Pixies

After I collimated the laser collimator, they agreed perfectly! The reason I fancied having a shot with the laser, was to be able to watch my progress while I was actually turning the primary adjusters (my arms aren't that long!). It was interesting seeing the effect of the locking screws - more like a fine tuning. I'll use the Cheshire as the main method and the laser for a quick check in the dark - as long as it proved to remain reliable against the Cheshire. The laser collimator cost <£20 from Sky's The Limit. The collimating jig cost a little less (see pics)

Filament bulb! You rebel!

Unfortunately, if I turn the brightness down, the reflection of the doughnut falls too. I'll probably need another Barlow

I'm joining the club too!

Hi, I have a collimation cap and Cheshire and have no problem collimating with them. Star tests are ok too. However, with a big dobsonian it's impossible to adjust the primary while looking down the Cheshire. So I bought a laser collimator - a cheap Starguider (<£20 new). It is adjustable and I've collimated it. I've been comparing the results using the laser with a Cheshire, and it's perfect. However, I thought I'd try the barlowed laser method, so bought a cheap 2nd-hand SW barlow (no expense spared with me!). However, I'm having a problem with it. When I stick the laser in the barlow, I get a reflection thrown back at the collimator surface that's so bright, it's stopping me see the shadow of the doughnut on the primary mirror. Even when out of the focuser, you can see it (see pic). Is it just the cheap barlow and non-coated lens surface? If I unscrew the barlow lens, turn it over and hold it back up to the end of the barlow tube, I don't get the reflection.

Hi, I had to roughen the felt to make sure it wasn't too slippery, otherwise it didn't take much to start it sliding down the tube when vertical. I didn't want to use anything too sticky - like rubber - otherwise it might be tricky to move around. The magnet is powerful enough not to fall off, though. I'm careful to make sure I have a good grip when placing it up against the OTA, so that it doesn't suddenly slam into it.

The Bresser 8" has very little range to move the scope down the rings. I'm already at the furthest limit and any further means I hit the base and can't get the scope pointing straight up. It currently only suffers for targets below 30deg and because I have quite a heavy finder (I also like to have the alt bearing 'brakes' quite loose). But I'll have problems once I get some big 2" EPs, I'm sure. You can't tighten the bearings on the fly, like a Skywatcher dob.

Hi Matt. Ex-Norwich here. Welcome to SGL OTBC!

Try the carbon star, T-Lyrae. It's part of Lyra (obviously) so well placed just now.

Made some counterweights as per:

I got a pair of 'recovery' magnets to repurpose as counterbalance weights for my dob which is a little top heavy. These things are used to fish for treasure in rivers, etc. There are whole websites dedicated to their sale. I got a pair weighing 750g each - so 1.5kg total. I didn't want to start too heavy or large. They were £8 each. They came with a plastic cover to stop scratching in transit, so I used epoxy to glue these in place. Then I stuck on a pair of those long thick felt floor protectors to keep the magnets off the surface of the OTA and stop them rotating. At voila:

Hi. Just saw that this was your first post. Welcome to SGL! This is an excellent thread on eyepieces, just read the first few pages and it'll help enormously: Let us know your budget and I'm sure you'll get lots of advise.

Oh well. At least we're not launching thousands of satellites up into low Earth-orbit which would confuse the early-warning detection systems. Doh!

I've just got a 10x60 Altair. It's pretty big. I could actually see M13 in it the other night despite not being able to see any of the keystone asterism because of light skies and light pollution. It's big though. As pointed out, it might be too much in a dark sky setting; showing too many stars and making finding more complicated. In which case I might end up stopping down the aperture! It is big, btw.

That'll be good for a table-top Dobsonian!

Hi. I was thinking about attaching my new 10x60 findersope to my sturdy old Velbon tripod, as a little grab-and-go scope. Is there an adapter for a synta/vixen type fixing to fit the standard camera tripod shoe? I can't find one using my Google powers. Ta

Hi again, Sorry if I didn't make myself clear. I'm not having issues keeping the scope in collimation. Far from it - it's very stable. Probably because the adjusters are at the tighter end of their range. I was just wondering if there was a preferred option. Perhaps I have found it more by luck than judgement!

Edinburgh: Last night I reckon the lowest magnitude I could see was 2.8. the summer triangle was OK, the 2 head stars of Draco were just there, but I couldn't make out the keystone asterism at all. I had to use binoculars and my 10x60 finder to locate M13. Going to take a break for a few weeks, I think.

Hi, Thanks for the answers. The Bresser has locking screws, and springs as well, by the feel of it. I was just aware that I usually adjusted the primary by tightening. So - instead of loosening one screw, i'd tighten the other 2 (if you see what I mean). I disn;t want to go too far, but nervous about loosening them all too much. Is there a recommended amount of tension / position when installing the mirrors? ie. a good starting point?

With the bright skies up here now, I'm going to take a few weeks' break from observing and focus on a few more practical and educational things. One thing I fancy is getting the collimation really dialled in. But I had one outstanding question. When adjusting the primary with the 3 screws, am I right in thinking you could evenly tighten or loosen all 3 screws equally and collimation would remain true - but the mirror would just be moved up or down the tube? Have I understood the mechanics correctly? I'm yet to remove the mirror assembly, so haven't seen it up close. But the impression I get is a spring-loaded assembly that is pushed back against the adjustment screws. So you could tighten them all against the spring force and move the mirror up the tube towards the secondary (very slightly), or loosen them off and the mirror would move back down the tube until you had loosened it enough for the springs to reach their extension limit, or the mirror meet a physical stop? It's a Bresser 8" dob. Is there a recommended tension/position for the mirror, around which the collimation adjustments should not deviate too much? I could imagine that if one adjusted collimation by only ever tightening the screws, it would eventually reach a limit? Ta

Last night was unexpectedly clear, so I got the scope out for a cheeky little session. However, as this was the first clear night I've had for 3 weeks I was caught out by how bright the sky was. I thought I'd go for the obvious target M13 But at 1am, the sky was still so light I couldn't even make out the keystone asterism. I ended up having to use my binoculars to find it, then roughly get the finder pointing in the right direction. But when I did, I could see the cluster in the finder view! It might be too much for dark skies though. I'll see. Perhaps if it is, I can make a mask to step-down the objective aperture of the finder.

A cheap pair of Praktica 10x50. The edges are a little fuzzy but centrally they are very sharp. I can see Jupiter's moons with them. I just love using them to scan an area before I attempt any star-hopping. But before I had a telescope, they were in use with a tripod for all my observing. I have shown the kids Andromeda through them.

I have just spoken to a friend with the same model. His RDF can be aligned just fine.

Ah! That's the issue. This is a scope where you can't adjust the primary.

The secondary mirror is quite large, with respect to the image of the primary. That will make the initial positioning of the secondary much more forgiving. So it's just a case of a quick alignment with the doughnut. Perhaps this is all part of the design?