azrabella

Ideally your scope is designed to operate at "infinity". The closer your subject the more back-focusing you will need. You should find that your 23mm eyepiece will require less back-focus than your 10mm eyepiece. Your target at 100 mtrs is too close. Probably nothing to worry about.

I tend to apply my rule of thumb to double stars. It is that:-

When the delta-m number (difference in magnitude) is bigger than the arcsecond separation it 'aint going to be easy regardless of scope size.

Even worse in S. Wales. Two sessions since Christmas. What did Private Frazer say..."Doomed. We're all doomed".

...and rename it "The Clouds at Night".

Yep, Zeta Piscum

Try this one. Works for me.

https://quickmap.lroc.asu.edu/layers?extent=-59.0021054%2C24.6332759%2C90%2C56.3425499&id=lroc&showTerrain=true&queryOpts=N4XyA&layers=NrBsFYBoAZIRnpEoAsjYIHYFcA2vIBvAXwF1SizSg&proj=10

I have been looking at the UFF's and it seems that the Svbony SV190 18mm Ultra Flat is a clone of the APM/Stellalyra eyepieces, at least according to the specs - and cheaper too. Might give that one a try.

Can any one of you wise people recommend a reasonably priced alternative to the Nirvana 16mm eyepiece? Whilst fine optically, I just cannot stand the ultra wide 82 degree field. I also find that it does produce kidney beaning due to its relatively tight exit pupil. I can work around this issue by extending the eyeguard somewhat. Trouble with this is that I lose the field stop (about 85/90% fov). I do love a sharp field stop.

Ideally I am looking for a something between 15 and 19mm (fov ideally around 65/70 degrees) to replace it with. But do bear in mind I'm on a limited budget.

Any advice warmly welcomed.

Anyone here had a chance to test/use the 34mm 72 degree 2"  eyepiece from SvBONY. If so, how do you rate it compared to say the Aero or Panaview equivalents. I have the 26mm version which has proved far better than I was expecting. Sharp to about 80% of the field using an f/8 Dob.

Likewise, only I substitute the laser for a 6x30 finderscope dual mounted with the 9x50 RACI.

I suppose a lot depends on what you observe. BST's have been my fall-back eyepieces for years, and at 60 degrees they are a good choice in most any scope. I also have two Nirvana eyepieces (13mm and 16mm) and they do take some getting used to, but when your brain/eye has made the adjustment then they are most useful additions. BTW, both less than £100 each new. My favourite eyepiece is an old SWA 70 degree 17mm. It fits midway between the BST's and Nirvana and is a good general purpose ocular - at least, for me.

Where did you get the magnets from? Such a good idea.

Any practical tips for counterbalancing a slightly top-heavy closed tube 150mm Dob. When angled at anything lower than 45 degrees the scope slowly drifts downwards due to heavy eyepieces. Need some kind of moveable weight (magnets) around the prime mirror end of the tube. I'm sure I am not alone with this niggle, so it would be interesting to know if there is a very simple solution, apart from the obvious, as I don't intend changing eyepieces.

Here's what I am using currently  - more practical than showy. Bit of a mungrel set. Functional, given my light-polluted sky.

Hand held binoculars, that is. Either as your preferred choice for observing or as an accompaniment to telescope work. Are you favouring roof prism, porro or monoculars. Bak 7, Bak4  or more traditional designs? I'm trying to make a final decision but with so many types to choose from, I seek your wise opinions. Also I would like to know if anyone can suggest binoculars with a well defined field stop. Lots of questions but I am sure someone has just the right suggestion.

Thanks in advance.

I'm wondering if any of you guys have used, or have any knowledge of these particular bins, especially for astronomy. They seem to get reasonably positive reviews from bird spotting enthusiasts and the like but I can't find much else with regard to night time performance.

Thanks in advance

Thanks wulfrun - same as mine. That'll do nicely - cheers.

Hi - I'm sure someone out there might have the answer to this one. I have one of the above but without the knurled locking thumbscrew. Any idea what size thread it might be as I need to order one. I think it might be an M4 diameter but I don't have anything to compare it to.

Anyone......?

Standard rule of thumb is that aperture over magnification is best.

As a past user of this scope, I would suggest a low power, wide field eyepiece of around 32mm focal length offering around 35x magnification, great for wide field scanning. A 2" eyepiece will allow a greater field of view than you can get from a standard 1.25" eyepiece. Something like a Panaview 32mm would be ideal. Then a medium power eyepiece, say around 18mm/15mm, giving around 66x/80x magnification. BST Starguiders are rated well on this site and can usually be had second hand. Then  I would suggest a medium/high power eyepiece around 8mm yielding around 150x magnification, again BST Starguider would be a good choice with this particular scope. Alternatively you might consider something like a Baader 8-24mm zoom eyepiece. Nice and sharp, but with a narrower field of view than you would get with the individual eyepieces.

Just an opinion.

If your scope has a solid tube then a shower cap works just fine.

Can anyone advise as to whether a 25mm BST Starguider (Explorer) will work reasonably well in an f/8 Dob? I have conflicting reports on this puppy. I have the 12mm version and that works very well indeed.

Good luck finding it - whatever "it" might be.

If Dark Energy is exponentially expanding the universe and Dark Matter adds hugely to the total mass of the universe something seems to be wrong with my simple understanding - surely mass should slow expansion???

Hi folks - has anyone dared try the "cheap as chips" SVBony 15mm 70 degree eyepiece yet. The specs look OK though words can be cheap. I don't think it's a Chinese clone of anything I am familiar with. They seems top be retailing for around a paltry £46 here in the UK. Is it worth a punt or is it likely to be a poor performer at f/8?