DaveL59

perhaps post a picture of the scope and lens and if you can, and the setup you are trying and if possible a pic of the image you see.

Are you using a diagonal or fitting the eyepiece directly into the focuser?

The diagonal may also need a clean, but being a mirror you need to do that in the correct way to avoid damaging it. Lens cleaner and wiping it will likely ruin it.

last night here there was too much cloud in the area it'd show so I didn't get another look, will try tonight tho before I go to bed, have to get a reasonably early one tonight unfortunately. 

I guess your camera is an optical viewfinder and no live-view?

Would make it harder unless it's naked eye visible as you'd have to take a shot and review and adjust/retry. My bridge is electronic viewfinder so pushing the exposure makes it vaguely visible, but in the end I just zoomed back and took a punt. Well overexposed but then I was playing hand-held leaning against a fence panel, upside tho is it picked out a decent amount of stars too.

Can't recall the exposure not but I think that was ISO1600 F4 and around 1/20s

A little editing pulling down the brightness etc yielded this version

Didn't shoot that raw tho, I'd have tried more and exposure bracketing if I'd have the tripod and remote release, but it disappears behind the roof on the right a little time after so I just enjoyed the view thru the binos after that. It should then become visible from the front of the house but the bright LED street lights make it hard work looking past the glare so I didn't bother 😉 

hi Paul

ideally you want a target a lot further than 50m to do this, so you may still be a touch out against the stars, but you could always tweak once you've had a chance to try them. Or nighttime using a distant street light if its all clouded over  

4 minutes ago, wookie1965 said:

Advertisement says no returns so I dont think I can do anything and since I have tried to adjust them he can say its my fault.

ack, sounds like seller knew there was a problem and just wanted shot of them  Ebay/paypal may still act in your favour tho if the ad says they are correctly aligned, but if there's signs you've tried to adjust that won't help of course. Hope they didn't cost too much if you end up stuck with them. An optical repair shop may be able to collimate them for you tho, give someone like east coast binoculars a shout and see what it'd cost.

sounds like the easiest solution Stu, just say they arrived out of alignment.

Unfortunately it's very easy to make things far worse trying to adjust them, takes a LOT of patience and good research beforehand and perhaps a degree of luck. Having tilt screws does make things easier though, first ones I did this with you had to shim the prisms and that took me around 5 hours popping a prism out, adjusting the shim, replace and try again... Rock solid now though and I learned a lot doing that work. Eccentric rings can be fun but quite doable again with patience and the right tools.

you mentioned before some instructions, hopefully they give the information?

One of the makers I recall did give instructions on how to align their astro binoculars and that is pretty generic, can't recall which it was now tho.

The problem is that the prisms, while set at right angles with respect to each other are not so with regard to the image you see. So each screw will alter the image on the diagonal. The lower prism/screw will shift the image top-right to bottom left and the top prism/screw will shift the image top-left to bottom right, if that makes sense. It's a bit like using an EQ mount or perhaps a better example, collimating a reflector, adjust only one screw and see the effect and if worse back it off to previous and try the other etc. 

4 minutes ago, Robindonne said:

If thats the reason then they lost a serious option in cutting weight ( metal, paint etc)

and after purchase you spend extra buying a shroud or making one, which is better...?

Are they new? In which case I'd return them.

If not then I'd adjust the right side if it'll bring the images into alignment and not make the exit pupil go further out to the edge. Could be that a prism is out of place in its seat if they've had a bump and while you might be able to twiddle the screws and get them usable it'll maybe shift again later and need this all doing over, or worse, chip and become useless.

I expect it acts as a dew and light shield

Nice shots just the same Chris and well done

Here was clouded out so didn't get another look. Like you though, where I'd nit used the bridge camera much in a while it was a re-learning process and of course in a rush you forget to do x or y. Did manage a couple shots the night before but had to push to ISO1600 to capture it before it disappeared behind a roof, tho I think better prep and setting up the tripod I could've done better at ISO400/800, maybe, but I was resting the camera on a wobbly fence so case of making do. 

