Observation Log - 28/10/2004

Subject:Planetary Nebulae
Seeing:Poor
Light:Poor
Location:Home (balcony/front landing)

Equipment

Scope:Meade LX90
Other:Lumicon UHC Filter, TeleVue 2x Barlow

Comments

Despite pretty awful seeing, clear nights are few and far between at the moment, so it's a matter of making the most of what you get. Yesterday I received a new Lumicon UHC filter, and a TeleVue 2x Barlow, so I had to test them out as soon as possible!

Having not collimated the LX90 in a while, I figured I'd see how it was doing. The Barlow allows a lot more magnification than I've had before, so I thought I'd see if things were still good at 400x. Seems like my previous attempt at 200x was pretty good - I got a nice round donut with the seconary's shadow right in the middle.

I was eager to try out the UHC filter on M27, but had to wait until about 20:00 UT before was low enough to be seen. The initial view (without the filter) wasn't exactly the best ever. I'm used to seeing the bright inner dumbbell form quite clearly on good nights, with a very slight hint of surrounding nebulosity under exceptional conditions. I then screwed the filter onto a 26mm Plossl and refocussed (the filter adds a few millimeters to the eyepiece, which doesn't entirely fit into the diagonal). And then... Wow! this favourite planetary of mine was suddenly much larger! The dumbbell shape was far clearer than before, and surrounded by a fuzzy circle of nebulosity. Very impressed with this filter.

Next up, M57 - by this time I was really wondering what to expect. The ring was quite easily visible without the filter, despite a large amount of aperture being blocked by a window frame. I've heard people use the term "jumps out" before when talking about these filters, and this is exactly what this nebula did! A very crisp, clear ring was now visible - a marked improvement on the eyepiece alone.

Over to Aquarius for the Saturn and Helix nebulae. Although small and very low, the Saturn Nebula was very clearly visible, even without the filter. With it, I'm quite sure I saw a slight elongation towards the center, much like a smaller version of Saturn's rings, tilted at 45 degrees. The Helix nebula was unfortunately too low and behind too much haze to be seen, even with the filter.

By around 21:00 UT, I'd set the scope up on the front landing. The moon was almost full, and I saw an opportunity to test out that new Barlow. With my 9.7mm Plossl and 2x Barlow I bumped the magnification up to around 400x. Details were still very sharp - most pleasing indeed! By putting the Barlow before the diagonal, I had a whopping 600x at my disposal and, amazingly, the image was still very sharp. Towards the edges of the disk, it was almost like looking down on the surface from a tiny port hole in some space ship!

Anyway - back to the nebulae! Unfortunately M76 was too high to be seen from this location. The California Nebula and M1 also remained elusive, despite using the UHC filter. However, over in Gemini, the Eskimo Nebula was rising and had now reached about 8 degrees above the horizon. Although completely invisible without the filter, it really did jump out when I popped it onto the eyepiece! Not much more than a small, fuzzy blob, but another win for the UHC filter.

The Pleiades (M45) were pretty much washed out by the moon, but I thought I'd have a look for some nebulosity using the filter. Apart from making many of the stars appear bright blus in colour, the filter had little effect on this target.

Before taking a break at 22:30 UT, I started experimenting with the 2x Barlow on Saturn. The jump from 200x to 400x was too much for the conditions but, surprisingly, the jump from 400x to 600x showed very little difference in image quality. Clouds started rolling in, but I'd be coming out later for part 2!

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