Quote:
Originally Posted by mental4astro
G'day John,  to IIS!
Like Michael said, some barlow lenses may not work, needing too more in-travel than your focuser may allow.
However, by the sounds of it, you did achieve focus, which leaves one of two possibilities.
The first was that the prevailing atmospheric conditions didn't allow for 195X to be used. The typical maximum possible is only 100X to 120X, REGARDLESS of the size of the scope you've got! 250X is pot-luck to achieve with minimal "boil" of the image. Anything more and you should be buying lottery tickets. My 5" scope gave fantastic images at 250X, but only when the atmosphere was stable, but it too was a very, very good scope.
The other thing it could be is that the mirror of your scope is spherical in shape, and not parabolic. Spherical mirrors are cheaper to produce, and if your scope has a long focal ratio, these spherical mirror can perform well. However, with the fast focal ratio your Heritage scope has got, if the mirror is spherical, you've got no chance of pushing the scope's magnification. The light from the primary mirror just won't come to the one focal point.
The GOOD news is that it sounds more like it was the prevailing atmospheric conditions that were the problem. A quick test would be to use your 25mm eyepiece with your barlow. If the image was still good, I'd suggest it is the atmosphere.
If things don't improve, I'd then suggest you talk to the folks who sold you the scope. If it is spherical, all the scope will be good for is low powers. You will not be able to get a good high power image from it.
I hope this makes sense.
Mental.  |
This. I used the Barlow again tonight and got impressive views of Jupiter and two of it's moons and just picked up Mars really well and also Saturn and its rings, just making out the Cassini division. To someone who still struggles with time and space and the distances associated with it I can only say wow to have see these things in real life. I have travelled far around the world, including to many famous historic sites throughout the Mediterranean but seeing Saturn tonight like that up in the night sky far surpasses anything I have ever seen.