Telescope Reviews: Follow the celestial path

Observation 9-13-09 11pm to 2am sky mag 5.2
used Oberwerk BT100 with 18mm AT Paradigm for 34x100, 1.7°fov, 2.9mm exit pupil
also used TV85 with 14mm Radian for 43x85 mono, 1.4°fov, 2mm exit pupil

Tested 33xBT100 for LM and found it could reach mag 11.4-11.5.

I spent a considerable time and created a sketch which will be added after I can scan it and convert it to jpeg. I used two measured stars that span 10 arcmin to judge comparative sizes of clusters.
edit - SKETCH ADDED

Berkley 58 - not seen, no hint of haze.

NGC 7790 - brightest star on se edge of a hazy unresolved spot. Haze bordered on nw by 4 stars curved to encircle the haze spot. No resolution within the haze. Total width no more than about 4 arcmin. (A mounted Fujinon 10x50 could see this only as a small averted hazy spot).

NGC 7788 - plotted 17 stars using 33xBT100. Fainter stars centered on a brighter asterism of 3 stars in a line with a slight bend. Uranometria shows the extent of NGC7788 spans between these 3 stars. About half of all the stars I plotted are just outside the boundaries of extent plotted in Uranometria, so all may not be a part of the true cluster. My plotted stars are scattered over about 10-12 arcmin area. Considering LM test above, I would say all of these stars are brighter than mag 11, the 3-5 brightest perhaps mag 9-10. (A mounted Fujinon 10x50 could see no more than 6 stars here across the full extent of 10 arcmin, no haze noted).

Harvard 21 - This was the faintest of the clusters seen. I suspected 4 very faint stars seen with averted vision. I could tell there was something at the spot with direct vision, but could not see anything defined directly. I plotted the 4 stars in the shape of an L, long leg ne to sw, short leg towards the east. Size, ? perhaps 1-1.5 arcmin. Estimate these 4 stars as mag 11.2 to 11.4.

King 12 - stars brighter than H21, also area a bit larger, perhaps 2 arcmin. I suspected seeing 6 stars, 2 pretty faint, 4 a bit brighter. Estm 4 stars perhaps mag 10.5 to mag 11.

A bit further out past 6 Cas I also noted
King 21 - at this spot I saw what I thought was a very tiny straight line of maybe 3 stars. No real resolution of the 3, but looked longer than just 2 stars. Perhaps mag 10.5. Less than 1 arcmin long.

The TV85 at 43x could not resolve any more stars or see any more in each of these clusters than what was seen with the BT100 at 34x. I counted exactly the same 17 stars in NGC7788 and still could not see BE58.

I did stop to take a look at M52 and NGC7789. NGC7789 was resolved to perhaps 20 stars with a broad extent of haze.

BTW, I'd like to add, out of numerous things I did in last nights observing session, observed a few galaxies, compared some limiting magnitudes, split a few doubes, searched out a few new objects, etc. this little project to critically view and sketch an area I've never mapped before was by far the most interesting and if you can believe it, the most fun. Thanks for this intersting challenge. Now I need to go read up and see if my visual descriptions match what is in the written details for these clusters.

edz

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Edited by EdZ (09/14/09 01:57 PM)