. Perhaps someone else with a Skywatcher 1.25 inch focuser has managed to find a way to improve it ?. I'd be interested myself if they have. Sorry that I don't have a handy solution but I can empathize !

Great piece on Theta Aurigae here by John Nansen: https://bestdoubles.wordpress.com/2012/04/20/theta-aurigae-and-the-light-of-its-passage-is-night-on-the-face-of-the-world/

Took me a long time and, eventually, a 12 inch scope to split Sirius It's a little easier now (the separation is more or less at it's max) but still a very tough challenge. Well done on Theta Aurigae though - it's a bit of a "classic"

I've just been looking at Theta Aurigae (prompted by your post). It does sound as if you have got it. I got it at 170x with my 100mm refractor. Doing the mental conversion between the refractor and the newtonian view, 300 degrees sounds about right and it corresponds with the Stella Doppie database data which says 302 degrees. I think you got it It is quite challenging because of the brightness difference between the A and B stars which makes otherwise straightforward separations much harder, eg: Sirius for the most extreme example.

That looks quite typical for a Synta scope. Their internal blackening is OK but nothing special in my experience. I hear what you say regarding the optics but I have to confess that I've owned two or three scopes over the years that I never managed to get a really satisfactory star test from I'm not suggesting that yours is like that I hasten to add. My 90mm F/11.1 produces pretty decent performance visually in terms of splitting double stars, detail on the moon and planets etc even if it's star test is not that great.

There may be a limit to how good you can get the collimation and star test with these F/5 achromats. A lot of them have an optical issue called spherical aberration (SA) in the form of either under or over correction to some degree. Many of the slower achromats from the same source have the same. It's worth keeping at it to get it as good as it can be but I feel there is likely to be a limit beyond which you would need to experiment with rotating one of the objective elements or even more drastic work to gain improvements. I have a 90mm F/11.1 achromat from the same manufacturer (Synta) and I've been fiddling with that for about 4 months now but it is still showing a little flaring of the star test despite my efforts. The next stage, when I have time, will be to experiment with the relative rotation of the lens elements to see if there is some "wedge" in one of them. It's a time consuming process though and we have not had enough clear nights to justify spending time on that.

Carry it with both hands, like the Terminagler

Good advice Its worth checking that before doing the stuff that I mentioned earlier in the thread. A floppy focuser is not going to help the star test ! With a bit of adjustment and maybe a re-grease these Skywatcher rack and pinion focusers can be made to work quite well.

Nice report ! One trick that can help the star image quality with these scopes can be done indoors in daylight. Point the scope upwards and keep it that way though this process. Remove the lens cap and dew shield. Loosen the lens retaining ring a couple of turns so that the lens elements are loose. Gently "slap" the objective cell all around it's sides. This gives the lens elements a chance to settle into their positions. Then very gently tighten the lens retaining ring again just enough to hold them in position. If the comatic stars continue to be an issue, you will need to think about the collimation of the scope. Having a laser collimator is helpful to check if the focuser is aligned with the central axis of the objective. With the diagonal off, shine the laser down the tube and note where the laser exits the objective - it should be pretty much bang in the centre. If it is not, tilting the focuser to get the laser central is required and then some form of shims to hold that tilt when the 3 screws that hold the focuser to the tube are tightened. Once you are confindent that the focuser optical axis is aligned with the objective optical axis, you can use a cheshire collimator (again without a diagonal in place) to see if there is objective tilt: The challenge with these simple refractors is that there is no focuser or objective tilt adjustment facility built in which is why shims are needed to apply any necessary tilt. Aplologies if you know all this !

Seems a good point to me

I suppose a legitimate question that can / should be asked is what will all these marvellous eyepieces that have been proposed show with the Tak 76 that the OP's current BST's and Baader zoom won't show ? In a number of cases (including my own suggestion) the proposals could involve spending £1000 plus. So just what does that buy in terms of tangible / specific performance gains over the eyepieces that Nicola currently has ? (I'm asking for a friend )

Does your GOTO tell you which targets your scope is likely to show well and those where you might recognize something in the eyepiece ? One of the great things about the book is that the targets are carefully chosen to be those which small instruments and new observers can both find easily and that will be interesting to observer. GOTO's, when set up properly, are great at pointing the scope at object X or Y but many objects may simply be either incredibly vague or invisible when you actually look though the eyepiece at them.

Some great sales people on here ! You pop in to ask about a couple of eyepieces and exit with a couple of sets of eyepieces, two additional scopes and a mount or two If Arkwright ran an astro shop .......

I'm very impressed at the efforts that folks will go to to get decent skies

Cracking eyepiece Michael

I agree. It keeps the forums rolling when it's cloudy though