Posts Made By: Martin Carey

Tonight I had the chance to check out a new Meade 5000 5.5mm plossl. I had ordered it as a friend's gift, but couldn't resist putting it first into the focuser of my 7" maknewt. It is a pretty eyepiece with the red band on the barrel, lying in its black velvet-lined case. The twist-up eye guard has a nice feel to it and stays in place. I was able to see the full field of view with it up about halfway, but not all the way. Eye relief on the plossl was tight but acceptable. Of course, the seeing tonight was bad, so I not only looked at saturn, but for a sharper image a streetlight about 40 yards away. I was able to compare it with a 6mm Radian. Their apparent fields of view appeared to be identical when I put an eyepiece in each eye. There is no question that this plossl has a wider field than other plossls I've had. Edge-of-field sharpness showed a gradual dropoff, and did not significantly break down at the extreme edge. Saturn's Cassini division faded out there but the banding on the globe and overall shape were still intact.
The street light afforded a fairly crisp image, looking at grains of dust on its plastic cover. I was not able to detect any real difference in center field sharpness as compared to the Radian, switching them back and forth several times. Brightness and contrast were too close to call. The principal difference was edge-of-field sharpness, the Radian being clearly superior. Unfortunately I didn't have another short plossl for comparison. I would like to try them out again on a night of better seeing, and with the moon well up. Overall, I'm impressed, and from these simple tests would guess that the 5000 plossls can be a very good frugal alternative to the Radians.

Hello To Everyone:
Does the reflectivity of the mirror coating affect image contrast in addition to brightness, and how much? It would seem that a more reflective surface will scatter less light and reflect it with less noise. So, I would want the best coatings possible, but the advantage at the eyepiece could be minor or nil. From my experiences with planetary Newtonians, good baffling, good optics, and smaller (good quality) secondaries contribute to good contrast. Right now I have two mirrors at L and L Optical, and I am having both the 6" and the 8" given semi-enhanced coatings, about 93% reflectivity. Both mirrors are f/8's for planetary, and I am looking for ways to squeeze as much performance from them as I can. Some opinions/experiences or research on this question. Some of you have excellent experience building planetary-optimized newts.

Hello Everyone,
This September we are planning a trip to southern Utah for two nights of the darkest sky we can find. The new moon falls on Labor Day Weekend. I've been looking at the light pollution maps linked on Clear Sky Clock, and noticed that the areas east and north of Escalante appear to be darkest, Bortle Scale of 1. With some altitude, our 20" and 25" dobs should be quite happy. Some of the Astromarters have mentioned sites around Escalante, and Griffin Top is 10,400 ft, northeast of Bryce Canyon. We used to go to Big Flat east of Beaver at 10,000 ft, but there is a little light coming from the town below.

We don't necessarily have to seek such high altitudes. Any suggestions for good sites? Also, if anyone is interested in joining us, you'd be welcome. There is nothing like the excitement of large scopes under very dark sky with a group of enthusiastic observers.

That is truly an inspirational shot. How does the photo compare with what you could see through the eyepiece?

Hello Bill,
That sounds like an exciting project you have! Do you have a design in mind that you could show us? I have been fascinated by the light weight designs that have been coming out, such as Greg Babcock and Albert Highe's. Keep us posted!

Florent, really superb photo of the trio. I would never have guessed the telescope was that size. Also your website is impressive. Keep up the great work!

Some of the digital cameras have zoom ratios of 10 to 1 and greater. My digital minicam has a ratio of 26 to 1. You can buy a 28 to 300mm lens for your slr. Used as an eyepiece they are not suitable, with narrow fields and other problems. It seems to this amateur that a clever designer could solve some of those problems for telescope use. I would surely be a customer if it were offered for under $1000.

With good seeing finally arriving in So. Cal Friday night, my 12" Lightbridge got a chance to show what it's made of. I gave it a very careful collimation w/ eye in the focuser, then laser, then star images. This is an easy scope to set up and align, especially after I put double springs in the primary cell. It looks as though Meade offset the secondary, although it may need refinement. Anyway, Saturn was getting low, so I concentrated on the moon. Straight Wall sunrise was wonderful, with the upper plateau lit up and strewn with tiny pit craters, while the plain below was still in darkness. Alpine Valley stood out starkly, and during steadier moments, I could see most of the rill, with some gaps, snaking its way away from Imbrium. My 8" f/8 is only able to resolve shorter segments, fleetingly. Crater Alphonsus has three volcanic vents, each with its own little 1 mile diameter crater, and here they were all resolved, with even smaller craters nearby. An additional indication of the good optics is the contrast, indicated by bright whites and pure blacks. Now, if Meade could just paint the tube rims and inside of the primary cell flat black (I did this myself), and sell an optional shroud and wheelbarrow wheels, the LB would be just right.