John

Make a new base out of quality plywood - much lighter than the stock MDF bases

1 hour ago, wibblefish said:

Good to know, thanks! Sadly with all the weird angles from neighboring buildings and streetlights in my garden it requires me to shift positions by a few meters if I need to move to what I want to observe though I guess I could do better planning and move less during the session! Food for thought certainly. 

I need to move my 12 inch dob a small distance here and there around the garden during a session.

Fortunately my current dob weighs around the same as a 10 inch so that's not too much of a problem - I can move it a short distance in one piece.

My old Meade Lightbridge 12 inch was much heavier and had to be moved, even short distances, in two parts.

These little things can make quite a difference to the practicalities of using these medium-larger scopes.

Excellent report Magnus - I enjoyed reading that

I can see that you are going to have lots of amazing sessions with that scope as the year progresses and the darker evenings arrive.

Interesting thread

With the exception of B33, the dark rifts in M42 and in the N A nebula, I've not paid much attention to dark nebulae. I'll follow this discussion I think and I'm taking notes !

I currently have 5 scopes that are my mainstays for observing. Four of them are over 15 years old now and one was made about 6 years ago.

They are frequently used and all get regular turns under the stars as the UK skies allow.

The older scopes have a few light marks on their tubes here and there from normal use. Optically they are all very clean (of course !). I'm probably the 3rd or 4th owner of those. The 6 year old scope I have owned from new and that is still in practically "as new" condition.

The 12 inch dobsonian had new coatings applied to it's mirrors 11 years ago. They still look to be in good condition and the scope continues to perform very well.

While decent telescopes are not inexpensive purchases, it is re-assuring to know that, if they suit you and you take a reasonable amount of care of them, they will last and perform well over many years of observing (or imaging, if that is your thing)

Edit: Minor point but I've just realised that I'm only actually the 2nd owner of my 130mm refractor during the 15 years of it's life. It's previous owner bought it new.

Quite an interesting article by EdZ on the Cloudynights forum on this topic:

https://www.cloudynights.com/articles/cat/articles/observing-skills/what-does-it-take-to-see-width-in-the-cassini-division-r1097

I should have added that seeing the division at the ring ansae is one thing but seeing it clearly defined all the way around the ring system can be a greater challenge / test.

I've sometimes had to work quite hard to see the Cassini Division clearly with scopes smaller than 100mm. I've never seen it with my (very old) 60mm refractor. At 100mm and above I've found it's a regularly observable feature, often strongly defined when the seeing is decent and the eye adjusted.

If I can't see the division reasonably well I usually knock planetary observing on the head for that session !

Of course it was much harder when the rings were edge on to us around the mid 1990's !

11 minutes ago, 0rcrest said:

well i just dived straight in and bought a 3.5 starguider ed for my heritage 130p -got it for £30 on ebay its massive inc case came today hoping for clear  skies and Jupiter )

The 3.2mm ?

That will give you 203x - useful when the conditions are decent

Good for Saturn and the Moon. Might be useful for Jupiter if the conditions are particularly good. Jupiter usually benefits from slightly lower magnifications but see how it goes

It's an old model - probably 30 years old, maybe more ?

Not in production for a long time.

It bears an older version of the Vixen branding.

Good quality I expect, Japanese made.

I've owned all the Nirvana's except the 7mm. I found the 4mm a rather good high power planetary performer 

The 28mm was part of my "group test" of big eyepieces posted many years ago now:

Park's (USA) used to do something similar - the H.I.T:

http://www.parksoptical.com/site/hit.htm

The 16 inch must be a bit of a beast !

We used to camp at Seatown - very dark down there !

Nice pub too and a walk up to Golden Cap to get your thirst up

1 hour ago, Tenby2 said:

I was looking at the SWA series

http://www.opticstar.com/Run/Astronomy/Astro-Accessories-Telescopes-Opticstar.asp?p=0_10_5_1_8_320

probably just the 10,15 and 20mm eps as budget is limited.

In an F/10 SCT they should work pretty well.

