View Full Version here: : First view of Sculptor Galaxy
07-09-2011, 07:35 PM
Had my first veiw of the Sculptor Galaxy on sunday night and wow was it big. Only just fitted into the field of view in the 25mm eye peice. However when i dropped in the 42mm 2inch in I lost almost all the contrast. Wondering if there is any way around this? As i would love to hit this target again. The moon was still up so it may have just been it washing out the sky. I dont own any filters yet so are these a possible solution? I was using a Skywatcher 14 Synscan. Other favorite of the night was M42. first time ive seen this in a while and still just as beautifull. Quite clearly looked like a cloudy releif of a wizards face side on. Big nose beard and all. A nice new perspective as its always looked like an orchid to me in higher mag.:question:
07-09-2011, 09:12 PM
Wait for the moon to rack off for sure.
There are plenty of 'nebula filters' but I'd recommend trying them before buying them.
I have a basic Meade 1.25" nebula filter if you want to try it.
Your 14 inch (~360mm) Skywatcher should be a great scope. From its specs, I see it has a 1600mm focal length.
Your 25mm EP gives a magnification of 1600/25=64 and an exit pupil of 360/64=5.6mm.
The 42mm EP gives a magnification of 1600/42=38 and an exit pupil of 360/38=9.5mm.
Your night-time eye pupil size is probably about 6mm but it could be much lower or slightly higher. This means your 42mm EP is losing a lot of light and contrast as 9.5-6=3.5mm of exit pupil diameter is not entering your eye.
The longest focal length EP to gain maximum light and contrast for your scope is 6x1600/360=27mm. So your 25mm is pretty close to ideal. Keep in mind that this assumes your pupil size is 6mm.
To get a bigger field of view, you need a near to 27mm EP with a larger apparent field of view, which will still preserve the exit pupil size.
To get a better view of NGC 253, you need darker skies. Wait until you get a moonless night. Your view of the galaxy will be better when it is in the western sky away from the brighter eastern Sydney skies. If you can get to a darker viewing sight out of the suburbs, it will be better again.
08-09-2011, 07:04 PM
Many thanks Peter and Rob for you kind help. I go to Canoelands for a lot of my observing as a friend of mine has a dark sky property out there. Come to think of it I cant understand why I didnt go back to NGC 253 later in the night as the moon set about 12.40 am. Kicking myself as I write this. Got excited trying some imaging with the Nextimage camera. Saw the sun come up yet again. I checked out NGC 253s position for the IIS astro camp and it will certainly be in a good position so will mark that as a definate goal for that weekend. Its nice to have the science of the eyepeice finally explained to me and Ill certainly look into the 27mm option as I dont have much of a collection yet. :thumbsup:
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