(IAAC) Collinder 421 - 24inch F/15

Observer: Yann POTHIER (France)
Your skill: advanced (many years)
Date and UT of observation: July 30 1992, ab.22hUT
Location & latitude: Chateau-Renard Obs. (France, latN44 40, longE06 28)
Site classification: mountain, alt.2990m (9000ft)
Limiting magnitude (visual): 6,5
Seeing (1 to 5 - best to worst): 3
Moon up (phase?): no
Instrument: Cassegrain 24inch F/15
Magnification: image intensifier + video camera
Filters used: no
Object: Collinder 421
Category: open cluster
Constellation: Cyg
Object data:  diam. 5.0' - 50' North of NGC 6910
RA/DE: 20h23.3, +4142'
Description: about 10 bright stars (3 of mag.10 and 7 of mag.11) are
scattered in the field (the system offers a 6'40" wide field), so the
diameter of the cluster must be around 6', with some fainter stars.
This is not a purely visual observation properly speakink but I have
experimented that this 24" intensified image on video screen ressembles a
visual sighting (with some extra infrared)...
I can provide an "intensified" image (24" telescope) of Collinder 421 to
anyone who can read the binhex encoding of Eudora (for Mac); just mail me
to try (ypothier@abi.snv.jussieu.fr), it works sometimes with other
Yann Pothier	tel: 01 43 41 43 29
11 impasse Canart, 75012 PARIS, FRANCE
Email: ypothier@abi.snv.jussieu.fr
Site : http://pegase.unice.fr/~skylink/publi/cielextreme