Astronomy:

New Equipment

 

The Latest Instrument of Observation:

In October 2005, after deciding I was ready for more aperature (bigger objective mirror), I took delivery of the latest version of my current "big" scope - the Meade LX-90 - in an even larger size.

I posted my first impressions to several Internet discussion groups, and discovered I was an early adopter of this new model. Please see full comments below. The jump from an 8 inch (200 mm) to a 12 inch (300mm) in a Schmidt- Cassegrain Telescope (SCT) is considerable in terms of both light gathering and weight. The new scope weights about 85 lbs (40 kg) fully assembled, versus 55 lbs for the smaller model. The finder scope and Autostar go-to computer system are also essentially identical to the older model, though the new model also includes a clamp holder for the computer handbox. A big change is the addition of Meade's proprietary Level North Technology (LNT). This device is a clock and compass combination which will find north and provide Autostar with the current time. The device was damaged during shipment, so is not mounted in these photos (see below para 2). Another major addition is Meade's Ultra-High Transmission Coating (UHTC), which as the name suggests, allows more light to pass through the corrector plate to the mirror. Other differences include a larger, contoured focus knob.

Notably, the fork mount and base, tripod, and drive gears, are the same as the smaller model. This suggests these components may be carrying very close to their maximum, given the increased size and weight of the larger optical tube assembly (OTA). The larger scope has an aftermarket accessory shelf attached atop the tripod.

Here are my initial comments, as posted in sci.astro.amateur, Yahoo SCT User, and Yahoo LX90 groups:

After 4 wonderful years with the classic 8 inch Meade SCT, I took delivery of a new 12 inch LX-90. I didn't need the advanced features of the more expensive LX-200, as I do very limited imaging. The 90 is a good solid design, so I decided to see how well it upsizes. Only three issues of note, thus far:

1) Yes, it's a large tube alright. The big tube on the same mounting base and tripod is pushing stability. Very wiggly compared to the 8, as expected. Takes about 2 seconds to dampen. Rubber anti-vibration pads for the tripod feet are a must - I didn't use them on the 8 inch, but the new one demands it.

2) The LNT module was damaged (plastic housing cracked in two). I don't know why Meade chose to mount it, and nothing else, on the tube body during shipment. My dealer called Meade and an entire module replacement is coming. I've never used LNT before, and have no idea if it is really a useful feature or not. Are a compass and Polaris out of style?

3) The long threaded tripod mounting bolt has a factory replacement. The early models shipped with a bolt that is too long to firmly hold the scope, as it hits the base's internal stop first. My dealer had the replacement. Alternative is to add a nut or two down near the knob end to take up the length.

The scope was in good collimation from the box, and went together quickly just like the 8 inch. The Autostar go-to computer performed perfectly on objects from zenith to horizon, and go-tos and tracking were accurate at high mags in a 14mm Plossl. The scope worked great with the f/6.3 focal reducer/corrector - dropping the magnification and providing a slightly wider apparent field of view. And the planets looked great in my binoviewer with 15mm Plossl eyepieces - though not surprisingly, I couldn't reach focus using both the corrector and the bino at the same time.

The aperature jump provided the expected increase in apparent brightness and increased level of detail on the usual target objects. Went through a quick list of favorites: nebulae (Triffid, Ring, Lagoon), globular clusters (M13 and M22), and planets (Uranus, Mars). Atmospheric seeing during the first night was only fair (5 on a scale of 10).

Other than the size, and some notable wiggle, it behaves just like the original. So far, I'm right at home with this upgrade.

-- JW