4 minutes ago, Don Pensack said:

They are all nice eyepieces.  The Delos is probably the sharpest of the bunch at the very edge, but it requires even more in focus than the 17.5 Morpheus.

The ES 92° is a very nice eyepiece and has a comfortable eye relief, but I found the exit pupil more finicky to attain and hold compared to the others.

It's now by far the most expensive of the 3 here in the US, recently going to $800USD (only £410 in the UK) versus $259 (Morpheus) and $352 (Delos)

It's also by far the heaviest. of the 3.  And I see a little edge of field astigmatism at f/5.75 and f/5.18.  I haven't used it in a faster scope yet.

The "Critical f/ratio" at which the eyepiece begins to perform more poorly are f/3 (Delos), f/4.5 (Morpheus), and f/4.75+/- for the ES.

They can be used at shorter f/ratios, of course, but with lesser edge performance, even in a coma corrector.

The respective weights are:

Morpheus--305g

Delos--409g

ES 17x92--1159g

Wonderful summary Don - thanks again

2 minutes ago, Don Pensack said:

Yes, it's been independently measured and no, it doesn't match specs claimed.  The 23.55mm field diameter they claim turns out to be ~21.7mm and the apparent field about 74° instead of 76 (all the other focal lengths are 78-79°).

Still, use the eyepiece, and it is so nice and pleasant to use, and sharp, and has such superb contrast, that that simply won't matter.   It became a favorite from the first hour I used one.  If you don't wear glasses, the 17mm Ethos is a tad better,

but then, it's, uh, a bit more expensive.

Thanks Don.

Have you compared the Morpheus 17.5mm to the 17.3mm Delos and / or the ES 17mm / 92 ?

(to save me the trouble of doing so !)

3 hours ago, F15Rules said:

That's just marketing-speak for Ultra Expensive!!

Dave

Like the term "Super Apochromat" which is being applied to a few refractor lines now ?

Back on the Morpheus range, does the actual AFoV of the 17.5mm Morpheus match the spec of 76 degrees ?. Has it been measured independently ?

7 minutes ago, Sargares said:

Yes I’m thinking the 12.5 morph + Barlow seems the most sensible option. Can Barlow the 9 then also for the likes of Saturn for higher magnification again. 
 

As @John says. When trying to be sensible and not let the gear acquisition syndrome get the better of you. It’s hard to argue with the Morpheus range. Competitive performance. Almost nagler FoV. Cheaper than the alternatives, in some cases by quite a lot. 

When thinking about using a barlow, be aware that it will push the already generous eye relief out a bit more. This may or may not cause an issue with eye placement - for me, having to "hover" my eye above the eye cup to find the correct placement is not enjoyable.

Focal Extenders, TeleXtenders and Powermates either lessen or remove this issue.

On your last point, in practice I'm not a "sensible" eyepiece person I'm afraid so not a good example to follow

11 minutes ago, jetstream said:

.... Keeping an open, non brand specific mind can help IMHO.

 

Yep - very  good advice !

Cherry pick the "best of"

I can see the temptation to go "all Morpheus" though given their pricing compared to their peers.

Really good skies here for the past couple of hours - dark, transparent AND steady 

Saturn, Jupiter, Neptune and the asteroid Pallas gave me some fine solar system viewing. 225x suited Saturn well, 150x Jupiter and 250x showed Neptune's little marble-like disk. Pallas is in the circlet of Pisces this evening at around 9th magnitude.

Much further afield galaxies were showing nicely. Messier 31 to the naked eye, Messier's 32, 33, 81 and 82 with 8x30 binoculars (pleased to see a trace of M33 with these). M33 showed indications of some shape / form through the 100mm scope at 64x. The scope added Messiers 110 and NGC 404 (Mirach's Ghost) to the galactic haul.

The Milky Way was showing quite strongly through Cygnus and towards Cassiopeia to the naked eye.

Rounded off with the magnificent "Sword Handle" double cluster in Perseus and the Pleiades rising heralding the Autumn / Winter constellations.

