Hickson group searching: gear and tips

My observing gear is decidedly low-cost. At f/8, my 6" Newtonian is more forgiving of low-end eyepieces than faster scopes. My primary eyepieces are a set of Orion Expanse "Wide-field" eyepices (also sold under the Adoroma and Pro-Optics brands). These 20mm, 15mm, 9mm, and 6mm EPs give roughly 65 degree apparent fields at 61x, 81x, 135x, and 206x; the latter two are used in detecting faint galaxies. In addition, I often use 7mm and 9mm University Optics orthoscopics, which give sharp, but small fields at 174x and 135x. A 10mm Siebert Standard (122x) sometimes fills in the "low" magnfication end of detailed observing. For these faint objects, I find that a wide field of view at a given power is important for locating the expected position of the objects. Also, optical quality is not quite as important when trying to detect diffuse objects with averted vision. Obviously, if you have a set of Naglers or Panoptics, those are the ones to use. But, don't be misled into thinking that is the only way to go. Near the center of the field, an ortho is as good as anything, and can always be used to confirm something seen with a less sharp, but wider field of view.

I personally use Uranometria 2000 as my primary "getting there" atlas. This goes deep enough to find the right 30 arcminute field of view, and then I can use the POSS photos that I give on the individual Hickson group pages.

If you haven't done a lot of searching for difficult objects for your combination of telescope and skies, increasing the magnification can be a big help, especially for small galaxies. The idea is that by making the small visible portion of the galaxy larger, you might have a better chance of detecting it. I will note that 203x is often a bit too much magnification for me. Otherwise, the usual techniques of averted vision, jiggling or nudging the telescope, and being comfortable, are key for pushing the limits.

Even if you are an experienced observer, you might still have room for improvement in your dark-adaption "hygiene". When I'm working on one of the faint groups for an hour or so, I have eyepatches for both eyes. The usual one for the non-observing eye so I can keep it open and relaxed when observing through the other one, but also one for the observing eye to flip down when I'm looking at charts with my non-observing eye, or even when looking at the sky in general. Especially from a dark site, you can lose dark-adaptation just from looking at the sky! Putting a thin black cloth over your head while observing can help, too, but I usually don't do that because most of my observing is in cool or outright cold weather and condensation is too big of a problem even in a dry climate. Other than the eyepatches, I have installed better eyecups on my eyepieces that needed them. I also usually wear thin black gloves and can hold one or both up to help with any stray light.

You probably ought to avoid significant quantities of caffeine, which actually destroys the chemical in your eye responsible for dark-adaptation. For that reason, I usually try to do my "hard" observing from about 1 to 3 hours after beginning; the 1st hour being spent on dark-adaptation and maybe doing a check of limiting magnitude near the end of the hour. Then, after a couple hours of the hard observing, I can relax a little for the rest of the night, and go for the caffeine if I feel I need the boost. I still try to take it easy on that until it is getting time to drive home.


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File last modified: 17 December 2004

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