Miscellaneous Astronomy
This is the jump off point for description/discussion of some of my:
Zoom eyepiece review (solar test)
On this page itself, I discuss computers, software, digital setting circles (DSC's), filters, and green lasers.
Laptop computers
My first unit was a three year old Dell Pentium II 266mhz unit I got on Ebay in Jan ’01. It came with a docking station (LAN capability), and 6.4GB drive. Worked fine until the great Leonid meteor shower, when I tried to image all night long. Dew apparently settled in through the keyboard and fried some of the circuitry. I lost some of the vertical portion of each display character, along with the aability to run off of DC power. The display degradation was a nuisance (couldn't read small Windows fonts), but never quite bad enough to make me bite the bullet and replace the laptop. (Funny thing is that glitch was confined to internal control circuity—displays fine on external moniter!). Have red filter velcroed to screen, even though work in night vision colors and w/minimum screen brightness. Use for imaging, and sometimes to play music CDs while observing. I eventually got the machine fixed in Dec ’02, when problems degenerated to point that laptop would no longer boot.
I replaced it in early 2004 with a Compaq Presario model 2135 (Celeron 1.8 ghz, 30 GB drive, 256 MB ram) with a spare battery I found on Ebay for under $500. I made this purchase after discovering that Compaq-- the last hold out still offering RS232C serial ports-- had finally discontinued them. (I don't think this was an enlightened business strategy so much as a lag before corporate parent Hewlett-Packard finally got around to updating the design on their Compaq subsidiary) Software like Cartes du Ciel that ran extraordinarily slowly on the old Dell runs acceptably on this machine.
I tend to use homemade red rubylith filters on my notebook computer screens to cut the brightness (the lowest setting and night vision display mode are still too much for a dark sky site), but may go for a commercial product since the homemade filters tend to pull away from the LCD and render it difficult to read.
Computer Software
While I have a couple of hard copy atlases and actually carry Tiron 2000 and the companion book into the field, I am a firm believe in planetarium software. It can display far more objects than could be contained in any atlas, and can be used to "drive" one's telescope through the sky, with an appropriate interface cable and software driver. It is slick to be slewing the scope manually through the sky while you watch crosshairs move on the atlas displayed on the computer screen. One of my favorite winter "games" to play before breaking down for the night is to pick a busy star field and see what the faintest object is that I can observe with averted vision, then identify it via a star catalog. I liked to see how close to the theoretical light gathering grasp of my telescope I could get.
Star catalogs
Beyond the usual suspects included with most planetarium programs, I have added the Hubble Guide Star catalog (which is far from complete down to even 14th Mag, since it is looking just for a representative field of guide stars rather than a comprehensive census). I added first the "lite" version of the US Naval Observatory catalog, and then the full USNO 2.0 catalog of virtually all stars down to ~19 M (over 500 million stars!) The downside of having multiple catalogs running simultaneously is that the same object may be plotted 3-4 times in nearly the same location, and with different names.
I got started with Earth Centered Universe (http://www.nova-astro.com/) as my primary planetarium program, and am still a registered user. It is very fast, and reasonably full featured.
I added "Cartes du Ciel" (http://www.stargazing.net/astropc/), a remarkable piece of freeware developed by a single dedicated French programmer. It can take virtually any star catalog published and can be customized in terms of display to mirror almost exactly whatever particular orientation you have in your eyepiece field of view. I also love the way it displays binary star data, using a line to indicate the direction and angular distance from the primary for each companion. It has an integrated lunar atlas program as well. It's sole real downside, in my opinion, is processing speed. It is coded in Delphi 6, which lends new meaning to the word 'sluggish'. On my old 266 mhz Pentium II, doing a simple 'zoom' in of one level of magnification would take over 10 seconds!
I tried "The Sky" level IV on a friend's computer, but found it unacceptable since it lacked an interface driver for the Magellan I DSC's I use on Frankenscope. It's also pricey (~$250).
