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(IAAC) Instrument: 90mm "ETX" Object: M13



Observer:  Todd Gross
Your skill:  Intermediate +
Date and UT of observation: 2/10/97 0900 GMT
Location & latitude: 22 miles west of Boston, Ma. 42.3N
Site classification: Suburban
Limiting magnitude (visual): 5.4 (calculated),  5.1(est)in vicinity of object
Seeing (1 to 5 - best to worst):  2-3
Moon up (phase?): No
Instrument: 90mm Meade ETX, F/15
Magnifications:  42x,71x,113x,150x,193x
Filters used: none
Object:  M13
Constellation: Hercules
Object data: Globular Cluster
RA/DE:  
Description: After trying to split M13 in various size scopes in 
"suburban" skies, I thought I would report my observations with
 the new Meade ETX spotting scope. M13 appears as a bright "cottonball"
with a hint of resolution at 42x. At 71x, indeed it begins to take on a 
somewhat "ground sugar" appearance, not resolved, but hinting at busting 
up into stars with averted vision. However, I still was not able to crack it
very 
well at 113x and 193x. With larger aperture, the greater magnification usually 
does the trick. So I took out my relatively high-light transmission 9mm Pentax
Ortho, & I was able to discern several individual star members at 150x, 
towards the edge of M13.. but the core still looking like it wanted to give way 
to being resolved, but just not quite there.
This is very similar, perhaps just a hair better than the view I obtained of M13
in similar sky conditions (actually, very slightly better sky conditions at
the time)
with a 70mm Televue Pronto. In sharp contrast to this, a 104mm Astrophysics 
Traveler was able to resolve many, many individual stars right towards core
with 
averted vision. It will be interested to see what the new Brandon 80mm is able
to achieve compared to the ETX.
- Todd
_________________________________
BOSTON TV METEOROLOGIST TODD GROSS
Weather/Astronomy Home Page: http://www.weatherman.com
Administrator, Meade Advanced Product User Group: mapug@shore.net
Administrator, New England Weather Observer Mail List, wxobs-sne@shore.net
IRC Channel Operator: #Weather, #Sciastro (Undernet)
Originator of the NE.WEATHER newsgroup
_________________________________
Email: toddg@weatherman.com    Work Phone# (617)725-0777