I assume these are porro, were they from Lidl? 

Tweaking the alignment at home is a tedious process and needs a lot of patience and very small adjustments to the prisms unless you've got the right gear that the pro's have. Did you tweak both sides or just on one side of the binocular?

Holding the bino a couple feet away how to the exit pupils look in the eyepieces, central or offset?

Daytime you can adjust and get them close but testing against the stars will give you a more definitive answer as you've found. I've done this on several binos now and on clear nights I've been in an out several times making small tweaks until I have them right. I find it easier to go in and adjust under lights as it's easier to see the screw rather than fumble in the dark and drop the jewellers screwdriver and try to find it, or worse the tiny adjuster grub screw. Best to work on one side only at a time (I start with the most offset exit pupil), else it can be like having 2 cats on leads and trying to take them for a walk  but be aware that if a large amount of adjustment is being made you may have started on the wrong side and the exit pupil may be well off centre.

I have also used a light indoors to help get them closer than using a roofline but getting sufficient distance makes that harder. I use the reflection of the light off the glass front door panel but even so that's only around 10 meters but I've found it works for me, guess because I've done it several times. Another option, if you can tripod mount them, use an object with a distinct Y or cross pattern, a distant bare branch or TV aerial as that'll give a much more defined view of the alignment than a roof.

Also when you are checking, don't forget that your eye will quickly accommodate any error in daylight as there's plenty of background for the brain to merge. To get around this use a dark card over one objective and while looking through the bino, remove it and note the first instant view. Repeat a few times to confirm and adjust then redo. Best to do this when your eyes aren't too tired as well.

Once done you may well find that someone else will find the same issue you were seeing, since you won't have collimated the 2 sides, merely adjusted the alignment to suit your specific IPD.

hope that helps.

ho hum, got a quick look at jupiter, clearly saw 2 moons and perhaps a third closer in with the old gal. Then cloud faded everything and more coming across, so packed it in for the night. Zero chance of Neowise tonight either, much heavier cloud to the north and pretty mottled all over so nothing much visible other than the odd star just peeking briefly thru small gaps to tease.

Still, feels like a successful day fettling this one so can't complain too much 🙂 

under astronomy tools at the top of the SGL page there's a calculator which should help  

13 minutes ago, murph_man99 said:

p!

I have been doing some reading and  I have little better idea of what I should be looking for in a telescope.  I will continue to read but I have a quick question.  I will be using the telescope mainly in the backyard ti view planets.  As a beginnner What should the aperture and magnification be?  I believe aperture of 5-6 would be good.?

 

 

down to what you can afford in your budget, what you can manage in terms of lugging it out and space to store it really. For a reflector if you look in the 6 to 8 inch range (150-200mm) you'd get good views I expect, for a refractor 4-inch (100mm) would be the low limit ideally and they get heavy above that requiring more expensive mounts.

Magnification will depend on how good the seeing is (clear sky etc) but 150-200x for planets is reasonable on good nights. 

You'll likely need to budget for better eyepieces in the long run as the supplied ones with most scopes are ok but not fantastic. Say £50 each for BST Starguider which are well regarded as an upgrade option. Which would depend on the scope you decide on but first get used to the scope as shipped before sinking more into the hobby you're just starting out on.

for me it's houses and trees but luckily it appeared between the neighbour's and the block backing onto the gardens from the parallel road. Luckily we're near the top of the hill so the obstructions diminish downwards 🙂 

Was lucky enough to see Hale-bop back then too, from blackheath common if I recall.

Looks tonight tho it's totally clouded up in the NW-N area for me

saw it for the first time last night 11PM in the binos, was hoping for another look tonight but is looking like cloud will cover the area it'd show in. Same for the SE where I was hoping for another look at Jupiter and Saturn. C'est la vie...

won't stop the small birdies from inspecting and maybe leaving small corrosive deposits tho 🙂 

I find I only get notifications if someone quotes me or likes a post, otherwise I don't see any alerts that someone posted to one of my threads, so can be a while before I pick up unless it's one I'm actively updating.