Digital Setting Circles
For Frankenscope, I picked up a Magellan I (http://www.meade.com/manuals/mgn1mn/) dirt cheap on Astromart. While I bought it primarily as an interface to the laptop computer, I discovered that it was a much better DSC than conventional wisdom credited (blame Meade bashing?), with a fairly easy to navigate user interface. I modified mine to use "quick release" connectors, since the base of Frankenscope must be taken apart and reassembled in the field.
On my New Mexico observing trip (New Mexico Observing report), I had the opportunity to use both the original Sky Commander and Celestron's Advanced Astro Master (http://www.starizona.com/basics/alignamf.html). While both were comparable in accuracy and (I believe) internal star catalogs, there was no contest between them in terms of ease of use. What could be done in 3-4 keystrokes on the Sky Commander took up to a dozen to do on the Celestron unit. I also liked the way the Sky Commander could do a two star alignment without having to be horizontally or vertically leveled first, and that it had no problem with Polaris being one of the initialization stars.
This positive experience reinforced my decision to get a Sky Commander unit for Natasha. Fortunately, Sky Engineering was beginning to ship the new Flash 4 model (http://www.skyeng.com/), which is the successor to the venerable original model. The Flash 4 has more on-board memory and will be flash upgradeable in the future. What matters for now is that it ships with 8000 tic encoders vs. the 4000 tic ones of the original Sky Commander, giving it higher theoretical pointing accuracy.
Filters
I never was much of a conventional "filter guy". I bought a set of 2" color filters in various Wratten numbers that are still sitting in their original boxes, and some have never graced a scope. I do find occasional uses for a variable polarizer for lunar or solar observing, though.
Everything changed when I took a chance and picked up the Sirius Variable Optics Filter (VFS) system (http://www.siriusoptics.com/). This three peak interference filter is an elegant one-filter solution to planetary observing in my opinion. By turning the radial dial, you can literally make various surface pop into and out of view on a planet's surface! It is less impressive as a deep sky filter, though. I modified my unit (of course!), putting Teflon tape into the housing to make the filter wheel turn more easily and quietly.
I do have Ultra High Contrast (UHC) and Oxygen (OIII) filters, and make some use of them, especially the OIII filter. After considerably research, I became one of the 'early adapters' of the Astronomik line of German filters (http://www.astrovid.com/further_details.php?pid=222), since I was impressed by their high transmission throughput and durability. I opted to get 1.25" filters, since only my largest eyepiece (Nagler 31 or its predecessor Panoptic 35) needed (or indeed, could accommodate) a 2" filter. The Veil Nebula through the OIII filter remains my favorite object, and has tempted me on more than a few occasions to think of springing for the 2" filter so that I could use my Nagler 31.
Green Lasers
Because I do a fair amount of "outreach" (public events and Boy Scout Astromony merit badge teaching), I find myself doing sky tours for reasonably large groups-- typically too many people to be taught effectively by the "follow my finger to that bright star" routine. I thus bought a green laser in ca. 2002, when they were still comparatively scarce (and pricey!). I think it is close to 5mw in power. I made a mount for my Oberwerk "Sky Window" binocular mount that allowed me to project the beam off of the mirror and see where the binoculars were pointing in the sky (which was otherwise difficult, since you observe by looking down rather than up with this attachment.) I use this infrequently and wouldn't do so when other observers were present (especially imagers), but it is nice to have for those solo occasions when I want to use this binocular aid. (This is less frequent now that I have the Bogen 3265 tripod head.)
While this 5mw laser has served me well, in dry conditions-- especially during the Winter-- the beam would frequently be nearly invisible to those not within a few feet of me, due to the lack of moisture or particulate matter in the air. I therefore bought a second "turbocharged" laser just for use on those occasions. It was tested as producing 14.2mw of power, which makes it a class IIIb unit not suitable for the general public, so I am especially careful to keep it out of young hands.
Note that I purchased both of these lasers well before the terrorist hype about using them to blind aircraft. They don't come out of my pocket if a plane is in line of sight, and I categorically refuse to let youngsters-- or non-astronomer adults-- handle them.
