John

"Clear Outside" is actually showing 3 nights this week with observing potential !!!!!

Moon should be out of the way as well. Just got to remember how to use the scopes now ........

One thing to bear in mind is that the tolerance for collimation error is greater the slower the scope.

For example, in an F/8 newtonian the so-called "sweet spot" for collimation is 11mm in diameter around the optical axis whereas for an F/5 it shrinks to just 2.8mm. The upshot of this is that fast newtonians need to be collimated that much more accurately if they are to be able to achieve their theoretical performance potential.

More on this here:

http://web.telia.com/~u41105032/kolli/kolli.html

I reckon you should be thinking about Vixen SLV's. They are really good planetary eyepieces and can be bought for less than £100 these days. Here is a review I did of them a while back - the 6mm was a wonderful planetary performer:

The EON 120 is an excellent refractor. Skywatcher used to carry the same scope under the Equinox label. Really good ED doublet objective lenses in these scopes.

Finding the right magnification is the key to getting E & F Trapezium. Not too little and not too much. Often I find that 150x - 200x is about right. I can see them regularly with my 120mm and 130mm refractors and sometimes with my 100mm / 102mm ones but not all the time with those.

10 hours ago, daslolo said:

We are promised clear sky on tuesday, I'll see if my pupils dilate enough.

92 degrees with no beans! that's amazing, and I see priced accordingly 🙈

 

 

The ES 92's are rather nice but also rather large and heavy !. The 17mm is the heaviest eyepiece that I currently own at 2.87 lbs / 1.3 kg:

I have a Skywatcher ED120 as well and can heartily recommend it. Mine is one of the older gold tube ones but optically it is really good.

When I got my Takahashi FC-100DL and TMB/LZOS 130mm triplet I did wonder if the ED120 would be redundant but not a bit of it - it stands up very well to the much more expensive and exotic competition.

Synta put a lot of care into the design and manufacture of the 120mm ED doublet objective and it shows in its performance in my view.

I'm interested in one of these (the £124 type rather than the £3K type !) for use with my 130mm triplet refractor. Does it eat up any focuser travel ?

Thanks

The Eskimo Nebula in Gemini is a good example of an object which is worth observing both with and without a UHC or O-III filter.

Without the filter, at 100x or more the central star of the planetary nebula is visible gleaming out from the centre of a small hazy disk. Add the filter and you often loose sight of the central star with small to medium aperture scopes but in return the layered structure of the nebulous disk becomes better defined and the nebulosity stands out better from the background sky.

I'm still not quite sure that it ever looks much like an eskimo or a clowns face (its other name) but it is a fascinating object and, like so many of these things, repays careful examination at varying magnifications and with and without filters. 

The Nirvana's are good eyepieces. The 16mm is not quite as good as the rest but still a pretty decent 82 degree eyepiece.

Pity that there are not more of them in the range.

"I'm sorry Dave but I'm afraid that I can't do that"

2 hours ago, johninderby said:

Maybe what we need are motorised knobs and voice activation so just place the scope in postion and say “Clamp scope” 🤔😁😁😁

As long as there is a check that says "Are you sure ?" if you say "Unclamp scope"

If it does not stipulate otherwise I would assume that the 110ED uses FPL-51 as the ED element. If FPL-53 is used they invariably tell you all about it !

I've not used one so I cant comment on how it handles CA.

Low cost UHC and O-IIIs simply dont work as effectively as better quality ones. I've found that to my cost over the years.

Lumicon and Astronomik are the names that I look for now.

I was just looking at the 1st photo that you posted in this thread. The collimation there looks goon enough to be getting most of the performance potential from the scope I would think.

I think the problem with collimation is, I think, many of us suffer to some degree with forms of mild OCD and we agonise about getting it "perfect" when scopes that are "near enough" will still show very nice image.

If you use the 1.25 inch barrel adapter on the 31mm Aspheric you do loose light from the outer parts of the field of view. The 32mm 1.25 inch plossl will probably be showing you as much sky. The Baader Aspherics are not that well corrected in the outer part of the field either so maybe not worth the investment for use in your F/6 dob.

Your Omni 32mm plossl is an average lower cost plossl but might be worth a try. With a decent O-III filter it should show you either the east or west segments of the Veil Nebula but you won't be able to fit both in the same field - you need a really wide field for that, more than your scope can deliver.

So to summarise I would probably stick with the Omni 32mm and use the 1.25 O-III filter with that.

I use a cheshire eyepiece followed by a star test. They tend to agree whereas the laser collimator that I have (well collimated) does not. I don't use the laser much now.

Currently I observe standing but I can see that might change in a few years time so I will have to investigate suitable observing chairs that will suit my scope setups.

I can see that observing sitting down can have some advantages in terms of maintaining eye positioning at the eyepiece and being relaxed.

I suspect my dodgy knees will force the issue in due course though

I don't have any photos of me actually observing I'm afraid. It probably looks rather comical so perhaps that's for the best !

Just now, johninderby said:

More expensive but a nice eyepiece and a bargain at the price and the wide fov can be very usefull.

https://www.harrisontelescopes.co.uk/acatalog/ovl4nirvana.html#SID=1677

I had one for a while - a very good high power eyepiece 

52 Cygni is usually a naked eye star (mag 4.2) and is key to finding and observing the Veil Nebula. The Western Veil runs right alongside the star. The Eastern Veil is the slightly brighter segment though - both shown below:

8 minutes ago, Louis D said:

...As far as Uranus and Neptune, more power just enlarges their non-stellar green and blue disks, respectively, but doesn't show any additional details in my experience.

 

Quite true with regards to the disks of these worlds but I have found using very high magnifications helps pick out their moons, which are very dim point sources of course.

Personally I might look for a 4mm which gives a more usable step from your 5mm. 240x to 300x makes some sense but I'm not sure that 240x to 375x is that practical.

I know that means a non-BST Starguider eyepiece. These seem to get reasonable reports:

https://www.firstlightoptics.com/skywatcher-eyepieces/skywatcher-uwa-planetary-eyepieces.html

Thanks for posting this re-working of this amazing image.

The image and the Carl Sagan commentary ought to be compulsory viewing at schools I reckon.

14 hours ago, merlin100 said:

... Would a decent 2X Barlow improve things?  The OEM one is plastic!

Yes. The image you see is only as good as the weakest element in the optical train.

What was it that Christopher Hitchens said ?:

"What can be asserted without evidence can also be dismissed without evidence."