Pixies

My guess is that the secondary is rotated, so you are seeing the primary aligned but it is being clipped by the fact that the secondary is not showing it's full face towards the focuser. A laser won't account for that, and a still show it being collimated correctly. A bit like this: Do you have a Cheshire or a collimation cap?

Also - is your star test like this: or more like this: or this:

can you take a pic?

Are these visible through an eyepiece, or AP only?

Yes. I believe I am doing the third test!

They look like binoculars lens caps!

Thanks. These are mostly volcano top EPs, so would have to be a little deeper I'll measure up and let you know.

Try taking our your eyepiece and have a look at the secondary mirror. It's that cracked?

Got some old bins off of fleabay last week. They were cheap and I had the option to return, so I thought it was worth a punt. A pair of Super Zenith 10x50s, which I fancied the look of. I know they were pretty common and still a budget choice back then. The optics are very clear and they appear to be well collimated. They wipe the floor with my old bins and I was pretty happy they were a good find. Tonight I was having a look at Albireo. I couldn't split them cleanly before with my old pair, but tonight with the new ones I could easily. However, what surprised me was how clean the split and how clear the colour difference was. Seeing wasn't great, but the transparency was good. Never having thought about double-stars and bins, I had a quick read. Albireo at 34" is supposedly easy to split. So I saw that the orange doube 61 Cygni was a wee bit tighter at 30" and checked that out. Again - easily split. This is all with a tripod, by the way. I then had a look at the Astro league binocular double star program and tried to find a pair with a tighter split that was visible from the back garden. Kappa Hercules (Marsic) as a split of 27" so I tried for that. I managed it too - although a little harder and I think probably at the top end of what I can split. So I'm pretty chuffed with the new bins. But I have no reference apart from my old ones, which I now realise were pretty poor. Is the above good performance for a pair of 10x50s that are nearly as old as I am?

Cheers. I've found some of the correct size on Astroboot. 3 for £6.50 I'll try them and see how they go.

Will do.

Yep - thanks both. I'll just need to get some 'matching' bolt cases. Recently, trying to observe Mars, it was the orthos that had the best views. But I'm pushing a dob, so it can be a wee bit tricky with them.

Hi Everyone, As the possibility of some dark-sky trips come up, I need to pull my finger out and sort out a storage case for my EPs and bits and pieces. A quick question regarding the older-style ortho EPs: I have a few. Some have mis-matched bolt cases and some have just the nose-piece cap but nothing protecting the volcano top. How do those with similar EPs keep them neatly stored in a foam-filled flightcase? The OCD in me would like them all to look similar. How were the volcano-topped EPs protected when they were delivered new? Cheers.

Cool. I'll PM you.

A wide FOV might be of benefit at a dark site. To give you a chance to see some things you wouldn't be able to see with the C8?

It's roughly 2/3 of the fl. So 25mm EP - 17mm eye relief 10mm EP - 7mm eye relief

The problem with straight finders on a large dob is that when looking at things near the zenith, you end up on your hands and knees trying to look up the finder. A RACI solves that - but it is hard to find a target with just a RACI alone, since you have no easy way to know exactly where you are pointing it. Say you wanted to start a star-hop from Vega. How do you find Vega with just a RACI? You have to try and guess and point the scope in the rough direction and hope for the best, with a straight finder you could keep both eyes open and then it's easier to line up the finder with the star. The Telrad/Rigel gets you on to your initial target, then you can star-hop with the RACI.

An excellent idea. how about this as al AltAz alternative: https://www.astroshop.eu/telescopes/skywatcher-telescope-n-130-650-explorer-130ps-az-5/p,55150

@Stardaze, another 10" Bresser dob owner, had issues with his Quikfinder - not just the fixing of it. They use glue-tape to fix onto the tubes. The Telrads have 3M tape which is very sticky and won't come off in a hurry. As John says, there have been some complaints about the tape used on the Quikfinders but this was fixed by using decent tape like 3M or Gorilla tape. With the Telrad, you stick the base onto the tube, and the actual finder is fixed to the base using a pair of thumbscrews.

Exciting. Like an early Christmas! I can recommend a book called "Turn Left at Orion". It'll be worth getting this in advance and having a good old read before your scope arrives. Basic info on astronomy, plus star-hopping advice and details of what to observe at different times of the year. I might suggest something to consider regarding you other purchases. A collimation cap is a good tool for collimating your scope, but it has some limitations. One of which is the difficulty in making sure the secondary mirror is aligned correctly under the focuser. Fortunately, this step is rarely required. Unfortunately, it'll likely be required when the scope arrives! It is a LOT easier to do this with a Cheshire collimator, so you might want to investigate this before the scope arrives - you have plenty of time.

I know. And the 'RACI' version is actually a polar finder with a polar reticule, rather than a cross-hair. https://www.firstlightoptics.com/finders/explore-scientific-8x50-90-degree-polarfinder-amici-prism.html

The finder/shoe supplied with the Bresser dobs is the one drawback with this scope. It wouldn't be a problem if there were suitable decent finders and mounts that would fit, but there is very limited choice - esp if you are looking for a RACI finder. Explore Scientific finder will fit though.

I ended up using just a single bolt/nut using the centre fixing hole. I have spare countersunk bolts/nuts if you want any. As I had 4 holes, I covered up the other two with the Telrad base. The remaining hole has been covered with a white plastic furniture plug.

Hi. I took John's advise with my 8" Bresser. That shoe he suggests (the Baader) doesn't need drilling. There are 2 types that come with the Bresser - one has 4 holes, the other 2. The Baader shoe fits either. Obviously with the 4 holed variety, you'll have some holes to plug. I found that I had to source some new bolts, to avoid having to use ones that would protrude to far into the tube. Are you in the UK? If so, I have plenty of spares if you feel you want to try different sized bolts.

@Markyttt's 6th Law is proving correct: Lesson no 6 - Collimation is a minefield of differing opinions, methods and equipment