Posts Made By: Inge Skauvik

I also just got my ultimate scope, a 12.5-inch Portaball which can be handled with relative ease (I'm not in the body-builders' league), great optics, and highly convenient to use.

The Newtonian is surprisingly popular. Perhaps this was because economy was one of the criteria to be considered.

I just acquired a 12.5-inch Dob with great optics, and a focal ratio of 1/4.8 (1500mm focal length). I have a series of 1.25" eyepieces (mainly orthos), which probably will do the job, but I'm also sometimes hit by the commercial bug which makes me curious about some of the new design eyepieces (perhaps some 2" pieces).
I would therefore like to put the question in the following way: Given my aperture and focal ratio, and a budget of 700$, what would be your choice of eyepieces? (I'm an all-round observer, and can't live without high powers)

One additional question. Will not a 35mm eyepiece give a too low power for a 12.5-inch in the focal range 1/4.8 - 1/5? (Concerned about exit pupil)

I find the visibility of M101 to be incredibly sensitive to the observing conditions. Thin clouds can extinguish it almost completely, and ambient light must be avoided in order to get a clear view of it.

Under perfect conditions it is possible to see some detail in this galaxy through mid-sized telescopes. With som attention I can make out the spiral pattern with a 12-inch scope at low power. I have also reports from observers who claim to see emission nebulae in M101 and other large, face-on spirals. (M33, M74, M100 ...)

Maybe a good eyepiece set could comprise a zoom eyepiece, a barlow, one low power wide field eyepiece and one or two high power/high definition eyepieces (orthos or monocentrics). A modestly priced set suiting my scope could perhaps consist of:

1: The BW Ultrawide 30mm (80 degree FOV)
2: The APM Zoom 9 - 26mm
3: 6mm UO ortho
4: Some decent 2x Barlow

Thanks all of you for useful advice. I'm not really in a hurry, but on within some time I plan to aquire one eyepiece for low power wide-field use, and a low power barlow will be a good supplement to my present 2.8x Klee.
I also have a gap in the high magnification range, and seriously consider one of the TMB monocentrics. The field is small, but it is very fun to use (giving me a "retro" feeling).

This is exactly how a star atlas SHOULD look like.

I own a few UO orthos, and presently I also borrow a few TMB monocentrics for comparison. My orthos have focal lengths of 5, 7 and 12.5mm respectively, whereas the TMB's are the 6mm, 8mm and 10mm.
All 6 eyepieces give very sharp images. The notable difference is the field of view which is modest for the orthos and small for the monocentrics.
For planets and close doubles I will always choose the eyepiece that gives the best magnification for the seeing conditions.
I worked with a scope with 1200mm focal length for a couple of years. During that period the 7mm ortho was my favourite eyepiece for planets and doubles. Under very good seeing conditions I used the 5mm instead. Now I have upgraded to a scope with 1500mm focal length and consider to get a 9mm eyepice (probably ortho, TMB's are expensive), since a power of about 170x seems very useful for my local seeing conditions.
Strangely enough, I find the monocentrics to be very fun to use on small DSO's. The 10mm monocentric seems to bring out more of the spiral structure of M51 than any other eyepiece I have.

Excellent!

I will try contributing on the new forum as soon as I have something to tell about. I'm occasionally making posts on the forum "astronomy.ru", and I think I recognise Dr.Alexander

Based on your adivce I ordered a 24mm Panoptic as a start. This hopefully will give me an image sharp to the edges at 62,5x power. I suppose I also can use it with my 2.8x Klee Barlow to get a power of 175x. Under my local seeing condition, this is very often the maximum power that can be used without getting annoyed by atmospheric effects.
(Fortunately, there are a few nights each year when much higher magnification can be applied.)

I also observed Saturday night, but from a different location and timezone. To be more specific, 59 deg N, 5 deg E, 00:30 - 03:00 CET.
No shadow transits on Jupiter were in progress as I arrived, but I noticed one of the moons approaching. Unfortunately I had to finish up before the transit started. The GRS, however, passed the meridian during my observation session.
Sky transparency was great, possibly the best I ever experienced, and seeing was good enough to split Eta Cornoae Borealis (0.6" pair). However, I concentrated on deep sky observation due to the good, dark conditions.
I viewed and identified no less that 75 galaxies during the session.

The highlight of the session was the view of M101, almost right overhead. The spiral structure was plainly visible with direct vision, and many bright patches could be seen in the spiral arms. A most beautiful view.

I was able to spot some of the fainter members of the Coma galaxy cluster (in addition to NGC4889 and 4874 which are bright in the 12.5-inch). The Coma cluster is not an impressive sight in a telescope of this aperture, but it is facinating to contemplate on the vast distances of the galaxies in this cluster.

NGC4236 in Draco was easy. And for the first time I was able to see stars in the great open cluster, NGC6791 in Lyra. Although not bright, this is one of my favourite open clusters.