Gave the leather a clean and feed and added some felt under those metal capping plates so they don't do any damage. The wood base has raw leather in the tube cut-outs which seems to work ok but now the scope turns more easily. Refitted the ancient Prinz finder scope and just been out and aligned it. It ain't great but at least it's something till I sort an alternate. With the damaged objective lens section blacked out the image is very good, you'd never know through the eyepiece  

Of course now it's out and ready to play the southern horizon is all clouds where the planets would rise (red squiggle) and traverse before I lose them to the oak tree in the south, that dreaded cloud god must've heard me saying earlier that I'd test this one out again tonight 🙄

NNW was heavy cloud earlier but seems to be moving so just might get lucky on Neowise again, time will tell...

So from the story so far...

It seems that while the lens fail was a disaster and I felt totally gutted at the time, it wasn't a complete disaster and the scope is in fact still quite usable. I do hope to source a replacement lens at some stage but it seems an 80mm will be too large and mean some mods that could change the look of the scope quite a bit. A 75mm would likely drop out or down the OTA unless I find a way to add to the lens retaining lip.

The ideal/easy solution would perhaps be to scavenge a battered Prinz 660 for the objective as that's a 76mm if I recall correctly... So I'll be keeping my out for one if I can find one at a reasonable price. Anyone got one they'd part with to be broken up I wonder?  

Meantime, back to thinking about restoration options on this lovely old scope 🙂 

Cleaned off the old glue and the to parts are still a very snug fit tho do come apart slightly easier now. Looking into the cell fully assembled, the lip that holds the lens in place is very narrow. Maximising the aperture I expect

From the OTA end

and the dew shield end

At least I can reassemble as-is and be comfortable that it won't suddenly come apart unless I'm yanking on the dew shield while I decide on which way to secure the parts in the future. A small m2 brass countersunk I think would work well and should eventually age to blend into the aged brass.

13 minutes ago, merlin100 said:

What do you think caused the lens to break, did something internally fall against it or was it external pressure on the OTA? 

I was working the lens cell to separate the inner tube and the lens became loose. Unfortunately it tilted as I turned the tube to try tease it further and the edge of the lens against the tube wall was likely too much and a chunk pinged away. Of course while rocking the outer tube side to side tiny amounts likely helped that as well. About to post pics of the cell tubes, the lens may well have found the lip which would have given it space to tilt.

edit: in fact the edge is visible in the pics above. The wide silver raised ring is where the lens sits and the inner tube presses home up to that point to hold it in place.

so some success, in the fridge for a good while, nice and cold. Refit into the OTA so I could use the securing screw to hold it. Was still tight going into the OTA tho even with that at room temps. Still quite tight but gentle rocking the shield and it edged it's way to freedom. 20 mins later and...

Seems the lower inner tube section was glued into place so something I may have to consider when I refit, or tap a small hole and use a screw instead, likely the latter to make future maintenance a bit easier is my thinking. Explains why it was so stubborn to remove even tho the glue wasn't bonding to both parts any more. The mist on the lens is just condensation after around 1.5 hours in the fridge then going into a warm room with the humidity we have today.

So the lens, seems it is 76.8mm diameter and 13.3 thick at the edge, cemented doublet. As you can see it is edge blackened as well tho doesn't appear to be coated, probably the norm back when this was made. Took the opportunity to black out the spall using a carbon black paint pen, should improve contrast till a replacement is found.

Will now clean off the old glue and see how well the tubes then fit and put it all back together again. Once the paint has fully dried so I can clean the lens I may give it a quick test in the garden and another run at the planets tonight

overtightened locking screws perhaps, deforming the threads slightly? or a touch of corrosion which can be cleaned up if you've a tap and die of the correct size.

or even "Which?" magazine... 😄 

I'll get me coat now... bye 😉