|
jgraham
Postmaster
Reged: 12/02/04
Posts: 6763
Loc: Dayton, Ohio
|
|
With the moon nearly full this evening I knew I wasn’t going to get much done so just for yucks I got my ETX-60BB out to test it with my shiny new Televue 5x Powermate. Much to my surprise I found using my trusty old 20mm Erfle (88x) this little scope nicely separated both pairs of epsilon Lyra, the double-double. With separations of 2.4” and 2.1” this shows the ETX-60BB delivers diffraction limited images with a theoretical limit of 1.9”. The diffractions rings weren’t the prettiest I’ve ever seen, but the pair were nicely split.
Pretty spiffy.
--------------------
-John
================================================
Homebuilt scopes from 4.25-16.5"
Meade LXD75-N6/SN6/SC8, DSX-90, ETX-60BB, ETX-125PE, DS-2130
Orion StarBlast, BinoViewers, Coronado PST
Rebel XT/XTi, DSI Pro (I, II, & III), DSI, LPI, Electronic Eyepiece, Phillips SPC900NC
Tasco 60mm Refractors
|
Treehopper
professor emeritus
Reged: 07/29/08
Posts: 582
Loc: Upstate NY
|
|
That's a pretty neat test, I've seen much larger scopes have a hard time splitting the double-double. Despite the moon, you must have had pretty steady conditions. Well done! 
--------------------
Tim
Champion of small aperture scopes everywhere!
Meade ETX-125PE
Meade ETX-80
Celestron FirstScope 76mm Mini-dob
 Updated: 09/16/2009
|
brianb11213
Carpal Tunnel
Reged: 02/25/09
Posts: 2113
Loc: 55.215N 6.554W
|
|
Quote:
That's a pretty neat test, I've seen much larger scopes have a hard time splitting the double-double. Despite the moon, you must have had pretty steady conditions. Well done!
The 60mm refractor I had when I was a kiddie (a few centuries ago) split the double double easily enough, even though the optical & mechanical construction quality was very poor to bad. Jet stream smearing can make it impossible in any scope, but given reasonable seeing, there is something badly wrong with a "larger" scope that has trouble.
Moonlight has no effect whatsoever on the steadiness of the air, it does make faint objects much harder to see but the reduction in glare can result in ideal condistions for observing brighter double stars & planets, as well as the moon itself.
|
|
0 registered and 3 anonymous users are browsing this forum.
Moderator: Shadowalker, oldsalt
Print Thread
|
Forum Permissions
You cannot start new topics
You cannot reply to topics
HTML is disabled
UBBCode is enabled
|
Thread views: 203
|
|
|
|
|
|
|
Previous
Index
Next
Threaded
Edit
Reply
Quote
[Re: 