Quote:
Originally Posted by Gem
What size scope do people think would be needed to complete all 600 objects?
I have always logged my observations but I have never systematically gone through a list like this. Usually I go constellation by constellation through Hartung's or some similar guide.
Should be fun! Best bit is that there are NO photos - only a list of objects. Things always look much more impressive if your expectations aren't raised by a Malin photo!
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Hi Grant,
I hope you enjoy working through the list. What scopes do you have?
What size scope you need to observe all the targets is very subjective. The major variables being the skill of the observer and the sky quality. Then again different people's sensitivity to different wavelengths of light can have an effect also. The Horsehead Nebula is a classic example of this. In a 25" Obsession under dark clear skies I see the Horsehead Nebula (Barnard 33) fairly comfortably, without any filters (yup a 25" er helps a lot
). I have had very experienced observers take over the eyepiece and see nothing. The main reason is the Emission Nebula (IC 434) which provides the illuminated backdrop, emits most of its light towards the red end of the visible spectrum. This is clearly evident in the AAT photograph in the attached link
http://spider.seds.org/ngc/ngc.cgi?i+434
What this means is someone with a low sensitivity to red light, no matter how good an observer they are and how good the conditions, will struggle to see it.
I have observed the targets on the list in a variety of scopes over a number of years. The vast majority in my 10" scope (about 90%). Several I have only done in my 18" scope and they can be a tough get in an 18". I have only recently acquired the 14" scope and haven't tried some of the more difficult ones in the 14". I can probably see deeper than 90% of people and I reckon I could get them all in a 14" under excellent conditions. In some cases it also comes down to knowing what you're looking for and using the right magnification to pop them. With some of the dimmer galaxies don't be scared to increase the magnification to increase the contrast. A few of the planetary nebula are small, consequently in a low power eyepiece they will look stellar and you could be looking right at the thing and not know it. Use more power! A couple of the more difficult targets IMO are the ESO Galaxies. For example ESO 350-40 (Cartwheel Galaxy in Sculptor) and ESO 118-31 (Reticulum Dwarf), would be tough in anything under 14".
Good luck with it!
Cheers,
John B