Posts Made By: Judson Mitchell

Harry
I have to admit owning the 20, 15, & 10mm GSO Superviews. They do not perform well in fast dobs and will likely leave you wanting. They are all gone. The center 50% of the field is reasonably focussed, but the rest is poor depending on the scope used. In your price range, you may want to consider the Hyperions at $99 from Alpine and cheaper on Astromart. Try the 13mm first then if your skies will support the higher mag go to the 8mm. Resist the temptation to buy cheaper unless you have the opportunity to try something before buying.

THere was a comprehensive article in one of the Astronomy Magazines about two years ago or less that evaluated different filters on a number of items. If someone doesn't cite that article I will try to do it Sunday when I get back home. It basically indicated that it was nearly a tossup between UHC and OIII with a slight edge to UHC.

Randy
Now that I am back, here is a reference on filters that may be of use to you.

http://pages.sbcglobal.net/raycash/filters.htm

Mike
Although the S&T Pocket Sky Atlas does not give actual dates; it does organize the star charts for optimum observing for given months, which in my book is sufficient. I like its organization and the fact that it plots stars to Mag 7 rather than somewhat less for a lot of other charts.

I used its format to manufacture my star charts which are commonly Mag 9 and some to Mag 12. It is the way the entire Atlas is laid out that works for me. In the back are lists of many of the objects by classification cross referenced to pages in the atlas.

The pages are 6" X 9", however the charts are actually larger than other atlases I have seen and the charts overlap in a useful manner. Plus, it is significantly more convenient to carry.

Randy
Having struggled through the use of straight through finders, erect image finders and right angle correct image finders, my choice is to have a telrad type finder to place me in the sky, then a correct image right angle finder to precisely locate my target.

The correct image finder provides a view that matches my star charts, whereas the erect image finder provides a mirror image which I find very difficult to use. Others seem to have mastered this problem since their scope may also be mirror image. My dob on the other hand provides an image rotated 180 degrees, which only requires me to rotate my star chart.

I could print my star charts mirror image then use an erect image finder, but that would cause me to reinvent my process.

A straight through finder on my dob is very difficult for me to use since it requires placing my head next to the tube, which can be very difficult at certain viewing angles. In addition, I have opted for a larger finder aperture (70mm) since a lot of my viewing is done in light polluted skies at home. Really comes in handy when the seeing is mag 4.

Another piece of information that may lean towards some explanation of the outburst is the boiling point of ethane which is approximately -88 C with a melting point of -172 C. A rapid or instaneous addition of energy that would raise the temperature above -88 degrees could cause a large scale vaporization of ethane which could be quite explosive. The quantity of energy required and the mechanism for that energy is left to the readers imagination.

Sorry; I was looking at an ad for a range finder and something snapped!

When you have gone fishing with a bamboo pole you selected at the hardware store, then took a tin can and tied it around your neck for the worms you dug from the garden, followed by making a stringer out of a coat hanger and cord, it seems so far away. Old pair of sneakers and go wading for bluegill.

For those of you who are scratching your head, the attached picture shows an example of my fishing equipment used as a teenager.

One simple trick with your feet is to use corn starch which tends to keep feet dryer preventing some of the cold. If that fails, then felt-lined sorrel boots and electric sox.

Victor
If you go from an 10" to a 16" scope, you are going to gain about one order of magnitude. Unless you are willing to travel to darker skies, the 16" is still going to leave you wanting. Even if you have mag +4 skies, the effect of the 16" will only make it as if you had mag +5 skies with the 10". But, mag +5 skies will only take you so far. First, I would find out what your 10" will do at a darker site. Then consider what the 16" will do for you based on that information. You need more information/experience with your current scope before making that plunge.

On the other hand, if you can trade up, this may be the time before your option runs out. But, don't expect miracles with your 16" from your light polluted back yard. Get thee to a dark site!

In association with the above post, here is a photo of my 1.5X Proxima compared to my 2X UO barlow. Note the difference in distance to the barlow lens compared to the EP position.