All in all a very nice 90 minutes of observing

3 hours ago, Piero said:

 

I'm glad that you bought a new telescope, but I'm a bit confused when reading your first post.

- First of all, I don't understand why you thought that the mirror needed to be recoated. Was this suggested by the previous owner?

- if the telescope is not collimated, it isn't possible to assess how it performs.

- if the coatings are damaged, the effect is more light scattering and a dimmer field of view, due to the reduction in reflectivity.

- whether the coatings are damaged (erosion, many many scratches) or the surface is significantly dirty / dusty, the effect on the views is pretty much the same. Therefore, I don't understand your statement when you said that a mirror should be cleaned only when absolutely necessary..

- finally, don't you think that if your mirror hadn't been left covered with dust and particles, fungi etc, maybe, this recoat would not have been necessary?

 

There is nothing wrong with cleaning optics, it's just maintenance really.  Recoatings is also maintenance although a bit more invasive.

If done properly, there is no harm.

The mirrors of these 1st generation Revelation branded dobsonians do seem to need re-coating quite early in the mirrors lives. At the time they were sold, it was quite widely rumoured that the over-coatings (usually quartz or similar) that protect the reflective coatings from degrading early were either quite poor or even not present on this line.

Over the years, I have seen quite a few of that vintage where the mirror coatings were notably degrading after quite a short time. The 8 inch version that I had (bought a couple of years old) included.

Once properly re-aluminised and then over-coated, the mirrors perform quite well though and the new coatings should last what would be considered a more normal span of time before requiring more attention.

As long as the buyer is aware of this then good bargains can be had, provided that the cost of re-coating is taken into account

2 hours ago, Tenby2 said:

Thanks a good read. Seems to me the Svbony could be the way to go, probably the set of 4, the 6mm maybe too much for my C8 but as cheaper to purchase than 3 individual eps and as soon as my work returns to some kind of normality I'll be buying a small refractor, but that's a decision for another day.

I'd like to find some more info on the opticstar eps first though I'm sure I read somewhere they are Meades!

It depends which Opticstar eyepieces you are referring to. These for example look pretty much identical to the Explore Scientific 82 degree range:

http://www.opticstar.com/Run/Astronomy/Astro-Accessories-Telescopes-Opticstar.asp?p=0_10_5_1_8_322

The Opticstar zooms seem identical to the Skywatcher Hyperflext zooms. The Opticstar 66 degree 66 degree wide angles seem identical to the Skywatcher UWA series (now discontinued) and Opticstar 70 degree eyepiece range seem very similar to the Skywatcher Panaview 2 inch eyepieces and the William Optics SWAN range.

All made by one or more manufacturers in the far east and they have been available under a variety of brandings over the years.

Your scope is not too fussy about eyepieces though so any of them would work pretty well in it.

Great report Gerry

With the giant planets low down, I've been finding the same - my refractors have constantly "punched above their weight" compared to my 12 inch dob.

When the planets are high in the sky, on nights where the seeing is good, the additional aperture can strut it's stuff much more convincingly.

It's good to have choices

Hope you enjoyed your coffee !

2 hours ago, Roy Challen said:

Wide angle eyepieces (80 degree+) can occasionally exhibit what is called the 'ring of fire'. I've forgotten the proper name for this. I'd be surprised if Televue EPs showed this though....

 

 

The Nagler 31 does show a glow around the field stop and for the 1st few degrees of it's field:

It's not noticeable when the eyepiece is used for deep sky type observing. I don't use my Nagler 31 for lunar / daytime observing.

8 minutes ago, Piero said:

The cell holding the lenses is collimated by the manufacturer. You should not try to adjust that as this might void your warranty.

 

The Bresser 127L, like it's Meade forebears, has a push pull collimation system built into the objective cell design.

Moonlite focusers come with tilt adjustment screws but I agree that most refractor focusers don't and need to be shimmed or have their attachment point screws tweaked if their optical axis is not square with that of the objective.

The optical axis of the focuser is the first thing you check and, if needed, sort out in refractor collimation, before going on to check the tilt of the objective lens.