DSO hunting magnitude

[Bigeye]

I know alot of factors will effect this but can anyone give me some idea of what visual magnitude i can expect to see upto with a Celestron Nexstar 127 SLT. I live on the fringes of Hemel Hempstead so have avarage LP and want to start checking out some DSO's other than m42 but don't want to waste my time looking for things I have no chance of seeing. I can short list DSO's with a mag figure that makes it worth hunting for.

Cheers

[Chiron]

The "additional" magnitude that you will get is given by

5 x log (Aperture / Pupil Size)

So for 127mm Mak and a pupil size of 6mm you will get about 6.5 magnitudes beyond whatever you can see with the naked eye. So if you can see something that magnitude 4 with the naked eye, the scope will give you (theoretically) 10.5.

However......

When you talk about DSOs you also have to consider surface brightness as they aren't point sources. For example the Triangulum galaxy is magnitude 5.7 but has a surface brightness of 23, so it's a bit elusive.

I have the Skymax 127, which is the same OTA (I think) as the Nexstar and they only galaxy I've definitely seen is Bode's galaxy (M81). But there are plenty of globular clusters (eg M13, 15, 53, 56) and many open clusters that are doable. The Crab (M1) and Ring (M57) nebulas are also doable.

Good Luck

XPN

[mdstuart]

Most people start with the Messier list for which you can find finder charts on the internet. Most will be readily visible with your scope..

PDA LIST OF NIGHT SKY OBJECTS

This is my effort at a web site for my own use but your welcome to look at it. Pick this month and maybe one wither side and go for the three or more star objects..

Mark

[Double Kick Drum]

Limiting magnitude will depend on how good your skies are. I can usually see stars down to magnitude 5.5 which means my scope (127mm refractor) can see down to magnitude 12.

The feintest fuzzies I can see are a magnitude brighter but this depends on their surface brightness. Galaxies with a SB of 13 or better are usually tolerant of light polluted skies, so long as you are not in the middle of a city.

As pointed out above, M33 in Triangulum is quite dim despite its overall high magnitude (due to its size).

Surface brightness can also be alittle misleading as it is an average. The core of a galaxy will always be offset by the outer regions.

M42 should be no problem although you may be too late to catch it until the end of the year. M31 the Andromeda galaxy should also be easy to see.

Best at the moment are the globular clusters M3, M53, M13 and M92 and galaxies M81 and M82.

Happy hunting!

[Bigeye]

many thanks for all the advice guys, lets just pray for some clear skies now

[Scott]

Most people start with the Messier list for which you can find finder charts on the internet. Most will be readily visible with your scope..

PDA LIST OF NIGHT SKY OBJECTS

This is my effort at a web site for my own use but your welcome to look at it. Pick this month and maybe one wither side and go for the three or more star objects..

Mark

hey Mark, this website looks great. can't wait for some descent weather to try it out.